Report on Hydrogen Production in India

APPENDIX -IV REPORT ON HYDROGEN PRODUCTION IN INDIA

Prepared by the

Sub-Committee on Research, Development & Demonstration for Hydrogen Energy and Fuel Cells of the Steering Committee on Hydrogen Energy and Fuel Cells Ministry of New and Renewable Energy, Government of India, New Delhi June, 2016

FOREWORD

Till the end of 20th Century carbonaceous substances like coal, natural gas, petroleum derived oils and wood were fulfilling the of energy needs of human society for heat, light and power (both motive and electric). With the passage of time, the rising world population and urge for better living standards by the people of developing regions of the world have resulted in over exploitation of conventional energy resources. This in turn has led to the increase in the demand for energy and reduction in availability of conventional fuels. Emission of various types of pollutants (such as particulates, carbon dioxide, and un-burnt hydrocarbons) as a result of the use of these fuels is not only affecting the health of living beings adversely but also contributing to greenhouse effect and climate changes. In view these concerns and ensuring energy security, the focus in the futuristic energy planning is shifting from carbon rich to carbon neutral and carbon free new and renewable energy sources. Hydrogen has been considered and identified as the potential energy carrier and as a leading contender for the “ideal” energy option of the future. On combustion it emits only water vapor. It may be produced through natural gas reforming, coal and biomass gasification, thermo-chemical route using the heat available at high temperature from nuclear reactors, electrolysis of water with surplus electricity available from grid or that produced from renewable sources of energy like hydro, wind, solar etc. Biological (fermentative and biophotolysis), photo-catalytic splitting of water (or photolysis), and photo- electrochemical methods are being considered as futuristic routes of producing hydrogen. Sufficient amount of hydrogen is also produced as byproduct in Chlor-Alkali units and petroleum refineries

In view of the rising aspiration of the increasing population, India is also concerned about the climate change and is therefore striving for developing technologies for harnessing renewable energy sources. Hence, hydrogen energy and fuel cell technologies are of utmost importance, which India needs to develop in a mission mode. Though the Ministry of New and Renewable Energy (MNRE) and several other government agencies at the central and state government levels are providing support for research, development and demonstration of hydrogen production and application, yet India is lagging behind while considering the global scenario. The MNRE, Government of India constituted a high power Steering Committee to prepare a status report and suggest the way forward for development of hydrogen energy and fuel cell technologies in the country. One of the five sub-committees was entrusted under the chairmanship of the undersigned with the responsibility of preparing this particular document focusing on the research and development of various hydrogen production technologies of relevance to the country.

This document is the result of the combined effort of all the members of the sub-committee, experts working in the area of hydrogen production, officials and staff of MNRE.

I am indebted to all the Members of the Sub-Committee and Special Invitees for their contribution, Dr. M. R. Nouni, Scientist ‘G’, Ministry of New and Renewable Energy and also the officials of the Project Management Unit – Hydrogen Energy and Fuel Cells at the Ministry, Dr. Jugal Kishor and Dr. S. K. Sharma in particular for their active role in organizing meetings and preparing this document.

30th June, 2016 (Prof. S. N. Upadhyay), Chairman, Sub-Committee on Research, Development & Demonstration for Hydrogen Energy and Fuel Cells

CONTENTS

Sl. No. Subject Page No.

I Composition of the Sub-Committee on Research, Development & Demonstration for Hydrogen Energy and i Fuel Cells II Terms of Reference ii III Details of Meetings iii 1 Executive Summary 1 2 Introduction 25 3 Hydrogen Production using Thermo-chemical Route from Carbonaceous feed-stocks: 35 (i) Carbonaceous feed-stock 37 (ii) Biomass feed-stock 54 4 Hydrogen Production by Electrolysis of Water 69 5 Bio-Hydrogen and Bio-Methane Production 95 6 Hydrogen Production through Thermochemical Routes 105 (Iodine-Sulphur and Copper-Chlorine Cycles) 7 Hydrogen Production by Photo-electrochemical Water 149 Splitting 8 Hydrogen Production by Other Technologies 163 9 Action Plan 171 10 Financial Projections and Time Schedule of Project 181 Activities 11 Conclusions and Recommendations 189 12 Bibliography 199 13 Annexure 207

I Composition of Sub-Committee on Research, Development & Demonstration for Hydrogen Energy and Fuel Cells

1. Prof. S. N. Upadhyay, Former Director, Institute of Technology, Banaras Hindu University, Varanasi and DAE-Raja Ramanna Fellow in the Department of Chemical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi - Chairman 2. Ms. Varsha Joshi, Joint Secretary / Shri A. K. Dhussa, Adviser (December, 2013 to March, 2015) / Dr. Bibek Bandyopadhyay, Adviser (upto December, 2013), MNRE 3. Dr. Sanjay Bajpai, Scientist ‘G’, Department of Science and Technology, Ministry of Science and Technology, New Delhi 4. Dr. Ashish Lele, CSIR-National Chemical Laboratory, Pune 5. Dr. S. Aravamuthan, Sci./ Engr.- ‘H’ & Deputy Director, Vikram Sarabhai Space Centre, Indian Space Research Organisation, Thiruvanthapuram 6. Shri A. Srinivas Rao, SO/G, Chemical Technology Division, Bhabha Atomic Research Centre, Mumbai 7. Dr. K. S. Dhathathreyan, Head, Centre for Fuel Cell Technology, Chennai (Retired on 31.01.2016) 8. Prof. O.N. Srivastava, Emeritus Professor, Banaras Hindu University, Varanasi 9. Prof. B. Viswanathan, Emeritus Professor, Indian Institute of Technology Madras, Chennai 10. Prof. Debabrata Das, Indian Institute of Technology Kharagpur, Kharagpur 11. Prof. L. M. Das, currently Emeritus Professor, Indian Institute of Technology Delhi, New Delhi (Retired on 30.06.2014) 12. Executive Director, Centre for High Technology, Noida 13. Dr. P. K. Tiwari, Desalination Division, Bhabha Atomic Research Centre as Representative of Principal Scientific Adviser to Govt. of India, currently Raja Ramanna Fellow at the Prof. Homi Bhabha National Institute, BARC, Mumbai (Retired on 31.01.2015) 14. Shri Sanjay Bandyopadhyay, National Automotive Testing and R&D Infrastructure Project (NATRIP), New Delhi / Shri Neeraj Kumar, Deputy Secretary, Ministry of Heavy Industries & Public Enterprises, (Repatriated to Parent Department in January, 2015) / Shri Nitin R. Gokarn, NATRIP, New Delhi (Repatriated in June, 2014 to Parent Cadre)

Special Invitees:

15. Prof. S. Dasappa, Indian Institute of Science, Bangalore 16. Dr (Mrs.) V. Durga Kumari, Indian Institute of Chemical Technology, Hyderabad

II Terms of Reference

1. To review national and international status of Research & Development, Technology Development and Demonstration with a view to identify the gaps. 2. To suggest the strategy to bridge the identified gaps and the time frame for the same. 3. To assess R & D infrastructure in the country. 4. To identify projects and prioritize them for support with the result oriented targets. 5. To identify institutes to be supported for augmenting R&D facilities including setting-up of Centre(s) of Excellence and suggest specific support to be provided. 6. To suggest strategy for undertaking collaborative R & D among leading Indian academic institutions and research organisations and also with international organisations. 7. To examine setting-up of a National Hydrogen Energy and Fuel Cell Centre as an apex facility. 8. To suggest strategy to take-up projects in Public-Private Partnership mode for the development of technologies based on transparency, accountability and commitment for deliverables. 9. To identify the technologies, which can be adopted for applications with time line? 10. To re-visit National Hydrogen Energy Road Map with reference to Research, Development & Demonstration and Technology Development activities

III Details of Meetings

The Sub-Committee on Research, Development and Demonstration (RD&D) met on 09.12.2013 and had detailed presentations and discussions on the activities relating to RD&D in the areas of hydrogen production, its storage & applications in power generation and vehicles based on IC engine & fuel cell technologies. The second meeting of the Sub-Committee was held on 03.03.2014 for the identification of thrust areas for hydrogen production, its storage & applications in power generation and vehicles based on IC engine, so as the Ministry may consider supporting projects in these areas. In the third meeting held on 18.11.2014 in the Ministry of New and Renewable Energy, New Delhi, detailed presentations and discussions were made on hydrogen production. Based on the input received from the expert members of the Sub-Committee and experts outside the Sub-Committee, a draft report on Hydrogen Production was prepared. This Draft Report was presented in the 5th meeting of the Steering Committee on Hydrogen Energy and Fuel Cells held on 11.08.2015 in MNRE, which gave some suggestions to modify the report. The draft report was modified incorporating these suggestions. The Steering Committee further requested that the Chairpersons of all the five Sub-Committees to meet and discuss uniformity of the reports and alignment of outcome of the reports. Accordingly, the draft report was again modified based on the suggestions given / decisions taken in the meetings of the Chairpersons of the Sub-Committees held on 11.09.2015, 16.12.2015 and 18.01.2016.

Note: Since the Sub-Committees on different aspects (Fuel Cell Development; Hydrogen Storage & Applications other than Transportation; Transportation through Hydrogen fuelled Vehicles and IPR, PPP, Safety, Standards, Awareness & Human Resource Development) of the Steering Committee on Hydrogen Energy and Fuel Cells, covered activities relating to Research, Development & Demonstration (RD&D) in their respective areas, it was decided that the Sub-Committee on Research, Development & Demonstration (RD&D) would focus only on hydrogen production.

iii

EXECUTIVE SUMMARY

1.0 Executive Summary

Preamble

1.1 Use of fossil fuels has become a part of daily energy needs and their requirement is increasing with the passage of time. Consumption of fossil fuels gives rise to the greenhouse gas emissions in the environment and causes ambient air pollution, which have now become global concerns. This coupled with the limited reserves of fossil fuels have encouraged and promoted the development and use of new and renewable energy sources, including hydrogen energy as an alternative clean fuel. The technologies for production of hydrogen from new and renewable sources of energy are not yet mature and the cost of hydrogen produced through new and renewable energy sources is still very high and is not competitive to that produced from fossil fuels. In order to meet the future energy demands in sustainable and environment friendly manner, technologies are required to be developed for the production, storage and applications of hydrogen in transportation sector as well as for portable and stationary distributed & non-distributed power generation. In some countries governments have started supporting these efforts.

1.2 Hydrogen is an energy carrier (a secondary source of energy) and is available in chemically combined forms in water, fossil fuels, biomass etc. It can be liberated with the electrical or heat energy input (generated from some primary energy source like fossil fuel, nuclear power or a renewable energy source such as - solar, wind, hydro-electricity, etc.). Presently the agriculture sector is the largest user of hydrogen (as nitrogenous fertilizer), with 49% of hydrogen being used for ammonia production (Konieczny et al., 2008)

1.3 Approximately 95% of the hydrogen produced presently comes from carbonaceous raw material, primarily of fossil origin. About 4% is produced through electrolysis of water.

1.4 Hydrogen is also produced as a by-product in Chlor-Alkali industries. There are around 40 such units in India, which produced nearly 66000 tons of by-product hydrogen during 2013-14. Around 90% of this by-product hydrogen is utilized for captive and other uses. Only a fraction of this hydrogen is currently used for energy purposes. Around 6600 tons of this hydrogen is still unutilized.

1.5 Hydrogen Production Technologies a) Reforming of Carbonaceous Sources: Conventional technologies for

hydrogen production are: i) Steam Methane Reforming ii) Partial Oxidation, iii) Auto-Thermal Reforming, iv) Methanol Reforming, v) Ammonia Cracking, vi) Thermo-catalytic Cracking of Methane, and vii) Novel Reformer Technologies. Steam Methane Reformers are commercially available for hydrogen production. In the United States, most hydrogen (over 90%) is manufactured by steam reforming of natural gas presently. High purity industrial hydrogen with 99.999% purity is produced from commercial hydrogen by pressure swing adsorption systems or by palladium gas membranes. Technologies for coal gasification are commercially available internationally. At national level, hydrogen is produced commercially in fertilizer plants and petroleum refineries by reformation of natural gas. There are extensive industry and government programs addressing to particular technical issues for small-scale reformers, and for syngas production in the country.

1.5.1 Compact “Fuel Cell Type” Low Pressure and Temperature Steam Methane Reformers were developed in small sizes to produce 50 to 4000 3 Nm H2/day internationally (Halvorson, et al, 1997).These have recently been adapted for stand-alone hydrogen production. Energy conversion efficiency in the range of 70%-80% is possible for these units. Internationally, a novel gasoline steam reformer with micro-channels was developed to reduce the size and cost of automotive reformers. Another 1 kW plate reformer, a more compact, low cost standardized design having better conversion efficiency, and faster start-up was developed for fuel cell systems. It yielded increased energy conversion efficiency (from about 70% to 77%) by reducing heat losses. Its lifetime is also expected to be increased from 5 to 10 years.

1.5.2 Membrane Reactors for Steam Reforming is another promising technology. Depending on the temperature, pressure and the reactor length, methane is completely converted, and very pure hydrogen is produced. This allows its operation at lower temperature and lower cost. A potential advantage of this system is simplification of the process design and capital cost reduction. Japan has built and tested a small membrane reactor for production of pure hydrogen from natural gas (at a rate of 15 Nm3/h).

1.5.3 Partial Oxidation (POX) Reformer: Large-scale partial oxidation systems have been used commercially to produce hydrogen from hydrocarbons such as residual oil, for industrial applications. Small-scale partial oxidation systems have recently become commercially available, but are still undergoing intensive R&D. These reactors are more compact than a steam reformer with efficiency of 70-80%. This technology is being used to install a natural gas reformer filling station to supply hydrogen to fuel cell buses and Hythane® buses at Thousand Palms, California. Several companies are involved in developing multi-fuel fuel processors for 50 kW fuel

cell vehicle power plants and to develop gasoline fuel processors based on

POX technology.

1.5.4 Auto-thermal reformers combine some of the best features of steam reforming and partial oxidation systems. Several companies are developing small auto-thermal reformers for converting liquid hydrocarbon fuels to hydrogen for the use in fuel cell systems. The auto-thermal reformer requires no external heat source and no indirect heat exchangers. Heat generated by the partial oxidation is utilized to drive steam reforming reaction. This is more compact than conventional steam reformers, and will have a lower capital cost and higher system efficiency than partial oxidation systems. Auto-thermal reformers are being developed for PEMFC systems by a number of groups

1.5.5 Methanol Reformation takes place with steam at moderate temperatures (250-350oC). These reformers have been demonstrated by several automakers in PEM fuel cell vehicles, where methanol is stored onboard. But no fuel cell vehicle manufacturer is currently using this technology. The advantages are compactness, better heat transfer, faster start-up and potentially lower cost. Internationally, units are produced for steam reforming of alcohols, hydrocarbons, ethers and military fuels. CJB Ltd., a British company built and tested a plate type steam methanol reformer and integrated the fuel cell system. A multi-fuel processor was demonstrated for pure hydrogen production via steam reforming of methanol, using a palladium membrane and micro-reactor technology to create a portable hydrogen source for fuel cells.

1.5.6 Ammonia Cracking: Ammonia is widely distributed in the country and available at low cost. It is relatively easy to transport and store, compared to hydrogen. It can be cracked at 9000C with up to 85% efficiency. Water is not required as co-feed. A costly separation unit Pressure Swing Adsorption unit for separating H2 and N2 would be required. Thermo-catalytic cracking of methane is still far from commercial application for hydrogen production. The primary issues are low efficiency of conversion and coking but relatively low capital costs are projected.

1.5.7 Sorbent-enhanced Catalytic Steam-reforming System: Syngas, produced using novel reformer technologies, has a substantially higher fraction of hydrogen than that produced in a catalytic steam-reforming reactor. Sorbent-enhanced systems are still at the demonstration stage, and show promise for low cost. Issues to be resolved include catalyst and sorbent lifetime and system design.

1.5.8 Hydrogen Separation through Ceramic Membrane: Globally, some research groups are developing ceramic membrane technology for separation

of hydrogen from syngas. The membranes are non-porous, multi-component metallic oxides that operate at high temperature (>700oC) and have high oxygen flux and selectivity. These are known as ion transport membranes (ITM). Conceptual designs were carried out for a hydrogen-refueling station dispensing 15000 m3/day hydrogen at 350 bar. This route offers a 27% cost savings compared to trucked-in liquid hydrogen.

1.5.9 Thermal plasma reformer technology can be used for the production of hydrogen and hydrogen-rich gases from methane and a variety of liquid fuels. Thermal plasma is characterized by temperatures of 3000-10000oC, and can be used to accelerate the kinetics of reforming reactions even without a catalyst. Plasma-reforming systems have been developed and used for evaluating the potential of this technology for small-scale hydrogen production. The best steam reforming results to date showed 95% conversion of methane and projected that the power required can be reduced by about half.

1.5.10 Hydrogen is currently produced for industrial applications by cracking carbonaceous fossil fuels. Natural gas reforming is currently the most efficient, economical and widely used process for production of hydrogen and has been utilized globally for many decades in the oil refinery and fertilizer industries. Steam reforming (SMR) has the lowest capital costs of the hydrogen production technologies with efficiencies in the range 60%–80%.

1.5.11 In spite of efforts to produce hydrogen by processes involving solar energy, wind energy, nuclear energy and bio-fuels, fossilized carbonaceous resources and their products remain the most feasible feedstock in the near term, and for commercial scale production of pure hydrogen, steam reforming remains the most economic and efficient route. b) Pyrolysis of Biomass and reformation of bio-oil and gaseous products

1.5.12 Biomass is a renewable source of energy and is available almost everywhere on the earth. Hydrogen content in biomass is roughly 6.5% by wt. Biomass is thermally decomposed / fast pyrolysed in the temperature range of 600 - 10000C at 1-0.5 MPa in an inert atmosphere to form vapors of dark brown bio-oil (about 85% oxygenated organics and remaining water), other gaseous products (H2, CH4, CO & CO2) and solid products(mainly charcoal). The bio-oil and gaseous products are then reformed to produce hydrogen. The maximum yield of hydrogen can reach up to 90% with the use of Ni- catalyst at 750-8500C. Alternatively, the phenolic components of the bio-oil can be extracted with ethyl acetate to produce an adhesive/phenolic resin co- product; the remaining components can be reformed as in the first option. The

product gas from both alternatives is purified using a standard Pressure Swing Adsorption (PSA) system. National Renewable Energy Laboratory (NREL) U.S.A. has developed a demonstration scale unit for the production of hydrogen from pyrolysis oil by steam reformation. The pyrolysis oil is also generated from biomass (such as peanut shells) in a fluidized bed. Slow pyrolysis gives high char yield and is generally not considered for hydrogen production. c) Gasification of Renewable Biomass and its Reformation

1.5.13 Biomass gasification is a sub-stoichiometric combustion process, in which pyrolysis, oxidation and reduction take place. Pyrolysis products

(volatile matter) further react with char and are reduced to H2, CO, CO2, CH4 and higher hydrocarbons (HHC). In this process, tar is formed, which may produce tar aerosols and polymerized compounds. Therefore, tar formation is undesirable. The gasifier may be so appropriately designed to reduce tar formation. Injection of secondary air is used to reduce tar formation. Indian Institute of Science (IISc), Bangalore has developed an open-top downdraft gasifier, in which effects of various parameters like, equivalence ratio (ER), steam-to-biomass ratio (SBR) residence time- temperature on efficiency are studied. Ni-based catalysts and alkaline metal oxides are used as gasification catalysts to improve gas product quality and conversion efficiency. The syngas yield increased from 353 g per kg of biomass to 828 g per kg of biomass by varying the pyrolysis temperature from 600 - 10000C.

1.5.14 Internationally, many countries are involved in the development of biomass gasification technology. The University of British Colombia, Canada is working on fluidized bed gasification and sorbent based hydrogen separation unit. The Gas Technology Institute (GTI), Chicago is working on a the demonstration project for direct generation of hydrogen from a down draft gasifier using a membrane reactor, The Energy Research Centre of the

Netherlands has developed a pilot plant scale unit of 800 kWth capacity based on gasification technology. The Technical University of Vienna is developing a Fast Internally Circulating Fluidized-bed (FICB) technology for steam-blown gasification of biomass in cooperation with Austrian Energy and Environment agency. A combined heat and power (CHP) plant (8MW) is in operation since 2002 in Güssing, Austria. Later on, Synthetic Natural Gas (SNG) production was also demonstrated in a methanation unit, which took a 1 MW SNG slipstream from the Güssing plant. The targeted production cost of hydrogen through this method is around US$ 2.5 to 3.5 /kg of hydrogen at large scale. The Biomass Gasification project of Gothenburg, Sweden aims to construct a synthetic natural gas (SNG) plant.

1.5.15 With the development of fuel cell systems in the country, MNRE focuses on the generation of hydrogen rich syngas through thermo-chemical conversion of biomass and its purification to fuel cell grade. IISc has recently concluded a project addressing these aspects. This encouraged work on the development of a prototype system to generate hydrogen rich syngas using oxy-steam gasification. The entire process has been optimized to generate a maximum of about 100 g of hydrogen per kilo gram of biomass. Syngas composition, hydrogen yield and performance parameters have been monitored by varying steam to biomass ratio and equivalence ratio. Results show that using dry biomass with oxy-steam improves the hydrogen yield, efficiency and syngas with lower heating value (LHV) compared to direct usage of wet biomass with oxygen. With the current experience of using biomass, about 70 g of pure hydrogen can be obtained per kg of biomass, which results in about 15 kg of biomass for every kg of hydrogen generated. d) Electrolysis of Water

1.5.16 Hydrogen can be generated through electrolysis of water. The water electrolysis can be carried out in three different ways viz., alkaline water electrolysis, acidic water (polymer electrolyte membrane based) electrolysis and high temperature ceramic membranes (solid oxides membranes) water electrolysis. Polymer electrolyte membrane (PEM) based water electrolysers are more advantageous than conventional water-alkali electrolysers due to their ecologically safe nature, production of hydrogen with high purity (>99.99%) and possibility to produce at high pressure.

1.5.17 The alkaline water electrolysis is a matured technology and is commercially available in megawatt range. It has a stack life is <90,000 h and system life of 20-30 years, energy requirement of around 6 kWh per Nm3 hydrogen and efficiency of 60-70%. In the case of PEM based water electrolysers stack life is <20,000 h and the system life is estimated to be around 10-20 years. These electrolysers are smaller, cleaner and more reliable systems than other electrolysers. Alkaline electrolysers are less expensive than PEM electrolysers due to use of non-noble metal (nickel based) catalysts, but consume more electricity. The major challenges of these electrolysers are related to corrosion and poisoning of the electrolysers by inadvertent incursion of CO2. The largest existing alkaline electrolysis plants are 160 MW plant in Aswan, Egypt and 22 MW plant operating in Peru (pressurized operation). The Brown Boveri electrolyser can produce hydrogen at a rate of about 4-300 m3/h.

1.5.18 The PEM water electrolyser is being deployed for the applications, where cost is a secondary issue. The membrane material for these electrolysers is Nafion from DuPont, USA. Besides Du Pont, Asahi Glass,

Dow Chemicals and others have also developed similar membranes either based on fluorinated or non-fluorinated polymers, which are commercially available. The fluorinated polymers have shown good performance for >5000 hours of operation in the fuel cells. However, there are other issues related to its operation such as increase of cross-permeation of gases with increase in pressure. As of now small and medium range PEM water electrolysers are available for laboratory use and other applications. Currently available PEM water electrolyser systems have a hydrogen production rate that varies from 0.06 to 75 Nm³/h whereas alkaline electrolysers have reached the hydrogen production rate of 760 Nm³/h.Siemens, FRG plans to build an electrolyser system to store wind power as hydrogen. The system will have a peak rating of up to 6 MW.

1.5.19 High temperature water electrolysis uses solid oxide electrolyte and offers advantage over alkaline and PEM electrolysers in terms of higher efficiency and lower capital costs. Solid oxide membranes are prepared from calcium and yttrium stabilised zirconium oxide. These electrolysers are operated at high temperatures (900–1000°C), which reduces the consumption of electricity for production of hydrogen by about 30% in comparison to other electrolysis processes at room temperature. Electricity consumed is about 2.6-3.5 kWh/Nm3 of hydrogen produced.

1.5.20 The Bhabha Atomic Research Centre (BARC), Mumbai has developed water electrolysers with high current density (4500 A/m2) based on indigenously developed advanced electrolytic modules incorporating porous nickel electrodes. A portable electrolyser of 1.5 Nm3/h hydrogen production capacity and large units of capacities 10 and 30 Nm3 /h hydrogen production have been developed. BARC has also planned to develop high temperature steam electrolyser of 1.0 Nm3/h hydrogen production capacity for technology demonstration purposes. CSIR-CECRI has developed activated nickel electrode for alkaline electrolyser. PEM water electrolyser of capacity 1.0 and 5.0 Nm3/h were also developed during 2012 and demonstrated with energy consumption of about 5.75 kWh/Nm3of hydrogen at 5-10 bar pressure. These technologies have been transferred to M/s. Eastern Electrolysers, New Delhi for further development. In addition, CSIR-CECRI has also demonstrated solar power integrated PEM based water electrolyser system of 0.5 Nm3/h capacity in 2012.The SPIC Science Foundation (SSF), Chennai has developed PEM based water electrolysers for hydrogen production at the rates of 0.5 and 1 Nm3/h. In these electrolysers titanium plate was platinised and used as bipolar plate. The SSF has also developed and demonstrated a PEM based water electrolyser system with the hydrogen production capacity of 60.0 lit/h using methanol as the depolariser. The energy consumption for hydrogen production was 2.0 kWh/Nm3.The Institute of Science and Technology, JNTU, Hyderabad has developed PEM based water electrolyser

to produce hydrogen at the rate of 36 L/h using Nafion membrane. The Centre of Fuel Cell Technology, Chennai (a project of International Advanced Research Centre for Powder Metallurgy, Hyderabad) has developed and demonstrated a 1.0 Nm3/h hydrogen production capacity electrolyser using similar concept but with much lower energy consumption of 1.40kWh/Nm3. It also demonstrated for the first time the use of carbon based materials in its construction and thus redcuing the capaital cost tredomnously. M/s. MVS Engineering Ltd, New Delhi are offering PEM water electrolyser technology on turnkey basis in partnership with Proton Onsite (USA) for hydrogen generation. Recently, such a system has been installed at the Indian Oil’s R&D Centre, Faridabad. A number of other companies are also reported to have commercialised alkaline water electrolyser for various industrial applications. In general, the production of hydrogen through electrolysis of water is a highly energy intensive (4.5-6.5 kWh/Nm3). High energy consumption coupled with high capital investment is the reason, why water electrolysis technology is not preferred in India for commercial purposes.

1.5.21 Acid and alkali based solid polymer electrolytes have been developed. Alkali based electrolytes use non-noble catalysts, but face challenges such as chemical stability in the electrochemical system. The electrolysers using acid based solid polymer electrolyte may be deployed on a small scale for distributed hydrogen production systems both in industry as well as remote areas for different applications. It is suggested to setup hydrogen production plants based on presently available technology, which can be manufactured in India and then conventional electrolyser may be replaced by the SPE based electrolysers in a phased manner. This will ensure the successful deployment of technology in the times to come. The estimated cost per kg of hydrogen is about $ 8.94, when produced on a 1 MW level.

1.5.22 The strategy to bridge the gap may be planned by identifying projects and the institutions to work in the relevant specialized areas and demonstrate their prototypes. Foreign collaborations may be solicited in specific areas. After successful demonstration of the prototypes, the R&D institutions may work with the industry through PPP Model for commercialization of the technology. Except the electrochemical stack, couple of Indian PSUs have core strength for manufacturing majority of subsystems and are very much capable in system engineering. Imported electrolyser stacks in different combinations may also be used and integration can be carried in the country. e) Bio-Hydrogen Process

1.5.23 The bio-hydrogen production may be an economical way of hydrogen production on the ground that the process takes place at ambient temperature and atmospheric pressure; while other processes are carried out at higher

temperatures & pressures. The major biological processes for hydrogen production are bio-photolysis of water by algae (if the algae is deprived of sulphur, it will switch from the production of oxygen, i.e. normal photosynthesis, to the production of hydrogen), dark and photo-fermentation of organic materials, usually carbohydrates by bacteria. One of the major problems faced by photo-fermentative reactors is the light shading effect generated by accumulation of pigment in the photo-fermentative microbes. Moreover, the rate of hydrogen production in bio-hydrogen reactors is also considerably low when compared with dark fermentation. Sequential dark and photo-fermentation process is a new approach for bio-hydrogen production. Dark fermentation reactions do not require light energy, so they are capable of constantly producing hydrogen from organic compounds present in wastewater throughout the day and night. Among all the biological hydrogen production processes, dark fermentation shows highest hydrogen production rates. This process holds promise for commercialization. Carbohydrate rich, nitrogen deficient solid wastes such as cellulose and starch containing agricultural and food industry wastes and some food industry wastewaters such as cheese whey, olive mill and bakers’ yeast industry waste water can be used for hydrogen production by using suitable bio-process technologies. Utilization of aforementioned wastes for hydrogen production provides inexpensive energy generation with simultaneous waste treatment. A prototype hydrogen bioreactor using waste as a feedstock is in operation at Welch's grape juice factory in North East Pennsylvania, USA. Another two- stage process where bio-hydrogen production process was integrated with bio-methanation is also being considered as a feasible option for improvement of gaseous energy recovery. This mixture of bio-hydrogen and bio-methane may be named as “hymet”.

1.5.24 Major contributors in biohydrogen production research are from United States of America, Canada, Malasiya, Indonesia, Thailand, China and India. Different microbes have been discovered in different parts of the world, each having unique hydrogen production ability. Shri AMM Murugappa Chettiar Research Centre, (MCRC), Chennai was involved in the development of hydrogen production through biological process from sugar and distillery wastes (effluents of M/s. E.I.D. Parry Ltd., at Nellikuppam, Tamilnadu). The Center has designed and developed a 125 m3 bioreactor, which produced

18,000 liters of gas per hour with about 60% hydrogen mixed largely with CO2 and CO. Mesophilic and thermophilic species were identified for hydrogen production. Indian Institute of Technology Kharagpur and Indian Institute of Chemical Technology, Hyderabad are currently setting up bio-reactors of 10m3capacity each based on distillery effluent and kitchen waste respectively and are expected to provide hydrogen yield of 30-50 m3 / day. For bio- hydrogen to be considered as renewable energy source, it should be produced from renewable raw materials like waste materials. Internationally

very few studies are available on commercial level units for bio-hydrogen production. Integration of bio-hydrogen with fuel cell was first mooted in 2012. This concept still needs a serious consideration since this technology is capable of producing hydrogen in a decentralized manner.

1.5.25 Hydrogen can be recovered equivalent to only 20 to 30 % of total energy through dark fermentation and therefore has limitations in commercialization, even though this process can be integrated with photo- fermentation. Theoretically, 12 moles of hydrogen /mole of glucose can be recovered from integrated dark and photo fermentation reactors but due to scaling up problem of photo-fermentation such two-stage process cannot commercialised. The dark fermentation for hydrogen production can be commercialised, if it is integrated with biomethantion process. The spent media of the dark fermentation is rich in volatile fatty acids and would be an ideal substrate for methanogens. The integration of these two processes might lead to 50-60% gaseous energy recovery. Most attractive point of such process is that the reactor used for hydrogen production could be used for bio-methanation also, thus separate reactors are not required. Biohymet production could be envisioned as renewable source of energy only, when it would be produced from renewable sources. f) Thermochemical splitting of water

1.5.26 Water can be dissociated at very high temperatures into hydrogen and oxygen through thermochemical splitting of water. A catalyst is required to make the process operate at feasible temperatures. The required energy can be either provided by nuclear energy or by solar energy, or by hybrid systems including solar and nuclear energy. More than 356 thermo-chemical cycles have been conceived which can be used for water splitting. Around a dozen of these cycles such as the iron oxide cycle, cerium(IV) oxide-cerium(III) oxide cycle, zinc-zinc oxide cycle, sulfur-iodine cycle, copper-chlorine cycle and hybrid sulfur cycle are under research/in testing phase. The iodine-sulphur (I- S) cycle is one of the most promising and efficient thermo-chemical water splitting technologies for the mass production of hydrogen, on which BARC, Trombay, Mumbai is working.

1.5.27 The I-S closed loop glass system has been operated continuously for a period of 20 hours at hydrogen production rate of 30 Lph. India is the 5th country to achieve I-S closed loop operation in glass system, after USA (1980), Japan (2004), China (2010) and South Korea (2009). USA aims to demonstrate commercial scale production of hydrogen using nuclear energy by 2017. European Union started working in this direction in 2004 with the objective to evaluate the potential of thermo-chemical processes, focusing on the I-S cycle which is to be compared with the Westinghouse hybrid (HyS)

cycle in view of the 2015 target for reduction of CO2 emissions from fossil fuels by more than 25% and hydrogen production cost of less than €2/kg. It has been found that hydrogen production costs based on small plants is most favorable using solar energy, while nuclear energy based plants are most economical at high power levels (> 300 MWth); hybrid systems may have their niche in the midrange of 100 to 300 MWth. Canada is investigating copper– chlorine family of thermo-chemical cycles with energy provided by the Canadian Super Critical Water Reactor and use of direct resistive heating of catalysts for SO3 decomposition in the I-S process. Japan has recently initiated R&D activities on the thermo-chemical cycles based on the UT-3 and I-S processes for hydrogen production and successfully achieved the operation of a bench-scale facility for hydrogen production at the rate of 30 Nl/h in a continuous closed I-S cycle operation over one week. While the efficiency was only ~10% for the bench-scale plant, the goal for the pilot plant is ~40%. In 2005, Japan have already initiated the activity to design and construct a pilot plant for hydrogen production at the rate of 30 Nm3/h under the simulated conditions of a nuclear reactor.

1.5.28 The Republic of Korea has targeted for 25 % (3 Mt/year) of the total hydrogen to be supplied by advanced 50 nuclear reactors by 2040. Korea launched its nuclear hydrogen program in 2004 targeting (i) generation of hydrogen for fuel cell applications for electricity generation, passenger vehicles, and domestic power and heating, and (ii) lowering hydrogen costs and improving efficiency of the related processes. Under this programme an underground VHT reactor of 200 MW thermal output is to be coupled with an I-S cycle to generate hydrogen from water. In 2005 People’s Republic of China initiated work on a demonstration project on ‘High Temperature Reactor – Pebble Module’. Both the I-S thermo-chemical cycle and high temperature steam electrolysis are selected as the potential processes for nuclear hydrogen production. The target has been set for commercialization of nuclear hydrogen production by 2020.

1.5.29 The Bhabha Atomic Research Centre has successfully demonstrated I- S process in closed loop operation in glass/quartz material in the laboratory. It is further planned to demonstrate closed loop operation in metallic construction. Other institutes / organisations will also be roped in depending upon their capabilities. Their broad plan is:

(i) Design and Demonstration of Atmospheric pressure operation all Metal closed loop system (AMCL). (ii) High pressure operation Bunsen reactor system has been designed and its commissioning is underway. (iii) Design and demonstration of high pressure Sulfuric acid decomposition system.

(iv) Design and demonstration of Hydriodic acid distillation and decomposition system. (v) Integration of all three high pressure systems to demonstrate, High pressure closed loop process.

1.5.30 The ONGC Energy Centre (OEC) started working on the three thermochemical processes such as Cu-Cl closed loop cycle, I-S closed loop cycle and I-S open loop cycle at engineering scale and all these processes will be compared before taking-up at the commercial level. In view of expensive and corrosive nature of materials used in these processes, OEC has planned to study and evaluate alternative materials. New plants may then be designed based on this evaluation of the alternative materials. CSMCRI, Bhavnagar has been involved in the ‘development of membranes’; IIP Dehradun is engaged in the ‘development of partially open-loop I-S cycle involving H2S incineration and experimental studies on Bunsen Reaction & HI decomposition’; IIT-Delhi is working on “prolonged stability tests of catalysts for HI decomposition reaction of I-S cycle.

1.5.31 Photo-catalytic and photo-electrochemical routes for hydrogen production are also being explored globally by several research groups. In India also some groups, namely, Indian Institute of Chemical Technology, Hyderabad; Institute of Minerals and Materials Technology, Bhubaneswar; Yogi Vemana University, Kadapa; SRM University; Kancheepuram, Shiksha ‘O’ Anusandhan University, Bhubaneswar and Centre for Materials for Electronics Technology, Pune are active in this area. Efforts are being made to come out with effective and robust photo-catalysts and photo- electrocatalysts, electrode materials and materials for reactors. Till date no large scale unit has been successfully designed and demonstrated. Concerted intensive efforts, however, are required to generate basic information and knowhow to take this area to the production for decentralized applications.

1.5.32 In photo-electrochemical water splitting, hydrogen is produced from water using sunlight and specialized semiconductors called photo- electrochemical materials. The Institute of Minerals and Materials Technology Bhubaneswar developed functional hybrid nano-structures for photo- electrochemical water splitting. The different photo-catalytic materials were developed for hydrogen production through water splitting. The developed materials yielded hydrogen e.g. 800-1000 mg hydrogen /batch with CdS photo-electrodes and CdS nano-crystal powder photo-catalysts, 4087 µmol hydrogen/h/g with 0.28 wt% Poly (3-hexylthiophene-2,5-diyl) (P3HT) modified

CdS and 11,901 µmol hydrogen/h/g with CdS-NaNbO3 core-shell nano-rods. Thus, CdS-NaNbO3 core-shell nano-rods was found to give maximum hydrogen production.

g) Other Technologies

1.5.33 Presently, Hydrogen Production by non-thermal plasma assisted direct decomposition of hydrogen sulphide is at research and development stage and no commercial technology is available globally. Among the several techniques tested for the production of hydrogen, Idemitsu Kosan Hybrid (IKC) electrolysis process consumes 3.6 kWh/Nm3 hydrogen, whereas steam reforming of methane, (the traditional approach for hydrogen production) demands still higher energy of 4.3 kWh/Nm3 hydrogen. 40% conversion of hydrogen sulphide by thermal decomposition can be achieved at temperature ~ 1500K. Most of the research in this area in the country has been focused on catalytic/ photocatalytic decomposition of hydrogen sulphide. Hydrogen sulphide under visible light to generate hydrogen is an attractive route of solar energy conversion, because hydrogen is 100% environmentally clean fuel in its cycles of generation and utilization. The Indian Institute of Technology Hyderabad developed the process of non-thermal plasma assisted direct decomposition of hydrogen sulphide into hydrogen and sulphur. Hydrogen production of 0.5 litre/minute was achieved in the laboratory. The reaction conditions can be still improved to decrease the energy consumption.

1.5.34 For the photo-splitting of hydrogen sulphide into hydrogen, extensive work has been carried out for the development of ultraviolet driven photocatalyst for water and hydrogen sulphide splitting. There is need to develop prototype batch photo-reactor for hydrogen production from hydrogen sulphide using solar energy and their field trials using gas emitted at refinery site. Internationally, many groups in Japan, Korea, U.S, Europe are working on development of active photo-catalysts for hydrogen generation under visible light irradiation. The National Institute of Advanced Industrial Science and Technology, Japan demonstrated first time in 2001 direct splitting of water by visible light over an In1.xNixTaO4photocatalyst. Nationally, a few groups are working on photocatalytic splitting of water and hydrogen and hydrogen sulphide into hydrogen under visible light. BARC is working on photocatalytic degradation of nuclear waste as well as water purification. IISc,

Bangalore is working on TiO2 based photocatalysts for organic waste degradation. IITs, Mumbai and Madras, CECRI, Karaikudi, IICT, Hyderabad and some universities in India are working on photodecomposition of organic pollutants. The Centre for Materials for Electronics Technologies (C-MET), Pune is also working on hydrogen generation by photocatalytic decomposition of toxic hydrogen sulphide and achieved hydrogen production from hydrogen sulphide at the rate of 8182.8 and 7616.4 µmol/h/g obtained from nanostructured ZnIn2S4 and CdIn2S4, respectively in presence of sunlight. This design is useful for continuous operation at large scale.

1.6.0 Suggested Action Plan

1.6.1 Based on the gap analysis undertaken between international and national state of art of technologies and recommendations to fill the gap by undertaking the projects as classified in the three broad categories: (a) Mission Mode (for the technologies, which are mature or near maturity for commercialization and with the participation of the industry); (b) Research & Development Mode (for the technologies, which are at the stage of prototype development, their demonstration as a proof of concept and preferably with Industry participation); and (c) Basic / Fundamental Research Mode (for advanced research on new materials and processes), the Action Plan for hydrogen production in the country has been devised as following:

1.6.2 The unutilized (around 6600 tonnes) by-product hydrogen from the Chlor-Alkali Units / Refineries may be used directly for the generation of power / in transportation applications (vehicles) based on IC engine technology. This hydrogen may further be purified (if required) for stationary power generation and on-board application in vehicles / material handling systems based on fuel cell technology. To utilize this hydrogen requisite power generating system / purification unit / compression system to fill cylinders for on-board application of hydrogen in vehicles / material handling vehicles (based on fuel cell technology) need to be set-up. The activity is to be completed by 2018.

1.6.3 Hydrogen has been produced from the conventional sources i.e. carbonaceous fuels like natural gas, coal etc. Hydrogen production by electrolysis, methanol or ammonia cracking is preferred for small, constant or intermittent requirements of hydrogen in food, electronics and pharmaceutical industries, while for larger capacities steam reforming of hydrocarbons /syn gas is preferred. Renewable-based processes like solar- or wind-driven electrolysis and photo-biological water splitting hold great promise for clean hydrogen production; however, advances must still be made before these technologies can be economically competitive. Thus, hydrogen production may be continued from the conventional (carbonaceous) fuels through the most competitive process namely auto-thermal reforming (steam reforming and partial oxidation) process till the technologies for hydrogen production from renewable sources become economically competitive. Scaling-up of the process of catalytic decomposition of natural gas for the production of H-CNG for the use in H-CNG fuelled vehicles (up to 2019), Development & demonstration of hydrogen production by Auto-thermal Process (up to 2020) and Basic / Fundamental Research for dissociation of gaseous hydrocarbon fuels to hydrogen using solar energy (up to 2022) may be carried out.

1.6.4 Biomass has been identified as potential source of renewable energy for hydrogen production. Biomass is gasified to hydrogen rich syngas, which may be reformed and purified to yield pure / near pure hydrogen. The technology of oxy-steam gasification of biomass for hydrogen products has been developed at a small pilot scale (2 kg/h) by the Indian Institute of Science, Bangalore. This may be promising technology for distributed hydrogen production. However, there are challenges associated with purification of hydrogen and scaling up. Research and development for hydrogen production by gasification of biomass may, therefore, be carried out including demonstration of technology at pilot scale (up to 2020).

1.6.5 Pure hydrogen may be obtained by electrolysis for fuel cells applications. The electrolyser system consists of various sub-systems. India is capable in system engineering and has core strength for manufacturing majority of sub-systems except electrochemical stack. Imported electrolyser stacks may be used with the indigenously developed sub-systems. The Institutions / Industry may be identified to work in PPP Model for commercialization of the balance of plant and simultaneously, the technology for the production of stack may be procured or developed indigenously. Solid polymer electrolyser (SPE) with 20,000 hours of operation is desirable and may have membranes based alkaline water electrolysis system integrated with solar photovoltaic system. For the immediate availability of hydrogen onsite, hydrogen may be produced by deploying solar energy powered Acid / Alkali based electrolysis systems based on available technology. Simultanously, development of (i) electrolysers based on indigenous acid based SPE (ii) alternate alkaline membrane up to 2018 (iii) alkaline 1 & 5 Nm3/h high temperature steam solid polymer water electrolyser (up to 2020) may be done and demonstrated and replaced old systems by the newly developed systems. Hydrogen production system by splitting water using renewable energies such as solar energy, wind energy and hybrid systems including electrolysis, photo-catalysis and photo-electro-catalysis may also be developed and demonstrated(up to 2022).

1.6.6 Hydrogen may be produced through dark-fermentation followed by the photo- fermentation of solid waste from agriculture & food industry and liquid waste from food industry. The integrated process is difficult to commercialise in view of the problems associated with the photo-fermentative reactors. Therefore, dark fermentation followed by bio-methanation may be studied, which can recover 50 - 60% gaseous energy from the waste. Only one reactor may be required for both processes – firstly, hydrogen production and subsequently, bio-methanation. The mixture of hydrogen and methane, so produced, is known as bio-hymet. The production of bio-hymet could be envisioned as renewable source of energy. This activity has been proposed to be taken up in Research, Development and Demonstration Mode up to

2019. Energy balance and process economic aspects may also be studied. Biological hydrogen production projects may also be taken up for demonstration in niche areas.

1.6.7 Another path for hydrogen economy has been suggested by the integration of fuel cell system with the bio-hydrogen production system. Such setups may be put strategically near to those places where supply of feedstock is easily available in adequate quantities. The electricity generated by such system may be used to electrify villages in a decentralized manner. It is suggested to take-up such activities in Mission Mode up to 2022.

1.6.8 The Bhabha Atomic Research Centre is engaged in the development of I-S technology in-house. This process in closed loop operation has been successfully demonstrated in glass/quartz reactor. Further, it has been planned to demonstrate closed loop operation of I-S in metallic reactor. ONGC Energy Centre is also working on I-S process in collaboration with IIT- Delhi, ICT Mumbai and CECRI, Karaikudi on both I-S open & closed loop and Cu-Cl cycles. Hydrogen generation @ 27 LPH has been achieved through Cu-Cl process under specified operating conditions. It is suggested to continue these activities using solar / nuclear heat in Mission Mode up to 2022.

1.6.9 Hydrogen production by water splitting through photolysis using solar energy may be undertaken upto 2022 in Mission Mode.

1.6.10 Other innovative method for hydrogen production, like hydrogen production by non-thermal plasma assisted direct decomposition of hydrogen sulphide, Photo-splitting of Hydrogen Sulphide including developmental effort for reduction in energy consumption for hydrogen production (up to 2022).

1.6.11 The total requirement of budget would be around Rs.285 Crore upto 2022.

1.7 Financial Projections for the Mission Mode, Research and Development Mode and Basic / Fundamental Research Mode projects are given as under:

S. Name of Project Estimated Cost No. Rupees in Crore A. Mission Mode Projects 1 Setting-up of purification unit / compression 20 system to fill cylinders for power generating system / on-board application of hydrogen in vehicles / material handling vehicles (based on fuel cell technology) to utilize surplus hydrogen from the Chlor-Alkali Units / Refineries (up to 2019). 2 Scaling-up of the process of partial reforming of 40 natural gas to produce H-CNG for H-CNG fuelled vehicles (up to 2019) 3 Development and demonstration of biological 20 hydrogen production from different kinds of wastes on bench scale, pilot scale and commercial production (up to 2022). 4 Hydrogen production by water splitting through 40 photolysis using solar energy (up to 2022). 5 Demonstration of closed loop operation of I-S in 50 metallic reactor and both I-S open & closed loop process and Cu-Cl cycle using solar / nuclear heat in Mission Mode (up to 2022). Sub-Total A 170 B. Research and Development Projects 6 Hydrogen production by auto-thermal process (up 20 to 2020) 7 Hydrogen production by gasification of biomass 10 including demonstration of technology at pilot scale (up to 2020) 8 Development and demonstration of electrolyser 10 based on indigenous acid based SPE and alternate alkaline membrane and its deployment to replace old systems (up to 2019). 9 Development and demonstration of alkaline 1 & 5 10 Nm3/h high temperature steam solid polymer water electrolyser and its deployment to replace old systems (up to 2020) 10 Development & demonstration of efficient alkaline 10 water electrolyser (upto 2018) 11 Development and demonstration of hydrogen 10 production by splitting water using renewable energies such as solar energy, wind energy and hybrid systems including electrolysis, photo- catalysis and photo-electro-catalysis (up to 2022) 12 Hydrogen production by reformation of bio-oil 5 obtained from fast pyrolysis of biomass (up to

2022). 13 Development of technology for production of syn- 5 gas (CO+H2) and hydrogen from reformation of natural gas / biogas using solar energy (up to 2022). 14 Integration of large capacity electrolysers with 5 wind / solar power units, which is not in a position to evacuate power to grid, for generation of hydrogen and its storage (up to 2022). Sub-Total B 85 C. Basic / Fundamental Research Projects 15 Dissociation of gaseous hydrocarbon fuels to 10 hydrogen using solar energy (up to 2022) 16 Other innovative method for hydrogen production 20 like hydrogen production by non-thermal plasma assisted direct decomposition of hydrogen sulphide, Photo-splitting of Hydrogen Sulphide including developmental effort for reduction in energy consumption for hydrogen production(up to 2022) Sub-Total C 30 Grand Total 285

ACTIVITIES ON HYDROGEN PRODUCTION MMP: Mission Mode Projects; RD&DP: Research & Development Projects; B/FRP: Basic / Fundamental Research Projects Sl. Time Frame (Year) Financial No. Category of Projects Outlay 2016 2017 2018 2019 2020 2021 2022 (Rs. in Crore)

Setting-up of purification unit / compression system to fill cylinders to utilize surplus 20 hydrogen from the Chlor-Alkali Units / Refineries

Scaling-up of the process of partial reforming of 40 natural gas for the production of H-CNG

Development and demonstration of biological hydrogen production from different kinds of wastes 20

1 Mission Mode Projects Phase I Phase II Phase III Bench Scale Pilot Scale Commercial

Production

Hydrogen production by water splitting through photolysis using solar energy 40

Demonstration of closed loop operation of I-S in metallic reactor and both 50 I-S open & closed loop process and Cu-Cl cycle using solar / nuclear heat

SUB-TOTAL 170

Hydrogen production by Auto-thermal Process 20

Hydrogen production by gasification of biomass including

demonstration of technology at pilot scale 10

Development, and demonstration of

electrolyser with indigenous acid based SPE & 10 alternate alkaline membrane and its deployment to replace old systems

3 Development and demonstration of alkaline 1 & 5 Nm /h high temperature steam solid polymer water electrolyser and its deployment to replace old 10 Research, Development systems & Demonstration 2 Development & demonstration of 10 efficient alkaline water electrolyser

Development and demonstration of Hydrogen production by splitting water using 10 renewable energies

Hydrogen production by reformation of bio-oil obtained from fast pyrolysis of biomass 5

Development of technology for production of syn-gas (CO+H ) and hydrogen from 2 5 reformation of natural gas / biogas using solar energy.

Integration of large capacity electrolysers with wind / solar power units, which is not in a position to evacuate power to grid, for generation of hydrogen and its storage 5

SUB-TOTAL 85

Dissociation of gaseous hydrocarbon fuels to hydrogen using solar energy 10

Other innovative method for hydrogen production like hydrogen production by non- thermal plasma assisted direct decomposition of hydrogen sulphide, Photo-splitting of Hydrogen Sulphide including developmental effort for reduction in energy consumption 3. Basic / Fundamental for hydrogen production 20 Research Projects SUB-TOTAL 30

GRAND TOTAL 285

INTRODUCTION

2.0 Introduction

2.1 Human being’s dependence on fossil fuels has made a deep impact on its reserves and natural climate. This has led to exhaustion of fossil fuels, emission of pollutants, and greenhouse gases responsible for global warming. It has been recognized that the crude petroleum oil output by the Organisation of the Petroleum Exporting Countries (OPEC) would not be able to meet the energy demands beyond 2045. To address the above issues, hydrogen is considered as one of the potential energy carrier for the future that is not only clean but also environmentally sustainable. Hydrogen may replace petrol and diesel used in the automobiles and even coal for large scale power generation. Presently, hydrogen is produced for non-energy applications and ‘quantum increase’ in hydrogen production will be required to enable its mass scale utilization as a fuel. To have sustainable hydrogen production, the energy and raw materials needed for this purpose ought to be renewable in nature. There are various methods which may be employed for generating hydrogen from renewable and non-renewable resources. However, the challenge lies in the production of hydrogen in a cost effective manner. As per US DOE, more than 50 million tonnes of hydrogen was produced globally in 2010, of which 46.3% was consumed for petroleum recovery and refining; 44.5% for ammonia production; 3.7% for methanol production; 2.0% for metal production and fabrication; 1.5% for electronics; 1.0% for food industry and 1.0% for other applications. About 95 % of the current hydrogen requirements are produced through fossil fuel sources. Currently, the agricultural sector is the largest user of hydrogen in the form of nitrogenous fertilizers, with 49% of hydrogen being used for ammonia production. Being a clean energy source, its future widespread use as fuel is likely to be in the transport and also in distributed power generation sectors. Hydrogen may indeed emerge to be a turning point for our nation, which is dependent heavily on the imported petroleum crude and natural gas for meeting its energy needs. Development, demonstration and commercialization of appropriate hydrogen production technologies and systems are, therefore, essential in the country, since these have advanced significantly world over.

2.2 Molecular hydrogen is not available on the earth in convenient natural reservoirs. Most hydrogen on the earth is bonded to oxygen in water and to carbon in live or dead and/or fossilized biomass. Currently manufacture of elemental hydrogen requires consumption of energy generated from a fossil or alternative sources. It produces carbon dioxide. Decomposition of water requires electrical or heat input, generated from some primary energy source (fossil fuel, nuclear power or a renewable energy- solar, wind, hydro- electricity, etc.). The energy provided by the energy source essentially provides all of the energy that is available in the hydrogen fuel.

2.3 Hydrogen may be produced from a variety of carbonaceous feed- stocks and/or water using a variety of technologies. Coal, natural gas, petroleum fractions and biomass can be converted to hydrogen through pyrolysis / gasification and reforming using several technologies like steam methane reforming, partial oxidation / auto-thermal reforming. About 95 % of the current hydrogen requirements is met from fossil fuel sources.

2.3.1 Steam Methane Reforming (SMR) is the most common, well- developed and fully commercialised process. It is the least expensive method of producing hydrogen; almost 48% of the world’s hydrogen is produced from SMR. The reforming reaction between steam and hydrocarbons is highly endothermic and is carried out in presence of specially formulated nickel catalyst contained in vertical tubes situated in the radiant section of the reformer. The SMR process is popular because natural gas, commonly used feedstock has high hydrogen content (four hydrogen atoms per carbon atom) and distribution network for the natural gas already exists. The simplified chemical reactions are:

CH4 + H2O = CO + 3H2 ∆ H = + 206 kJ/mol (for methane) CO + H2O = CO2 + H2 ∆ H = - 41 kJ/mol (CO shift reaction)

The Pressure Swing Adsorption (PSA) purification unit separates hydrogen from mixture of product gases by adsorption of CO, CO2 and CH4. This process is commonly used to supply large quantities of hydrogen gas to oil refineries, and ammonia and methanol plants.

Cost of hydrogen production through SMR technology is highly dependent on the scale of production. Large capacity modern SMR hydrogen plants have been constructed with hydrogen generation capacities exceeding 480,000 kg hydrogen/day. These large hydrogen plants typically are co- located with the end users in order to reduce hydrogen gas transportation and storage costs. In addition, SMR technology is also scalable to smaller end-use applications. SMR can also be applied to other hydrocarbons such as ethane and naphtha. Heavier feed-stocks, however, cannot be used, because they may contain impurities and the feed to the reformer must be in vapour form. Other processes such as partial oxidation (POX) are more efficient with higher hydrocarbons.

2.3.2 Hydrogen production from coal gasification is also a well-established commercial technology, but is only competitive with SMR, where oil and/or natural gas are expensive. Three primary types of gasifiers are used: fixed bed, fluidized bed, and entrained flow. Because there are significant coal reserves in many areas of the world, coal could replace natural gas and oil as

the primary feedstock for hydrogen production. However, this technology has environmental impacts (e.g., feedstock procurement) that may prove to be a significant impediment in the future.

2.3.3 Non-catalytic partial oxidation of a hydrogen-rich feedstock (such as natural gas, coal, residue oil, petroleum coke, or biomass) is another pathway for hydrogen production. With natural gas as a feedstock, the partial oxidation process typically produces hydrogen at a faster rate than SMR, but it produces less hydrogen from the same quantity of feedstock. The overall efficiency of this process (50%) is less than that of SMR (65%-75%) and pure oxygen is required. Two commercial technologies for this conversion are available (i) Texaco Gasification Process, and (ii) Shell Gasification Process. As a result of increasing natural gas prices, further development of natural gas partial oxidation technology has been slowed down. The use of a solid fuel like coal is also possible, through gasification, to produce a synthetic gas (syngas) that can then be used in a partial oxidation process to obtain hydrogen as product.

2.3.4 Like gasification of coal, biomass may also be gasified using a variety of methods, primarily indirect and direct gasification. Indirect gasification uses a medium such as sand to transfer heat from the char combustor to the gasification vessel. In direct gasification heat is supplied to the gasification vessel by the combustion of a portion of the feed biomass. In general, hydrogen produced via direct gasification is expected to cost slightly more (i.e., 5%) than that from the indirect mode.

2.3.5 In Biomass pyrolysis, biomass may be thermally decomposed at a high temperature (in the range of 600-10000C) in an inert atmosphere to form a bio-oil composed of about 85% oxygenated organics and remaining water. The bio-oil is then steam reformed using conventional technology to produce hydrogen. Alternatively, the phenolic components of the bio-oil can be extracted with ethyl acetate to produce an adhesive/phenolic resin as a co- product; the remaining components can be reformed as in the first option. The product gas from both alternatives is purified using a standard pressure swing adsorption (PSA) system.

2.3.6 The Kvaerner-process or Kvaerner carbon black & hydrogen process (CB&H) is a method, developed in the 1980s by a Norwegian company for the production of hydrogen from hydrocarbons (CnHm), such as methane, natural gas and biogas. Of the available energy of the feed, approximately 48% is contained in the hydrogen, 40% is contained in activated carbon and 10% in the superheated steam.

2.4 Electrolysis of Water

The Electrolysis of water uses electrical energy to split water molecules into hydrogen and oxygen. Large-scale electrolysis of brine (saltwater) has been commercialised for chemical applications. Some small-scale electrolysis systems also supply hydrogen for high-purity chemical applications, although for most medium- and small-scale applications of hydrogen fuels, electrolysis is cost-prohibitive. For renewable technologies, the capital costs dominate. The cost of the electricity is a major concern because it is three to five times more expensive as “feedstock” than fossil fuels. In fact, the high cost of the electricity is the driving force behind the development of high-temperature steam electrolysis. In this process, some of the energy driving the process can be supplied in the form of steam instead of electricity. For example, at 1000°C, more than 40% of the energy required could be supplied as heat.

Current best process to have an efficiency of 50 - 80% and 1 kg of hydrogen with specific energy of 143 MJ/kg (about 40 kWh/kg) requires 50 - 79 kWh electricity. At the cost of electricity as $0.08/kWh, hydrogen from electrolysis would cost $4.00/kg hydrogen, which is 3 to 10 times the price of hydrogen obtained from steam reforming of natural gas. The price difference is due to the efficiency of direct conversion of fossil fuels to produce hydrogen, rather than burning fuel to produce electricity. Hydrogen from natural gas, used to replace e.g. gasoline, emits more CO2 than the gasoline it would replace, and so is of no help in reducing greenhouse gases.

2.4.1 High Pressure Electrolysis

High pressure electrolysis is the electrolysis of water by decomposition of water (H2O) into oxygen (O2) and hydrogen gas (H2) by means of an electric current being passed through the water. This differs with the standard electrolyser in terms of the hydrogen output at around 120-200 bar (1740- 2900 psi). By pressurizing the hydrogen in the electrolyser the need for an external hydrogen compressor is eliminated, the average energy consumption for internal compression is around 3%.

2.4.2 High Temperature Electrolysis

Hydrogen can be generated from energy supplied in the form of heat (950–1000 °C) and electricity through High Temperature Electrolysis (HTE). The electricity and heat generated through a nuclear reactor could be used for splitting hydrogen from water. Research into high-temperature nuclear reactors may eventually lead to a hydrogen supply that is cost-competitive with natural gas-steam reforming. General Atomics predicts that hydrogen produced in a High Temperature Gas Cooled Reactor (HTGR) would cost

$1.53/kg. In 2003, steam reforming of natural gas yielded hydrogen at $1.40/kg. HTE has been demonstrated for hydrogen production at laboratory scale (with a product having calorific value of 108 MJ (thermal) per kg) but not at a commercial scale. This is lower-quality "commercial" grade Hydrogen, which is unsuitable to use in fuel cells.

2.5 Photo-electrochemical Water Splitting

Using electricity produced by photovoltaic systems offers the cleanest way to produce hydrogen. Water is broken into hydrogen and oxygen by electrolysis—a photo-electrochemical cell (PEC) process which is also named artificial photosynthesis. Research aimed toward developing higher-efficiency multi-junction cell technology is underway by the photovoltaic industry. If this process is assisted by photo-catalysts suspended directly in water instead of using photovoltaic and an electrolytic system, the reaction is in just one step, which can improve efficiency.

2.6 In photo-electro-catalytic production, a gold electrode is covered in layers of indium phosphide (InP) nanoparticles and an iron-sulphur complex is introduced into the layered arrangement, which when submerged in water and irradiated with light under small electric current, produces hydrogen with an efficiency of about 60%. The electricity production itself involves large transformation losses, however, the efficiency of hydrogen production through electrolysis relative to the primary energy content of the fuel input to generation would be significantly lower. In certain cases, it may be economical to use off-peak electricity, if it is priced well below the average electricity price for the day; however, such market applications would have to be balanced with other potential electricity supplies, the cost versus benefits of appropriate metering and rate design, and the implied reduction in utilization of the electrolysis unit, as described above. The development of such an application could also support other technologies, such as plug-in hybrid electric vehicles.

2.7 Hydrogen through Thermal Splitting of Water:

2.7.1 Concentrated Solar Thermal Energy: Very high temperatures are required to dissociate water into hydrogen and oxygen. A catalyst is required to make the process operate at feasible temperatures. Heating the water can be achieved through the use of concentrating solar power. Hydrosol-II is a 100-kilowatt pilot plant in Spain, which uses sunlight to obtain the required 800 - 1,2000C to heat water. It has been in operation since 2008. The design of this pilot plant is based on a modular concept. As a result, it may be possible that this technology could be readily scaled up to the megawatt

range by multiplying the available reactor units and by connecting the plant to heliostat fields (fields of sun-tracking mirrors) of a suitable size.

2.7.2 A promising long-term technology is the use of concentrated solar energy for hydrogen production via electrolysis. Two primary process configurations are used with this method. In the first, ambient temperature electrolysis, concentrated solar energy is used to generate alternating current (AC) electricity, which is supplied to the electrolyser. The second is the high- temperature electrolysis of steam. In this system, the concentrator supplies both heat and AC electricity to convert steam (1273 K) to hydrogen and oxygen. In this system, an SOFC system would be operated in a reverse mode to generate hydrogen instead of electricity. This technology is in an early stage of development.

2.8 There are more than 356 thermo-chemical cycles for the production of hydrogen by splitting water (without using electricity) though only around a dozen of these cycles such as the iron oxide cycle, cerium(IV) oxide- cerium(III) oxide cycle, zinc-zinc-oxide cycle, sulphur-iodine cycle, copper- chlorine cycle and hybrid sulphur cycle are under research and in testing phase. These processes can be more efficient than high-temperature electrolysis, typical in the range from 35 - 49% (lower heating value) efficiency. Thermo-chemical production of hydrogen using chemical energy from coal or natural gas is generally not considered, because the direct chemical path is more efficient. None of the thermo-chemical hydrogen production processes have been demonstrated at production levels, although several have been demonstrated in laboratories.

2.9 Biological Hydrogen Production

It is the fermentative conversion of organic substrate to bio-hydrogen manifested by a diverse group bacteria using multi enzyme systems involving three steps similar to anaerobic conversion. Two different fermentation routes- dark fermentation and photo-fermentation routes are available. Dark fermentation reactions do not require light energy, so they are capable of constantly producing hydrogen from organic compounds throughout the day and night. Photo-fermentation differs from dark fermentation because it only proceeds in the presence of light. Biological hydrogen can be produced in an algae bioreactor. In the late 1990s it was discovered that if the algae is deprived of sulphur, it will switch from the production of oxygen, i.e. normal photosynthesis, to the production of hydrogen.

Biological hydrogen can also be produced in bioreactors that use feed- stocks other than algae, the most common feedstock being waste streams. The process involves bacteria feeding on hydrocarbons and excreting

hydrogen and CO2. The CO2 can be sequestered successfully by several methods, leaving hydrogen gas. A prototype hydrogen bioreactor using waste as a feedstock is in operation at Welch's grape juice factory in North East, Pennsylvania.

2.10 Bio-catalyzed Electrolysis

The electrolysis using microbes provides another possibility of producing hydrogen besides regular electrolysis of water, with bio-catalyzed electrolysis, hydrogen is generated after running through the microbial fuel cell and a variety of aquatic plants can be used. These include reed sweet- grass, cord-grass, rice, tomatoes, lupines, algae.

HYDROGEN PRODUCTION USING THERMOCHEMICAL ROUTE FROM CARBONACEOUS FEED-STOCKS

3.1 Hydrogen Production from Carbonaceous Sources

3.1.1 Introduction:

Hydrogen has been projected as one of the few long-term sustainable clean energy carriers, emitting only water vapour as a by-product during the combustion or oxidation process. Approximately 95% of the hydrogen produced presently comes from carbonaceous raw materials derived primarily from a fossilized carbonaceous feed-stock. Only a fraction of this hydrogen is currently used for energy purposes; the bulk serves as a chemical feedstock for fertilizer, petrochemical, food, electronics and metallurgical processing industries. Hydrogen share in the energy market is increasing with the implementation of fuel cell systems and the growing demand for zero- emission fuels. Hydrogen production will need to keep pace with this growing market.

The use of hydrogen for petrochemicals, fertilizers and as clean and renewable energy carrier will increase substantially in the coming years as even more stringent environmental legislations are enforced. Low sulfur gasoline and diesel fuels will become mandatory and harmful emissions will have to be reduced drastically. Hydrogen will be required by refiners and specialty chemical manufacturers to meet the global need for cleaner products. The growing fuel cell market will be dependent on hydrogen as a primary fuel source. The Hydrogen Posture Plan, published by Energy Efficiency and Renewable Energy (EERE), USA in February 2004, envisaged a complete transition to a hydrogen economy by 2030–2040.

However, hydrogen is not readily available in sufficient quantities and the production cost is still high for transportation purpose. The technical challenges to achieve a stable hydrogen economy include improving process efficiencies, lowering the cost of production and harnessing renewable sources for hydrogen production.

3.1.2 International Status & Commercialisation

Conventional technologies for hydrogen production are: a) Steam Methane Reforming b) Partial Oxidation c) Auto-Thermal Reforming d) Methanol Reforming e) Ammonia Cracking f) Thermo-catalytic Cracking of Methane g) Novel Reformer Technologies

A. Steam Methane Reforming

1. Process Description

Catalytic steam reforming of methane is a well-known, commercially available process for hydrogen production. Hydrogen production is accomplished in several steps: steam reforming, water gas shift reaction, and hydrogen purification.

CH4 + H2O ↔ CO + 3 H2 ∆H= +206.16 kJ/mol CH4

The steam reforming reaction is endothermic and requires external heat input. Economics favors reactor operation at pressures of 3 to 25 atmospheres and temperatures of 700 to 850°C. The external heat needed to drive the reaction is often provided by the combustion of a fraction of the incoming natural gas feedstock (up to 25%) or from burning waste gases, such as purge gas from the hydrogen purification system. Heat transfer to the reactants is accomplished indirectly through a heat exchanger. Methane and steam react in catalyst filled tubes. Typically, the mass ratio of steam to carbon is about 3 or more to avoid "coking" or carbon build-up on the catalysts.

After reforming, the resulting syngas is sent to one or more shift reactors, where the hydrogen output is increased via the water-gas shift reaction which "converts" CO to H2. CO + H2O ↔ CO2 + H2 ∆H = - 41.15 kJ/mol CO

This reaction is favored at temperatures of less than about 600°C, and can take place at as low as 200°C, with sufficiently active catalysts. The gas exiting the shift reactor contains mostly H2 (70-80%) plus CO2, CH4, H2O and small quantities of CO. For hydrogen production, the shift reaction is often accomplished in two stages. A high temperature shift reactor operating at about 350-475°C accomplishes much of the conversion, followed by a lower temperature (200-250°C) shift reactor, which brings the CO concentration down to a few percent by volume or less. Hydrogen is then purified. The degree of purification depends on the application. For industrial hydrogen, pressure swing absorption (PSA) systems or palladium membranes are used to produce hydrogen at up to 99.999% purity.

2. Status of Various Types of Steam Methane Reformers

a) Conventional Steam Methane Reformers

Steam methane reformers have been built over a wide range of sizes. For large-scale chemical processes such as oil refining, steam reformers produce 25 to 100 million standard cubic feet of hydrogen per day (1 scf = 0.02832 m3 or 28.32 L). These systems consist of long (12 meter) catalyst filled tubes, and operate at temperatures of 850oC and pressures of 15-25 atm, which necessitates the use of expensive alloy steels. Capital costs for a

20 million scf H2/day steam reformer plant (including the reformer, shift reactor and PSA) are about $200/kW H2 output; for a 200 million scf/day plant capital costs are estimated to be about $80/kW H2.Refinery-type (high pressure, high temperature) long tube reformers can be scaled down to as small as 0.1-1.0 million scf/day (the scale needed for producing hydrogen at refueling stations), but scale economies in the capital cost are significant. The capital cost is about $750/kW H2 at 1 million scf/day and $4000/kW H2 at 0.1 million scf/day. Small-scale conventional (long tube, high temperature) steam methane reformers are commercially available from a number of companies, which normally produce large steam methane reformers for chemical and oil industries. The main design constraints for these systems are high throughput, high reliability and high purity (depending on the application).

The disadvantages of conventional long tube steam reformers for hydrogen refueling station applications are their large size (12-meter long catalyst-filled tubes are commonly used), and high cost (which is due to costly materials requirements for high temperature, high pressure operation, and to engineering/installation costs for these one of kind units). For these reasons, it is generally believed in the hydrogen and fuel cell R&D communities that a more compact, lower cost reformer will be needed for stand-alone hydrogen production at refueling stations. b) Compact “Fuel Cell Type” Steam Methane Reformers with Concentric Annular Catalyst Beds

At small sizes, a more cost effective approach is to use a lower pressure and temperature reformer, with lower cost materials. Steam methane reformers in the range of 2000 to 120,000 scf H2/day have been developed for use with fuel cells, and have recently been adapted for stand- alone hydrogen production. In these systems, the heat transfer path is properly engineered to make the device more compact, and the reformer operates at a lower pressure and temperature (3 atm, 700°C), which relaxes materials requirements. Estimates of mass produced costs for small .fuel cell type. steam methane reformers indicates that the capital cost for hydrogen

production plants in the 0.1 to 1.0 million scf/day range would be $150-

$180/kW H2 assuming that 1000 units were produced.

The capital costs per unit of hydrogen production ($/kW H2) are similar for fuel cell type small reformers and conventional, one-of-a-kind large reformers, assuming that many small units are built. Energy conversion efficiencies of 70%-80% are possible for these units. c) Plate-type Steam Methane Reformers

Another innovation in the design of steam methane reformers for fuel cell systems is the plate-type reformer. Plate-type reformers are more compact than conventional reformers with long, catalyst-filled tubes or annular-type reformers with catalyst beds. The reformer plates are arranged in a stack. One side of each plate is coated with a steam reforming catalyst and supplied with reactants (methane and steam). On the other side of the plate, anode exhaust gas from the fuel cell undergoes catalytic combustion, providing heat to drive the endothermic steam reforming reaction. The potential advantages of a plate reformer are more compact, standardized design (and lower cost), better heat transfer (and therefore better conversion efficiency), and faster start-up (because each plate has a lower thermal inertia than a packed catalyst bed).

The various reactors in the steam methane reformer system (e.g. desulfurizer, steam reformer, water gas shift reactor, and CO clean-up stage) are made up of plates of a standard size, greatly reducing the capital cost. Heat transfer and heat integration between reactors is facilitated.

Plate-type steam methane reformers have not yet been commercialised for fuel cell systems, but may allow for future capital cost reduction by simplifying system design. d) Membrane Reactors for Steam Reforming

Another promising technology is the .membrane reactor, where the steam reforming, water gas shift and hydrogen purification steps all take place in a single reactor. Methane and steam are fed into a catalyst-filled reactor under pressure. On one side of the reactor is a high selectivity palladium membrane that is selectively permeable to hydrogen. As the steam reforming reaction proceeds, the hydrogen is driven across the membrane by the pressure difference. Depending on the temperature, pressure and the reactor length, methane can be completely converted, and very pure hydrogen is produced, which is removed as the reaction proceeds. This allows operation at lower temperature, and use of lower cost materials. A potential advantage

of this system is simplification of the process design and capital cost reduction due to the need of fewer process vessels.

There is huge spurt in industrial R&D activity on membrane technologies for syngas and hydrogen production. Interest by major energy companies in applying membrane technology to large-scale syngas and hydrogen production may have significant “spin-offs” for small-scale hydrogen production as well. Recently patents have been issued on membrane reactor reforming to a number of companies involved in fuel processor design for fuel cells and on related ion transport membrane technology to oil companies, Exxon, BP Amoco, Indiana, Standard Oil, USA and other industrial gas companies like Air Products and Praxair. Recently Praxair and Argonne National Laboratory launched a programme to develop a compact, low-cost hydrogen generator based on ceramic membrane technologies. Steam, natural gas and oxygen are combined in a catalyzed auto-thermal reforming reaction. Oxygen is derived from air, using an oxygen transport ceramic membrane (OTM) that operates at about 800-1000oC. High purity hydrogen is removed using a high selective hydrogen transport membrane, also operating at 800-1000oC. The OTM has been developed by Praxair and others in the Oxygen Transport Membrane Syngas Alliance (BP, London, Amoco,Indiana Statoil, Norway, Sasol, Johannesburg), South Africa, since 1997, and is now undergoing Phase II pilot demonstration. The hydrogen transport membrane is being developed at Argonne National Laboratory, and is in an early stage of development.

In Japan, the Tokyo Gas company has built and tested a small membrane reactor for production of pure hydrogen from natural gas at a rate of 15 Nm3/h (about 12,000 scf/d), as well as steam reforming and partial oxidation systems. Aspen Systems has demonstrated a membrane reactor for steam reforming methane, ethanol and gasoline.

B. Partial Oxidation

1. Process Description

Another commercially available method for deriving hydrogen from hydrocarbons is partial oxidation (POX). Here, methane (or some other hydrocarbon feedstock such as oil) is oxidized to produce carbon monoxide and hydrogen according to

CH4 + 1/2 O2→ CO + 2 H2 ∆H = -36 MJ/kmol CH4

The reaction is exothermic and no indirect heat exchanger is needed. Catalysts are not required because of the high temperature. However, the

hydrogen yield per mole of methane input (and the system efficiency) can be significantly enhanced by use of catalysts. A hydrogen plant based on partial oxidation includes a partial oxidation reactor, followed by a shift reactor and hydrogen purification equipment. Large-scale partial oxidation systems have been used commercially to produce hydrogen from hydrocarbons such as residual oil, for applications in refineries, etc. Large systems generally incorporate an oxygen plant, because operation with pure oxygen, rather than air, reduces the size and cost of the reactors.

Small-scale partial oxidation systems have recently become commercially available, but intensive R&D activities are still underway. Small- scale partial oxidation systems have a fast response time, making them attractive for following rapidly varying loads, and can handle a variety of fuels, including methane, ethanol, methanol, and gasoline.

The POX reactor is more compact than a steam reformer, in which heat must be added indirectly via a heat exchanger. The efficiency of the partial oxidation unit is relatively high (70-80%). However, partial oxidation systems are typically less energy efficient than steam reforming because of the higher temperatures involved (which exacerbates heat losses) and the problem of heat recovery. (In a steam methane reforming plant, heat can be recovered from the flue gas to raise steam for the reaction, and the PSA purge gas can be used as a reformer burner fuel to help provide heat for the endothermic steam reforming reaction. In a POX reactor, in which the reaction is exothermic, the energy in the PSA purge gas cannot be fully recovered).

Because they are more compact, and do not require indirect heat exchange (as in steam reforming), it has been suggested that partial oxidation systems could cost less than steam reformers. Although the partial oxidation reactor is likely to be less expensive than a steam reformer vessel, the downstream shift and purification stages are likely to be more expensive.

Developing low cost purification technologies is the key, if POX systems are to be used for stationary hydrogen production. Another approach is using pure oxygen feed to the POX, which incurs high capital costs for small-scale oxygen production, but eliminates the need to deal with nitrogen downstream. Oxygen enrichment of incoming air is another way of reducing, but not eliminating, the amount of nitrogen. Innovative membrane technologies such as the Ion Transport Membrane (ITM) may allow lower cost oxygen for POX reactors. This is being investigated by Air Products in its research related to ITMs, and by Praxair and partners in its oxygen transport membrane programme.

2. Status of Partial Oxidation Systems

A number of companies are involved in developing small-scale POx systems. Small POx systems have been developed, for use with fuel cell systems, by Arthur D. Little and its spin-off companies Epyx and Nuvera. Epyx is supplying the onboard gasoline reformer for the USDOE’s gasoline fuel cell vehicle project. Epyx recently formed a joint company with DeNora called

Nuvera, to commercialise POX reformer/PEM fuel cell systems. Nuvera has reportedly shipped gasoline reformers to automotive companies for testing.

Hydrogen Burner Technology (HBT), Inc., California, USA has developed a range of hydrogen production systems based on POx. This includes a reformer that produces very pure H2 for cogeneration in buildings. HBT, with funding from the California Air Resources Board, is installing a natural gas reformer filling station for Sunline Transit at Thousand Palms, CA, to supply hydrogen to fuel cell buses and Hythane® buses. HBT has a joint venture with Gaz de France to distribute HBT’s products in Europe. Phoenix Gas Systems (a HBT sub group) develops systems for industrial hydrogen gas generation.

Argonne National Laboratory, Lemont, Illinois, USA has developed a POx reformer suitable for use in vehicles. The USDOE is supporting work on POx systems for onboard fuel processors for fuel cell vehicles through the Office of Transportation Technologies Fuel Cell Program. Several companies are involved in developing multi-fuel fuel processors for 50 kW fuel cell vehicle power plants. These include:

 As part of the Arthur D. Little/ Epyx/ Nuvera partnership, a gasoline fuel processor built by Epyx was demonstrated with a PEM fuel cell. Plug Power, Latham, New York is building an integrated 50 kW gasoline/PEMFC system, based on the Epyx reformer.  McDermott Technology Inc., Alliance, Ohio, USA and Catalytica Energy Systems Inc., Arizona are developing a multi-fuel fuel processor for a 50 kW fuel cell.  Hydrogen Burner Technologies, Inc. is developing a multi-fuel processor for a 50 kW fuel cell.

In addition, a number of automotive companies are in joint ventures to develop gasoline fuel processors based on POX technology. These include:

General Motors. USA has joined with Exxon Mobil, USA to develop an onboard gasoline fuel processor.

International Fuel Cells, South Windsor, USA has partnered with Shell Hydrogen, Torrance, USA to develop and market a variety of fuel processors.

Projects to use POx systems in stationary fuel cells include:

Tokyo Gas Company, Japan, has demonstrated a POx system for 1 kW fuel cell cogeneration system.

McDermott Technology, Inc. (MTI), USA and Catalytica Energy Systems Inc., Tempe, Arizona, United States are working together to develop compact fuel processors for use with PEMFCs and solid oxide fuel cells (SOFCs). This system is designed to reform gasoline and Naval Distillate for PEMFCs.

C. Autothermal Reforming

1. Process Description

Autothermal reformers (ATRs) combine some of the best features of SMR and POx systems. Several companies are developing small ATRs for converting liquid hydrocarbon fuels to hydrogen for use in fuel cell systems. In autothermal reforming, a hydrocarbon feed (methane or a liquid fuel) is reacted with both steam and air to produce a hydrogen-rich gas. Both the SMR and POx reactions take place. For example, with methane

CH4 + H2O ↔ CO + 3 H2 ∆H = +206.16 kJ/mol CH4

CH4 + ½ O2→ CO + 2 H2 ∆H = -36 MJ/kmol CH4

With the right mixture of input fuel, air and steam, the POx reaction supplies all the heat needed to drive the catalytic steam reforming reaction. Unlike the SMR, the ATR requires no external heat source and no indirect heat exchangers. This makes ATRs simpler and more compact than SMRs, and it is likely that ATRs will have a lower capital cost. In an ATR all the heat generated by the POx reaction is fully utilized to drive the steam reforming reaction. Thus, ATRs typically offer higher system efficiency than POx systems, where excess heat is not easily recovered. As with a SMR or POx system, water gas shift reactors and a hydrogen purification stage are needed.

2. Status of Autothermal Reformers

ATRs are being developed by a number of groups, mostly for fuel processors of gasoline, diesel and logistics fuels and for natural gas fueled

PEMFC cogeneration systems. These include:

Argonne National Laboratory is testing ATR systems and catalysts International Fuel Cells (IFC), South Windsor, USA designed an ATR that runs on logistics fuels. BWX Technologies, Inc., Lynchburg, Virginia, and McDermott Technology, Inc. Using the IFC ATR, a system was designed to reform Naval distillate for shipboard fuel cells Fraunhofer Institute for Solar Energy Systems, Freiburg, Germany is designing ATRs for LPG and diesel fuel. Degussa Metals Catalyst, Cardec Ag, Hanau, Germany is developing catalysts for ATRs used with gasoline Johnson-Matthey, Hamilton Bermuda developed a .Hot-Spot. autothermal reformer, capable of reforming methanol and methane Honeywell and Energy Partners, USA are developing a 50 kW PEMFC system for buildings cogeneration. Both SMR and ATR are being tried. Daimler-Chrysler, USA is developing an ATR for gasoline reforming McDermott Technology, Inc. (MTI), USA and Catalytica Energy Systems Inc.,Tempe, Arizona, United States are developing a small autothermal reformer for use with diesel and logistics fuels on ships, based on an IFC design. A regenerable desulfurization stage is important for Navy diesel fuel with 1% sulfur. Partners in this activity are McDermott Technology, Inc. and Catalytica Advanced Technologies, California, USA Ballard, Burnaby, Canada,BWX Technologies, Lynchburg, Virginia, USA and Gibbs & Cox, Arlington, Virginia, USA The Idaho National Energy. USA and Environment Laboratory (INEEL), USA with MTI and Pacific Gas and Electric, USA have recently begun work on developing a 10 kW ATR system for hydrogen refueling station applications. Analytic Power, Canada has assessed multi-fuel reformer technology, including ATR. IdaTech, Bend, Oregon, United States has developed a multi-fuel reformer, which produces very pure hydrogen from methane. It is

likely that the reformer is either a POX or ATR type. Recently, Hydrogen Burner Technologies, Inc., Long Beach, California, US began development of an autothermal reforming system for use with fuel cells and for hydrogen production.

D. Methanol Steam Reforming

1. Process Description

Methanol is a liquid fuel that can be more easily stored and transported than hydrogen. Because it can be readily steam reformed at moderate temperatures (250-350oC), methanol has been proposed as a fuel for fuel cell vehicles. Experimental fuel cell vehicles with onboard methanol reformers have been demonstrated by Daimler-Chrysler, USA and Toyota and Nissan, Japan. Although methanol steam reforming technologies are being developed for fuel processors onboard fuel cell vehicles, it has also been suggested that hydrogen might be produced by steam reforming of methanol at refueling stations (Ledjeff-Hey et al. 1998).

The reactions for production of hydrogen via methanol steam reforming are as follows:

CH3OH ↔ CO + 2 H2, ∆H = 90.1 kJ/mol; Methanol reforming CO + H2O ↔ CO2 + H2 ∆H=-41.2 kJ/mol; Water gas shift reaction

or combining these:

CH3OH + H2O ↔ CO2 + 3H2

The reaction takes place in the presence of copper/zinc catalysts in the temperature range 200- 350°C. Overall the reaction is endothermic, requiring the application of heat, through an indirect heat exchanger, to a catalyst filled tube or catalyst plate. Good thermodynamic conversion has been reported for steam-to-carbon ratios of 1.5 and temperatures of 250-350°C. Various types of methanol steam reformers have been designed. Earlier designs use catalyst filled tubes that are indirectly heated via combustion of some of the incoming methanol fuel. More recently, there has been an effort to develop plate type reformers for methanol reforming. These have a number of potential advantages including compactness, better heat transfer, faster start- up and potentially lower cost. Membrane reactors have also been built for steam reforming methanol.

For refueling station applications, a hydrogen purification stage, either pressure swing adsorption unit or a membrane separation type, unit may be required. The cost of the hydrogen production system might be lower for a methanol steam reformer because it would operate at much lower temperatures than a steam methane reformer. The cost of hydrogen produced from methanol would be higher than hydrogen from small-scale steam methane reforming, because methanol is a more expensive feedstock than

natural gas.

2. Status of Methanol Steam Reformers

Researchers at Los Alamos National Laboratory, USA have conducted research on methanol steam reforming for PEM fuel cells. Researchers at Argonne National Laboratory, USA have also simulated and built methanol steam reformers. Several automakers demonstrating fuel cell vehicles have developed onboard steam reformers for methanol. These include Excellis Fuel Cell Engines (DaimlerChrysler) of USA, and Toyota and Nissan of Japan. The European Commission funded two projects to develop onboard fuel processors for fuel cell vehicles as part of the JOULE II project. The MERCATOX project had the goal of producing a prototype integrated methanol reformer and selective oxidation system.

Wellman CJB Ltd., a British company that has produced units for steam reforming of alcohols, hydrocarbons, ethers and military fuels, coordinated the MERCATOX project. The reformer consists of a series of catalytic plates, with combustion of anode off-gas on one side and reforming on the other side. Loughborough University designed the gas clean-up system. Wellmann built and tested a plate type steam methanol reformer and integrated the system, Rover Cars Company addressed manufacturing and vehicle design issues, and Instituto Superior Technico undertook modeling work

 Northwest Power Systems (now called IdaTech), Thief River Falls, Minnesota, United States has developed a multi-fuel processor. They have demonstrated pure hydrogen production via steam reforming of methanol, using a palladium membrane for the final purification step  Researchers at InnovaTek, Inc., Richland, Washington, USA have demonstrated microreactor technology to create a portable hydrogen source for fuel cells by reforming methanol  Researchers at Mitsubishi Electric Corporation, Japan are developing a compact, plate-type steam methanol reformer  Researchers at the Royal Military College, Ontario, Canada, are studying the effects of catalyst properties on methanol reforming  Researchers at Honeywell, USA are developing a compact plate-type steam methanol reformer for automotive applications  Researchers at NTT Telecommunications Laboratory, and Tokyo University are developing a compact plate-type steam methanol reformer for automotive applications

 Researchers at Gerhard-Mercator-Universitat, FRG, are developing compact membrane reactors for methanol steam reforming

E. Ammonia Cracking

Ammonia is widely distributed to consumers today, is low cost and is relatively easy to transport and store, compared to hydrogen. These attributes make it a potential candidate for use as a hydrogen carrier for fuel cell applications.

Ammonia can be dissociated (or cracked) into nitrogen and hydrogen via the reaction:

2 NH3 -> N2 + 3 H2

The reaction is endothermic, and ammonia cracking takes place in indirectly heated catalyst filled tubes. The dissociation rate depends on the temperature, pressure and catalyst type. The reaction rate is increased by o operating at temperatures of 700 C or above, although dissociation can occur at temperatures as low as 350oC. The main impurities are traces of un- reacted ammonia and nitrogen oxides. The concentration of un-reacted ammonia must be reduced to the ppm level for use in PEM fuel cells, although alkaline fuel cells are not as sensitive to this. For PEMFC applications, where low levels of ammonia impurity are required, a recent study recommends reaction temperatures of 900oC .The overall efficiency of fuel processor systems based on ammonia cracking has been reported to be up to 85%. Maximum values of about 60% were reported in another recent study, by Analytic Power, for small ammonia crackers for PEM fuel cell applications, where up to 40% of the product hydrogen was combusted to supply heat to drive the dissociation reaction and to compensate for heat losses.

A potential advantage of ammonia cracking for hydrogen generation in a fuel cell system is simplicity of reactor. Unlike a steam reformer system, water is not required as a co-feed with the fuel, and no water gas shift reactors are needed. When an ammonia cracker is closely coupled to a fuel cell, no final hydrogen purification stage is needed. Because nitrogen is inert and has no effect in the fuel cell, it is simply passes through as a diluent. For pure hydrogen production based on ammonia cracking, however, a costly separation of H2 and N2 would be required, for example by using a PSA unit or a hydrogen selective membrane. The cost of pure hydrogen production through ammonia cracking has not yet been estimated.

F. Thermo-catalytic Cracking of Methane

In this approach, methane is broken down into carbon and hydrogen in the presence of a catalyst at high temperature (850-1200oC), according to the reaction

CH4 → C + 2 H2 ∆H = 17.8 kcal/mole CH4

This reaction is endothermic, requiring energy input of about 10% of the natural gas feedstock. Researchers at the Florida Solar Energy Center, USA have studied thermocatalytic methane cracking. This technology is still far from commercial application for hydrogen production. The primary issues are low efficiency of conversion and coking (carbon fouling of the catalyst). Catalytic cracking of other hydrocarbons has been investigated by researchers at Gerhard- Mercator-Universitat at Duisburg, Germany. Frequent regeneration of the catalyst is required to remove accumulated carbon, but relatively low capital costs are projected because of the system’s simplicity.

G. Novel Reformer Technologies

1. Sorbent Enhanced Reforming

Recently several authors have investigated the possibility of sorbent enhanced steam methane reforming. Here, an absorbent (such as calcium oxide) is mixed with the steam reforming catalyst, removing the CO and CO2 as the steam reforming reaction progresses. The resulting syngas has a substantially higher fraction of hydrogen than that produced in a catalytic steam-reforming reactor. A syngas composition was recently reported of 90%

H2, 10%CH4, 0.5% CO2 and <50 ppm CO. This reduces the need for downstream processing and purification, which can be expensive in a small- scale steam reformer. Moreover, when CO2 is removed by the sorbent, the reaction can take place at lower temperature (400-500oC vs. 800-1000oC) and pressure, reducing heat losses and material costs. Sorbent-enhanced systems are still at the demonstration stage, and show promise because of their low cost. Issues requiring further research include catalyst and sorbent lifetime and system design.

2. Ion Transport Membrane (ITM) Reforming

Air Products, in collaboration with the USDOE and other members of the ITM syngas team (Cerametec, Chevron, Eltron Research, McDermott Technology, Norsk Hydro, Pacific Northwest Laboratory, Pennsylvania State University, University of Alaska, and University of Pennsylvania, all from

USA), are developing ceramic membrane technology for generation of H2 and

syngas. The membranes are non-porous, multi-component metallic oxides that operate at high temperature (>700oC) and have high oxygen flux and selectivity. These are known as ion transport membranes (ITM). Conceptual designs were carried out for a hydrogen-refueling station dispensing 0.5 million scf/day of 5000 psi hydrogen, following work by Directed Technologies, Inc. Initial estimates show the potential for a significant reduction in the cost of high pressure H2 produced via this route at the 0.1 to 1.0 million scf/day size. For example, compared to trucked-in liquid hydrogen, the ITM route offers a 27% cost savings. Oxygen can be separated from air fed to one side of the membrane at ambient pressure or moderate pressure (1-5 psig) and reacted on the other surface with methane and steam at higher pressure (100-500 psig) to form a mixture of H2 and CO. This can then be processed to make hydrogen or liquid fuels. Various configurations for the ITM reactor were examined, and a flat-plate system was chosen because it reduced the number of ceramic-metal seals needed. An independent effort to develop oxygen transport membranes is ongoing at Praxair in conjunction with the Oxygen Transport Membrane Syngas Alliance.

3. Plasma Reformers

Thermal plasma technology can be used in the production of hydrogen and hydrogen-rich gases from methane and a variety of liquid fuels. Thermal plasma is characterized by temperatures of the order of 3000-10,000oC, and can be used to accelerate the kinetics reforming reactions even without a catalyst. The plasma is created by an electric arc. Reactant mixtures (for example, methane plus steam or diesel fuel plus air and water) are introduced into the reactor and H2 plus other hydrocarbon products are formed. Researchers at MIT, USA (Bromberg et al. 1999) have developed plasma- reforming systems. The plasma is created by an electric arc in a plasmatron. One set of experiments involved partial oxidation of diesel fuel. Steam reforming of methane was also investigated. The best steam reforming results to date have shown 95% conversion of methane and specific energy use (for electricity for the plasmatron) of 14 MJ/kg H2 (an amount equal to about 10% of the higher heating value of hydrogen). It is projected that the power required for the plasmatron can be reduced by about half. With the National Renewable Energy Laboratory (NREL) and BOC Gases, MIT researchers are evaluating the potential of this technology for small-scale hydrogen production. Researchers at Idaho National Energy and Environment Laboratory (INEEL), USA and DCH are also working on plasma reforming (DOE Hydrogen R&D Program Annual Operating Plan, March 2000).

4. Micro-channel Reformer

Researchers at Pacific Northwest National Laboratory, USA have

developed a novel gasoline steam reformer with micro-channels. The aim of this work is to reduce the size of automotive reformers.

Over the past ten years, the rapidly growing interest in fuel cell and hydrogen technologies has led to a variety of efforts to develop low cost small-scale fuel processors and hydrogen production systems. The trend has been to develop more compact, simpler and, therefore, lower cost reformers. From the conventional long tube refinery-type steam methane reformer, fuel cell developers moved toward more compact heat exchange-type steam reformers (which are now commercialised as fuel cell components and for stand-alone hydrogen production). Plate type reformers are now undergoing development and testing for fuel cell applications and may be the next step in compactness and simpler design. In plate reformers, each plate has a double function (on one side, the reforming reaction take place, on the other, catalytic heating drives the reaction). POx systems and ATRs offer simpler first stages than steam reformers, but involve more complex purification systems. Advanced purification systems are being devised for these reformers. Sorbent enhanced reforming is another approach that combines several steps in one reactor, with the potential of capital cost reductions. An area of intense interest in the fuel cell and hydrogen R&D communities is development of membrane reactors for reforming. Membrane reactors offer further simplification, because the reforming, water gas shift and purification step take place in a single reactor. Very pure hydrogen is removed via hydrogen- selective permeable membranes. Membrane reactor systems are being tested at small scale.

In parallel with fuel cell developments, there has been a growing interest in innovative technologies for syngas production among large chemical and energy producing companies. For example, ion transport and oxygen transport membranes are under development for syngas applications. These are now being applied to hydrogen production as well. Application of membrane technology to syngas and hydrogen systems is an active area of research in the fuel cell R&D community and among large-scale producers of syngas such as oil companies. In addition, oil companies such as BP Amoco, U. K.; Shell, Houston, USA and Exxon/Mobil, Houston, Texas are involved in joint ventures to develop fuel processors and hydrogen infrastructure demonstrations, such as hydrogen refueling stations based on methane reformers. The oil companies are positioning themselves to become suppliers of hydrogen transportation fuel in the future.

3.1.3 National Status and Commercialisation Efforts by industry

The focus of RD&D in India has been on production of hydrogen from renewable sources of energy.

(a) Status of Hydrogen Production Technologies in India

The Indian Institute of Chemical Technology (IICT), Hyderabad designed and developed a methanol reformer to produce around 10,000 litres/hour hydrogen for coupling with 10 kW fuel cell. It was operated for 1000 hours and data was collected. Based on this data a scaled up methanol reformer to produce around 50,000 litres/hour hydrogen was designed and developed to demonstrate the technology by coupling with 50 kW fuel cell system. The reformed gas contained around 75% hydrogen with pre-mixed methanol and water. The product gas was further processed to lower down

CO2 and CO content to the extent less than 10 ppm, which is desirable for use in PEMFC system for power generation.

IICT, Hyderabad also developed three catalysts viz, Ni/SiO2 (NS), Ni/ Alumina Sol [Ni/Al2O3] Ni/ Alumina Plural (NAP) [Ni/Al2O3] for reformation of glycerol at 500-650ºC on bench scale for hydrogen production to generate data of reaction kinetics to scale-up reformer. Based on this data a skid mounted reactor was fabricated and installed at the institute. The life of these catalyst lasted for several hours.

The Centre for Energy Research, SPIC Science Foundation, Chennai (stopped R&D activities on hydrogen energy and fuel cells) designed, developed and demonstrated a PEM methanol electrolyser for the production of hydrogen at the rate of 1 Nm3/hour at an operating temp of 50-60oC. The energy consumption was around 2.02 kWh/Nm3hydrogen produced. The hydrogen gas obtained from this electrolyser contains considerable amount of methanol, which can be removed bypassing it through water scrubber and chiller. This hydrogen is almost free from CO2 and CO.

Central Institute of Mining and Fuel Research (CIMFR), Dhanbad developed an ovel process for the production of hydrogen from renewable and fossil fuel based liquid and gaseous hydrocarbons by non-thermal plasma reformation technique. A non-thermal plasma reactor of 0.5 litre capacity was developed for reformation of hydrocarbons to produce about 12 litres/minute hydrogen enriched gas mixture. Conversion of methane to hydrogen has been studied in a quartz reactor by non-thermal plasma. Experiments have been conducted for non-thermal plasma reformation of soybean oil, methanol and ethanol with both conventional cylindrical fuel reformer as well as vortex type reformer. Appreciable hydrogen production was also achieved with naphtha. Bio-diesel will also be tried for hydrogen production through this process.

The Indian Institute of Technology Hyderabad is working for the transformation of greenhouse gases like methane and CO2 into for

syngas/H2bylow temperature plasma catalysis. This will be achieved by optimizing conditions like reactor design, diluting gas, discharge gap, residence time of the gas, screening of various catalysts, etc. for a hybrid non- thermal plasma reactor. Heterogeneous catalysts will be searched / synthesized to arrive at a robust and cost-effective catalytic non-thermal plasma reactor for syngas production. Earlier IIT Hyderabad had worked on developing a process for dissociation of hydrogen sulphide into hydrogen and sulphur using non-thermal plasma process. b) Gap Analysis & Way Forward

There are already extensive industry and government programmes addressing particular technical issues for small-scale reformers, and for syngas production. We have not attempted to list research priorities for each type of reformer, or select a particular technical area for basic research. Instead, we suggest that the National/International agencies develop collaborative projects aimed at enhancing interactions between researchers engaged in small-scale hydrogen production (fuel cell and hydrogen researchers) and those engaged in large energy production (oil and chemical companies). The purpose of the proposed projects would be to examine the potential impact of recent technical progress for small- and large-scale hydrogen energy production.

One project could be to identify areas where ongoing research on large-scale syngas technologies could lead to development of small- scale hydrogen production systems for vehicles, and vice versa. To identify such areas, the MNRE could convene a group of industry and academic researchers from fuel cell, hydrogen and energy producing communities to discuss issues for small-scale reformers for hydrogen production. This group might have particular interest in technologies that could have applications in small- and large-scale hydrogen

production and could ultimately facilitate capture ofCO2 during hydrogen fuel production. Membrane technology would appear to be a good candidate for such an information exchange meeting, but other areas might be identified. If gaps in technical knowledge were identified, this could help focus future reformer development efforts.

3.2 Hydrogen Production through Biomass Gasification

3.2.1 Biomass is a renewable source of energy and can be considered as a distributed source for hydrogen production. However, out of all different routes of hydrogen production from biomass, gasification is likely to be the most economical and sustainable process. The basic steps for getting pure hydrogen out of biomass through gasification are similar to those for coal, methane and naphtha reforming based processes.

3.2.2 International Status

Research & development work in the area of production of hydrogen using biomass is being carried out at the international level by various organisations. However, till date no commercial technology is available to generate hydrogen from biomass. The reported hydrogen production is mainly through fluidized bed gasification or conversion of pyrolytic oil. The work done at various institutions/ organisations is summarised below:

The University of British Colombia, Canada, is working on fluidized bed gasification and sorbent based hydrogen separation unit. The National Renewable Energy Laboratory (NREL), U.S.A. has demonstrated production of hydrogen from pyrolysis oil by steam reforming. This pyrolysis oil was obtained from peanut shells in a fluidized bed by pyrolysis process. Some studies were done on pyrolysis and gasification of rubber, poplar wood, yellow pinewood and residual branches of oil palm tree as fuel in a thermally controlled environment and steam was passed at the desired flow rate over a fixed mass of biomass for gasification. The gasifier was operated in the temperature ranges of 600-10000C and 800 - 9000C. Maximum yield of hydrogen was obtained in the temperature range of 600-10000C. The hydrogen yield was about 20 g per kg of biomass through pyrolysis and 97 g per kg of biomass through steam gasification, with over 55% volume fraction of hydrogen in the syngas. The influence of temperature on various performance parameters was evaluated and analyzed. There were no significant changes in syngas and hydrogen yield at various gasification temperatures but the pyrolysis temperature had a considerable effect on the overall yield. The syngas yield increased from 353 g per kg of biomass to 828 g per kg of biomass by varying the pyrolysis temperature from 600 to 10000C with a reduction of over 50% in solid residue at the end of the process. The reaction rates enhanced significantly with increase in temperature, 35 g of substrate took 200 min for complete gasification at 6000C compared to 29 min at 10000C for constant flow of steam at 3.1 g/s. The extremely slow rate of the char-steam reaction is cited as the reason for the slow rate of gasification at low temperatures. High temperature and long residence time were identified

as important parameters that favor higher H2 yields. Over 30% higher energy yield was reported from gasification compared to pyrolysis due to significant contribution of the char-steam reaction.

Gas Technology Institute (GTI), Chicago, has been working on demonstration project for direct generation of hydrogen in a down draft gasifier using a membrane reactor. The Energy Research Centre of the Netherlands (ECN) has developed gasification technology, which has progressed to a pilot plant scale (800 kWth).Currently ECN, with other partners is planning to construct a 12 MWth synthetic natural gas (SNG) plant in Alkmaar, the Netherlands. The gasifier has been designed with a tar scrubbing unit. Methanation of the product gases is done after removing sulphur, chloride and CO2. The Technical University of Vienna has developed a fast internally circulating fluidized-bed technology for steam-blown gasification of biomass in cooperation with Austrian Energy and Environment. This technology is being employed in the Gothenburg Biomass Gasification (GoBiGas), project, which aims at constructing a SNG plant in Gothenburg, Sweden. At Gussing, Austria, an 8 MW combined heat and power plant is in operation since 2002. Later on, SNG production was demonstrated in a methanation unit, which took a 1 MW SNG slipstream from the Güssing plant. There has been no reported work on fixed bed gasification. The targeted cost of production of hydrogen was around US$ 2.6/kg.

3.2.3 Biomass Pyrolysis

Pyrolysis is the heating of biomass at a temperature of 600-10000C at 0.1–0.5 MPa in the absence of air to convert biomass into gaseous compounds, liquid oils, and solid charcoal. Pyrolysis can be further classified into slow and fast pyrolysis. As slow pyrolysis gives high char yield, it is generally not considered for hydrogen production. Fast pyrolysis is a process where biomass feedstock is heated rapidly (at 150-250oC/s) in the absence of air, to form vapour and subsequently condense it to a dark brown bio-liquid. The following products are obtained from the fast pyrolysis process:

(i) Gaseous products include H2, CH4, CO, CO2 and other Higher Hydro Carbons (HHC) depending on the organic nature of the biomass. (ii) Liquid products include tar and oils that remain in liquid form at room temperature like acetone, acetic acid, etc. (iii) Solid products are mainly composed of char and almost pure carbon plus other inert materials.

Although most pyrolysis processes are designed for biofuels production, hydrogen can be produced directly through fast or flash pyrolysis,

if high temperature and sufficient volatile phase residence time are allowed as follows:

Biomass +heat →H2+ CO +CH4 + HHC + C (char) - - (i)

CO, methane and other hydrocarbons are reformed catalytically in subsequent stages to get more hydrogen. Besides the gaseous products, the oily products can also be processed for hydrogen production. The pyrolysis oil can be separated into two fractions based on water solubility. The water- soluble fraction is used for hydrogen production while the water-insoluble fraction for adhesive formulation.

Studies have shown that when Ni-based catalyst is used, the maximum yield of hydrogen can reach 90%. Bio-oil needs to be steam reformed at 750- 850 0C in presence of nickel based catalyst followed by shift reaction. With additional steam reforming and water–gas shift reaction, the hydrogen yield can be increased significantly. Temperature, heating rate, residence time and type of catalyst used are important pyrolysis process control parameters. In favor of gaseous products especially in hydrogen production, high temperature, high heating rate and long volatile phase residence time are required.

3.2.4 Biomass Gasification

Biomass gasification is sub-stoichiometric combustion process, in which pyrolysis, oxidation and reduction take place. Pyrolysis products

(volatile matter) further reacts with char and are reduced to H2, CO, CO2, CH4 and HHC.

Biomass + heat + O2 → H2 +CO + CO2 + CH4 + HHC + char - (ii)

Unlike pyrolysis, gasification of solid biomass is carried out in the presence of oxidiser. Besides, gasification aims to produce gaseous products, while pyrolysis aims to produce bio-oils and charcoal. One of the major issues in biomass gasification is to deal with the tar formation that occurs during the process. The unwanted tar may cause the formation of tar aerosols through polymerization to a more complex structure, which are not favorable for hydrogen production through steam reforming. This tar formation may be minimized by: i) designing gasifier properly, ii) with controlled operation (in terms of temperature and residence time) of gasifier and iii) with additives/catalysts.

Tar may be thermally cracked at temperature above 10000C. The two- stage gasification and secondary air injection in the gasifier may also reduce tar formation.

The use of some additives (dolomite, olivine and char) inside the gasifier also helps in tar reduction. When dolomite is used, 100% elimination of tar can be achieved. Catalysts not only reduce the tar content, but also improve the gas product quality and conversion efficiency. Dolomite, Ni-based catalysts and alkaline metal oxides are widely used as gasification catalysts.

H2 content in biomass is only around 6.5% (by wt.). But using steam as the gasifying agent and air/O2 as the oxidizer, enhances the H2 output considerably. One of the major advantages of the gasification is that the process is carbon neutral and it has flexibility in using various types of biomass including agricultural and municipal solid waste.

3.2.5 Thermo-chemical Conversion of Biomass: As a process for hydrogen generation this route had never been a prime area of research, but major emphasis was towards standardizing the gasification system for power generation using reciprocating engines and for thermal applications. Biomass gasification has been identified as a possible process for producing renewable hydrogen. Most of the research has been stimulated by the techno- economics, based on gasifier performance data acquired during proof of concept testing.

In recent years, many researchers have explored the gasification of biomass for hydrogen production using different reactor configurations. In a fluidized bed reactor steam was introduced with oxygen and nitrogen under temperature controlled conditions. The reactor was externally heated to control the reactor temperature and the reactant flow rates were varied to determine the effect of the equivalence ratio and the steam to biomass ratio on the gas quality. H2 yield showed pronounced improvement with increasing reactor temperature. Increasing the temperature from 800 to 9500C (at SBR =

1.8 and ER = 0.18) doubled the yield of H2 from 28 to 61 g per kg of biomass. The effect of increased steam to biomass ratio (SBR) and equivalence ratio (ER) on the hydrogen yield suggests that increasing the SBR (at an ER = 0) from 1.1 to 4.7 increased the hydrogen yield from 46 to 83 g per kg of biomass, whereas reducing the ER from 0.37 to 0 (at SBR = 1.7) enhanced the H2 yield from 23 to 60 g per kg of biomass. The maximum H2 volume fraction in syngas is reported as 57% at SBR of 4.7 and ER of 0, while maintaining the bed temperature at 8000C The reported tar levels are in the range of 6 g per kg of dry fuel, amounting to about 2500 ppm of tar and can have serious implications on the downstream elements for hydrogen separation.

Oxygen-steam gasification has been reported using pinewood

(CH1.6O0.6) with 8% moisture as fuel in a fixed bed downdraft gasifier. The 1.3 m high and 35 cm diameter downdraft gasifier was preheated up to 9000C by igniting the feedstock and circulating the heat by a fan. Later, biomass was placed over a bed of charcoal and oxygen was injected from multiple points. Saturated steam at near ambient pressure was used. The oxy-steam gasification was performed with ER varying between 0.22 and 0.26 and SBR varying between 0.4 and 0.8 (molar basis). The maximum hydrogen yield reported is 49 g per kg of dry biomass at ER of 0.25 and SBR of 0.8.A high tar yield in the range of 3 to 20 g per kg of biomass was reported.

The effect of heating rate, temperature and SBR on H2 yield, tar reduction and char residue was also studied in a co-current flow using a 1.8 m long downdraft reactor of 20 mm diameter with legume straw and pine sawdust as feed-stock. Steam was injected at 3000C, keeping the reactor at the desired temperature using electrical heating coils. SBR (on mass basis) was varied from 0 to 1 while working in a temperature range of 700 - 8500C. Steam and biomass flow rates were simultaneously controlled for different SBR values keeping residence time constant. At 8000C, using legume straw as the substrate, H2 yield peaked at SBR (mass basis) 0.6 to 40.3% (volume fraction), reporting significant reduction in tar from 66.6 g/Nm3 at SBR of 0 to 23.1 g/Nm3 at SBR of 0.6. Reduction in char residue is reported with increase in SBR keeping temperature constant at 8000C, resulting in 5.5 % char residue at SBR of 0 and 2.8 % at SBR of 0.6. Increase in syngas and H2 yield with reduction in tar and char residue is reported with increase in temperature. Keeping the SBR (mass basis) constant at 0.6, temperature was varied and significant reduction in tar and char residue is reported. Tar content in syngas got reduced from 62.8 g/Nm3 at 7500C to 3.7 g/Nm3 at 8500C while char residue reduced from 7% to less than 2% in the same temperature range. Dalian University of Technology, China inferred that addition of steam favored tar and char reduction and subsequent increase in syngas and H2 yield due to tar steam reforming, cracking and char gasification enhanced by higher reaction rates at higher temperature.

Results from the previous work suggest the choice of gasification over pyrolysis for higher hydrogen yield and efficiency. The literature has indeed provided details on the various thermo-chemical conversion processes, behavior of different reactor configurations and influence of various process parameters like SBR, ER and temperature on hydrogen yield and overall performance. It must be emphasized that the thermochemical conversion of biomass to syngas, rich in hydrogen is one of the efficient processes. Steam gasification of biomass has been studied in a batch reactor under the controlled conditions but less exploited in a fixed bed reactor for continuous

hydrogen production. Further, the results from the literature indicate low hydrogen yield and issues arising from the gas contaminated with higher molecular weight compounds, i.e., the “tar”, inducing difficulty in separating hydrogen from the syngas mixture.

Depending upon the type of fuels used, there are different kinds of gasifier, differing in design. All these processes can be operated at ambient or increased pressure and serve the purpose of thermo-chemical conversion of solid biomass. Five major types of gasifiers are- fixed-bed updraft, fixed-bed downdraft, fixed-bed cross-draft, bubbling fluidized bed, and circulating fluidized bed gasifiers. This classification is based on the means of supporting the biomass in the reactor vessel, the direction of flow of both the biomass and oxidant, and the way heat is supplied to the reactor. Fixed bed gasifiers are typically simpler, less expensive, and produce a lower heat content producer gas. Fluidized bed gasifiers are complicated, expensive, and produce a gas with a higher heating value. Table 3.1 compares the advantages and limitations of different type of gasifier designs.

Table 3.1: Relative advantages and disadvantages of different types of gasifier

Gasifier Advantages Disadvantages Updraft  Mature for small-scale heat  Feed size limits fixed bed applications  High tar yields  Can handle high moisture  Scale limitations  No carbon in ash  Low heating value gas  Slag formation Downdraft  Small-scale applications  Feed size limits fixed bed  Low particulates and low tar  Scale limitations  Low heating value gas  Moisture-sensitive Bubbling  Large-scale applications  Medium tar yield fluid bed  Feed characteristics  Higher particle loading  Direct/indirect heating  Higher heating value gas Circulating  Large-scale applications  Medium tar yield fluid bed  Feed characteristics  Higher particle loading  Higher heating value gas Entrained  Can be scaled up  Large amount of carrier flow fluid  Low tar formation gas  Low methane content gas  Higher particle loading  Higher heating value gas particle size limits

The fixed bed gasifiers are broadly classified as updraft, downdraft and cross draft depending on the direction of air flow. Downdraft type of gasifier, in which the fuel and air move downwards, is widely used because it generates combustible gas with low tar content. The reactor design used until recently was the closed top, with the upper portion of the reactor acting as a storage bin for the fuel. The air is allowed to enter at the lower part, which generally contains charcoal. The developmental work at the Indian Institute of Science, Bangalore (IISc) on wood gasifier has resulted in a design with an open top with air entering both at the top and at the bottom through air nozzles. This feature has resulted in a design which can handle wood chips of higher moisture content up to 25%, and produce gas with low tar levels (< 30 ppm). The low tar level is due to the stratification of the of the fuel bed helping in maintaining a large bed volume at high temperature. In steady operation, the heat from the combustion zone near the air nozzles is transferred by radiation, conduction and convection upwards causing wood chips to pyrolyse and loose 70-80% of its weight. These pyrolysed gases burn with air to form CO2 0 and H2O raising the temperature to 1000-1100 C.The product gas from the combustion zone further undergoes the reduction reactions with char, to generate combustible products like CO, H2 and CH4.

3.2.6 Exergy and Energy Analysis

Apart from the demand and usefulness, energy efficiency is one of the most important criteria to assess the performance and sustainability of any technology. In the gasification process, the first law of thermodynamics permits conservation of the total energy in the conversion of solid fuel to gaseous fuel and the second law restricts the availability of energy (exergy) transformed to useful form. In the case of gasification process, evolution of gaseous species increases the entropy and introduces irreversibility in the overall thermo-chemical conversion process. During the conversion of solid fuel to gaseous fuel, apart from the process irreversibility, the transformation of chemical energy in the solid fuel partly to thermal energy as sensible heat cannot be converted to the desired output i.e., chemical enthalpy in the gaseous species. Evaluating the energy efficiency based on the energy output to the energy input and identifying the energy loss from the system to the environment is appropriate while considering the device. This approach may not be sufficient while evaluating the process and the device together as a system. Identifying the internal losses arising due to the irreversibility is important towards understanding any energy conversion process and probably helps in redesigning the system elements. Exergy analysis thus helps in evaluating the conversion process and provides an insight towards optimizing, by minimizing the losses, if any.

The exergy efficiency of a fast pyrolysis bio-oil production plant was analyzed using Aspen Plus software. Based on this analysis it was found that the exergy efficiency is 71.2% and the components for the exergy losses were also identified. The areas that had been identified for improvement were biomass drier, milling process for size reduction and heat exchanger used for pre-heating the combustion air.

In the area of biomass gasification, researchers have performed exergy analysis based on equilibrium analysis using Engineering Equation Solver

(EES) software. With the focus on H2 production, from a gasifier reactor of 0.08 m diameter and 0.5 m height using sawdust as the fuel, exergy and energy efficiencies were estimated. The heat loss from the reactor was modeled assuming isothermal condition. Tar, generally an issue for gasification process and its utilization, was considered as a useful product (fuel) and modeled as benzene molecule in the system. Effects of varying the SBR (steam to biomass ratio) from 0.2 to 0.6 were studied, by varying steam flow rate from 4.5 kg/s to 6.3 kg/s and biomass feed rate from 10 kg/s to 32 kg/s was considered. In the analysis, temperature was varied between 700 0 and 1200 C and its influence on the H2 yield, exergy and energy efficiency was also studied. The maximum exergy efficiency reported is about 65% with minimum near SBR of 0.4.It has been shown that maximum specific entropy generation is between 0.37 and 0.42.The lower value of the exergy efficiency has been argued due to the increase in internal irreversibility with the varying

SBR. H2 yield was saturated at around SBR of 0.7. It is evident that in the temperature range of 700-12000C, char-steam reaction plays a significant role and H2 yield increases significantly till carbon boundary point (at SBR of 1.5). Carbon boundary at SBR of 1.3 has been reported in another study. The equilibrium values at higher SBR’s are not used in the analysis performed using EES software.

Extensive analysis was carried out on the availability and irreversibility of the biomass gasification process. The exergy efficiencies of air and steam gasification with pyrolysis were compared. Equilibrium studies were employed using non-stoichiometric method based on minimizing the Gibbs free energy. Steam gasification proved to be a more efficient process compared to air gasification and pyrolysis. Steam gasification efficiency was reported as 87.2% compared to 80.5% for air gasification. In the case of pyrolysis, the efficiency was 76.8%. The physical, chemical exergy and sensible enthalpy of gas and their variation with SBR and ER were also analyzed. In the case of air gasification, carbon boundary was identified at ER of 0.25 beyond which no carbon is available for gasification. Beyond the carbon boundary point, the efficiency decreased and losses were credited to oxidation of fuel gas to CO2 and H2O leading to higher sensible heat and lower chemical energy in the product gas. Similarly, in the case of steam gasification, carbon boundary was

identified at SBR of 1.3 beyond which introducing extra steam led to loss in input energy used in steam generation. The coupling of exothermic oxidation of carbon with endothermic water-gas and Boudouard reaction was argued for the better efficiency of gasification over pyrolysis. The researchers have not been ableto clearly identify reasons towards higher efficiency achieved in the case of steam gasification over air gasification.

Thermodynamic analysis was conducted for oxygen enriched air gasification of pine wood. The oxygen fraction in gasifying media was increased from ambient condition (21% O2) to 40% O2 on the mole basis; the balance being N2. Increase in exergy and energy efficiencies with O2 fraction was observed. Exergy efficiency of 76% with 21% O2 increased to over 83% with 40% O2 while H2 and CO mole fractions in the product gas decreased from 22% to 11% and 19% to 14% respectively. Increase in reaction zone temperature with increase in O2 fraction was cited as the reason for higher efficiencies. Specific reasons towards the reduction of H2 and CO with increase in O2percent were not discussed. The higher efficiencies at higher O2fractions seems inconsistent based on the analysis of exergy and energy efficiencies with the variation in temperature.

It is evident from the literature on the exergy and energy analysis of gasification systems that largely equilibrium analysis based results have been used. The heterogeneous reaction system during gasification is very complex and it cannot be approximated with the thermodynamic equilibrium model. The gas composition, quality and hence the efficiency of a gasification system depends significantly on the residence time of the reacting species at the given temperature which inherently depends on the reactor geometry, design and process parameters. The heterogeneous reactions that occur inside the reactor are both diffusion and kinetic limited depending upon the reactants.

3.2.7 National Status (Including Commercialization Efforts by Industry)

The development of the technology (internationally), to harness this route has taken place in spurts. The most intensive efforts were put during the Second World War to meet the scarcity of petroleum sources for transport needs of the civilian and military sectors. Some of the most studies on wood gasifierswere basic as well as developmental related.

In India, during the initial developmental efforts, Department of Non- conventional Energy Sources (now MNRE) took an important decision to field test the technology developed by various research and industrial groups. This was carried out during 1997 to 2000. The major emphasis was on the water pumping application in the range of 5 to 50 HP. Around 1700 systems (35

MW equivalent) were installed in field under the MNRE’s demonstration program on biomass gasification.

There has been an activity for developing reliable industrial package for both power generation and thermal application in the later period of the year 2000. In the power generation sector, the emphasis shifted from dual fuel to pure gas engine mode; in order to compete with the grid costs as the fossil fuel prices increased. Gas engines could not accept producer gas as a fuel as it was not commercially available and some of the research groups carried out the R & D to operate engines on producer gas. While various groups developed skills to adapt natural gas engine to operate on producer gas, Indian Institute of Science, working with Cummins India Limited (CIL) succeeded in developing a package for producer gas engines. Currently, CIL would be the first Indian engine manufacturer to produce engines using producer gas as fuel.

Apart from several other factors, MNRE’s role both in research, development and implementation of the biomass gasification programme has been very critical. There are only 4 – 5 groups involved both in the development and implementation of the technology packages either directly or using licensees. There have been differences in the technology packages developed among these groups. M/s ASCENT, Sacramento, USA have developed packages for woody biomass, fine biomass and a combination of the two. A closed top gasification system has been used for conversion process. Rice husk gasification system is designed separately to handle rice husk as received. The Research Group at Tata Energy Research Institute has developed technology packages for woody and briquetted biomass using throat-less gasifier with closed top. The Sardar Patel Renewable Energy Research Institute, Vallabh Vidhyanagar, Gujarat has been involved in the development of technology packages for dual fuel and thermal application, using both forced and natural drafts depending upon the requirements. Indian Institute of Science, Bangalore has developed a multi-fuel gasification system to accept woody biomass or biomass briquettes. The largest capacity power plant connected to the grid using gas engines supplied by Cummins India

Limited has been built. Systems of varying capacity (up to 1 to 10 MWth) have been developed. While there have been large numbers of gasifier systems implemented by gasifier manufacturers, but very limited operational data is available in the public domain for analysis and reporting, consolidating the performance of the system/s and providing an account of operational experience.

The IISc, Bengaluru has developed an open-top downdraft gasifier, where residence time of gases increases inside the reactor and high temperature of the char bed is maintained, which improves conversion

efficiency and reduces formation of higher molecular weight compounds. Figure 3.1 provides an input on the use of dolomite as a bed material for fluid bed gasification system to reduce the tar levels. It can be seen that the tar level varies from 10 to 50g/m3 depending upon the bed material used in typical fluid bed gasification.

Figure 3.1 Average benzene and tar concentration in per kg of dry gas

Use of air gasification system for power generation has been established and options to biomass for various other outputs as indicated in the Figure 3.2 which suggests various biomass conversion process to end use energy efficiency.

It is evident that the biomass gasification based power cycle has the conversion efficiency in the range of 40 % while the hydrogen generation could be in the range of 60 %.

As stated earlier, very limited work has been carried out in the area of hydrogen generation from biomass. Most of the activities are at bench scale except some of the research carried on the existing steam gasification platform, where a small portion of the gas is being taken through the gas train for generating pure hydrogen. The overall yield of hydrogen is about 42 g/kg of biomass.

The National Institute of Technology, Calicut is engaged in the research activities of hydrogen production by thermo-chemical method in fluidized bed gasifier under catalytic support and its utilization. Under this activity a 7.5 kW capacity bubbling ptimizat fluidised bed biomass gasifier was

Figure 3.2: Biomass to fuel efficiency for various outputs from biomass conversion processes designed and developed for performance evaluation. The effect of process parameters on air gasification of rice husk and air-steam gasification of saw dust and coconut shell were studied. Stoichiometric thermodynamic equilibrium models for air and air-steam gasification of different biomasses were developed using MATLAB software validated with experimental data. The developed models were used to analyse the effect of various process parameters like gasification temperature, steam to biomass ratio and equivalence ratio on gas composition, lower heating value and yield of syngas and first and second law efficiencies. An Eulerian-Eulerian model for air- steam gasification of sawdust was also developed using Fluent13 software. The particle motion inside the reactor was optimized using various drag laws derived from Kinetic Theory of Granular Flow. In these models biomass pyrolysis was not considered.

3.2.8 Action Plan

3.2.8.1 Gap Analysis & Strategy to Bridge the Gap with Time Frame

In the recent times the focus at MNRE has been on generating hydrogen rich syngas through thermo-chemical conversion of biomass. Couple of research projects has been sponsored in this sector with the focus on hydrogen production. In view of the abundant availability of biomass in the country, work in this area needs to be consolidated and continued to fill in the

existing gaps in R&D and design and demonstrate pilot/full size units within a reasonable time frame.

As a part of the MNRE supported R&D activity, Indian Institute of Science, Bangalore has completed a project addressing the above aspects of hydrogen production through the thermo-chemical conversion of biomass. This has resulted in developing a prototype to generate hydrogen rich syngas using oxy-steam gasification.

The entire process has been optimized to generate a maximum of about 100 g hydrogen/kg biomass. The process has also been studied to look at possibility of generating the hydrogen rich syngas for FT process as well with H2:CO ratio of about 2.

Syngas composition, hydrogen yield and performance parameters were monitored with varying steam to biomass ratio and equivalence ratio. Experiments were conducted by varying SBR from 0.75-2.7 and ER ranging from 0.18-0.3. Figure 3.3 shows the gas analysis data of an operation of over 4 hours.

Figure 3.3 : Gas composition using oxygen and superheated steam (SBR = 1.45, ER = 0.25)

Experiments and kinetic studies in the complex heterogeneous reacting system have been conducted with wet wood and oxygen as well as with dry wood and oxy-steam. Table 3.2 summarizes the data from the experimental results using wet wood with oxygen and dry biomass with superheated steam. Results show that using dry biomass with oxy-steam

improves the H2 yield, efficiency and syngas LHV compared to direct usage of wet biomass with oxygen.

Table - 3.2 : Results, analysis and comparison while using dry biomass with superheated steam

Dry biomass with superheated steam

H2O to biomass ratio 0.75 1 1.4 1.5 1.8 2.5 2.7 ER 0.21 0.18 0.21 0.23 0.27 0.3 0.3

H2 yield (volume fraction, %) on dry 41.8 45.2 43.1 45.2 49.6 51.7 50.5 basis CO yield (volume fraction, %) on dry 27.6 24.9 26.5 24.9 17 12.8 13 basis -1 H2 yield (g kg of biomass) – 66 68 71 73 94 99 104 Experimental result -1 H2 yield (g kg of biomass) – Equilibrium 87 88 102 101 99 107 117 analysis result

Percent of H2 yield from moisture/steam (%) 21.4 20.2 28 27.7 43.7 44.3 48.1

(65.5 g H2 in biomass)

H2/CO 1.5 1.8 1.6 1.8 2.9 4.0 3.9 LHV (MJ Nm-3) 8.9 8.6 8.8 8.7 8 7.5 7.4 H O volume fraction in 2 0.8 1.4 1.6 2 1.9 2.3 2.4 syngas (%) Fraction of heat available through 4.2 2.7 2.2 1.9 1.3 0.8 0.8 CO+CH4 in syngas for steam generation Hydrogen efficiency (%) 73.7 63.2 67.2 63.5 70.5 61.0 63.7 – Gasification efficiency 82 73 75 74 78 67 66 (%) – Exergy efficiency (%) - 85 81 80 77 84 78 70

Using dry wood and oxy-steam as gasifying agents, 104 g hydrogen was obtained per kg biomass compared to a maximum of 63 g H2 per kg biomass with wet wood and oxygen. The gasification efficiency with oxy- steam gasification was found to be 85.8% compared to 61.5% with wet biomass at H2O to biomass ratio of 0.75. Hydrogen yield in syngas, as high

as, 1.3 kg/h was achieved. Syngas with LHV of as high as 8.9 MJ Nm-3 was obtained, which is almost twice the energy content in producer gas obtained through air gasification. At lower SBR of 0.75, the low hydrogen yield of 66 g per kg biomass was achieved with higher gasification efficiency of 85.8% -3 and higher LHV of 8.9 MJ Nm , and with an increase in SBR, H2 yield increased to 104 g per kg of biomass with lower efficiency of 71.5% and -3 LHV of 7.4 MJ Nm . H2 fraction in syngas and H2/CO ratio is a very critical parameter for the conversion of syngas to liquid fuel through FT synthesis. Varying the SBR from 0.75-2.7, hydrogen fraction in syngas has been obtained ranging from42-52% (molar basis) and H2/CO ratio is found to be varying from 1.5 to as high as 4. At lower SBR values, the energy content in

CO and CH4 yield is sufficient for raising steam.

With the current experience of using biomass, about 70 g pure hydrogen can be obtained per kg biomass, which results in about 15 kg biomass for every kg of hydrogen generated.

Having generated hydrogen rich syn-gas, it is important to utilize this gas for hydrogen production for applications like PEM fuel cells, SOFC, etc. This calls for purification of the syngas to various levels depending upon the end use.

3.2.8.2 Identification of the major institutions / industry for augmenting R&D facilities including setting-up of Centre(s) of Excellence and suggest specific support

Indian Institute of Science, which has been carrying out research activity in the area of bio-energy for over three decades, is well positioned to take the responsibility of Center for Excellence in the area of biomass to hydrogen through various routes. IISc is concentrating on thermo-chemical route of hydrogen production – Oxy–steam gasification of biomass, which has been demonstrated with hydrogen yield of about 100 gms per kg of biomass use. Apart from the various thermo-chemical routes that are being researched, IISc also has groups working in the area of engines, materials, storage, fuel cell, etc.

HYDROGEN PRODUCTION BY ELECTROLYSIS OF WATER

4.0 Hydrogen Production by Electrolysis

4.1 Introduction

Hydrogen can be generated from water by electrolysis or thermolysis. There are mainly three types of water electrolysis processes reported in literature. These are classified as: alkaline, acidic (membrane based) and high temperature ceramics (solid oxides) on the basis of electrolytes used. Of these three types, development of the last one is still at the laboratory level. A highly promising method of hydrogen production is electrolysis of water, using power from solar photovoltaic cells (Figure 4.1).

Figure 4.1: Hydrogen generation using solar photovoltaic cells

4.1.1 Polymer Electrolyte Membrane based Water Electrolysis

Polymer electrolyte membrane (PEM) based water electrolysis offers a number of advantages for the electrolytic production of hydrogen and oxygen in comparison with the conventional water-alkali electrolysers, such as ecological safety, high gas purity (more than 99.99% for hydrogen), the possibility of producing compressed gases for direct pressurized storage without additional power inputs and higher safety level. The membrane used in these electrolysers is Nafion-brand perfluorinated ion-exchange membrane of US Company DuPont (Figure 4.2). The PEM electrolysers based on solid polymer electrolyte (SPE) technology were developed in 1966 by the General Electric (USA) and designed for special purposes (spaceships, submarines,

etc.) as well as for industrial and analytical laboratory applications (in gas chromatography).

Figure 4.2: Schematic drawing of PEM cell

Membrane based water electrolysis can be classified on the basis of their electrolytes as alkaline (alkali / anion exchange membrane), or based on proton / cation exchange membrane. In water electrolysis using cation exchange membrane the oxygen and proton are generated at anode (Equation 1), the generated proton then passes through the cation exchange membrane and combines with electrons at the cathode to generate hydrogen (Equation 2). The membrane acts as an electrolyte as well as a barrier for preventing mixing of hydrogen and oxygen generated at cathode and anode compartments respectively.

+ − Anode (oxidation): 2 H2O(l) → O2(g) + 4 H (aq) + 4e --(1)

+ − Cathode (reduction): 2 H (aq) + 2e → H2(g) --(2)

The electrode reactions in case of alkaline electrolysis are different from those of acid electrolysis as shown in Equations 3 and 4. Here, cathodic reduction of water generates hydrogen and hydroxyl ion (Equation 3), which passes through an anion exchange membrane. At the anode hydroxyl ions are oxidized (Equation 4) generating oxygen.

- − Anode (oxidation): 4 OH (aq) → O2(g) + 2 H2O(l) + 4 e --(3)

− - Cathode (reduction): 4 H2O(l) + 4e → 2H2(g) + 4 OH (aq) --(4)

The hydrogen thus produced in the process needs to be utilized in a device that will convert it into electricity, e.g., fuel cells or it can also be utilized in internal combustion engine.

Specifications of State-of-the-Art Alkaline and PEM Electrolysers as reported in the NOW-study are given in Table 4.1.

Table 4.1: Specifications of State-of-the-Art Alkaline and PEM Electrolysers as reported in the NOW-study.

Specifications Alkaline electrolysis PEM electrolysis Cell temperature (0C) 60-80 50-80 Cell pressure (bar) <30 <30 Current density (mA/cm-2) 0.2-0.4 0.6-2.0 Cell voltage (V) 1.8-2.4 1.8-2.2 Power density (mW cm-2) <1 <4.4 Voltage efficiency HHV (%) 62-82 67-82 Specific energy consumption: 4.2-5.9 4.2-5.6 Stack (kW h Nm-3) Specific energy consumption: 4.5-7.0 4.5-7.5 System (kW h Nm-3) Lower partial load range (%) 20-40 0-10 Cell area (m2) >4 <0.03

H2 production rate: Stack- <760 <10 system (Nm3 h-1) Lifetime stack (h) <90000 <20000 Lifetime system (y) 20-30 10-20 Degradation rate (mV h-1) <3 <14

Advantages and Disadvantages of Alkaline and PEM Electrolysis are given in Table 4.2.

Table 4.2: Advantages and Disadvantages of Alkaline and PEM Electrolysis.

The PEM electrolysers offer smaller, cleaner and more reliable systems than competing electrolysis systems based on other technologies. Alkaline electrolysers are relatively less expensive but consume more electricity compared to PEM electrolysers wherein highly precious metals are being used in PEM cell stack.

4.2 Alkaline Water Electrolysis

Electrolysis phenomenon was discovered by Troostwijk and Diemann in 1789. Alkaline water electrolysis is one of the earliest methods employed for hydrogen production. Sodium hydroxide or potassium hydroxide are used

as electrolytes and the cell is normally operated at about 700C. The alkaline electrolyser cell consists of two nickel based electrodes separated by a gas- tight diaphragm. This assembly is immersed in a liquid electrolyte that is usually a highly concentrated aqueous solution of KOH (25–30 wt.%). It uses microporous diaphragm to separate cathode and anode chambers. The product gases are completely prevented from cross diffusing through diaphragm. This results in the reduction of efficiency of the electrolyser. The three major issues associated with alkaline electrolysers are i) low partial load range, ii) limited current density, and iii) low operating pressure. The energy required to produce 1 nM3 hydrogen /h is around 6 kWh. This is a matured technology with a large number of industries supplying these electrolyser units for a wide variety of applications. These electrolysers are less expensive as non-noble metal catalysts are normally used. Alkaline electrolysis has been used extensively for hydrogen production commercially up to the megawatt range.

4.2.1 Challenges

The major challenges with alkaline water electrolyser (AWE) are corrosion related issues and poisoning of the electrolytes by inadvertent incursion of CO2. The energy required to produce hydrogen is still high compared to the theoretical requirements. The other issue is developing high pressure systems. Present method involves a separate receiver and compressor sections in the electrolysis plant. This requires development of polymeric membranes with anion exchange capability.

4.2.2 Current Technology

 State of the Art Alkaline Electrolyser, Efficiency: 60-70% (LHV)  Operating temperature: up to 80oC  Operating pressure: 1 – 25 atm  Cost: ~$1000 - 2500/kW

4.2.3 Future Technology: Increasing the Capacity & Efficiency and Reduction in Cost

 System efficiency should reach 70-80% (LHV) by advanced electrolyser technology

 Industrial size electrolyser (MW level)  Cost should be reduced to $300 - 500/kW (Cost of Hydrogen at $2/kg)

4.3 Polymer Electrolyte Membrane (PEM) based Water Electrolysis

The drawbacks of alkaline electrolysers were overcome by the development of solid polymer electrolyte concept by General Electric, USA, in the 1960’s. The membranes used were sulfonated polystyrene membrane. This concept is also referred to as proton exchange membrane or polymer electrolyte membrane (both with the acronym PEM) water electrolysis, and less frequently as solid polymer electrolyte (SPE) water electrolysis. The polymeric membrane based water electrolysers till now have used cation exchange membrane. Water electrolysis with a polymer electrolyte membrane (PEM) cell possesses certain advantages compared with the classical alkaline process like increased energy efficiency and specific production capacity and simplicity in construction with a solid electrolyte operating at a low temperature. Direct application to water electrolysis was not possible at that time because available Solid polymer electrolytes (SPEs) were lacking sufficient chemical stability. This was mainly due to very oxidizing conditions found at the anode of water electrolyser where oxygen is evolved at high electrode potential values (close to +2 V vs. NHE). At the end of the sixties, more stable sulfonated tetrafluoroethylene based fluoropolymer-copolymers, (E.I. DuPont Co., Nafion®) products were made available for water electrolysis applications. This membrane exhibits high chemical stability both in strong oxidizing and reducing conditions up to 1250C.

Ultra-pure water is fed to the anode compartment of the electrolysis cell, which is made of porous titanium and activated by a mixed noble metal oxide catalyst. The membrane conducts hydrated protons from the anode to the cathode side. Appropriate swelling procedures have led to low ohmic resistances enabling high current density of the cells. The standard membrane material used in PEM water electrolysis units is Nafion® 117 and is manufactured by DuPont, USA. The cathode of such an electrolyser consists of a porous current collector with either Pt or, in more recent designs, a mixed oxide as electrocatalyst. Individual cells are stacked into bipolar modules with titanium based separator plates providing the manifolds for water feed and gas evacuation.

The polymer electrolyte membrane (Nafion, Fumasep) have high proton conductivity, low gas crossover, compact system design and high pressure operation. The low membrane thickness (~20-300 m thick) is in part the reason for many of the advantages of the solid polymer electrolyte.

PEM electrolysers can operate at much higher current densities, capable of achieving values above 2 A cm-2, this reduces the operational costs and potentially the overall cost of electrolysis (Tables 4.1 and 4.2). Ohmic losses limit maximum achievable current densities, with a thin

membrane capable of providing good proton conductivity (0.1 - 0.02 S cm-1), higher current densities can be achieved. The solid polymer membrane allows for a thinner electrolyte than the alkaline electrolysers.

The low gas crossover rate of the polymer electrolyte membrane results in yielding hydrogen with high purity, as described in Table 4.2 and allows for the PEM electrolyser to work under a wide range of power input. This is due to the fact that the proton transport across the membrane responds quickly to the power input, not delayed by inertia as in liquid electrolytes. As discussed above, in alkaline electrolysers operating at low load, the rate of hydrogen and oxygen production reduces while the hydrogen permeability through the diaphragm remains constant, yielding a larger concentration of hydrogen on the anode (oxygen) side thus creating a hazardous and less efficient conditions. In contrast with the alkaline electrolysis, PEM electrolysis covers practically the full nominal power density range (10-100%). PEM electrolysis could reach values over 100% of nominal rated power density, where the nominal rated power density is derived from a fixed current density and its corresponding cell voltage. This is due to low permeability of hydrogen through Nafion (less than 1.25 x 10-4 cm3s-1cm-2 for Nafion- 117, standard pressure, 800C, 2 mA cm-2).

4.3.1 Drawbacks

Problems related to higher operational pressures in PEM electrolysis are:

1. Cross-permeation phenomenon, which increases with pressure. 2. PEM membranes being highly acidic are corrosive and require use of distinct materials. These materials must not only resist the harsh corrosive low pH condition (pH ~ 2), but also sustain the high applied over-voltage (~2 V), especially at high current densities. 3. The catalysts used, current collectors and separator plates also need to be corrosion resistive. 4. Only a few materials can be selected in this harsh environment, such as noble catalysts (platinum group metals-PGM e.g. Pt, Ir and Ru), titanium based current collectors and separator plates (Figure 4.3).

Figure 4.3: Component overview for a typical PEM water electrolyser.

Numbers of publications as a percentage of total publications directly related to PEM water electrolysis over the years including the percentage published related specifically to modeling (source: ISI web of knowledge) are given in Figure 4.4.

Figure 4.4 : Number of publications as a percentage of total publications directly related to PEM water electrolysis over the years including the percentage published related specifically to modeling (source: ISI web of knowledge).

Performance range of published polarization performance curves from 2010 to 2012 for a PEM electrolysis single cell operating with Ir anode, Pt cathode, and Nafion membrane at 800C is given in Figure 4.5.

Figure 4.5 : Performance range of published polarization performance curves from 2010 to 2012 for a PEM electrolysis single cell operating with Ir anode, Pt cathode, and Nafion membrane at 80oC

4.4 Hydrogen Utilization

Fuel cells have emerged as an alternative source of energy/energy conversion devices in portable as well as stationary mode. A variety of fuel cells such as phosphoric acid fuel cell (PAFC), alkaline fuel cell (AFC), molten carbonate fuel cell (MCFC), solid oxide fuel cell (SOFC) etc. have been developed and a few of them are commercially available. Other than PAFC, all the commercially available fuel cells such as MCFC or SOFC operate at high temperatures and therefore their use remains limited to stationary power generation applications. Electrolyte leakage is a major drawback of the liquid electrolyte fuel cells. Proton Exchange Membrane(PEM) Fuel Cells otherwise known as solid polymer electrolyte fuel cells can operate at temperatures close to 80oC has large number of applications in civil, aviation and military areas both in portable and stationary power generation mode. Constant research and development activities across different laboratories of the world are in progress to prepare cost effective eco-friendly membranes to make affordable PEMFCs.

4.5 High Temperature Water Electrolyser (HTWE)

Using solid oxide fuel cells (SOFC) in the reverse mode is a recent trend in hydrogen generation. The HTWE has an advantage over alkaline and PEM electrolysers, because they can achieve a higher efficiency and lower capital costs over a wider range of current densities and cell voltage. The high temperature electrolysis splits steam at a temperature above 800oC. This process uses calcium and yttrium stabilised zirconium oxide (YSZ) membranes. Operation of the cell at high temperatures (900–1000°C) reduces the amount of electricity needed to produce hydrogen by about 30% as compared to electrolysis process at room temperature. Electricity consumed is about 2.6-3.5 kWh/Nm3 of hydrogen produced. Nuclear reactors operating in the same temperature range are ideally suited for this purpose.

4.6 International Status

International status of the published work available in open literature is summarized in Table 4.3.

The largest existing alkaline electrolysis plants are: KIMA fertilizer plant in Aswan, Egypt with a capacity of 160 MW and 132 modules, and a 7 module 22 MW plant in Peru (pressurized operation). Another highly modularised unit is the Brown Boveri electrolyser, which can produce hydrogen at a rate of about 4–300 m3/h.

Table 4.3: List of Companies Manufacturing Alkaline Electrolysers

Manufacturer Cell Type Rated Location production (Nm3/h) AccaGen alkaline (bipolar) 1-100 Switzerland Avalence alkaline (monopolar) 0.4-4.6 USA Claind alkaline (bipolar) 0.5-30 Italy ELT alkaline (bipolar) 3-330 Germany ELT alkaline (bipolar) 100-760 Germany Erredue. alkaline (bipolar) 0.6-21 Italy NEL Hydrogen alkaline (bipolar) 10-500 Norway Hydrogenics alkaline (bipolar) 10-60 Canada H2 Logic alkaline (bipolar) 0.66-42.62 Denmark Idroenergy alkaline (bipolar) 0.4-80 Italy Industrie Haute alkaline (bipolar) 110-760 Switzerland Technologie Linde alkaline (bipolar) 5-250 Germany PIEL, division of ILT alkaline (bipolar) 0.4-16 Italy Technology Sagim alkaline (monopolar) 1-5 France

Teledyne Energy alkaline (bipolar) 2.8-56 USA Systems Norsk Hydro ( 0.5 to1 alkaline (bipolar) Upto 485 Norway bar, 61-72 LHV efficiency) Stuat Energy ( 1 to 25 alkaline (bipolar) Upto 50 USA bar ; 73-75% LHV efficiency)

The PEM water electrolyser was developed before 1966 and introduced by General Electric Corporation, USA. In 1979 the cells operating at 1A.cm-2 800C at 1.8V was reported. Based on this technology high pressure electrolysis cells were designed and tested. All these efforts were basically for NASA, US Navy aircraft carriers and nuclear submarines for hydrogen generation and oxygen supply for life support systems. Several types of cell and system configurations were evaluated and an ultimate size of one cell unit was found to be 0.23 ft2. The Nafion-120 membranes with catalysts of platinum, platinum-iridium-tantalum etc. were used for the membrane- electrode assembly. The preparation of the membrane–electrode composites was very expensive. By the end of this project economic evaluation indicated a prohibitively high cost of such units. This system was suitable only for

specific applications, where cost is secondary and so the technology could not attain commercial status for large scale hydrogen generation.

Billings Energy Corporation, Provo, Utah, USA also described their version of PEM electrolyser having Nafion membrane coated with lead- dioxide anode and nickel cathode catalysts, the performance of which was very poor. The cell showed about 5.0V at 400mA/cm-2 at 500psig. On using platinum for both anode and cathode they could improve the performance to about 3.25V at 600 mA/cm2with an efficiency of efficiency of 45%. Because of the high loading of the noble-metal catalysts and the higher resistance of the membranes, the efficiency and economics were far from acceptable standard.

United Technologies Corporation, East Hartford, USA was reported to be engaged in the development of PEM electrolyser modules, probably with the GE concept, with 22 cells of 0.23ft2 each for US navy and space applications and also described a regenerative fuel cell unit of 1-2 kW capacity.

ABB Switzerland was also active in the PEM electrolyser development during 1976 to 1998. The ABB technology has been demonstrated in two commercial versions of 100kW capacity at Stellram SA, Nyon, Switzerland and Solar-Wasserstoff-Bayern GmbH. The general design features are: Nafion-117 with platinum cathode catalyst and graphite current collector and the anode was Ru-Ir mixed oxide with porous titanium anode current collector. At 1 A.cm-2 and 800C, the cells exhibited 1.75V. Both plants had to be stooped after three years of operation from 1987 due to the high level of hydrogen in oxygen (>3%) and the membrane was found to have been damaged in part of the cells. The cells were refurbished and operated till 1998. The cause of failure of the cells was found to be related to the assembling faults causing mechanical stresses and also due to the membrane degradation.

The Electrolysis 2000 project was initiated in France and different aspects of the system were investigated at various laboratories during the 90’s. Laboratory cells have been tested with typical voltage of 2.1V at 1 A.cm-2. The European Commission (EC) is actively supporting different projects within the 6th and 7th Framework Programmes. The main deliverable of the GenHyPEM project was on the development of a PEM water electrolyser with a hydrogen production capacity ranging from 0 up to 1 3 o Nm H2/hour, operating in the 0-90 C temperature range and the 1-50 bars pressure range and this project was carried out by the Institut de ChimieMole´culaire et des Mate´riaux, France in 2008. Apart from these developments, many research laboratories and academic institutions and universities are engaged in studies on both the fundamental and applied aspects of the PEM water electrolyser system.

The recent reports of the commercial availability of small and medium range PEM water electrolysers for laboratory utility and for other applications are from three major industries.

Proton Energy Systems, USA is currently offering 0.5, 1 and 10 m3 per hour hydrogen delivery systems, suitable for power generation through fuel cells. This may be the so called state-of the-art hydrogen generator with a number of advanced features for safe and efficient generation of hydrogen. The system delivers hydrogen at a high purity (99.999%) and pressure of 170 to 200 psi with an overall average energy requirement of 5.7 to 6.4 kWh/Nm3 3 H2 for the 1 Nm /hr H2 generators. M/s ITM power, UK is also offering PEM 3 based Water electrolyser system in the range of 11- 75 Nm H2/h capacity. Hamilton Sundstrand, a subsidiary of United Technology Corporation, East Hartford, USA has reported to be offering a system containing stacks upto 65 cells of 0.23 ft2 active area, operating up to 3 A.cm-2 that can deliver hydrogen up to 750 psig. This system is intended mainly for strategic applications.

The third report is from Fuji Electric Corporate Research and Development, Japan is about the development of 25 dm2 PEM water electrolyser under the WE-NET program. The electrolytic cells were fabricated with their own experimental membranes with low equivalent weight, low thickness & high ionic conductivity and reports a test cell performance of 1.555 to 1.58V at 1 A.cm-2 and 80oC. All the cell hardwares are based on the most improved structure and fabrication techniques.

Siemens, FRG plans to build an electrolyser system to store wind power as hydrogen. The system will have a peak rating of up to 6 MW. The project, which will cost 17 million, is being financed with the support of the German Federal Ministry of Economics and Technology as part of the Energy Storage Funding Initiative. The system involves highly dynamic PEM high- pressure electrolysis that is particularly suitable for high current density and can react within milliseconds to sharp increases in power generation from wind and solar sources.

Currently available PEM water electrolyser systems have a hydrogen production rate that varies from 0.06 to 75 Nm³/hr. This is very low in comparison to alkaline electrolyser production rates that have already reached 500 Nm³/h. With regard to the lifetime, the membrane represents the critical component of PEM system. Even though the lifetime of PEM electrolysis systems were significantly improved in the last 10 years, it is still limited due to the nature of solid polymer electrolyte membrane, and it is below 20,000 h. PEM electrolysers are less mature, produced in smaller quantities, and therefore more expensive than alkaline electrolysers. It is expected that the lifetime will be prolonged up to 60,000h in the long term

predictions. Even though there is no clear relation between operating conditions and degradation processes of the stack, in some cases operating conditions can lead to membrane perforation.

The concept of high-temperature electrolysis production of hydrogen from steam was investigated first in the 1980s by Dornier System GmbH, Friedrichshafen, Postfach, Germany in the project called ‘‘High Operating Temperature Electrolysis, HOT ELLY’’. After that Westinghouse Electric Co. and Japan Atomic Energy Research Institute (JAERI) made efforts to carry out HTWE experiment through tubular single cells and planar cells. Then the research and development efforts on HTWE became slow due to the cheap and sufficient supply of fossil energy. Now once again the HTWE technology for hydrogen production is becoming popular again, because of two major context changes the prospects of transition to a hydrogen-based economy due to the shortage of fossil energy and the prospects for the development of advanced primary energy to supply highly efficient heat sources. In 2004, researchers at the U.S. Department of Energy’s Idaho National Laboratory (INL) and Ceramates, Inc. of Salt Lake City, USA announced a breakthrough development in hydrogen production from nuclear energy. They have demonstrated a 15 kW integrated laboratory scale (ILS) facility with a hydrogen production rate of 0.9 Nm3/h.

They achieved the highest-known production rate of hydrogen by HTSE with an electrolysis efficiency of almost 100%. This development is viewed as a crucial first step toward large-scale production of hydrogen from water, rather than fossil fuels and a milestone in the hydrogen energy research field. Department of Energy (DOE) of the United States hoped that INL can commercially produce hydrogen production by HTSE before 2017 to reduce the dependence of fossil fuel. In Jan, 2005, the news of large-scale hydrogen production through HTSE by nuclear reactor was voted by 584 Chinese academicians and chosen as one of the ten biggest scientific news of the world in 2004, which indicated the deep concern about the hydrogen and nuclear energy development progress in China. Subsequently, GE Company, a joint effort of University of Nevada, Las Vegas and Argonne National Laboratory, European Union (the coordinator including European Institute for Energy Research, Swiss Federal Laboratories for Materials Testing and Research, Deutsches Zentrum fur Luft- und Raumfahrt and Rise National Laboratory, the University of Iceland and Icelandic New Energy, French CEA, Japan and Korea successively initiated HTWE research programs around 2005.

Institute of Nuclear and New Energy Technology (INET), China started R&D projects for nuclear hydrogen production in 2005. Thermo-chemical water splitting by an iodine-sulfur (IS) process and HTSE process using

SOEC are mainly concerned currently with the heat utilization system of nuclear reactor (HTR-10). In the last three years, HTWE research group experienced preliminary investigation, feasibility study, equipment development and hydrogen production technology.

Cylindrical design was favored for the prototypes model in the 1980s. Current investigations focus on planar designs. Planar type HTWE technology is being utilised, because it has the best potential for high efficiency due to minimised voltage and current losses. These losses also decrease with increasing temperature.

Perflurosulfonated membranes were synthesized from tetrafluoroethylene as the starting material. These membranes have a PTFE like back bone with side chains terminating with sulfonic acid groups. Besides Du Pont, Asahi Glass and Dow Chemical’s also developed similar membranes. However, the length of the side chains and the distance between the side chains were different (Table 4.4). The equivalent weight of these electrolyte membranes ranged from 800 to 1200g equivalent of protons in dry form. Thickness was in the range of 50 to 260 m. Apart from perfluorosulfonated membrane like Nafion there are several other electrolyte membranes made either from perfluorinated or non-fluorinated chemicals and are commercially available. Some of these electrolyte membranes are given in Table 4.5. The hydrophilic region having sulfonic acid groups forms clusters in the presence of water. The overlapping clusters form a transport channel responsible for the proton transport in the membrane. Since the proton transport takes place through the cluster region, the conductivity is highly sensitive to the water content of the membrane. The fluorinated polymers have shown the best of the performance in the fuel cells (>5000 hrs of operation). However, there is a need to develop alternate non fluorinated polymers. Besides high cost, the fluorinated membranes contribute to environmental burden during their preparation as well as disposal of the polymers. It is recently reported that fluorinated compounds such as hydrofluoric acid and other fluorinated fragments are released in the water during operation. There has been constant effort to develop alternate polymers by various researchers around the world and their method of preparation is tabulated in Table 4.6.

membranes manufactured by different manufacturedby companies. membranes

Table 4.4: Schematic structure of perfluorosulfonicacid Tablestructure Schematic 4.4:

Table 4.5: Commercially Available SPETableMaterials 4.5: Commercially

Table 4.6: Different Membranes and their Detailed Description.

Sl.No. Membrane Description

Perfluorinated Membranes/Partially Fluorinated Polymers 1 Gore-Select Membrane Composite membrane; a base material preferably made of expanded PTFE that supports perﬂuorinated sulfonic acid resin, PVA etc. 2 BAM3G (Ballard Inc) Polymerization of ,,- triﬂuorostyrene and subsequent sulfonation

Grafted Polymers 3 ,, - Trifluorostyrene Grafting of ,,-trifluorostyrene and grafted membrane PTFE/ethylene copolymers 4 Styrene grafted and Pre-irradiation grafting of styrene onto sulfonated poly(vinylidene a matrix of PVDF after elec-tron beam fluoride) membranes [PVDF- irradiation. The proton conductivity g-PSSA] can be increased by crosslinking with DVB

Non-fluorinated 5 -methyl styrene blend Partially sulfonated -methyl styrene PVDF composite with PVDF 6 Sulfonated poly(ether Direct sulfonation of PEEK in conc. etherketone) (SPEEK) sulfuric acid medium 7 Sulfonated poly(ether Partially sulfonated polysulfones sulfone) 8 Sulfophenylatedpolysulfone Sulfophenylation of polysulfone 9 Methylbenzenesulfonated These alkylsulfonated aromatic PBI/methylbenzenesulfonate polymer electrolyte posses very good poly(p- phenyleneterephthal thermal stability and proton amide) membranes conductivity when compared to PFSA membranes, even above 80 ◦C 10 Sulfonated napthalenic Based on sulfonated aromatic polyimide membrane diamines and dihydrides. Its performance is similar to PFSA 11 Sulfonated poly(4- Derived from poly(p-phenylene) and phenoxybenzoyl-1,4- structurally similar to PEEK. Direct phenylene) (SPPBP) sulfonation to produce the electrolyte.

12 Poly(2-acrylamido-2- Made from polymerization of AMPS methylpropanesulfonic acid) monomer. AMPS monomer is made from acrylonitrile, isobutylene and sulfuric acid

Acid Base Blends 13 Imidazole doped sulfonated Complexation with imidazoles to polyetherketone (SPEK) obtain high proton conductivities 14 Sulfonated poly(ether Sulfonated poly(ether etherketone) etherketone) (SPEEK)-PEI (SPEEK)-Poly ethylene imine (PEI) blended 15 Sulfonated poly(ether Composite membranes based on etherketone) (SPEEK)-PBI highly sulfonated PEEK and PBI blend

16 PBI-H3PO4 PBI doped with phosphoric acid

4.7 National Status

R&D on alkaline electrolysers in India dates back to early eighties. BARC and CECRI were very active in developing materials for this type of electrolysers as well as stacks. Compact alkaline electrolysers have been designed and demonstrated in Chemical Engineering Group (ChEG), BARC in the late eighties. BARC has developed water electrolysers with high current density based on indigenously developed advanced electrolytic modules incorporating porous nickel electrodes. A 40-cell electrolysis module incorporating Porous Nickel Electrode operates at a high current density of 4500 A/m2 which is much higher than conventional cells in the market (1500 A/m2 or below). The electrolyser operates at 550C and 0.16 MPa to produce 10 Nm3/h of hydrogen. They have also now developed alkaline water electrolyser of 30 Nm3/hr capacity and this technology is available for production.

In 1990’s CSIR-CECRI had reported a new Lanthanum Barium Manganate based oxygen evolution catalyst and Nickel-Molybdenum-Iron based composite based cathode materials for alkaline water electrolysis. They also developed a monopolar unit alkaline water electrolytic cell and demonstrated the performance of 1.8 V at 300 mA.cm-2 in 6 M KOH at 303 K. In 2008, CSIR-CECRI transferred process know-how for development activated nickel electrode for alkaline water electrolysis to M/s Eastern electrolyser, Noida.

Energy Research and Development Association (ERDA), Vadadora has demonstrated the concept of wind hydrogen using commercial alkaline water electrolyser (AWE) for practical distribution generation system in 2013.

This project was financially supported by MNRE. The integrated system consisted of wind turbine (2X5kw), alkaline water electrolyser (1.1Nm3/hr), hydrogen storage tank (1Nm3, at 5kg/cm2), battery bank (6x 200Ah at 12 V) and IC engine (650VA) and it was installed at Savli (about 30 km away from Vadodara, Gujarat). The battery was used to provide consistent electrical power output and avoid short term intermittent fluctuations. Hydrogen fuelled IC engine was operated when wind along with battery is not able to meet the load demand.

The National Institute of Solar Energy, Gwalpahari, Gurgaon has installed a 120 kW solar photovoltaic systems to produce electricity for generation of hydrogen through the water electrolyser and is geared up to demonstrate and evaluate the performance of various technologies of hydrogen energy. The hydrogen, so generated will be stored in high pressure cylinders. As and when required, it would be utilized for stationary power generation through fuel cell and dispensed through the dispenser unit into hydrogen fuelled vehicles (3-wheelers & 4-wheelers), meant for demonstration.

The following companies are reported to be engaged in manufacturing AWE for various industrial applications:

Company Production capacity M/s. Sam Gas Projects Pvt. Ltd., Ghaziabad - 201 015, Uttar Pradesh 1 to 50 Nm3 / h M/s. Rak Din Engineers, New Delhi 0.072Nm3/h M/s. Vaayu Tech Engineering, Ghaziabad, Uttar Pradesh 50 Nm3/h M/s. S. S. Gas Lab Asia, Delhi - 110 095 10Nm3/h M/s. Vemag Engineers Private Limited, Baroda, Gujarat 1-50 Nm3/h M/s. Eastern Electrolyser limited, Noida, Uttar Pradesh 201301 --

The CSIR-CECRI developed a PEM based hydrogen production (capacity 40 and 80 litres/h) water electrolyser system under a MNRE funded project during 2003-2006. Subsequently they have developed 1.0 and 5.0 Nm3/hr capacity PEM water electrolyser under 11th Five year plan CSIR Network Project during 2012 and demonstrated the same with the energy consumption of 5.75 kWh/Nm3 of hydrogen. The electrolyser was designed using circular type platinum coated titanium flow field plate, platinum black cathode and iridium oxide anode. The developed electrolyser stack can deliver the hydrogen at 5-10 bar pressure. Recently this technology has been

transferred to M/s. Eastern electrolyser, New Delhi and this company has started to work with CSIR-CECRI for further development. In addition, CSIR- CECRI has also demonstrated solar power integrated PEM based water electrolyser system of 0.5 Nm3/h capacity in 2012.

SPIC Science Foundation ( SSF) was also engaged in development of PEM based water electrolyser for hydrogen generation and developed electrolyser stacks of capacity 500 lit/hour (0.5 Nm3/hour) Hydrogen and 1000 lit/hour (1 Nm3/hour) Hydrogen, under DST-TIFAC funded project . They used platinised Titanium plate as bipolar plate. The proto-type 0.5 Nm3/h capacity hydrogen generator was demonstrated at the Indian Meteorological Department (IMD), Thiruvananthapuram in Feb’ 2006, to utilise the hydrogen for lifting the weather balloons used to collect atmospheric data.

Centre for environment, Institute of Science and technology, JNTUH, Hyderabad has also developed indigenous PEM based water electrolyser of 36 lit/h Hydrogen Production capacity using Nafion 115 under BRNS funded project in 2010.

Hydrogen generation using PEMWE concepts using depolarisers have also been reported from some Indian labs. This types of work has also been reported from some labs in USA. For the first time, SSF developed and demonstrated PEM based water electrolyser system, which used methanol as a depolariser. In this method, pure hydrogen can be generated with a much lower energy consumption compared to water electrolysis. Electrolyser stack was developed using titanium flow field plate, carbon supported Pt-Ru and Carbon supported Platinum catalyst for anode and cathode respectively. This was demonstrated with the hydrogen production capacity of 60.0 lit/h under MNRE funded project during 2006. The energy consumption for hydrogen production was 2.0 kWh/Nm3.

In 2012, The Centre of Fuel Cell Technology, Chennai (a project of International Advanced Research Centre for Powder Metallurgy, Hyderabad) demonstrated of 1.0 Nm3/h hydrogen production capacity electrolyser using similar concept but with much lower energy consumption of 1.40 kWh/Nm3. It also demonstrated for the first time use of carbon based materials in its construction and thus redcuing the capaital cost tredomnously. ARCI-CFCT is carrying out a large amount of work in identifying suitable depolarisers, which can redcue the cost of hydrogen .

Sea water electrolsyis to produce hydrogen is being pursued at CSIR- CECRI and the Centre of Fuel Cell Technology, Chennai. Novel electrocatalayts have been developed . However the energy cost remains still high .

M/s. MVS engineering Ltd , New Delhi offer turnkey supply for PEM technology in partnership with proton onsite (USA) for customers looking for non-alkaline solution for hydrogen generation by water electrolysis.

Indian Oil’s R&D Centre recently commissioned India’s first Hydrogen fuel dispensing station at its R&D Centre at Faridabad. The pilot station provides a hands-on experience with on-site Hydrogen production, storage, distribution and supply. The hydrogen is being produced by water electrolysis method using imported PEM electrolyser system.

In general, the production of hydrogen through electrolysis of water is a highly energy intensive method (4.5-6.5 kWh/Nm3). Because of its high energy consumption and also of the quite substantial investment, water electrolysis technology is not widely used in India for commercial purposes. The challenges for widespread use of water electrolysis are also the durability.

BARC has a roadmap for development of solid oxide fuel cell and development of materials and methods are underway for SOFC power packs. They have a plan to utilise this development for the development of High temperature steam electrolyser of 1.0 Nm3/h hydrogen production capacity for technology demonstration purposes. Development of proton conducting high temperature materials is another major R&D thrust. Besides BARC, CGCRI, IIT-D has initiated some work in this area recently.

4.8 Gap Analysis & Strategy to Bridge the Gap

 Identification of projects and prioritize them for support with the result oriented targets.  Identification of the major institutions / industry for augmenting R&D facilities including setting-up of centre(S) of excellence and suggest specific support.  Partnership with foreign institutions including technology adaption from abroad.  Identification of the institutions for setting up of demonstration plants.  Identification of institutions / industry to work on PPP model for commercialization of the developed processes.  Identification of technologies for adoption in specific applications with time line.

The electrolyser system consists of various subsystems like electrochemical stack, power rectifiers, control systems, instrumentation for monitoring various processes, water purification, pumps, multistage compressors, pressure vessels, and multiple number of other engineering

subsystems involved while integration as per customer requirements to develop complete system. Except for the electrochemical stack, couple of PSU’s in India has core strength for manufacturing majority of aforementioned subsystems and very much capable in system engineering. Imported electrolyser stacks in different combinations may be used and integration can be carried in the country.

4.9 Action Plan

Development of alternate solid polymer electrolytes that are stable in the electrolysis cells more than 5000 hours of operation would be of desirable. The SPE is either acid or alkaline based, the acid based electrolysis system requires noble metal catalysts, and alkaline membrane based electrolysis require cheaper electro-catalyst like nickel. It is ideal to have alkaline membranes based water electrolysis system that works on the solar energy derived from solar cells. However, presently alkaline based SPE faces numerous challenges such as chemical stability in the electrochemical device. These challenges are lesser for either phosphoric acid based electrolysis cells or alkali based electrolysis systems using diaphragm. Due to this the following path is suggested with an idea of immediate goals of onsite hydrogen production using presently available technology and replacement of the traditional technology with the membrane based electrolyser in a phase wise manner. Following steps are envisaged. (i) Solar energy based (a) Acid based electrolysis system (b) Alkali based electrolysis system (ii) Development of electrolysers based on indigenous acid based SPE (iii) Development of alternate alkaline membrane (iv) Development of alkaline SPE based electrolyte system (v) Replacement of traditional systems as in 1 by the new membrane based system

4.10 Possible Incentives to Promote Industry Participation

Industry participation is the most essential factor for the successful implementation as well as utilisation of the hydrogen produced using the electrolysis method. Currently industry uses other methods for the production of hydrogen; such industries can earn carbon credits by use of electrolysis based hydrogen production.

(i) To begin with government can set up few demonstration plants in an industrial area to augment the hydrogen produced by these industries for their own production.

(ii) A comparative study of this method with the age old methods can carried out and an educative program can be undertaken to show the techno-economic feasibility of the electrolysis method. (iii) Subsidy may be provided or the industry may earn carbon credits for putting up such plants.

4.11 Summary & Conclusions

Solid polymer electrolyte (SPE) based electrolysis process is a clean process of hydrogen production when coupled with photovoltaic based solar cells. Development of solid polymer electrolytes both acid and alkali based would be the key for successful development of these systems. Alkali based electrolytes are preferred over the acid based ones due to the use of non- noble catalysts, however alkali based SPE faces challenges such as chemical stability in the electrochemical system. The acid SPE based electrolyser may be deployed on a small scale in a distributed hydrogen production systems both in industry as well as for remote areas. It is suggested to setup hydrogen production plants based on presently available electrolysers which can be manufactured in India and then replace these conventional electrolyser with the SPE based electrolysers in a phase wise manner. This will ensure the successful deployment of technology in time to come.

4.12 Cost Estimate of Hydrogen Generation

Hydrogen Generation on a 1 MW system Assumptions Utilization factor 75% Plug Cost of Electricity ($/kW) $ 0.12 Plug Efficiency % 77% Calculated Efficiency kWh/kg 51.0 Plug CapEx 10 year program kg / Day Cost kg of H2 $ / kg 1 MW System 450 $ 1,975,000 1,231,875 1.603247

Opex Cost Total Cost $ / kg Maintenance per year $ 35,000 $ 350,000 0.28412 Spare Parts over proyect $ 60,000 $ 600,000 0.487062 Electrical Cost $ 753,908 $ 7,539,075 $ 6.12 Water Cost $ 54,750 $ 547,500 $ 0.44

Total Cost of per kg of H2 produced $ 8.94

BIO-HYDROGEN AND BIO-METHANE PRODUCTION

5.0 Bio-Hydrogen and Bio-Methane Production

5.1 Biological Hydrogen production process has gained importance in recent years. In early 1990s biological hydrogen production came in lime light in energy policy of many government institutions throughout the world.

Biological H2 production takes place mainly at ambient temperature and atmospheric pressure which makes this process less energy intensive than other conventional processes (chemical or electrochemical process).

Microbial species capable of producing H2 belong to different taxonomic and physiological types. Pivotal enzyme complex involved in H2 production are hydrogenase or nitrogenase. These enzymes regulate the hydrogen production process in prokaryotes and some eukaryotic organisms including green algae. The excess electrons generated during catabolism inside the cells are disposed in the form of H2 by the action of hydrogenase protein.

The biohydrogen production process can be classified into two broad group viz. light dependent and light independent process. Light mediated processes include direct or indirect biophotolysis performed by algal species and photo-fermentation performed by purple non-sulphur bacteria. Dark fermentation is performed by heterotrophic organotrophic microbes. The algae use their photo-synthetic apparatus and solar energy to convert water into chemical energy. In this process, oxygen is produced as by-product. This oxygen acts as inhibitor of enzyme system responsible for hydrogen production.

The coupling of two separate stages of micro-algal metabolism i.e photosynthesis and fermentation for hydrogen production is termed as indirect

‘bio-photolysis'. The fixation of CO2 into storage carbohydrates (e.g. starch in green algae, glycogen in cyanobacteria) is coupled with fermentation of these stored energy reserve for H2 production under anaerobic conditions. This process is not marred with the problem of oxygen accumulation. Thus it is considered more efficient than direct photolysis of water. To compete with alternatives sources of renewable H2 production process, such as photovoltaic electrolysis, the bio-photolysis processes must achieve close to an overall 10% solar energy conversion efficiency. To achieve high solar conversion efficiencies, certain biotechnological steps are required. One of such steps could be reduction of number of light harvesting pigments or use of metabolically engineered cell that are more efficient in fermentation of stored carbohydrates to H2.Improvement of bioprocess parameters could lead to the solution of scaled up operation of photo bioreactor for hydrogen production.

Among all the biological H2 production processes, dark fermentation shows highest H2 production rates. This process holds promise for commercialization. If evolution of microbes is considered, as the availability of

organic matter on earth varied, the fermentative microbes capable of H2 production i.e. fermentative bacteria evolved with the appearance of organic material on earth. These microbes adapted themselves to different growth conditions (mesophilic temperatures, thermophilic temperatures, etc.) and complexity of the substrate. They are heterotrophic in nature and produce H2 under anaerobic conditions. The metabolism of these microbes involves utilization of simple sugars and production of electron donors in terms of NADH. The substrate-level phosphorylation is the only way of ATP production under anaerobic conditions. The NADH thus produced is used by Fe-Fe

H2ase enzyme complex to produce molecular hydrogen in obligate anaerobes. In case of facultative anaerobes, the format lyase enzyme breaks format to molecular hydrogen and carbon dioxide. Format lyase is also known as Ni-Fe hydrogenase whose turnover number is lower than Fe-Fe H2ase. Thus obligate anaerobes are reported as highest H2 producing organisms. Theoretical maximum yield for hydrogen production is 4 moles / mole of glucose. Fermentative microbes growing at thermophilic temperatures are reported to produce hydrogen at high rate. There are many advantages of thermophilic bioH2 production viz. at thermophilic temperature the thermodynamics of H2 production is more favorable. Moreover, temperatures greater than 600C lead to pathogen destruction and reduce the chances of unwanted contaminations. Very few end-metabolites are produced under thermophilic regime. These end-metabolites are generally composed of ethanol, acetate, butyrate, propionate, etc. The presence of these molecules in the spent media leads to extra burden of waste disposal.

The photoheterotrophic process converts the volatile fatty acid rich spent media of dark fermentation to hydrogen. Photo-fermentative bacteria such as Rhodopseudomonas, Rhodobactersp, Rhodospirullum sp., etc. are the major photo-fermentative bacteria. Light intensity, light wavelength and illumination protocol are the major factors that drive the photo-fermentation.

Theoretically, H2 production from 1 mole of acetate, propionate and butyrate are 4, 7 and 10 moles, respectively. Thus integration of photo-fermentation with dark fermentation was considered for the maximization of gaseous energy recovery (Figure 5.1). But there were many operational challenges of using photo-fermentative bacteria. One of the major problems faced was the light shading effect generated by accumulation of pigment in the photo- fermentative microbes. Moreover, the rate of H2 production was also considerably low when compared with dark fermentation. Photo-bioreactor design and scale up challenges have hampered the implementation of integration of photo-fermentation with dark fermentation. Poor light conversion efficiency of these organisms and requirement of external light source made this process energy intensive.

Another two-stage process where bioH2 production process was integrated with bio-methanation was also considered as a feasible option of improvement of gaseous energy recovery. Since bio-methanation process is a well-established process, the implementation of such integrated process holds a lot of promise. Scaling up of biomethantion process is relatively easy and less costly. Thus the mixture of bio-hydrogen and bio-methane can be collectively called under the eponym of “HyMet”.

Figure 5.1 Gaseous Energy Recovery in Two-stage Integrated Process.

5.2 International status: First review on bio-hydrogen production was published in Nature Biotechnology as “Bio-hydrogen production deserves serious funding”. Subsequently, impetus on bio-hydrogen gained momentum in early 21st century. Major contributors in bio-hydrogen production research were from United States of America, Canada, Malaysia, Indonesia, Thailand, China and India. National Renewable Energy Laboratory (NREL), Oak Ridge USA, funded initial bio-hydrogen studies in USA. Enzymatic bio-hydrogen production and bio-hydrogen from waste paper was the major initiative taken by NREL. Different microbes were discovered in different parts of the world, each having unique hydrogen production ability. Potential of E. coli in bio- hydrogen production and its metabolic engineering was explored by

Hellenbeck in the year 2006. Many mesophilic species were explored for hydrogen production. Enterobacteraerogenes was one of the commonly studied facultative anaerobes. Obligate hydrogen producing microbes were popular species due to their higher H2 yields. Thermophilic bio-hydrogen research gained importance by 2004. ThermophilicClostridium thermolacticum was reported for the first time for bio-hydrogen production. Pusan National University, Pusan, South Korea studied Thermophilic H2 production from glucose at 55-64oC using a continuous trickling biofilter reactor (TBR) packed with a fibrous support matrix. The biogas composition was around 53 % of H2 and 47 +/- 4% of CO2 by volume. The thermophilic TBR is superior to most suspended or immobilized reactor systems reported thus far. This is the first report on continuous H2 production by a thermophilic TBR system. As time passed on, need of renewable feedstock for bio-hydrogen production was realized, as for bio-hydrogen to be considered as renewable energy source, it should be produced from renewable raw materials only. The concept of waste management coupled with energy generation was popularized. In 2003, Logan et al. first reported the possibility of wastewater management along with hydrogen production. Major surge in bio-hydrogen research was in the year 2004. Dark fermentative H2 production using packed bed reactor was first explored by Logan et al.in 2004. Up till now significant research has been done on bioH2 production. Many studies were done in pilot scale units. Internationally very few studies are available for commercial H2 production. Integration of bio-hydrogen with fuel cell was first mooted by Marta S. Basualdo in 2012.This concept still needs a serious consideration since this technology can produce H2 in decentralized manner for low and medium level electricity needs.

5.3 National Status

In India, first dedicated pilot-scale bio-hydrogen production unit using distillery effluent was reported by Shri AMM Murugappa Chettiar Research Centre (MCRC) using defined bacterial co-culture. MCRC has developed a biological process for generation of hydrogen from sugar and distillery wastes using the effluents at M/s. E.I.D. Parry Ltd., at Nellikuppam, Tamilnadu. MCRC has been working on scaling this technology using a 125 m3 bioreactor which has produced 18,000 liters of total gas per hour with about 60% hydrogen mixed largely with CO2 and CO. Indian Institute of Technology Kharagpur was one of the leading institutions involved in bio-hydrogen research for more than a decade. IIT Kharagpur demonstrated high rate of hydrogen production in packed bed reactor configuration in a pilot scale unit. Its main emphasis was on utilization of organic wastes for energy generation. Under the leadership of IIT Kharagpur an attempt for commercialization of bio- hydrogen production was envisioned through the mission mode project “Biohydogen through Biological Routes” sponsored by MNRE. IIT Kharagpur

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is also involved in development of novel and cheap media composition which would make the product cost effective. It is mainly focused on the identification of cheap nitrogen sources that can replace the need of yeast extract and tryptone in the fermentation media. Moreover, it is also involved in waste to energy concept. Use of distillery effluent, starchy wastewater and lingocellulosic biomass as substrates are receiving more attention. Other collaborators in this group include institutions with varied experiences in bio- hydrogen production. Indian Institute of Chemical Technology, Hyderabad has developed rapid screening methodology for selecting organic waste for bio- hydrogen production. Jawaharlal Nehru Technological Institute, Hyderabad has developed mixed consortia from mangroves sludge and hot spring for hydrogen production. The Tata Energy Research Institute (TERI), New Delhi has a well-established large scale bioreactor facility for bio-hydrogen production. It is involved in thermophilic H2 production process. Banaras Hindu University and Allahabad University were chosen for photo- fermentation studies.

Under a Mission Mode Project on Biological Hydrogen Production sanctioned by MNRE in 2009, two 10 m3 capacity reactors are under installation at IIT Kharagpur and IICT Hyderabad using distillery effluent and kitchen waste respectively. These bio-reactors are expected to produce 30- 50 m3 of hydrogen per day. In addition, technical document for setting up an industrial level reactor will also be developed under this project. In collaboration with IIT Kharagpur, Naval Material Research Laboratory (NMRL), Mumbai has been planning to integrate bio-hydrogen with chemical fuel cells for electricity generation. Other institutions/universities such as Anna University, Institute of Genomics and Integrative Biology India, New Delhi, etc are also actively involved in bio-hydrogen production.

The National Institute of Technology, Raipur recently started working on the development of Microbial Electrolytic Cellfor economic and energy efficient bio-hydrogen production from leafy biomass by electro-hydro- genesis.

Indian Association for the Cultivation of Science, Kolkata is working on the development of a bio inspired catalyst that would efficiently catalyse hydrogen evolution and give better understanding about the mechanism of the hydrogen evolution reaction (HER) by the [Fe-Fe]- Hydrogenase enzymes which will in turn be helpful in the development of better HER catalyst in terms of performance and turnovers. Novel hydrogenase model complexes (catalysts) have been synthesized with a clickable alkyne group. For robust and successful immobilization of the catalyst onto the electrode surface, the graphene oxide is modified with aza-amine with azide group to get aza terminated ITO supported graphene as electrode material and the alkyne end

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of the catalyst is clicked onto electrode with Cu(I) as the catalyst. The catalysts so developed will be used for production of H2 from H2O.

5.4 Action Plan and Suggestions

Hydrogen production through dark fermentation has certain limitations.

Gaseous energy recovery in terms of only H2 might not be sufficient to make this process commercially viable. Only 20 to 30 % of total energy can be recovered through H2 production. Even though integration with photo- fermentation, theoretically, 12 moles of H2 /mole of glucose can be recovered but due to scaling up problem of photo-fermentation such a two-stage process is difficult to commercialise. To make the dark fermentative hydrogen production worthy of commercialisation, it should be integrated with the biomethantion process. The spent media of the dark fermentation is rich in volatile fatty acids that would be an ideal substrate for methanogens. Bio- methantion technologies are well established and are easy to scale up. The integration of these two processes might lead to 50-60% gaseous energy recovery (Figure 5.2). Most attractive point of such a process is that the reactor used for H2 production could be used for bio-methanation. So, separate reactor is not required. This would lead to decrease in operational cost of the entire process. Bio-hymet production could be envisioned as renewable source of energy only when it would be produced from renewable sources. Any organic compound which is rich in carbohydrates, fats and proteins could be considered as possible substrate for bio-hymet production.

The advent of technology, such as fuel cell that converts hydrogen to electricity has infused new life to the implementation of hydrogen based economy. The path of hydrogen economy would be realized through the implementation of fuel cell system with the bio-hydrogen production systems. The efficient fuel cells, that would be able to perform at ambient temperatures and would require minimum maintenance, are the major advantages towards their commercialization. Till now very few steps have been taken on demonstration of integration of bio-hydrogen production with fuel cells. It would be interesting to see the performance of continuous bio-hydrogen production when connected to fuel cells.

The bio-hydrogen setup should be put strategically near to those places where supply of feedstock is cheap and easily available. The electricity generated by such process could be helpful for rural electrification. Development of such process would lead to decentralized use of hydrogen.

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Figure 5.2 Bio-hymet Concept for Maximum Gaseous Energy Recovery

International and National status and gaps of technologies of bio- hydrogen production routes have been compared in Table 5.1.

Table 5.1 Comparison of Bio-hydrogen Production Routes

Techno International National Technology Suggestions logy Status status Gaps Direct Techno- Techno- Expensive and Development of Biophotolysis logical logical difficulty in mutant strains

advancement advancemen scaling up of resistant to O2 was not t was not photo- toxicity, encouraged encourage bioreactor, Development of

inhibition of H2 cheap material of production construction for due to oxygen photobioreactors toxicity,

H2 production rate are not encouraging

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Indirect Technological Technologic Expensive and Development of Biophotolysis advancement al difficulty in strains that are was not advancemen scaling up of more efficient in encouraged t was not photobioreact starch encourage ors, accumulation H2 production and rate are not fermentation, encouraging Development of cheap material of construction for photobioreactors Photo- Scale up pilot Lab scale Expensive and Development of fermentation plant of 100 L stage difficulty in mutant strains was scaling up of having low developed photobioreact pigment content, ors, heterologous Shading effect over expression of pigments of produced by clostridialH2ase, the microbes, Development of poor cheap material of photosynthetic construction for efficiency, photobioreactors

H2 production rate are not encouraging Dark Pre Pre Scale up Use of fermentation commercial commercial problem, customized stage stage development packed bed of large scale reactor systems bioreactors, for high rate of screening of H2 production, potential Use of organic microbes, raw industrial and material household waste availability, as feedstock, Storage of H2, Development of Purity of H2 cheap gas produced is scrubbing not sufficient technologies to be supplied such as water to fuel cells scrubbing

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HYDROGEN PRODUCTION THROUGH THERMOCHEMICAL ROUTES

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6.0 Hydrogen Production through Thermo-chemical Route

6.1 Introduction

Thermo-chemical splitting of water to produce hydrogen was considered as one of the potential methods which can be scaled up for large scale generation. In this context to provide quality heat for the process use of energy sources such as nuclear and solar etc., was considered, as these sources were being envisaged by these sources for input heat were attracting worldwide attention. With regard to the choice of likely process routes for development the iodine-sulfur (I-S) and copper-chlorine (Cu-Cl) cycles were considered having potential for scale up hydrogen generation, however, the process was complex and required multi-disciplinary approach to develop suitable technology. Currently globally, these cycles are at different stages of development and are yet to be commercially proven.

The iodine-sulfur (I-S) cycle is one of the most promising and efficient thermo-chemical water splitting technologies for the massive production of hydrogen. As competing processes, other options such as HTSE, hybrid sulfur cycle and Cu-Cl cycle are also being studied for the production of hydrogen.

Schematic of thermo-chemical water splitting cycle is shown in Figure 6.1.

Figure 6.1: Schematic of thermo-chemical water splitting cycle

Schematic and conditions of a typical Cu-Cl closed loop is shown in Figure 6.2 and Figure 6.3.

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Figure 6.2: Schematic of a typical Cu-Cl closed loop

Figure 6.3 Schematic and conditions of a typical I-S closed loop

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6.2 International Status

Integrated I-S loop cycle has been demonstrated in the following countries:

Country Year

USA : 1980

European Union : NA

Canada : NA

Japan : 2004

South Korea : 2009

China : 2010

India : 2013

Country wise status and plan on I-S process is discussed below.

6.2.1 United States of America: The Nuclear Energy Research Initiative (NERI) was established with the goal to demonstrate the commercial scale production of hydrogen using nuclear energy by 2017. The modular helium reactor (MHR) has been suggested as the Generation IV reference concept for nuclear hydrogen generation on the basis of either the I-S thermo- chemical cycle or HTSE.As part of the national hydrogen research programme, the US DOE created the Nuclear Hydrogen Initiative (NHI) with the objective to advance nuclear energy for the support of a future hydrogen economy. The frame was widened with the start of the International Nuclear Energy Research Initiative (I-NERI) for bilateral or multilateral international cooperation supporting R&D activities for Generation IV reference concept of the NHI and the advanced fuel cycle R&D. The objectives of I-NERI include the development and demonstration of technologies which enable the nuclear power based production of hydrogen by non-fossil based water splitting hydrogen production processes. The I-S cycle development project has been taken up by an international consortium led by General Atomics and comprising also the Sandia National Laboratory (SNL), USA and the French Commissariat of Atomic Energy (CEA). Between 2003 and 2008, the US DOE promoted nuclear hydrogen programmes in the USA which concentrated on:

- Hybrid sulphur thermo-chemical cycle development at the Savannah River National Laboratory (SRNL); - High temperature electrolysis development at the Idaho National Laboratory (INL);

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- I-S process development at the General Atomics.

Through a down selection activity led by INL and carried out in 2009to systematically evaluate and select the best technology for deployment with NGNP (Next Generation Nuclear Plant), the HTSE was adjudged as the most appropriate advanced nuclear hydrogen production technology that presents the greatest potential for successful deployment and demonstration at NGNP. But it was also stated that both Westinghouse hybrid (HyS) and I-S processes exhibit attractive attributes for hydrogen production, which supports not abandoning either technology for future consideration.

6.2.2 European Union: High Temperature Thermo-chemical Cycles (HYTHEC) was a STREP (Specific Targeted Research Project) with six partners starting in 2004 and running over almost four years. Its main objective was to evaluate the potential of thermo-chemical processes, focusing on the I-S cycle to be compared with the HyS cycle.

Nuclear and solar were considered as the primary energy sources, with a maximum temperature of the process limited to 950°C. A preliminary reference sheet of the I-S cycle has been conceptualized and optimized to a ‘reference’ flow sheet by coupling to a single 600 MW indirect cycle Very- High-Temperature Reactor (VHTR). The reactor, fully dedicated to hydrogen production, is designed as a ‘self-sustaining concept” delivering both electricity to meet the plant’s own total power demand and heat to run the Hydrogen production process at a rate of 110 t/d and an overall plant efficiency of ~35%.

A preliminary evaluation of the hydrogen production costs based on solar, nuclear and hybrid operation led to following results: small plants are powered most favorably by solar energy, while nuclear plants are most economical at high power levels (> 300 MW(th)); hybrid systems may have their niche in the midrange of 100 to 300 MW(th).

The 2015 targets defined for high temperature thermo–electrical– chemical processes with solar–nuclear heat sources are reduction of CO2 emissions for fossil reforming by more than 25% and hydrogen production cost of less than €2/kg

HycycleS is a new European project that started in 2008 involving nine European and four associated international partners. Following in the footsteps of the HYTHEC project, the three year project HycycleS (2008– 2010) was aimed at the qualification of ceramic materials and reliability of components for the essential reactions in thermo-chemical cycles. The focus was on the decomposition of sulphuric acid as the central step of the hybrid- sulphur (HyS) cycle and the I-S cycle.

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The final aim was to bring thermochemical water splitting closer to realization by improving the efficiency, stability, practicability and economic viability.

6.2.3 Canada: In close cooperation with the Argonne National Laboratory (ANL) in the USA and the University of Ontario, Institute of Technology (UOIT) and other universities, Atomic Energy of Canada Limited (AECL) is investigating the copper–chlorine family of thermo-chemical cycles with maximum temperatures that can be provided by the CANDU Mark 2 SCWR (Super Critical Water Reactor). But apart from this cycle, AECL research includes investigating the use of direct resistive heating of catalysts for SO3 decomposition in the I-S process.

6.2.4 Japan: In recent years, JAEA has undertaken extensive R&D on the thermo-chemical cycles based on the UT-3 and I-S processes for H2 production. It is most advanced in the study of the I-S cycle, with the successful operation of a bench-scale facility having achieved a hydrogen production rate of 30 NL/h in continuous closed cycle operation over one week. This process is now considered the prime candidate for the demonstration of nuclear assisted hydrogen generation.

The next step, which started in 2005, is the design and construction of 3 a pilot plant with a production rate of 30 Nm /h of H2 under the simulated conditions of a nuclear reactor. While the efficiency was ~10% for the bench- scale plant, the goal for the pilot plant is ~40%.

As a backup hydrogen production method, the high temperature electrolysis has also been investigated, but has not yet gone beyond lab-scale testing (Figure 6.4)

Figure 6.4: Plan of proposed R&D activities

6.2.5 South Korea: The projected hydrogen economy in the Republic of Korea requires that 25 % of total hydrogen be supplied by advanced nuclear

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reactors by 2040. This amount of hydrogen is around 3 Mt/year and it is expected to be produced in 50 nuclear hydrogen units. The nuclear policy in Korea is led by its Atomic Energy Commission (AEC) which collaborates with the Korean Institute of Energy Research (KIER), Korean Atomic Energy Research Institute (KAERI), and the Korean Institute of Science and Technology (KIST).

Korea launched its nuclear hydrogen program in 2004 with two targets as under:

(1) Generation of hydrogen for fuel cell applications such as electricity generation, passenger vehicles, and residential power and heating, and

(2) Lowering hydrogen costs and improving efficiency of the related processes.

The following nuclear hydrogen programs were approved by AEC:

 NHDD—“Nuclear Hydrogen Development and Demonstration” program which started after 2011 and go up to 2030

(Milestones: 2022—prototype construction, 2026—technology demonstration, 2030—technology commercialization).

 Hydrogen production program with two phases:

– I: Hydrogen production from natural gas, petroleum naphtha, and electricity (ending in 2025)

– II: Hydrogen production from coal, nuclear energy and renewable energy (ending in 2040)

 For the reference case design of the VHTR-H2 system, an underground VHTR reactor of 200 MW thermal output will be coupled with an I-S cycle to generate hydrogen from water

 I-S cycle development. It runs in parallel with NHDD (Nuclear Hydrogen Development and Demonstration) and GIF (Generation IV International Forum) programs and it has two phases:

– I: 2006–2011 for development of key technologies

– II: 2012–2017 for performance improvement and validation

I-NERI-Korea participates in the I-NERI program of DOE with joint projects with the Idaho Nuclear Laboratory and Argonne National Laboratory. Korea also established two major joint research agreements, namely:

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(1) Nuclear Hydrogen Joint Development Centre (NHDC) with General Atomics,

(2) Nuclear Hydrogen Joint Research Centre with China (via INET).

6.2.6 China: R&D on hydrogen production through water splitting using HTGR as a process heat source was initiated in 2005 as one component of China’s HTR-PM (High Temperature Reactor – Pebble Module) demonstration project. Both the I-S thermo-chemical cycle and high temperature steam electrolysis have been selected as potential processes for nuclear hydrogen production.

Beginning with preliminary studies, the R&D programme, now part of the HTR-PM project, will be conducted in phases as under:

– Phase one (2005–2009): verification of nuclear hydrogen production;

– Phase two (2010–2012): bench-scale testing;

– Phase three (2013–2020): pilot-scale testing, R&D on coupling technology with reactor, nuclear hydrogen safety;

– Phase four (after 2020): commercialization of nuclear hydrogen production.

Other countries such as Italy, South Africa and France are also working on different thermo-chemical cycles including I-S and Cu-Cl processes.

6.3 National Status 6.3.1 Work Done by Bhabha Atomic Research Centre R & D for the Production of Hydrogen by Splitting Water using nuclear Heat: Successful feasibility demonstration of cyclic operation of the process provided fillip to intensify the development effort for tackling variety of issues like efficient integrated process schemes, equipment, materials and analytical techniques etc. Efforts are also on to demonstrate the operation under prototypical conditions to generate data for assessing the viability of the process for large scale deployment.

The road map for I-S process development is shown in Figure 6.5.

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Material Studies

Experimental Research Design and

Validation and Development Simulation

Bench Scale Demonstration

150 Lit H /Hr 2

Pilot Scale Demonstration

3 13 M H2/Hr

Demonstration with 600 MW HTR th

3 80,000 M H /Hr 2

Figure 6.5: Road Map for I-S Process

High temperature reactor based iodine-sulfur (I-S) thermo-chemical cycle offers a promising approach to the high efficiency production of large volumes of hydrogen from water.

The I-S cycle consists of three sections as expressed in following equations:

o SO2 + I2 + 2H2O = 2HI + H2SO4 (25 – 120 C) ------(i) o H2SO4 = H2O + SO2 + 0.5O2 (800 – 900 C) ------(ii) o 2HI = H2 + I2 (350-450 C) ------(iii)

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The Equation (i) is the Bunsen reaction where water is split by sulphur- dioxide (SO2) & iodine (I2) at relatively low temperature. Equation (ii) is the highest temperature reaction of the cycle where high temperature is achieved using Nuclear (High Temperature Reactors) / Solar heat. Equation (iii) is hydrogen iodide (HI) decomposition reaction, where HI is decomposed into hydrogen (H2) & iodine by heating at intermediate temperatures. The I-S process is a closed loop process as the chemicals SO2 & I2 are recycled back to the system, water & heat are the only input and the output is hydrogen (H2) as product and oxygen (O2) as the by-product.

Initially Bunsen reaction studies were carried out at Chemical Technology Division of BARC to study the overall reaction kinetics. A sketch of the apparatus used in the experiments of SO2 chemical absorption in water containing iodine is shown in Figure 6.6.

Figure 6.6: Schematic of Bunsen Reactor Setup

The experimental results for the SO2 absorption into aqueous solution containing iodine are shown in Figures 6.7 & 6.8.

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Figure 6.7: SO2 Inlet Partial Pressure Vs Absorption Rate

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Figure 6.8: Batch Time (Experimental) Vs Batch Time (Calculated)

The other reactions of I-S process require catalyst. In house catalysts are developed and tested in BARC. Chemistry Division, BARC has developed catalyst for sulfuric acid decomposition and Heavy Water Division, BARC has developed catalyst for HI decomposition reaction. The test facility and characterization is shown in the Figure 6.9& 6.10.

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HI Catalyst Characterized and tested at 350°C

Catalyst HI decomposition temperature fraction

% 423 K 0.4

523 K 3 %

623 K 14 %

Figure 6.9: HI Decomposition Test Facility and Catalyst Characterization

Fresh catalyst Used catalyst

SO2 yield: as a function of acid flux

Cr0.2Fe1.8O3 more active than Fe2O3

Figure 6.10: Catalyst Characterization for Sulfuric Acid Section

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As a first step to demonstrate the I-S process and feasibility of closing the loop, Chemical Technology Division, BARC has initiated the efforts for the same. The I-S closed loop system has been worked out in glass/quartz equipment, operating at atmospheric pressure and prototypical temperature conditions.

Figure 6.11: Layout of Closed Loop Figure 6.12: Boxed up Arrangement Glass System (CLGS) for CLGS.

The closed loop glass setup (Figure 6.11 and Figure 6.12) is divided into 3 sections as given below:

1. Bunsen Section a. Bunsen Reaction b. Liquid-Liquid Separation c. Acid Purification

2. Sulfuric Acid Section a. Sulfuric Acid Concentration b. Sulfuric Acid Decomposition

3. HI Section a. HIx Distillation b. HI Decomposition and HI Recovery c. Hydrogen Purification

The pictures of various equipment/systems during operation are given in Figures 6.13 to 6.17.

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Interface of two phases

Figure 6.13: Bunsen Reactor during Operation & Liquid- Liquid Phase Separation

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Figure:6.14 SO3 Decomposition Experiment

Figure 6.15: HIx Distillation Equipment

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Fig 6.16: Sulfuric Acid Concentrator and Decomposer

Fig 6.17: HI Decomposition System

The closed loop glass system is operated continuously for a period of 20 hours at the hydrogen production rate of 30 lph. India is the 5th country in

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the world to achieve I-S closed loop operation in glass system, after USA, Japan, China and South Korea. The Chemical Technology Division, BARC is also pursuing the studies on Bunsen reaction and phase separation at high pressures in Metallic Bunsen System (MBS) and sulfuric acid decomposition studies in High Pressure Sulfuric acid Decomposition System (HSDS). This will give substantial inputs for the closed loop metallic system at higher pressures (Figure 6.18 and Figure 6.19).

Figure 6.18: Reactor & Separation System

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Figure 6.19: Feed System

Schematic of Operations Envisaged in Integrated Reactor of HSDSis given in Figure 6.20.

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Figure 6.20: Schematic of Operations Envisaged in Integrated Reactor of HSDS

Cut View of Integrated Reactor of HSDSis shown in Figure 6.21.

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Figure 6. 21: Cut View of Integrated Reactor of HSDS

Heavy Water Division, BARC is working on reactive distillation route to produce hydrogen by splitting of HI acid. Desalination Division, BARC is working on alternate route for HI decomposition section studies using electro- electro dialysis for concentration and membrane reactor for decomposition of HI to produce hydrogen.Alumina Supported Silica Membraneis shown in Figure 6.22.

Figure 6.22: Alumina Supported Silica Membrane

Membrane Reactor for HI Decomposition is shown in Figure 6.23.

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Figure 6.23: Membrane Reactor for HI Decomposition

Chemical Technology Division, BARC has taken the initiative to carry out the I-S process demonstration in engineering material of construction. For that purpose Atmospheric Metallic Closed Loop (AMCL) is being taken up by the division. The P&ID is ready for the setup. Process designing for the setup is underway.

The Chemical Engineering Division, BARC has started working on 3- step Copper Chlorine (Cu-Cl) process. The Chemistry Division, BARC along with Chemical Technology Division, BARC have started working on Hybrid Sulfur (Hy-S) process.

6.3.2 Work Done by ONGC Energy Centre

ONGCEnergy Centre (OEC) is working on sections of I-S process through IIT-Delhi, CECRI Karaikudi. ONGC is working on Cu-Cl process through ICT-Mumbai. They have demonstrated proof of principle experiments and are going ahead with design to demonstrate 25 NL/h Hydrogen production capacity lab-scale unit. OEC started several sub-projects in collaboration with some of the leading research institutions for research on the initial proof of principle process development, which were to be followed up by further development work to scale up the process.

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In case of Cu-Cl cycle, the originally proposed five step cycle by Argonne National Laboratories, USA has been modified and established. Several novel designs especially in electrochemical section were made to improve the system. The energy calculations showed that there is no additional energy requirement in the modified cycle as compared to originally reported ANL cycle and also reconfirmed that it is a non-catalytic process. Efforts made to cross-confirm the data generated in electrochemical cell parameters generated in the studies at ICT, Mumbai confirmed further that the data is in the range reported in a parallel project study undertaken at CECRI, Karaikudi.

Based on proof of concept studies, a conceptual closed-loop Cu-Cl process for hydrogen generation@ 25L/h was developed to design and fabricate a metallic lab-scale engineering process facility with indigenous sources. A model metallic reactor fabricated initially helped freezing the design and fabrication of hydrogen generation, CuCl2 hydrolysis, decomposition and oxygen generation reactors. This approach has resulted in considerable time and cost saving in the project besides instilling confidence in indigenous capability development. A spray drier system was designed and fabricated for drying CuCl2 to produce very fine and pure CuCl2 powder. The electrochemical set up required in the integrated closed-loop operation was developed using the data generated through series of electrochemical cells of varying capacities viz., 2A, 5A, 12A finally leading to design/fabrication of 60 A stack with improved designs and indigenous fabrications using commercially available materials viz., electrodes, membranes, cell materials etc. During the studies, a novel method was developed for complete conversion of CuCl after electrolysis reaction based on which a suitable process gadget was designed to enable trouble free closed-loop operation of the cycle.

In the integrated facility indigenously developed for closed-loop operation all reactors viz., hydrogen, oxygen generation, CuCl2-hydrolysis and decomposition along with electrochemical system were individually checked for their performance and found to be working as per desired specifications. Several facilities required for transfer of solids between individual units were developed with a newly designed and fabricated flexible screw conveyor along with provision for liquid transportation between various units across the loop.

The engineering scale process plant, now installed at ICT, Mumbai is proposed to be shifted to OEC project site in Panvel.

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In the I-S cycle, electrochemical Bunsen reaction and electro dialysis technique for HI enrichment were established at lab-scale with minimum cross-contamination levels across membrane and without any side reactions. Model codes were developed in simulation work undertaken to address scaling up and issues related to integration with the remaining sections of the cycle. In H2SO4 decomposition section of this cycle, a cost-effective, high performing and highly stable non-Pt-based catalyst system was developed and tested in an in-house designed, fabricated pilot scale metallic reactor system equivalent to 150 L/h of H2 generation. Performance of selected catalyst system under lab stage was evaluated further in this reactor at 900±50°C and 10-15 bars and found to be highly satisfactory. Mechanistic studies on catalytic decomposition of H2SO4were completed. In HI decomposition section, a highly performing transition metal based catalyst system was developed that yields conversion being close to equilibrium values at 500-550°C. The catalysts were stable for over 100 hrs. Through a short study techno-economic feasibility of open loop I-S cycle was also evaluated.

The research work performed by OEC and the collaborating institutions have thus been able to successfully establish the proof of concept for developing both Cu-Cl and I-S cycles and has led to setting up metallic closed loop lab scale engineering facility in Cu-Cl cycle. These accomplishments are major steps in technology development for these two processes and achieved for the first time in the country.

ONGC Energy Centre has been able to successfully develop the indigenous process, several process equipment and trained manpower in the country. The collaborative R&D on both cycles has resulted in publications/presentations of 46 technical papers in national / international conferences and Journals. The research work has also resulted in filing of 7 Indian patents. In addition, keeping in view the recent international developments in research in Cu-Cl cycle, which is considered most potential for scale up, OEC has filed 3 international patents related to Cu-Cl cycle in six countries (UK, USA, Canada, Japan, Korea and China). In the last few months USA and Japan have accepted our patent application on multi-step Cu-Cl cycle and patent has been granted in these two countries.

Scheme of R&D activities related to I-S cycle at OEC, Mumbai is given in Figure 6.24.

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Figure 6.24 Scheme of R&D activities related to I-S cycle at OEC, Mumbai

6.3.3 Highlights of the R&D Work

The OEC had planned to implement the project work in two distinct stages viz., establish the proof of concept, followed by the lab-scale development in association with collaborative research group for the selected process route and thereafter, setting up of the pilot plant at OEC premises at appropriate time to transform the developed knowledge and expertise to further scale up. In this context, a total of 16 collaborative sub- projects and 1 in-house project were undertaken as per details given below:  8 sub-projects to establish proof of principle of both the Cu-Cl and I-S cycles

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 3 sub-projects to establish alternate paths for these cycles  1 sub-project to establish closed-loop operation of Cu-Cl cycle  1 sub-project to establish techno-economic feasibility of open-loop cycle  3 sub-projects to addresses various issues related to simulations / modeling, scale up / bridging the gaps for achieving closed loop operations  1 In-house sub-project on simulation of I-S and Cu-Cl Cycle

The details of various collaborative sub-projects / in-house projects undertaken in line with the scope of the work are given in Table 6.1:

Table 6.1 List of Collaborative Sub- projects in I-S and Cu-Cl Cycles

1 Proof of Principle of Cu-Cl Cycle (3 Sub-projects) Sl. Title of the Project Institute Amount Amount Status No Duration / Start committed Released Date / End Date (Rs Lakh) (Rs Lakh) 1.1 Preliminary process ICT, 80.40 80.40 Completed analysis for copper- Mumbai chlorine (Cu-Cl) thermochemical hydrogen production process 42 months / 01.07.07 / 31.12.10 1.2 Experimental data CECRI, 6.23 6.23 Completed collection on Karaikudi oxidation of CuCl and recovery of Cu 10 months / 28.04.08 / 28.02.09 1.3 Studies on the CECRI, 10.70 10.70 Completed electrolysis of CuCl Karaikudi & recovery of Cu – Energy Optimisation – Phase II 9 months / 27.02.10

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/ 26.11.10 Sub Total-1 97.33 97.33 2 Proof of Principle of I-S Cycle (5 Sub-projects)

2.1 Studies on the IIT-Delhi 107.74 107.74 Completed catalytic decomposition of Sulfuric acid in the I-S process for Hydrogen production 57 months / 11.01.08 / 11.10.12 2.2 Studies on Bunsen IIT-Delhi 102.77 102.77 Completed reactor for production of sulfuric acid and HI using electrochemical cell48 months / 21.01.08 / 21.01.12 2.3 Concentration of IIT-Delhi Completed HIx Solution Using Electroelectrodialys is 48 months / 21.01.08 / 21.01.12 2.4 Catalytic IIT-Delhi 45.63 45.63 Completed Decomposition of Hydrogen Iodide

(HI) into I2 and H2 57 months / 29.09.08 / 30.06.13 2.5 Development of IIT-Delhi 31.64 31.64 Completed Hydrogen Transport Membrane Reactors for Hydrogen Iodide decomposition followed by hydrogen removal 36 months / 29.09.08 / 28.09.11

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Sub Total -2 287.78 287.78 3 Simulation of I-S Cycle (1 Sub-project)

3.1 Simulation studies Dr. 4.09 4.09 Completed on the sulphur- Babasaheb iodine (I-S cycle) Ambedkar closed loop Univ.Loner thermochemical e, process for Maharashtr production of a (BATU) hydrogen using suitable simulation and application software 24 Months / 15.12.09 /15.12.11 Sub Total -3 4.09 4.09 4 Design, Installation and Lab Scale Demonstration of Closed Loop Operation (1 Sub-Project) 4.1 ICT – OEC Process ICT, 767.87 767.87 Completed for Copper-Chlorine Mumbai (Cu-Cl) Thermo- chemical Hydrogen Production – Phase-II 30 months / 23.02.12 / 22.08.14 Sub Total -4 767.87 767.87 5 Additional Studies / Alternate paths in Cu-Cl Cycle and I-S Cycles Cu-Cl Cycle (1 Sub-Project) 5.1 Electrolysis of CuCl CECRI, 25.91 25.91 Completed – HCl system for Karaikudi the preparation of

CuCl2& H2 - A Feasibility Study 23 months / 05.04.10 / 04.03.12 Sub Total -5 25.91 25.91 I-S Cycle (2 Sub-Projects) 5.2 Experimental ICT, 2.20 2.20 Completed Studies for Mumbai Reaction of Metals with HI 1.5 months

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/ 10.01.11 / 23.02.11 5.3 Experimental ICT, 9.85 9.85 Completed Studies for Mumbai Reaction of Metals with Hydroid Acid &Detailed Studies on Decomposition of Certain Transition Metal Iodides 5 months / 14.09.11 / 13.02.12 Sub Total -6 12.05 12.05 Techno-economical Studies on Partially Open-loop I-S Cycle (1 Sub- project) 5.4 Techno Economic CSIR-IIP, 13.47 13.47 Completed Feasibility of Open Dehradun Loop Thermo- chemical S–I cycle

of H2S split for Carbon-Free Hydrogen Production in Petroleum Refinery 4 months / 10.01.12 / 09.05.12 Sub Total -7 13.47 13.47 Additional studies to address scaling up issues in I-S Cycle (2 Sub- projects) 5.5 Modeling of IIT, Delhi 10.86 7.61 Completed Membrane Electrolysis Cell for Bunsen Reaction and Electro- Electrodialysis Unit for concentration of Hix Solution 9 Months / 08.02.13 / 07.11.13

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5.6 Mechanistic IIT, Delhi 17.48 11.19 Completed Studies on the Catalytic Decomposition of Sulfuric Acid in the I-S Cycle for Hydrogen Production 12 months / 25.02.13 / 24.02.14 Sub Total -8 28.34 18.80 Grand Total (Sub 1236.84 1236.84 Total 1-8) 6.0 Simulation Studies OEC - - Completed on Thermochemical (In-house) Iodine-Sulfur& Copper-Chlorine Cycle for Hydrogen Production 5 Years / May 2010 – Sept. 2015)

The linkage between various sub-projects is shown in Figure 6.25.

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Figure 6.25 Linkage between various sub-projects

6.3.4 Highlights of the R&D Work (i) Cu-Cl Cycle  The proof of principle experiments for all reactions of Cu-Cl cycle have been successfully completed, using a combination of thermo-chemical and electrochemical routes. This has resulted in development of a ICT- OEC modified and patented Cu-Cl cycle.  In modified cycle; hydrolysis step was suitably modified to overcome problems faced in formation and characterization of copper oxychloride.  Detailed thermo-chemical calculations of the modified route indicated that there is no excess heat demand in the modified route.  Analytical test methods and procedures to facilitate trouble free operations during closed-loop operations have been standardized  In the electrochemical reaction, based on a novel cell design 2A cell has been fabricated. It resulted in low cell voltage of 0.7 ± 0.1V along

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with >90% current efficiency, 5-10μ particle size of copper generated in the process under operating conditions that could be directly used as feed / reactant in the Cu-HCl-Hydrogen generation reaction.  Kinetic studies for all reaction steps of the Cu-Cl cycle have been performed and from the activation energy value it has been confirmed that this is a non-catalytic reaction process.  Based on the experimental data generated in the proof of principle experiments, a basic flow sheet has been initially developed for the closed-loop experiment to generate hydrogen @ 2.73 liters per hour (lph), subsequently revised to 5 L/h and finally to @ 25 L/h to align with market supply of various process gadgets.  Detailed studies on flow simulations, cold flow experiments etc., have been performed to finalize the reactor configuration.  A 5 Ampere electrochemical cell has been fabricated. The performance of the cell showed that cathodic current density of 133mA/cm2 at a cell voltage of 0.7 ± 0.1 V.  Further scale up to a 12A electrochemical system was done with improved design. A cathodic current density of 187 mA/cm2 at 0.7 ± 0.1V could be achieved.  Aerial oxidation of CuCl solutions has been found to be a major issue in electrochemical step. A novel method has been developed for complete conversion of CuCl after electrolysis reaction. Accordingly a suitable process gadget has been designed and fabricated for onsite application during closed-loop operation.  Based on the outcome of electrochemical studies, a 60A stack has been developed to integrate with thermal reactors.  Initially a representative metallic model reactor system for hydrogen generation @ 25 L/h has been designed and fabricated to study all thermal reactions based on which design /fabrication of all the other reactors viz., hydrolysis, decomposition and oxygen generation reactors has been taken up. This approach has helped in reducing the cost and meeting the project time line.  Hydrogen generation @ 27 L/h in the hydrogen generation reactor has been achieved under specified operating conditions.  Hydrolysis reactor has been operated at 450°C and the reactor is behaving ideally. When the oxygen generation reactor was run at 500°C; the experimental data indicated oxygen production @ 13.7 L/h.

 CuCl2 decomposition reactor has yielded fine CuO powder and Cl2 gas at 475oC.

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 Experimental runs on commissioned spray drier system have been

performed for drying CuCl2 at 140°C and the units have delivered desired results. Data generated on the dryer unit have resulted in

encouraging results in which very fine and pure CuCl2 powder has been obtained as confirmed by UV-Visible spectroscopy, iodometric and titrimetric methods.  Simulations / Modeling studies in Cu-Cl cycle have been performed on Aspen Plus simulator. Flow sheets for individual sections/ process leading to integrated system / process have been developed. Energy balance and mass balance has been calculated and compared with theoretical values.  Proof of principle of alternate electrochemical reaction pathway has been established at CECRI, Karaikudi. The studies have shown that 100% efficiency at low cell voltage (0.8V) and 250A/m2 current density at 80°C under ambient pressure conditions could be achieved. Based on lab studies, a 25A scale electrochemical cell has been designed to work under specified operating conditions. The study has enabled further modification in Cu-Cl cycle in reducing number of steps/ processes.  Solid handling problems in various sections for transfer of solid copper and copper oxide between individual units have been achieved with a newly fabricated flexible screw conveyor based on a novel ICT- design. Provision for liquid transportation between various units across the loop. Facility for Integration of various individual reactors leading to form a closed-loop has been completed.

The details the reactions in ICT-OEC route of Cu-Cl cycle is given in Table 6.2:

Table 6.2: The ICT-OEC route of Cu-Cl cycle

S. No. Reactions ICT-OEC route : Cu-Cl Cycle

1 Hydrogen Generation 2Cu(s) + 2HCl(g) → 2CuCl(l) + H2(g)

2 Electrochemical 4CuCl(l) → 2CuCl2(aq) + 2Cu(s)

3 Drying 2CuCl2(aq) → 2CuCl2(s)

4 Hydrolysis CuCl2(s)+H2O(g) → CuO(s)+ 2HCl(g)

5 Decomposition CuCl2(s) → CuCl(l)+½ Cl2(g)

6 Oxygen Generation CuO(s)+½ Cl2(g) → CuCl(l) +½ O2(g)

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(ii) I-S Cycle  Proof of concept of complete cycle has been established using a combination of electrochemical and thermo-chemical reactions.  Bunsen reaction has been successfully carried out at lab-scale using a two-compartment membrane electrolysis cell consisting of graphite electrodes and Nafion-117 membrane.  Excess iodine used could be reduced by 75% compared to direct contact mode. The current efficiency close to 100% has been achieved and absence of side-reactions has been confirmed  Cross-contamination has been found to be much lower than the direct contact mode; loss of sulfate ions to HIx section (~12%) has been noticed due to limitation on membranes.  Electro-Electro Dialysis (EED) technique has been established and demonstrated in lab-scale to concentrate HIx solution beyond its azeotropic concentration.  Only Nafion membranes have been found useful In electrochemical work  Model codes for simulation work on electrochemical Bunsen and EED sections for I-S cycle has been successfully developed to address scale-up issues and integration with the remaining sections of the cycle.

 In H2SO4 decomposition study, a lab-scale model quartz reactor system has been designed and assembled to screen various catalysts.

Several transition metal/metal oxide based catalysts viz., Fe2O3/Al2O3, Fe2O3/ZrO2, CoO/Al2O3, CuO/ZrO2, Fe2O3, Cr2O3, CuFe2O4, ZnCr2O4, FeCr2O4, NiCr2O4, CuxCr3-xO4 etc. were screened and relative performance of some of these catalysts were determined.  Detailed kinetic and thermodynamic studies have been performed on promising catalyst systems. Based on the studies, a cost-effective, high performing and highly stable non-Pt-based catalyst system for catalytic

decomposition of H2SO4 has been developed.  For the decomposition of H2SO4, High Temperature-High Pressure (HTHP) bayonet type metallic reactor for pilot scale operation equivalent to 150 mph in terms of H2 generation was successfully designed, fabricated & commissioned at IIT-Delhi using in-house expertise and indigenous resources.  The proven catalyst system under lab-stage evaluation has been further evaluated under high pressure (10-15 bars) - high temperature (900±50°C) experimental conditions for 24hrs. Results of this study

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have indicated encouraging trend with the conversions in the order of ~90%.  The developed catalyst has been found to be stable for longer durations under the actual operating conditions. It is relatively cost- effective and superior to the available products reported. Data generated for high pressure high temperature (HP-HT) operation is suitable for onsite application and integration in closed loop operation.

 Mechanistic studies on catalytic decomposition of H2SO4 have been completed to address scaling up issues and integrate this step with remaining sections of the cycle.  A lab-scale model quartz reactor system has been designed and assembled to screen various catalysts under operating conditions of HI decomposition.  Several transition metal (Fe, Co, Ni) based catalysts and mixed metal catalysts like Pt-Ni combinations have been synthesized and screened over various catalyst beds viz., Alumina, Vanadia, Molybdina, Zirconia, Activated Carbon, and SiC in the temperature range 400-550°C.  The generated data have indicated that nickel based catalysts worked better with the conversion being close to equilibrium values (~22%) at 500-550°C.The catalyst deactivation studies performed over 100 hrs also indicate a marginal decrease of nickel based system activity to ~20% at the end of the test.  Studies on alternate pathways in I-S cycle for HI decomposition involving Metal – HI reaction has also been established to explore the possibility of ease of operation by avoiding less energy efficient distillation processes.  Techno economic feasibility of open loop thermo-chemical I-S cycle has been successfully evaluated.  Simulation / modeling studies of I-S open/closed-loop cycle and alternate routes have been successfully carried out using Aspen simulator. Individual flow-sheets have been developed leading to Integration of different sections with one another. Energy requirement based on theoretical basis and efficiency calculations has been performed.

Cu-Cl Cycle, I-S Cycle and I-S Cycle Open Loop for Hydrogen Generation are compared in Table 6.3.

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Table 6.3. Comparison of Cu-Cl Cycle, I-S Cycle and I-S Cycle Open Loop for Hydrogen Generation

Sl. Attributes Cu-Cl Cycle I-S Cycle I-S Cycle No. Open Loop 1 No. of Steps 6 Step Process 3 Step Process 2 Step Process (Combination of (Combination of (Combination of Electrochemical & Electrochemical Classical Thermochemical & Bunsen & Hi Reactions) Thermochemical Decomposition Reactions) of HI with Reactive Distillation step) 2 Establishment Proof of concept Proof of concept Collaborative of Proof of for all 6 steps for all 3 steps Work is in Concept have been have been Progress established (OEC established and Collaborators) (OEC and Collaborators) 3 Maximum 550°C 900°C 500°C

Temperature (O2 Generation) (H2SO4 Section) (Oxidation of Encountered H2S)

4 Total Energy 668 kJ/molH2 675 kJ/molH2 562 kJ/mol Requirement

5 MoC Relatively Lower Higher Relatively Lower Temperature (Max Temperature Temperature 5500 C) (Max 9000 C) (Max 5000 C) 6 Catalyst Not catalytic Catalysts Catalysts process required for both required for HI

H2SO4 and HI Decomposition Decomposition 7 Separation Solid – Liquid Liquid – Liquid Separation by Liquid – Liquid Separation of Reactive Gases Separation complex distillation in HI azeotrope decomposition step 8 Membranes Imported Imported Not Required (Required in (Required for (when Classical electrochemical EBR and EED Bunsen step) steps) Reaction is followed)

9 Electrodes Required Required Not Required

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(when Classical Bunsen Reaction is followed) 10 Process 5 Step = 52.57% Using Reactive 51% Efficiency 4 steps distillation = 51%  Nuclear Energy: (GA) Generation IV Supercritical EBR & EED Water Cooled (Ideal case) = Reactor (SCWR) 46.5% = 51% Solar Energy: Using molten salt = 70% 3 Step = 40%

11 By-products / No waste as all No waste as all H2SO4 which Wastes products are products are can be sold for recycled recycled industrial use

7. Indigenous Equipment Development

Hydrogen Generation Reactor System is shown in Figure 6.26.

Figure 6.26: Hydrogen Generation Reactor System

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12A Electrochemical Cell with perforated Pt plate as anode is shown in Figure 6.27.

Figure 6.27: 12A Electrochemical Cell with perforated Pt plate as anode

Spray Dryer System is shown in Figure 6.28.

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Spray Nozzle: Hastelloy C

Control Panel

Drying Pump Chamber

(Borosilicate glass)

Blower Scrubber

(SS 316)

Cyclones

(Borosilicate

glass)

Figure 6.28 Spray Dryer System

CuCl2 Decomposition Reactor is shown in Figure 6.29 and Hydrolysis Reactor is shown in Figure 6.30.

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Figure 6.29: CuCl2 Decomposition Reactor

Figure 6.30: Hydrolysis Reactor

Oxygen Generation Reactor is shown in Figure 6.31.

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Figure 6.31: Oxygen Generation Reactor

Cu-Cl closed loop facilty is shown in Figure 6.32.

Figure 6.32:. Cu-Cl closed loop facilty

High Temperature-High Pressure Reactor for H2SO4 Decomposition is shown in Figure 6.33.

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Figure 6.33: High Temperature-High Pressure Reactor for H2SO4 Decomposition

H2SO4 pilot plant facility is shown in Figure 6.34.

Figure 6.34: H2SO4pilot plant facility

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HYDROGEN PRODUCTION BY PHOTO-ELECTROCHEMICAL WATER SPLITTING

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7.0 Hydrogen Production by Photo-electrochemical Water Splitting

7.1 Introduction

The ever increasing energy demands and rapid consumption of fossil fuels has triggered urgent need of sustainable and renewable sources of energy. A lot of research and its commercialization have already been done in the areas of solar photovoltaic, however, it requires storage of energy due to its limited operation in day-time only. Hydrogen is one of the most promising fuels due to its highest energy density (120 MJ/Kg). Environment and energy crisis issues can be addressed if Hydrogen can be produced in a clean and efficient manner. Steam methane reforming is most commonly used for Hydrogen production in industries. Source for methane reforming is a fossil fuel and moreover CO2 gas is emitted as shown in reaction 1 & 2.

CH4 + H2O → CO + 3H2 ------(1)

CO + H2O → CO2 + H2 ------(2)

Renewable production of Hydrogen through solar energy is essential considering environmental issues and can also cater to the energy needs. There are several ways of Hydrogen production through solar energy. However water splitting is considered as the “Holy Grail” of sustainable hydrogen economy. Water splitting phenomenon was first observed by

Researchers in Kanagawa University, Yokohamaduring1972 where TiO2 electrode was irradiated with UV light and Hydrogen was produced by reduction reaction at cathode and oxygen is produced at anode by oxidation reaction.

University of Notre Dame, Notre Dame, Indiana worked on photocatalytic water splitting. Photocatalytic water splitting consists of a powder catalyst dispersed in water or in some suitable solution. Catalyst used in this process needs to be photoactive and should be capable of generating necessary charge particles to activate redox reactions. Minimum bandgap required to split water can be calculated from the relation in between Gibbs free energy and potential as given below:

ΔG =-nFE

Where ΔG is the change in Gibbs free energy, n is number of electrons transferred in chemical reaction, F is faraday constant and E is the bandgap. For water splitting, ΔG = 237KJ/mol, n=2 and F=96500 C/mol. Therefore “E = 1.23V”, is the minimum potential and hence minimum bandgap of 1.23eV is required to split water. Thermodynamic bandgap requirement for water splitting

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Figure 1: Thermodynamic bandgap requirement for water splitting.

Solar hydrogen production from direct photo electrochemical (PEC) water splitting is the ultimate goal for a sustainable, renewable and clean hydrogen economy. In PECwater splitting, hydrogen is produced from water using sunlight and specialized semiconductors called photo electrochemical materials, which use light energy to directly dissociate water molecules into hydrogen and oxygen. This is a long-term technology pathway, with the potential for low or no greenhouse gas emissions. While there are numerous studies on solving the two main photo-electrode (PE) material issues i.e. efficiency and stability, there is no standard photocell or photoreactor used in the study. The main requirement for the photocell or photo-reactor is to allow maximum light to reach the PE.

The PEC water splitting process uses semiconductor materials to convert solar energy directly to chemical energy in the form of hydrogen. The semiconductor materials used in the PEC process are similar to those used in photovoltaic solar electricity generation, but for PEC applications the semiconductor is immersed in a water-based electrolyte, where sunlight energizes the water-splitting process. PEC reactors can be constructed in panel form (similar to photovoltaic panels) as electrode systems or as slurry- based particle systems, each approach with its own advantages and challenges. To date, panel systems have been the most widely studied, owing to the similarities with established photovoltaic panel technologies.

Photo-electrochemical process consists of an electrode of semiconductor material, which is photoactive and is capable of generating electron hole pair when light (photons) is incident on its surface. One of the advantages of photo-electrochemical cells is reduction and oxidation reaction happens at different electrodes eliminating the need for separation of gases.

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However, chemical stability of materials inside electrolyte solution or water is a challenging issue.

Schematic diagram of a typical photo-electrochemical cell consisting of n-type semiconductor photoanode, reference (SCE) and metal cathode for water splitting is shown in Figure 2.

US DoE has set following benchmarks for commercialization of PEC water splitting technology for hydrogen production.

 Criteria 1: 10% Solar to Hydrogen conversion efficiency.

 Criteria 2: Stability against Chemical, electrochemical and photo- corrosion. Working time of at least 1000-hour without significant degradation.

 Criteria 3: Cost of hydrogen production should be economical.

Figure 2: Schematic diagram of a typical photo-electrochemical cell consisting of n-type semiconductor photoanode, reference (SCE) and metal cathode for water splitting.

7.2 Process of water splitting

The crux of water splitting process lies in the redox reaction with the participation of generated charge carriers through solar radiation at catalyst surface (or active sites). Materials used for catalysts or electrode preparation are semiconductor in nature. Therefore, they have a defined band gap which

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is a result of the separation of conduction and valence band. Moreover band edges also play an important role in the selection of the material. Conduction band edge should be more negative than the reduction potential of the hydrogen and valence band edge should be more positive than the oxidation potential of oxygen for water splitting. When light of a particular wavelength is incident on the catalyst, electron-hole pair is generated only if the photon energy is more than the band gap of the material. Electron is then migrated to the conduction band leaving a hole in the valence band.

Next step is separation of charge carriers and their movement to the surface of the catalyst. For an efficient process, mean life time of the generated carriers should be high or recombination rate should be low. Recombination rate in a semiconductor material is affected largely by crystal defects. Crystal defects acts as electron traps which neutralizes holes. To inhibit recombination of electron-hole pair, a co-catalyst is generally used. Generally used co-catalysts are platinum, nickel, ruthenium, rhodium, palladium, iridium and rhodium. Another requirement of co-catalysts is to impede the back reaction in between hydrogen and oxygen. However, in photo-electrochemical, charges are separated by putting a separate electrode of aforementioned noble metals.

A research group in Kyoto University, Kyoto, Japan worked on the non- equilibrium interfacial phenomena occurring under microgravity in water electrolysis. Once separated electron and hole pair is available, redox reaction can be conducted on the surface of catalyst/co-catalyst. Hydrogen ion is reduced to hydrogen gas by the transfer of trapped electron and hydroxyl ion is reduced to oxygen gas by neutralizing the hole in valence band. Oxidation reaction in water splitting is a 4-electron transfer process and therefore, valence band has to be deep enough for transfer of charges.

+ − Reduction at cathode: 2 H (aq) + 2e → H2(g)

+ − Oxidation at anode: 2 H2O(l) → O2(g) + 4 H (aq) + 4e

7.3 Evaluation Parameters

Evaluation of a water splitting system is done on the basis of amount of gas (hydrogen and oxygen) evolved in due course of time. Amount of gas is measured in moles and therefore unit for rate of evolution is mol per unit time (for instance; µmol/hour). Parameter Quantum Yield can be used to compare different photoactive material under similar operating conditions (Modern Aspects of Electrochemistry, New York).

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Number of reacted electrons Quantum Yield =  x 100% Number of absorbed photons

Actual quantum yield is usually more than the quantum yield mentioned above. This difference can be computed if the incident light spectrum and absorption spectrum of the material is known. Overall efficiency can be computed on the basis of total input energy versus total output energy. In case of solar hydrogen production, input energy is the incident Sun’s energy and output energy is the energy content of evolved hydrogen gas.

Output energy of hydrogen Solar to hydrogen efficiency =  x 100% Energy of incident solar light

(mol H2/s) x (237kJ/mol) =  x 100% (Inc Power W/m2) X Area (m2)

In photo-electrochemical, another term specified as ‘applied bias photon to current efficiency’ is more suitable as an external source is usually required for transfer of charge particles from main electrode to counter electrode.

Applied Bias solar to hydrogen efficiency

Current density (mA / cm2) x (1.23 – Vbias) (V) =  x 100% 2 Ptotal (mW/cm ) at AM 1.5G

7.4 National and International Status

Photo-electrochemical water splitting for hydrogen generation is based on solar energy and water, both of which are renewable sources. Energy for stationary and transportation applications can be retrieved from hydrogen with low carbon foot print and climate impact. Ever since in the first report, Researchers in Kanagawa University, Yokohamaduring1972 demonstrated the feasibility of hydrogen generation via photo-electrochemical splitting of water, lot of efforts have been made by different workers across the globe to exploit this process for commercial production of hydrogen. Main focus of this research has been to search for an ideal semiconductor that can be used as efficient photo-electrode in this process. However, the long cherished goal of reaching at least 10% conversion efficiency has so far remained unachieved. Working at this efficiency, with photo-current generation at the rate 10-15 mA

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cm-2, would imply that the cost of hydrogen production would be economical. This would be a cost competitive against the existing costs of conventional fuels and would make this process commercially viable. Another issue important in the process is of semiconductor material durability in contact with PEC cell electrolyte. It is desired that the material should remain stable at least for 2000 working hours.

Researchers in Yerevan State University, Armeniain2005 has concluded that among different semiconductors used for PEC water splitting, the best efficiency is detected in metal oxide photo-electrodes, which were partially reduced and contained an optimal concentration of impurities. In the ongoing search for a material with above desired characteristics, in recent years several new dimensions have been added (plate 1). Use of mixed oxides, Combinatorial approach and designing of high throughout fast screening procedures, adoption of density functional theory to screen the materials, Use of phosphides, Selenides, Graphene and CNT based systems and layered structure are some recent developments in this field of research. Besides above mentioned work, research pertaining to geometry orientation and shaping of nanomaterial (by orthogonalizing direction of light absorption, charge collection, charge separation/ transportation), exploring bandgap and band alignment as a function of composition, doping and morphology for engineering structures, which have features favorable for water photolysis, are also being explored.

Few of the promising material(s) system for application in PEC water splitting are given in Plate 1.

The Institute of Minerals and Materials Technology (IMMT), Bhubaneswar developed functional hybrid nano structures for photo electrochemical water splitting. The different photo-catalytic materials developed for hydrogen production through water splitting, which were continuously operated for 6-7 hours. Among the developed materials like CdS photo-electrodes and CdS nano-crystal powder photo-catalysts with yield of 800-1000 mg/batch, 0.28 wt% P3HT modified CdS with yield of 4087 µmol/h/g and CdS-NaNbO3 core-shell nano-rods with yield of 11,901 µmol/h/g, the CdS-NaNbO3 core-shell nano-rods was found to give maximum hydrogen production.

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Strategies being Properties required? tried

 Band gap energy ≈ 2 eV PEC  Doping  Strong optical absorption Water  Long life time of charge Splitting  Surface carriers  Conduction and Valance Material Modifications Issues band edges to straddle water redox potentials  Layered  High Stability in electrolytes Structures  Non Toxic & Economical Systems Investigated:  Dye ResultHighlights Sensitization

New concepts/ Emerging Trends ……….. Swift Heavy Ion irradiation

Nanocomposites Bio inspired Quantum  MixedMetal Oxides Ion catalysts Dots Implantatio n

Fe2O3- Bio-inspired Co- CdSe QD electro- ZnO modified Graphene catalyst CoPi on deposited on α-Fe2O3 with Cu ion Nano- the surface films implantation composite Plate 1: Few of the promising material(s) system for application in PEC water splitting

7.5 Action Plan

Action plan consists of two main activities: (i) basic R & D towards the identification, synthesis and laboratory-scale PEC measurements on prospective materials/material systems; (ii) up-scaling of the materials/systems found promising with respect to their solar-to-hydrogen conversion efficiency and stability under longer illumination time. Research will be conducted under following lines:

I. Laboratory-scale studies on prospective materials and their performance evaluation

Core activity 1: Exploration on promising semiconductors/systems

Extensive R & D is required to be undertaken concerning the photo- electrochemical measurements for hydrogen generation via photo-splitting of water by employing the promising semiconductors. Thin films of the semiconductors would be converted into electrode by adopting the standard procedure and used in PEC water splitting studies. For converting films into electrode, initially an electrical contact would be generated using silver paint and copper wire. The Ohmic contact so prepared and all the sides of film

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(except the front side) would be sealed with the coating of an opaque and non-conducting epoxy. So prepared thin film working electrodes would be used as photo-sensitive working electrode, in conjunction with platinum counter electrode and saturated calomel electrode (SCE, as reference electrode), at varying electrolyte conditions. Nature and concentration of the electrolyte and its pH would also be varied in order to optimize the conditions of hydrogen evolution. Current (I) – Voltage (V) characteristics of PEC cell would be studied, both under darkness and illumination. By observing the I-V plots, onset voltage for photo-current would be determined, and based on these measurements the performance of PEC cell would be evaluated. As mentioned above this constitutes the core activity in the proposal. The sustained R & D effort in this direction by the investigators for the past 15 years has led to few of the promising material-options in this regard that need to be tested at the next level, which involves their integration with pilot-scale hydrogen generation reactor and the performance evaluation of such reactors both under controlled conditions as well under real-time solar illumination. However, as is evident from the literature survey and the recent emerging trends in this vital area of research, the material issue is yet not finally settled. As a matter of fact, each of the existing material-options has its own drawbacks and the researchers are trying to crack those issues.

Core Activity 2: Scale-up studies and related issues

Moving towards solar energy fed pilot-scale hydrogen generation reactors such that it can perform efficiently under field conditions, this core activity has been chalked out. The above mentioned two semiconductor systems would be investigated for this purpose in the beginning. However, any new material/ system that promises to be even better as observed under core activity 1, would also be incorporated in the work-plan under this activity. Key work elements involved, especially pertaining to the synthesis of large area electrodes would be as:

 Suitable synthesis methods as described in objectives to be used for preparation of electrodes.

 First-level up-scaling studies with existing facilities at Dyalbagh Educational Institute, Agra. Electrodes of at least 3 different dimensions to be fabricated and tested under controlled laboratory conditions.

 Scaling of electrodes from 1cm2 to 150 cm2 active area. Feasibility of maximum area of electrode (150 cm2) to be determined by conducting experiments. These experiments will be conducted with state of the art instruments at IOC-R&D which is a part of the procurement activity of the present project plan. Two routes of large area electrodes shall be

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explored – one having single large area electrode and the other – several small electrodes connected in suitable configuration so as to result into large area exposure

 Empirical modeling of performance versus increase in the area of electrodes. Determining maximum feasible size of the electrode that can be incorporated in the reactor.

 Study on scaling of counter electrode with respect to increase in the area of working electrode.

 Optimization of interconnection design for working and counter electrodes.

II. Studies on reactor design and fabrication.

Core Activity 3: Designing the Reactor

Designing reactor: Theoretical modeling and testing

 Study of different losses associated with electrode and electrolyte interfaces.

 Qualitative and quantitative study of electrolyte and electrode resistance components.

 Study on feasibility of packaging electrodes in parallel connections, their associated losses and optimum size possible for a reactor.

Core Activity 4: Fabrication of Reactor

Actual design of the reactor will be taken up after study on electrodes. Key step of the work planned are mentioned below:

 A lab scale reactor will be fabricated to support scale-up activities for performance evaluation of electrodes of different sizes. Basic design would be similar to that of a twin compartment reactor. Separate compartments will be available for working and counter electrode. This will eliminate need for the separation of evolved gases (hydrogen and oxygen). Moreover, reactor will be air tight and provision will be made to sample evolved gases for analysis. Furthermore, an additional provision will be provided to input feed without opening the reactor or without interrupting the ongoing process.  An electronics circuit will be designed to supply constant external bias to the electrodes. Initially battery will be used for supply and subsequently efforts will be laid to try to use photovoltaic panel for supplying external bias to electrodes.

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 A bigger bench scale reactor will also be fabricated as a part of the project. This bench scale reactor will exhibit a maximum active area of ~ 900cm2. All the challenges faced in the lab scale reactor will be addressed in the design of this reactor. Bench scale reactor will also have the provision of two compartments wherein both the hydrogen and oxygen gases can be separated. Benchmark data will be generated by controlled indoor testing with large area illumination continuous light solar simulator.

Core Activity 5: Fabrication of Reactor

Performance evaluation

Under controlled laboratory conditions

 It is proposed to set up a continuous solar simulator in laboratory which can illuminate electrodes up to a maximum area of~ 900 cm2.

Under real-time solar illumination outdoor field conditions

 Real-time testing will be taken up after laboratory testing. Performance will be evaluated with respect to the real time data obtained from a weather station already in place at IOC-R&D.

7.6 Summary and Recommendations

Among the various material groups for the photo-electrodes, semiconductor metal oxides are relatively inexpensive and have a better photo-chemical stability, many metal oxides have been extensively studied and significant progress has been achieved in past two decades both nationally and internationally.

Among the metal oxides; Iron, copper, bismuth vanadium and zinc have been researched globally for their performance in photo water splitting. Promising results have been achieved with aforementioned metal oxides; nano-wire arrays of hematite has shown a promising current density of 3.44 mA/cm2, oxides of Bismuth has been reported with current density up to 2.3 2 2 mA/cm , current density of the order of 2.34 mA/cm for Cu2O sample (1 at. % Ag) under visible light illumination at 0.8 V/SCE has been reported.

While the search for new and more efficient semiconductor materials/systems for above application would continue, studies are also needed on up scaling the device by initiating R & D efforts in this direction.

Metal oxides, viz. Fe2O3, TiO2, ZnO, CuO, Cu2O, SrTiO3, BaTiO3 etc are important class of semiconductors, viewed largely as prospective material systems for PEC applications. Further, in order to overcome certain limitations associated with these metal oxides, these were subjected to various

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modifications viz. doping, swift heavy ion irradiation, dye sensitization etc., yielding varied improvements on their performances. Nanocomposites, bio- inspired systems, quantum dots, and ion implantation are amongst the different newly emerged concepts that have drawn the attention of researchers and are being investigated with lot of hope and expectations.

Research on scale-up and reactor is equally important as that of the material research. Efficient and reliable materials need to be studied further for scalability. Demonstration at lab scale and pilot scale can be significant towards realizing the ultimate potential of the technology.

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HYDROGEN PRODUCTION BY OTHER TECHNOLOGIES

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8.0 Hydrogen Production by Other Technologies

8.1 Hydrogen Production by non-thermal plasma assisted direct decomposition of hydrogen sulphide 8.1.1 Hydrogen Sulfide is an inorganic compound that causes severe odor problems. The emission of Hydrogen Sulfide from petroleum industry, coal gasification and animal industry has to be regulated as the odor threshold for Hydrogen Sulfide is 1 ppbv. Hydrogen sulphide occurs as a by-product in the production of coke form sulfur- containing coal, the refining of Sulphur- containing crude oils, the production of carbon disulphide, the manufacturer of viscose rayon, and in the Kraft process for producing wood pulp. Hydrogen sulphide is the most dangerous of the gases produced by the anaerobic decomposition of manure. Large amounts of Hydrogen Sulfide are produced worldwide, mostly from natural gas production and oil refining. Yearly tonnages of H2S can be deprived from sulfur production, 14.4 million tons from sour gas and 9.6 from refineries, worldwide. This sour gas potentially contained about 342, 000 tons (3.8 billion cubic meters) of hydrogen. Oil refineries and upgraders use hydrogen as well as make H2S, and for this reason constitute a logical location for a H2S dissociation plant.

Conventional methods to controls hydrogen Sulfide include absorption (wet scrubbing), absorption, incineration (thermal and/or catalytic), and bio- filtration. The widely employed Claus method is based on partial combustion of hydrogen sulfide into sulfur dioxide followed by the catalytic conversion of

H2S + SO2 mixture into elemental sulfur and water. Earlier methods were focused on recovery of elemental sulfur, however the desired reaction would be the production of hydrogen by direct oxidation of hydrogen Sulfide, which is endothermic and thermodynamically unfavorable.

An alternative approach is to use Non-thermal Plasma (NTP) generated at atmospheric pressure and room temperature. NTP, the fourth state of the matter consists of energetic electrons, radicals, atoms and molecules. At low consumption of energy, NTP produces highly energetic electrons that initiate the chemical reaction leaving the background gas nearly at room temperature. Recently dielectric barrier discharge (DBD) reactor with catalytic sintered metal fibre (SMF) electrode has been tested for the abatement of volatile organic compounds. It was demonstrated that the metal oxide modified SMF electrodes, performance of the NTP technique could be improved.

8.1.2 International Status

It is known since long that strong healing decomposes hydrogen sulphide. Thermal decomposition has recently been implemented at the pilot

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scale at a gas plant in Alberta. Conversions close to equilibrium have been observed. An economic study showed that costs for thermal decomposition would be close to those for conventional processes. Improvements in separation technologies are needed to enable commercial implementation of thermal decomposition.

As of today there is no commercial technology for the production of hydrogen from hydrogen sulphide. The conventional method for hydrogen sulphide removal is the Claus process, which produces sulfur and water instead of hydrogen and sulfur that are beneficial. Besides sulfur recovery limitations, major disadvantage of the Claus process is that the valuable product hydrogen is converted into water. Moreover, the cost of tail gases cleanup from Claus plant can exceed the value of sulfur recovered if the environmental regulations become more stringent. Regarding the catalytic process, only limited information has been reported, where none of the catalysts was promising. One of the reasons could be the severe reaction conditions like high operation temperature (>2000K). Among the several techniques tested for the production of hydrogen, Idemitsu Kosan Hybrid (IKC) electrolysis process has been considered as feasible. It is based on absorption of hydrogen sulphide by Ferric chloride aqueous solution followed by electrolysis to generate hydrogen and sulfur. IKC process consumes 3.6 kWh/Nm3 hydrogen, whereas steam reforming of methane, the traditional approach for hydrogen production demands still higher energy of 4.3 kWh/Nm3hydrogen. Like-wise, 40% conversion of hydrogen sulphide by thermal decomposition can be achieved at temperature ~ 1500K, which is equivalent to 2.76kWh/Nm3 of hydrogen. At this temperature considerable amount of by-products like SH were produced. Formation of pure Sulphur and hydrogen was observed only above 2273K. The practical limitation of this technique is the operating conditions and separation of products at this temperature. The main advantage of carrying out hydrogen sulphide decomposition in the novel DBD reactor is the production of hydrogen in an economically feasible manner under ambient conditions.

8.1.3 National Status

Most of the research in this area has been focused on catalytic/photocatalytic decomposition of hydrogen sulphide. However, in both the cases, catalyst deactivation due to the deposition of sulphur decreases the efficiency. But, photocatalytic decomposition of hydrogen sulphide to hydrogen and sulphide offers some promise. Hydrogen sulphide under visible light to generate hydrogen is an attractive route of solar energy conversion, because hydrogen is 100% environmentally clean chemical fuel in its cycles of generation and utilization. Although hydrogen generation from water in visible light represents a potentially viable route of solar energy conversion, till date only marginal conversion efficiency has been achieved (5.1% quantum

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yield with sacrificial agents and 2.5 % from pure water. Obviously, the difficulty in achieving high efficiency is attributed to the involvement of many high energetic reactive species in the thermodynamically uphill water spilling reaction.

The Indian Institute of Technology Hyderabad developed the process of non-thermal plasma assisted direct decomposition of hydrogen sulphide into hydrogen and sulphur. This process is feasible and advantageous over Claus process where sulphur alone is recovered from hydrogen sulphide. It is possible to achieve hydrogen production at about 160 kJ/mole that corresponds to energy conversion of 2 kWh/Nm3 of hydrogen, which is less than the energy required for hydrogen production from SMR (about 346 kJ/mole of hydrogen). A packed bed configuration with glass tubes reactor showed best performance of the reactor which was attributed to the change in discharge properties. MoOx supported on Al2O3 catalysts showed better conversion compared to CoOx and NiO due to deactivation of CoOx and NiO quickly due to sulphur poisoning. Hydrogen production of 0.5 litre/minute was achieved in the laboratory. The NTP technology is environmentally friendly and operationally simple. Another advantage of the suggested process is that the hydrogen produced is free from impurities, hence secondary purification can be avoided. The reaction conditions can be still improved to decrease the energy consumption.

8.2 Hydrogen Production by Photo-splitting of Hydrogen Sulphide

8.2.1 Hydrogen sulphide is a toxic gas occurs widely in natural gas fields and is produced in large quantities as a byproduct in the coal and petroleum industry. Currently this toxic gas is converted into sulphur using Claus’s process or released into the atmosphere. Photo-splitting of hydrogen sulphide into hydrogen can be an attractive option by conventional the Claus’s process. Hydrogen sulphide Cleavage process might be used in industrial procedures where hydrogen sulphide or sulphides are formed as a waste whose rapid removal and conversion into hydrogen is desired. Currently, for this application oxide catalysts have been studied but due to certain limitations, researchers are trying to develop catalyst which can absorb maximum part of solar radiation and are active under natural solar light. Extensive work has been carried out for the development of ultraviolet driven photocatalyst for water and hydrogen sulphide splitting. However, there is a demand for highly efficient photocatalyst for production of hydrogen under visible light irradiation. Stability and efficiency of these catalysts still low and need improvement. There is need to develop prototype photo reactor for hydrogen production from hydrogen sulphide using solar energy and field trials using gas emitted at refinery sites using a batch type photoreactor.

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8.2.2 International Status

Semiconductors mediated heterogeneous photocatalysis has become an attractive technology for environmental pollution remedy, particularly due to its potential to degrade a wide range of inorganic and organic compounds in both waste gases and water. The initial reaction step consists of of electron-hole pair’s production by irradiating the semiconductor with light having an energy content equal to or higher than the band-gap of semiconductor. After separation of photogenerated electrons and holes due to trapping by species adsorbed on the semiconductor, redox reactions occur between trapped electrons and holes and adsorbate. Most of the semiconductor photocatalysts investigated are metal oxides (e.g. TiO2, ZnO, SnO2, WO3) and chalcogenides (e.g. CdS, ZnS, CdSe, ZnSe, CdTe) [1-5]. As hydrogen-based power and transportation technologies develop the need for an effective hydrogen source to power fuel cells in the hydrogen economy. Hydrogen from photo-electrochemical cells is believed to offer the prospect of such a source. Photocatalytic splitting of water using n-type TiO2 under UV illumination was first reported over 30 years ago by Researchers in Kanagawa University, Yokohama. Since then a number of photocatalytic compounds have been investigated with the aim of improving catalyst activity and stability in the irradiated aqueous environment. In 2001 Zou et al. first demonstrated the direct splitting of water by visible light over an In1.xNixTaO4 photocatalyst. As energy conversion devices, water-splitting photo-electrochemical cells convert photon energy to the Gibbs free energy of hydrogen and Oxygen via excited electron states in the photocatalyst. These excited electron states result from the promotion of valance band electron to a level above the conduction band edge on the absorption of an incident photon. In practice, any energy in the excess of the bandgap energy will be dissipated as heat since electrons promoted to higher states readily thermalise to the conduction band edge. Internationally, the research on hydrogen generation from hydrogen sulfide and water is still at academic level. No commercial process has been developed yet. Many groups in Japan, Korea, U.S, Europe is working on development of active photocatalysts for hydrogen generation under visible light irradiation. University of Tokyo, Japan has done extensive work on photocatalysts for water splitting and recently has reported many UV and visible light catalysts.

Considering the depletion of other energy sources, it is quite essential to develop new sources of energy. Development of active photocatalyst for photo-hydrogen generation will be advantageous for future energy demand.

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8.2.3 National Status

In India, large number of groups is working on photocatalytic decomposition of organic waste and toxic materials. Very few groups are working on photocatalytic splitting of water and hydrogen and hydrogen sulphide into hydrogen under visible light. Few research group in BARC are working on photocatalytic degradation of nuclear waste as well as water purification. Some research teams in IISc, Bangalore are working on TiO2 based photocatalysts for organic waste degradation. In addition to this, some researchers in IIT, Mumbai and Madras, CECRI, Karaikudi, IICT, Hyderabad and few universities in India are working on photodecomposition of organic pollutants. But the photo catalysis work has not crossed the development of other possible new active photocatalyst other than TiO2andCdS. The current trend in the country is only the degradation of waste or organic using TiO2/Cds photocatalyst. Only C-MET Pune is working on hydrogen generation by photocatalytic decomposition of toxic hydrogen sulphide. In India, the development of active photocatalyst for pure hydrogen generation by water and hydrogen sulphide splitting is still at academic level. It is essential to develop catalysts useful under solar light for the decomposition of water/hydrogen sulphide into hydrogen. The hydrogen sulphide from the refinaries and mines is continuously emitted into the atmosphere as a result air in the bin such areas is highly polluted. C-MET is developing new class of photocatalysts which are stable and active under sunlight.

The Centre for Materials for Electronics Technologies (C-MET), Pune has developed the prototype photo reactor for hydrogen production from hydrogen sulphide at the rate of 8182.8 and 7616.4 µmol/h/g was obtained from nanostructured ZnIn2S4 and CdIn2S4, respectively under Natural Sunlight (UV optical absorption edge at 557nm for ZnIn2S4 and 576nm for CdIn2S4). The reactor has been designed for the facile operation and considering the safety aspects. The sparger was fixed as a H2S distributer, which also acts as a particle disperser. This design is useful for continuous operation at large scale.

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ACTION PLAN

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9.0 Action Plan

9.1 Hydrogen is a byproduct along with the production of caustic soda and chlorine in the Chlor-Alkali units. These units are continuously working towards better utilization of hydrogen and have succeeded in achieving 90% utilization during 2014-15. The remaining hydrogen amounting to around 6600 tonnes may be utilized in energy related applications, since it emits no pollution except water and heat. This hydrogen may be used directly for the generation of power / in transportation applications (vehicles) based on IC engine technology. For fuel cell application, hydrogen may further be purified (if required), for use in stationary power generation and on-board application in vehicles / material handling systems (based on fuel cell technology), etc.

9.2 Hydrogen has been produced from the conventional sources i.e. carbonaceous fuels like natural gas, coal etc. For small capacities hydrogen production by electrolysis, methanol or ammonia cracking for small, constant or intermittent requirements of hydrogen in food, electronics and pharmaceutical industries and for larger capacities steam reforming of hydrocarbons / syngas are preferred. These sources release CO2 in the atmosphere. The average rate of growth of CO2 in the atmosphere is around 2.1 ppm per year and its concentration in air has increased from 381.90 ppm in 2006 to 398.55 ppm in 2014. India has proposed to reduce emissions by 33-35% by 2030 over the 2005 levels by boosting clean (non-fossil & including renewable) energy in electricity generation to 40% (at least another 150GW) and by adding sinks through trees and forests. Renewable-based processes like solar- or wind-driven electrolysis and photo-biological water splitting hold great promise for clean hydrogen production; however, advances must still be made before these technologies can be economically competitive. Thus, hydrogen production may be continued from the conventional (carbonaceous) fuels through the most competitive process namely auto-thermal reforming (steam reforming and partial oxidation)process till the technologies for hydrogen production from renewable sources become economically competitive.

9.3 Biomass has been identified as potential renewable source for hydrogen production. It is carbonaceous source and produce CO2, which is released to the atmosphere. Biomass is gasified to hydrogen rich syngas, which may be reformed and purified to yield pure / near pure hydrogen. The technology is being developed in the country by IISc, Bangalore. Some other institutes like NIT, Rourkela and NIT Cochin have also been engaged in R&D work for hydrogen production through gasification of biomass. IISc developed a prototype for production of 2 kg/h hydrogen through Oxy-steam gasification process with hydrogen yield of 100 gm/kg of biomass used.

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9.4 Electrolysis is a method by which hydrogen may be obtained in pure form. This hydrogen may be used directly in the fuel cells applications. The cost of hydrogen production by this method is high due to high capital investment and operating cost (i.e. electricity consumption). Electricity generated by the solar energy / wind energy / hydro resource may be used to nullify carbon emission in the atmosphere, but these technologies require high capital investment. The electrolyser system consists of various subsystems like electrochemical stack, power rectifiers, control systems, instrumentation for monitoring various processes, water purification, pumps, multistage compressors, pressure vessels, and multiple number of other engineering subsystems involved and requires integration as per customer requirements to develop complete system. Except an electrochemical stack, India has core strength for manufacturing majority of aforementioned subsystems and very much capable in system engineering. Imported electrolyser stacks in different combinations may be used and integration can be carried in the country. The institutions / industry may be identified to work in PPP Model for commercialization of the balance of plant and simultaneously, the technology for the production of stack may be procured or developed indigenously.

9.5 Solid polymer electrolyser (SPE) with 20,000 hours of operation are desirable. SPE is either acid or alkali based, the acid based electrolysis system requires noble metal catalysts, and alkaline membrane based electrolysis require cheaper electro catalyst like Nickel. It is ideal to have membranes based alkaline water electrolysis system integrated with solar photovoltaic system. However, alkaline based SPE faces numerous challenges such as chemical stability in the electrochemical device. These challenges are lesser for either phosphoric acid based electrolysis cells or alkali based electrolysis systems using diaphragm. Due to these problems, the following steps are suggested in the sequential order:

(i) Deployment of solar energy powered a. Acid based electrolysis system b. Alkali based electrolysis system for immediate onsite hydrogen production using available technology. (ii) Development of ectrolysers based on indigenous acid based SPE (iii) Development of alternate alkaline membrane (iv) Development of alkaline SPE based electrolyte system (v) Replacement of old systems by the newly developed systems

9.6 Hydrogen may be produced through dark and photo-fermentation process. The dark fermentation has certain limitations and can yield hydrogen in terms of energy recovery ranging 20 to 30 % of total energy. This process

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may be integrated with photo fermentation, but such a two-stage process is difficult to commercialise. However, theoretically, 12 moles of H2 /mole of glucose can be recovered. If the dark fermentation followed by bio-methantion process may lead to gaseous energy recovery ranging from 50 to 60%. In this process the same reactor may be used for H2 production and later for bio- methanation, which would curtail the operational cost. The mixture of hydrogen and methane so produced is called bio-hymet. The production bio- hymet could be envisioned as renewable source of energy only when it would be produced from renewable sources. Any organic compound which is rich in carbohydrates, fats and proteins could be considered as possible substrate for bio-hymet production. Another path of hydrogen economy has been suggested by the integration of fuel cell system with the bio-hydrogen production system. Such setups may be put strategically near to those places where supply of feedstock is easily available in adequate quantities. The electricity generated by such system may electrify villages in a decentralized manner.

9.7 Bhabha Atomic Research Centre has successfully demonstrated I-S process in closed loop operation in glass/quartz material in the laboratory. It is further planned to demonstrate closed loop operation in metallic construction. Other institutes / organisations will also be roped in depending upon their capabilities. The broad plan is given below:

(i) Design and demonstration of atmospheric pressure operation all metal closed loop system (AMCL). (ii) High pressure operation Bunsen reactor system has been designed and its commissioning is underway. (iii) Design and demonstration of high pressure sulfuric acid decomposition system. (iv) Design and demonstration of hydroiodic acid distillation and decomposition system. (v) Integration of all three high pressure systems to demonstrate, high pressure closed loop process.

The following challenges have been envisaged for the metallic system, which are to be dealt with in this endeavor:

(i) Fabrication of exotic material based equipment, such as Tantalum, Hastelloy, Silicon Carbide etc. (ii) Development of special seals, compatible for high temperature, high pressure and corrosive chemicals for metallic system. (iii) Development of special instrumentation and controls for metallic system.

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9.8 ONGC Energy Centre (OEC) is of the view that three potential thermo- chemical processes (Cu-Cl closed loop cycle, I-S closed loop cycle and I-S open loop cycle) first be studied at engineering scale and compared before deciding to take up at the commercial level. The OEC has planned to study and evaluate alternative materials used in process and plant design, keeping in view the corrosive nature and use of expensive materials in the process. The following work has been undertaken by the Centre: (i) Indigenous membranes are being developed with CSMCRI, Bhavnagar and expected to be completed by January, 2018.

(ii) Development of partially open-loop I-S cycle involving H2S incineration, experimental studies on Bunsen reaction and HI decomposition would be completed within two years with IIP Dehradun. (iii) Work on “Prolonged stability tests of catalysts for HI decomposition reaction of I-S cycle have recently been taken-up jointly with IIT-Delhi. (iv) Suitable materials for design and development of process reactors for I-S cycle are being identified. The work is in progress.

The OEC has planned to start research on identification, development and testing of suitable materials for design and construction of large size indigenous reactors for Cu-Cl process, keeping in view the corrosive nature of materials used in the Cu-Cl process.

9.9 Photo-electrochemical Water Splitting

Indian Oil Corporation Limited Research and Development Centre, Faridabad made a plan to conduct laboratory-scale studies on prospective materials and their performance evaluation. The details are given below:

Core activity 1: Exploration on promising semiconductors/systems: Extensive R & D is required to be undertaken concerning the photo- electrochemical measurements for hydrogen generation via photo-splitting of water by employing the promising semiconductors. Thin films of the semiconductors would be converted into electrode by adopting the standard procedure and to be used in PEC water splitting studies. These thin film working electrodes would be used as photo-sensitive working electrode, in conjunction with platinum counter electrode and saturated calomel electrode (SCE, as reference electrode), at varying electrolyte conditions. Current (I) – Voltage (V) characteristics of PEC cell would be studied, both under darkness and illumination. The performance of PEC cell would be evaluated. Promising material-options in this regard that need to be tested at the next level, which would be involved their integration with pilot-scale hydrogen generation reactor and the performance evaluation of such reactors both under controlled conditions as well under real-time solar illumination.

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Core Activity 2: Scale-up studies and related issues: Solar energy fed pilot-scale hydrogen generation reactors to perform efficiently under field conditions will be developed. The above mentioned two semiconductor systems would be investigated. New promising material/ system would also be incorporated in the work-plan under this activity. Key work elements involved the synthesis of large area electrodes including suitable synthesis methods for preparation of electrodes. First-level up-scaling studies with existing facilities at Dyalbagh Educational Institute, Agra will be done. Electrodes of different dimensions need to be fabricated and tested. Feasibility for scaling of electrodes from 1cm2 to 150 cm2 active area is to be determined by conducting experiments with state of the art instruments at IOCL - R&D. Two routes of large area electrodes shall be explored – one having single large area electrode and the other – several small electrodes connected in suitable configuration. Empirical modeling of performance versus increase in the area of electrodes will be done. Maximum feasible size electrode will be determined that can be incorporated in the reactor. Study on scaling of counter electrode with respect to increase in the area of working electrode and optimization of interconnection design for working and counter electrodes would be done.

III. Studies on reactor design and fabrication.

Core Activity 3: Designing the Reactor: Theoretical modeling of reactor will be designed and tested. Different losses associated with electrode and electrolyte interfaces will be studied. Qualitative and quantitative study of electrolyte and electrode resistance components will be taken up. Feasibility of packaging electrodes in parallel connections, their associated losses and optimum size possible for a reactor will be studied.

Core Activity 4: Fabrication of Reactor: Actual design of the reactor will be taken up after study on electrodes. A lab scale reactor with a twin compartment reactor will be fabricated to support scale-up activities for performance evaluation of electrodes of different sizes. Separate compartments will separate the evolved gases (hydrogen and oxygen).An electronics circuit will be designed to supply constant external bias to the electrodes. Initially battery will be used for supply and subsequently efforts will be laid to try to use photovoltaic panel for supplying external bias to electrodes. A bigger bench scale reactor having the provision of two compartments will also be fabricated with a maximum active area of ~ 900cm2. Benchmark data will be generated by controlled indoor testing with large area illumination continuous light solar simulator.

Core Activity 5: Fabrication of Reactor: Performance is to be evaluated under controlled laboratory conditions. It is planned to set up a continuous

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solar simulator in laboratory which can illuminate electrodes up to a maximum area of~ 900 cm2.

Under real-time solar illumination outdoor field conditions testing will be taken up after laboratory testing. Performance will be evaluated with respect to the real time data obtained from a weather station at IOCL-R&D.

9.10 Presently, Hydrogen Production by non-thermal plasma assisted direct decomposition of hydrogen sulphide is at research and development stage and no commercial technology is available. Electrolysis process consumes 3.6 kWh/Nm3 hydrogen, whereas steam reforming of methane, the traditional approach for hydrogen production demands still higher energy of 4.3 kWh/Nm3 hydrogen. 40% conversion of hydrogen sulphide by thermal decomposition can be achieved at temperature ~ 1500K. Nationally, most of the research in this area has been focused on catalytic/ photocatalytic decomposition of hydrogen sulphide. Hydrogen sulphide under visible light to generate hydrogen is an attractive route of solar energy conversion, because hydrogen is 100% environmentally clean chemical fuel. The Indian Institute of Technology Hyderabad developed the process of non-thermal plasma assisted direct decomposition of hydrogen sulphide into hydrogen and sulphur. Hydrogen production of 0.5 litre/minute was achieved in the laboratory. The reaction conditions can be still improved to decrease the energy consumption. Further R&D is required in this area.

9.11 For the photo-splitting of hydrogen sulphide into hydrogen, extensive work has been carried out in the development of ultraviolet driven photocatalyst for water and hydrogen sulphide splitting. There is need to develop prototype photo reactor for hydrogen production from hydrogen sulphide using solar energy and field trials using gas emitted at refinery sites using a batch type photoreactor. The research on hydrogen generation from hydrogen sulfide and water is still at research level. No commercial process has been developed yet. Nationally, very few groups are working on photocatalytic splitting of water and hydrogen and hydrogen sulphide into hydrogen under visible light. Few research group in BARC are working on photocatalytic degradation of nuclear waste as well as water purification.

Some research teams in IISc, Bangalore are working on TiO2 based photocatalysts for organic waste degradation. In addition to this, some researchers in IIT, Mumbai and Madras, CECRI, Karaikudi, IICT, Hyderabad and few universities in India are working on photodecomposition of organic pollutants. The Centre for Materials for Electronics Technologies (C-MET), Pune is working on hydrogen generation by photocatalytic decomposition of toxic hydrogen sulphide. C-MET is developing new class of photocatalysts which are stable and active under sunlight. C-MET, Pune has developed the prototype photo reactor for hydrogen production from hydrogen sulphide at

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the rate of 8182.8 and 7616.4 µmol/h/g was obtained from nanostructured

ZnIn2S4 and CdIn2S4, respectively under Natural Sunlight. This design is useful for continuous operation at large scale. There is a scope to carry R& D in this area.

9.12 The Institute of Minerals and Materials Technology (IMMT), Bhubaneswar developed functional hybrid nano structures for photo electrochemical water splitting. The different photo-catalytic materials developed for hydrogen production through water splitting, which were continuously operated for 6-7 hours. Among the developed materials like CdS photo-electrodes and CdS nano-crystal powder photo-catalysts with yield of 800-1000 mg/batch, 0.28 wt% P3HT modified CdS with yield of 4087 µmol/h/g and CdS-NaNbO3 core-shell nano-rods with yield of 11,901 µmol/h/g, the CdS-NaNbO3 core-shell nano-rods was found to give maximum hydrogen production. Research & Development may be continued in this area.

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FINANCIAL PROJECTIONS AND TIME SCHEDULE OF PROJECT ACTIVITIES

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10.0 Financial Projections

10.1 Hydrogen Production from Carbonaceous Feed-stock like Natural Gas, Coal etc. using Thermo-chemical Route

(i) Mission Mode Projects: Scaling-up of the process of partial reforming of natural gas for the production of H-CNG for the use in vehicles (upto 2019) - Rs.40 Crore (ii) Research and Development Projects: Development & demonstration of hydrogen production by auto-thermal process (upto 2020) - Rs. 20 Crore (iii) Basic / Fundamental Research Projects: Dissociation of gaseous hydrocarbon fuels to hydrogen using solar energy (upto 2022) - Rs. 10 Crore

10.2 Hydrogen Production from Carbonaceous Source like Biomass Feed- stock as Renewable Source using Thermochemical Route

(i) Mission Mode Projects: Research and development for hydrogen production by gasification of biomass, including demonstration of technology at pilot scale (upto 2020) - Rs. 10 Crore (ii) Research and Development Projects: Hydrogen production by reformation of bio-oil obtained from fast pyrolysis of biomass (upto 2022) - Rs.5 Crore

10.3 Hydrogen Production using Electrolytic Processes - Low and High Temperature Electrolysers

(i) Research and Development Projects: Development & demonstration of 1 Nm3/hr high temperature steam electrolyser and 5 Nm3/hr indigenously developed solid polymer water electrolyser (upto 2020) - Rs. 10 Crore (ii) Research and Development Projects: Development & demonstration of efficient alkaline water electrolyser (upto 2018) - Rs. 10 Crore (iii) Research and Development Projects: Development and demonstration of clean and sustainable hydrogen production by splitting water using renewable energies such as solar energy, wind energy and hybrid systems. This also includes electrolysis, photo-catalysis and photo-electro-catalysis (upto 2022) -Rs. 10 Crore iv) Integration of large capacity electrolysers with wind / solar power units when there are not in a position to evacuate power to grid for providing hydrogen (upto 2022). -Rs. 5 Crore

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10.4 Bio-Hydrogen Production

i) Mission Mode Projects: Development and demonstration of biological hydrogen production from different kinds of wastes like effluents from distillery, brewery, paper mills, wastewater from city, dairy, tannery, slaughter house, chemical & pharmaceutical industries, agro / food processing industry residues like cane molasses, noodle and potato processing, poultry litter, de-oiled algal cakes, food (canteen) waste through dark or/and photo fermentation. Demonstration of prototypes at various levels followed by bench scale and pilot plant. After successful demonstration commercial production may be commenced (Upto 2022) -Rs.20 Crore ii) Mission Mode Projects: Hydrogen production by water splitting using photolysis using solar energy (Upto 2022) -Rs.40 Crore iii) Research and Development Projects: Hydrogen production together with methane through biological processes from different kinds of organic wastes, including industrial effluent. Energy balance and process economic aspects may also be studied (Upto 2019) - Rs.10 Crore iv) Research and Development Projects:Development of

technology for production of syn-gas (CO+H2)and hydrogen from reformation of natural gas / biogas using solar energy (up to 2022. - Rs.5 Crore

10.5 Hydrogen Production through Thermochemical Cycles

Mission Mode Projects: Hydrogen production by water splitting using thermo-chemical route (open / closed loop Iodine-Sulphur cycle and Copper – Chlorine cycle) using solar / nuclear heat (upto 2022) - Rs.50 Crore

10.6 Other innovative method for hydrogen production such as hydrogen production by non-thermal plasma assisted direct decomposition of hydrogen sulphide, Photo-splitting of Hydrogen Sulphide including developmental effort for reduction in energy consumption for hydrogen production (up to 2022). -Rs.20 Crore

10.7 Projects for utilization of byproduct hydrogen at Chlor-Alkali units / refineries: Development and demonstration of prototype systems for purification of by-product hydrogen from Chlor-Alkali units / refineries for the use in fuel cells to generate power for captive use or its

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compression for filing in cylinders to use them on-board in hydrogen fueled vehicles / material handling systems (based on fuel cell technology) (Upto 2019) - Rs.20 Crore ______Total requirement (Upto 2022) -Rs.285 Crore ______

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Setting-up of purification unit / compression system to fill cylinders to utilize surplus 20 hydrogen from the Chlor-Alkali Units / Refineries

Scaling-up of the process of partial reforming of 40 natural gas for the production of H-CNG

Development and demonstration of biological hydrogen production from different kinds of wastes 20

1 Mission Mode Projects Phase I Phase II Phase III Bench Scale Pilot Scale Commercial

Production

Hydrogen production by water splitting through photolysis using solar energy 40

Demonstration of closed loop operation of I-S in metallic reactor and both 50 I-S open & closed loop process and Cu-Cl cycle using solar / nuclear heat

SUB-TOTAL 170

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Hydrogen production by Auto-thermal Process 20

Hydrogen production by gasification of biomass including

demonstration of technology at pilot scale 10

Development, and demonstration of

electrolyser with indigenous acid based SPE & 10 alternate alkaline membrane and its deployment to replace old systems

Development and demonstration of Hydrogen production by splitting water using 10 renewable energies

Hydrogen production by reformation of bio-oil obtained from fast pyrolysis of biomass 5

Development of technology for production of syn-gas (CO+H ) and hydrogen from 2 5 reformation of natural gas / biogas using solar energy.

Integration of large capacity electrolysers with wind / solar power units, which is not in a position to evacuate power to grid, for generation of hydrogen and its storage 5

SUB-TOTAL 85

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Dissociation of gaseous hydrocarbon fuels to hydrogen using solar energy 10

GRAND TOTAL 285

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CONCLUSIONS AND RECOMMENDATIONS

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11.0 Conclusions and Recommendations

11.1 Conclusions

11.1.1 Hydrogen has been widely used in chemical industries to manufacture fertilizers, chemicals, ammonia, saturated fatty acids (vanaspati ghee), etc. Its use in non-energy applications is expected to increase further in coming years substantially. It is an energy career and not a primary source of energy. It is gaining importance as a futuristic clean (pollution free) and sustainable (on the basis of its production from renewable sources of energy) fuel for stationary power generation and transportation. Hydrogen may be produced from direct or indirect source of energy and hydrocarbon. The fossilized carbonaceous feed stocks, like natural gas, naphtha or coal, etc., (source of hydrocarbon and chemical energy) are being used for producing hydrogen through steam reforming, plasma reforming, coal gasification, partial oxidation, and co-conversion using steam. Hydrogen is also being produced from electrolysis of water.

11.1.2 The conventional carbonaceous feed stocks are limited. The non- fossilized renewable carbonaceous materials, such as biomass, agro-waste, rubber wastes, urban solid waste, de-oiled seed cakes, waste cooking oil etc. contain carbon and may be used for producing hydrogen. All these feed- stocks emit CO2 (a greenhouse gas) and other polluting gases. Hydrogen is also produced through low or high temperature electrolysis of water, which is abundantly available on earth. The electricity used for this process may be generated using fossil fuels or through the use of solar energy / wind energy.

11.1.3 In view of the current developments and efforts at the national level for the deployment of fuel cells as the back-up power system for the telecom towers and demonstration of vehicles based on the hydrogen IC engine technology as well as fuel cells, it is the right time to set-up hydrogen production facilities on small, medium and large scales to derive meaningful insights regarding realisation and management of hydrogen energy infrastructure in the country.

11.1.4 Substantial quantity of surplus hydrogen is available as byproduct hydrogen. It may be tapped to meet immediate requirement for research, development and demonstration of various hydrogen based projects. The Government may consider extending support to create facilities for tapping this hydrogen. In India, currently the byproduct hydrogen amounting to around 6600 tonnes hydrogen (10% of total byproduct hydrogen) is available as unutilized with the Chlor-Alkali units. This hydrogen may be further purified (if required), compressed, bottled and transported to the sites for use in stationary power generation and on-board application in vehicles / material

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handling systems, etc. This surplus volume of by-production hydrogen is, however, quite small to meet the future needs of the gas for energetic uses. A concerted effort is required to transform the laboratory results into hydrogen production facilities.

11.1.5 Biomass can be processed (pyrolysed / gasified) for obtaining hydrogen rich syn-gas. The hydrogen needs to be separated out and purified to different levels of purity depending on the application needs from the hydrogen rich syn-gas. The biomass is considered to be easily available in large quantities. The research outcome of biomass gasification suggests addressing to the need of hydrogen generation from biomass through the thermo-chemical conversion process. The R&D experience in the country on the biomass gasification is rich and can be utilized for technology development of hydrogen production. Internationally, hydrogen generation by gasification is being pursued and shortlisted as an economical way to address to hydrogen production problem.

11.1.6 Water can be decomposed into hydrogen and oxygen through electrolysis. It is an energy intensive process. The available technologies in the world’s market are alkaline and solid polymer electrolyte (SPE) based water electrolyser. Alkaline water electrolysis is cheaper due to use of nickel catalysts, but efficiency is lower (60-75%) than that (65–90%) of SPE water electrolysers, which are expensive due to the use of noble metal catalyst (e. g. platinum) and are operated at higher current densities. The SPE water electrolysers are possibly, capable of producing cheaper hydrogen, if its production is taken up on large scale. The efficiency of SPE water electrolyser is more at higher temperature and pressure (around 120-200 bar). In high pressure electrolysis external hydrogen compressor is eliminated and hence around 3 % as average energy consumption for compression of hydrogen is saved. This SPE based electrolysis process can also be operated with the electricity generated from the solar photovoltaic systems or wind mills, which have large potential. Several large installations coupling solar energy or wind farms with water electrolysers have come up world over. Most of these are implemented through consortium of several companies. SPE technology up to 1 Nm3/h has been developed indigenously and its technology has been transferred to industry.

11.1.7 The thermo-chemical cycles are processes, where water is decomposed into hydrogen and oxygen via a series of chemical reactions using intermediates, which are recycled. As the heat can be directly used, these cycles have the potential of a better efficiency than alkaline electrolysis. The required energy can be either provided by nuclear energy / solar energy. The iodine-sulfur closed & open loop (I-S) cycle and Cu-Cl closed loop cycle are most promising and efficient thermo-chemical water splitting technologies

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for the massive production of hydrogen. BARC has successfully demonstrated in the I-S closed loop operation in glass / quartz materials in the country. It has been planned to take-up demonstration of the same process in metal construction. The ONGC Energy Centre (OEC) has set-up an engineering scale plant for Cu-Cl closed loop cycle process, which will be operated for one year and alternative materials for platinum as electrode has been undertaken for development at this plant. OEC is also working with CSMCRI, Bhavnagar on indigenous development of polymeric charged membranes for thermochemical hydrogen generation processes; with IIP, Dehradun for the development of partially open-loop I-S cycle involving H2S incineration & experimental studies on Bunsen reaction and HI decomposition and with IIT Delhi on prolonged stability tests of catalysts for HI decomposition reaction of I-S cycle. OEC has also planned to carry out research on identification, development and testing of suitable materials for design and construction of large size indigenous reactors for Cu-Cl process, keeping in view the corrosive nature of materials used in the Cu-Cl process.

11.1.8 Hydrogen can be produced from dark fermentation (equivalent to 20 to 30% of the total energy content of the feed). This process followed by photo fermentation, 12 moles of H2 /mole of glucose can be recovered theoretically, but it is difficult to integrate the two processes for commercialization. The dark fermentation can be integrated with the bio-methantion process (to yield 50-60% gaseous energy recovery), where methane may be produced from the spent media of the dark fermentation, which is rich in volatile fatty acids that is an ideal substrate for methanogens. The most attractive point of such a process is that both the processes may be carried out one after the other in the same reactor (H2 production followed by bio-methanation. So, separate reactor is not required. This would lead to decrease in operational cost of the entire process. Bio-hythane production may be envisioned as renewable source of energy only when it would be produced from renewable sources. Any organic compound which is rich in carbohydrates, fats and proteins could be considered as possible substrate for bio-hymet production.

11.1.9 Steam-methane reforming (SMR) and coal gasification are the technologies established globally for hydrogen production. They are commercially ready, though the cost is high. Still there is scope for carrying out R&D activities for coming out with cheaper catalysts and efficient reforming units.

11.1.10 Auto-thermal reformers (ATRs) combine some of the best features of steam reforming and partial oxidation systems. Several companies are developing small auto-thermal reformers for converting liquid hydrocarbon fuels to hydrogen for the use in fuel cell systems. The auto-thermal reformer requires no external heat source and no indirect heat exchangers. Heat

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generated by the partial oxidation is utilized to drive steam reforming reaction. This is more compact than steam reformers, and it will have a lower capital cost and higher system efficiency than partial oxidation systems. Auto-thermal reformers are being developed for PEMFC system by a number of groups.

11.1.11Solar hydrogen production from direct photo electrochemical (PEC) water splitting is the ultimate goal for a sustainable, renewable and clean hydrogen economy. In PEC water splitting, hydrogen is produced from water using sunlight and specialized semiconductors called photo electrochemical materials, which use light energy to directly dissociate water molecules into hydrogen and oxygen. Indian R & D organisations are engaged in the extensive R & D of photo-electrochemical technology.

11.1.12 The efforts are required to develop other/new innovative method for hydrogen production, like hydrogen production by non-thermal plasma assisted direct decomposition of hydrogen sulphide, Photo-splitting of Hydrogen Sulphide including developmental effort for reduction in energy consumption for hydrogen production

11.1.13 To start with, the country may adopt technologies from abroad, especially to build large installations, for which we may not have the expertise straightaway. For medium and small installations, Indian R & D organisations and industries could chip in well.

11.1.14 The Ministry may constitute a group of experts, which may review from time to time, the plan and actual development and deployment of hydrogen based systems and devices in the field in order to assess the future hydrogen requirement. The group will then suggest ways and means to fulfil hydrogen requirement through various technologies being developed in the country or to be imported from abroad.

11.2 Recommendations

11.2.1 India has announced its Climate Action Plan for reduction of emissions by 33-35% by 2030 over the 2005 levels, boosting clean (non-fossil & including renewable) energy in electricity generation to 40% (at least another 150GW), while adding carbon sinks — tree and forest cover to remove carbon dioxide from the atmosphere — amounting to 2.5-3 billion tonnes of CO2 by 2030. Thus, the country has targeted to enhance nuclear power from 5 GW to 63 GW by 2032 and doubling wind capacity to 60 GW by 2022, solar capacity from 4 GW to 100 GW by 2022.

11.2.2 In view of the India’s Climate Action Plan, the technologies for hydrogen production may be targeted accordingly. The first target may be

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focused on the efficient utilization of byproduct hydrogen of the Chlor-Alkali units. At the end of the financial year 2014-15, only 10% of byproduct hydrogen is available. Remaining 90% byproduct hydrogen is being utilized, ~40% in chemical industries,~37% as fuel in boiler heating for captive use and ~13% being bottled for sale.After utilization of surplus un-utilized 10% byproduct hydrogen, next target may be made to utilize ~37% hydrogen efficiently, which is currently being used as fuel in boiler heating for captive use. Alternate sources may be used for heating purpose. In-house stationary power generation may be one of the most effective ways of utilizing hydrogen. The government may consider incentivizing this application of hydrogen for its cost effective utilization.

11.2.3 The present facilities of hydrogen production may be utilized to supply hydrogen for purpose of carrying out the activities on the research, development and demonstration for hydrogen production and its applications for stationary power generation and vehicles.

11.2.4 From the gap between international and national state of art of technologies, it has been visualized that India has to take a leapfrog to come at par with the international level. This gap is to be planned in time bound project mode (with foreign collaboration, if required) and therefore, the projects may be classified in the following three categories viz. National Mission Projects, Research & Development projects and Basic / Fundamental Research projects:

11.2.5 The National Mission Projects may cover projects with the participation of the industry for the technologies, which are mature or near maturity for commercialization after the short development time and those may be taken up on large scale demonstration. Such projects would be multi-disciplinary in nature. These projects may involve more than one institution (with a lead institution), which are already involved in the implementation of research & development activities. The outcome of such projects should be a compact, comprehensive, marketable and user friendly product. The resources and the infrastructure facilities of the involved institutions may be pooled together to achieve the common goal.

11.2.6 The Research & Development projects may include the projects in which the technology is at the stage of prototype development and its demonstration as a proof of concept. Industry participation should be preferred for these projects. Such projects may be undertaken on different subjects like design, research & development of the individual system components, sub-systems, integration of systems after the basic research has shown encouraging results. Engineering research and development must be a part of such projects.

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11.2.7 The Basic / Fundamental Research projects will cover search / development of new materials for the development of components, catalysts and new processes in the area of hydrogen production.

11.2.8 These categories may be further elaborated as under:

a) Mission Mode Projects

(i) Development and demonstration of biological hydrogen production from different kinds of wastes like effluents from distillery, brewery, paper mills, wastewater from city, dairy, tannery, slaughter house, chemical & pharmaceutical industries, agro / food processing industry residues like cane molasses, noodle and potato processing, poultry litter, de- oiled algal cakes, food (canteen) waste through dark or/and photo fermentation. Demonstration of prototypes at various levels followed by bench scale and pilot plant. After successful demonstration commercial production may be commenced. (ii) Research and development for hydrogen production by gasification of biomass, including demonstration of technology at pilot scale. (iii) Hydrogen production by water splitting using photolysis and thermo-chemical route using solar and nuclear heat.

b) Research and Development Projects

(i) Hydrogen production together with methane through biological processes from different kinds of organic wastes, including industrial effluent. Energy balance and process economic aspects may also be studied. (ii) Development & demonstration of 1 Nm3/h high temperature steam electrolyser (HTSE) and 5 Nm3/h indigenously developed solid polymer water electrolyser (SPWE). (iii) Development & demonstration of efficient alkaline water electrolyser. (iv) Development and demonstration of clean and sustainable hydrogen production by splitting water using renewable energies such as solar energy, wind energy and hybrid systems. This also includes electrolysis, photo-catalysis and photo-electro-catalysis.

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c) Basic / Fundamental Research Projects

(i) Dissociation of gaseous hydrocarbon fuels to hydrogen using solar energy. (ii) Any other innovative method for hydrogen production, like hydrogen production by non-thermal plasma assisted direct decomposition of hydrogen sulphide, Photo-splitting of Hydrogen Sulphide, including developmental effort for reduction in energy consumption for hydrogen production

(d) Projects for Utilization of Byproduct Hydrogen at Chlor-Alkali Units / Refineries

Development and demonstration of prototype systems for purification of by-product hydrogen from Chlor-Alkali units / refineries for the use in fuel cells to generate power for captive use or its compression for filing in cylinders to use them onboard in hydrogen fueled vehicles / material handling systems (based on fuel cell technology).

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BIBLIOGRAPHY

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12.0 Bibliography

12.1 Hydrogen Production from Carbonaceous Biomass Feed-stock using Thermochemical Route

1. Konieczny A, Mondal K, Wiltowski T, Dydo P.,Catalyst Development for Thermocatalytic Decomposition of Methane to Hydrogen. 33, 2008, Int J Hydrogen Energy, pp. 264–272. 2. Meng Ni, Dennis Y.C. Leung, Michael K.H. Leung, K. Sumathy. An Overview of Hydrogen Production from Biomass. Fuel Processing Technology 87 (2006) 461 – 472 3. Sandeep K, Dasappa S. Oxy–steam Gasification of Biomass for Hydrogen Rich Syngas Production using Downdraft Reactor Configuration. International Journal of Energy Research, 2014, 38, pp. 174–188. 4. Mukunda H S, Dasappa S, Shrinivasa U. Open-Top Wood Gasifier (Renewable Energy – Sources for Fuels and Electricity). S. l. : Island Press. pp. 699-728. 5. Dasappa S, Paul, P J Mukunda, H S, Rajan, NKS, Sridhar, G., Sridhar. H V., Biomass Gasification Technology – A Route to Meet Energy Needs, Current Science, 2004, 87( 7), pp. 908-916. 6. Tuomi, S., Kurkela, E., Simell, P., and Kaisalo, N., Gasification Concept Testing for Dual Fluidized-bed based SNG Process, VTT Technical Research Centre of Finland, POB 1000, FI-02044 VTT, Espoo, Finland. Proceedings of the ICPS – 2013, pages 397-472. 7. Bridgewater, A. V., Renewable Fuels and Chemicals by Thermal Processing of Biomass, Chemical Engg. Journal, 2003, 91, pp. 87- 102. 8. Ahmed, I., Gupta, A. K., Characteristic of Hydrogen and Syngas Evolution from Gasification and Pyrolysis of Rubber., Int J Hydrogen Energy, 2011, 36, pp. 4340–4347. 9. Ahemad, I., Gupta, A. K., Kerdsuwan, S., Nipattulmmakul, N., Hydrogen and Syngas Yield from Residual Branches of Oil Palm Tree Using Steam Gasification, Int J Hydrogen Energy 2011, 36, pp. 3835–3843. 10. Turn, S., Kinoshita, C. Zhang, Z., Ishimura, D., Zhou. J., An Experimental Investigation of Hydrogen Production from Biomass Gasification, Int J Hydrogen Energy , 1998, Vol. 23(8), pp. 641-648. 11. Pengmei L V, Yuana Zhenhong, Longlong Maa, Chuangzhi Wua, Yong Chena, Jingxu Zhu, Hydrogen-rich Gas Production from Biomass Air and Oxygen/Steam Gasification in a Downdraft Gasifier, Renewable Energy 10/2007; 32(13):2173-2185.

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12. Wei, L., Xu, S., Zhang, L., Liu, C., Zhu, H., Liu, S., Steam Gasification of Biomass for Hydrogen-rich Gas in a Free-fall Reactor, Int J Hydrogen Energy , 2007, 32, pp. 24–31. 13. Pereira, E. C., Silva, J. N., de Oliveira, J. L., Machado, C. S., Sustainable Energy: A Review of Gasification Technologies, Renewable and Sustainable Energy Reviews, 2012, 16, pp. 4753– 4762. 14. Arnavat, M. P., Bruno, J. C., Coronas, A., Review and Analysis of Biomass Gasification Models, Renewable and Sustainable Energy Reviews, 2010, 14, pp. 2841–2851. 15. Dasappa, S. Shrinivasa, U., Baliga, B. N., Mukunda, H. S., Five Kilo Watt Wood Gasifier Technology: Evolution and Field Experience, Sadhana , 1990, Vol. 14(3), pp. 187-212. 16. Peters, J. F., Petrakopoulou, F, Dufour J., Exergetic Ananlysis of a Fast Pyrolysis Process for Bio-oil Production, Fuel Processing Technology, 2014, 119, pp. 245–255. 17. Abuadala, A, Dincer, I., Naterer, G. F., Exergy analysis of hydrogen production from biomass gasification, International Journal of Hydrogen Energy , 2010, 35, pp. 4981–4990. 18. Prins, M. J.,Ptasinski,, K. J., Janssen, F. J. J. G., Thermodynamics of Gas-Char Reactions: First and Second Law Analysis, Chemical Engineering Science, 2005, 58, pp. 1003 – 1011. 19. Silva V B, Rouboa A., Using a Two-stage Equilibrium Model to Simulate Oxygen-Air Enriched Gasification of Pine Biomass Residues., Fuel Processing Technology, 2013, 109, mpp. 111– 117. 20. Ptasinski K J, Prins M J, Pierik A., Exergetic Evaluation of Biomass Gasification, Energy, 2007, Vol. 32 (4), pp. 568–74. 21. Karamarkovic R, Karamarkovic V., Energy and Exergy Analysis of Biomass Gasification at Different Temperatures. Energy, 2010, 35, pp. 537–549. 22. Sues A, Juras M, Ptasinski K J., Exergetic Evaluation of 5 Biowastes-to-Biofuels Routes via Gasification, Energy, 2010, 35, pp. 996–1007. 23. Lucasa, C.,Szewczyka, D., Blasiaka, W., Mochida, S., High Temperature Air and Steam Gasification of Densified Biofuels. 27, 2004, Biomass and Bioenergy, pp. 563–575. 24. Umeki, K., Yamamoto, K., Namioka, T., Yoshikawa. K, High Temperature Steam-only Gasification of Woody Biomass. 87, 2010, Applied Energy, pp. 791-798. 25. Dasappa, S., Experimental and Modeling Studies on the Gasification of Wood-char. Ph.D. thesis. Indian Institute of Science, India. 1999.

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26. Generator Gas "The Swedish Experience from 1938-1945 (translation)", Solar Energy Research Institute, Colorado, NTIS/Sp.33-140. SERI, 1979 27. http://mnre.gov.in/ 28. www.ankurscientific.com/ 29. http://www.teriin.org/ 30. http://www.spreri.org/ 31. CGPL–2009 http://cgpl.iisc.ernet.in/site/Home/tabid/36/Default.aspx 32. Fail S., Diaz, N., Konlechner, D., Hackel, M., Sanders, E., Rauch, R., Harasek, M., Bosch, K., Schwenninger, F., Zapletal, P., Schee, Z., and Hofbauer, H., .An Experimental Approach for the Production of Pure Hydrogen Based on Wood Gasification, Presented at the 13th International conference on Polygeneration Strategies, Vienna, Austria 2013.

12.2 Gasifiers, Reformers and Electrolysers

1. Winter C. J., International Journal of Hydrogen Energy 34(2009), S1-S52 2. Bastien J. and Handler C., IEEE 2006, 1-4244-0218-2/06 3. www.eai.in 4. Nouni M. R., Green Power 2008, Intenational Conference cum Exhibition on Renewable Energy Technologies, 2008 5. www.ITM–power.com 6. Wendt H. Water Splitting Methods. In: Winter C.-J., Nitsch J, editors. Hydrogen as an Energy Carrier – Technologies, Systems, Economy, Springer Verlag; 1988 7. www.hysolar.com 8. LIrong Ma, Sheng Sui, Yuchun Zai, International Journal of Hydrogen Energy, 2009, 34:678-84 9. Rubin E. S., 4th Annual SECA, 2003 10. www.thuega.de 11. www.dvnkema.com 12. www.afhypac.com 13. Fuel Cell Industry Review 2012 (www.fuelcelltoday.com) 14. National Hydrogen Energy Board, Ministry of New and Renewable Energy, New Delhi, National Hydrogen Energy Road Map – 2006 (abridged report – 2007) 15. Nouni M. R., Akhshay Urja (Renewable Energy) News Letter 5(5), 2012, 10-15, 16. Minsitry of New and Renewable Energy, Presentation to IPHE Steering Committee, 2012 17. Central Electrochemical Research Institute, Kraikkudi – Brochure, PEM based Hydrogen Generator

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18. Rengarajan Balaji, Natarajan Senthil, Subramanyan Vasudevan, Subbiah Ravichandran, Swaminathan Mohan, Ganapathy Sozhan, Sonanatha Madhu, Jeevarathanam Kennedy, Subramanian Pushpavanam, Malathy Pushpavanam, International Journal of Hydrogen Energy, 36 (2011), 1399 – 1403 19. Venkatkarthick R., Elamathi S., Sangeetha D., Balaji R., Suresh Kannan B., Vasudevan S., Jonas Davidson D., Sozhan G., Ravichandran S., Journal Electroanalytical Chemistry, 697, 2013, 1 – 4 20. www.newIndpress.com 21. International Symposium & Exhibition on Fuel Cell Technologies, FUCETECH 2009, 11th - 13th November, 2009, Nehru Centre, Worli, Mumbai 22. Basu, S., Second International Conference on Hydrogen and Fuel Cells, Dec 1 - 3, 2013, Goa 23. Basu, S., Workshop on On-board Power Source for Defense and Aerospace applications, R C I Hyderabad, DRDO, June 2014 24. UKH2 Mobility: Synopsis of Phase 1 Results, February 2013 25. http://energy.gov/articles/energy-department-launches-public- private-partnership-deploy-hydrogen-infrastructure

12.3 Hydrogen Production using Electrolytic Processes - Low and High Temperature Electrolysers

1. Magnet, H. R., and Berger, C., "Handbook of Fuel Cell Technology," Prentice- Hall, Englewood Cliffs, NJ, USA, p. 425, 1968. 2. Bockris, J. O., and Srinivasan, S., Fuel Cells: Their Electrochemisry, New York: McGraw-Hill, 1969. 3. Smitha, B., Sridhar, S., and Khan, A. A., Journal of Membrane Science, vol. 259, pp. 10-26, 2005. 4. Yoko, , H., Sodaye, H., Shibahara, Y., Honda, Y., Tagawa, S., and Nishijima, S., Polymer Degradation and Stability, vol. 95, no. 1, pp. 1-5, 2010. 5. B. Bahar, A. R. Hobson, J. A. Kolde and D. Zuckerbrod, U.S. Patent 5,547,551 (1996). 6. Wei, J., Stone, C., and Steck, A.,.Patent 5422411, June 1995. 7. S. Heitala, S., M. Paronen, M., S. Holmberg, S., J. Nasman, J., Juhanoja, J., Karjalainen, M., Serimaa, R., Tivola, M., Lehtinen, T., . Parovuori, K., Sundholm, G., Ericson, H., Mattsson, B., Torell, L., and F. Sundholm, F., Journal of Polymer Science, vol. 37, pp. 1474- 1753, 1999. 8. Sodaye, H. S., Prabhakar, S., and Tewari, P. K., in National Seminar on Membrane Science & Technology: Challeges and Opportunities, Jorhat, 2004.

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9. Wang, F., Hickner, M., Kim, Y. S., Zawodzinski, T. A., and McGrath, J. E., Journal of Membrane Science, vol. 197, pp. 231- 242, 2002. 10. Lafitte, B., Karlsson, L. E., and Jannasch, P., Rapid Macromol Commun, vol. 23, pp. 896-900, 2002. 11. Rikukawa, R., and Sanui, K., Progress Polymer Science, vol. 25, pp. 1463-1502, 2000. 12. Genies, C., Mercier, R., Sillion, B., Corner, N., Gebel, G. and Pineri, M., Polymer, vol. 42, pp. 359-373, 2001. 13. Lawrence, R., USA Patent 4214969, July 1980. 14. K. D. Kreuer, Journal of Membrane Science, vol. 185, p. 13, 2001. 15. Jochen, K., Andreas, U., Frank, M., and Thomas, H., Solid State Ionics, vol. 125, no. 1-4, pp. 243-249, 1999. 16. Haiqui, Z., Li, X., Zhao, C., Fu, T., Shi Y., and. Na, H., Journal of Membrane Science, vol. 308, no. 1-2, pp. 66-74, 2008. 17. Thomas, T., and Jari, I. K., Journal of Membrane Science, vol. 313, no. 1-2, pp. 86-90, 2008. 18. Haubold, H. G., Vad, T., Jungbluth, H., and Hiller, P., Electrochim Acta, Vol. 46, pp. 1559-1563, 2001.

12.4 Bio-Hydrogen Production

1. Armor, J. N., “The Multiple Roles for Catalysis in the Production of

H2”, Applied Catalysis A: General. 1999; 176: 159-176. 2. Benemann J R. Hydrogen Biotechnology: Progress and Prospects. Nature Biotechnol 1996; 14:1101–3. 3. Momirlan M, Veziroglu T N. Current Status of Hydrogen Energy. Renewable Sustainable Energy Rev. 2002; 6:141–179.

4. Collet C., Adler N., Schwitzguébel J P., Paul Péringer P., Hydrogen Production by Clostridium thermolacticum during Continuous Fermentation of Lactose, Int J Hydrogen Energy. 2004; 29(14): 1479-1485. 5. Oh, Y. K., Kim S. H., Kim, M. S., and Park, S., Thermophilic Biohydrogen Production from Glucose with Trickling Biofilter. Biotech Bioengineering. 2004; 88(6): 690–698. 6. Potential for Wastewater Treatment Systems Based on Microbial Fuel Cells and Biological Hydrogen Production. ACS, Division of Environmental Chemistry - Preprints of Extended Abstracts. 2004; 44(2):1474-1477. 7. Zangh H., Logan B., Biological Hydrogen Production from an Unsaturated, Packed-bed Bioreactor. ACS National Meeting Book

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of Abstracts 2004: 228(1); 300. Abstracts of Papers - 228th ACS National Meeting; Philadelphia 8. Degliuomini L.N., Biset S., Luppi P., Marta S. Basualdo, A Rigorous Computational Model for Hydrogen Production from Bio-ethanol to Feed a fuel Cell Stack, Int J Hydrogen Energy. 2012; 37(4): 3108- 3129. 9. Vatsala, T.M., Raj, M., Manimaran, A., A Pilot-scale Study of Biohydrogen Production from Distillery Effluent using Defined Bacterial Co-culture. Int J Hydrogen Energy. 2008; 33(20): 5404- 5415.

12.5 Hydrogen Production through Thermochemical Cycles (Iodine- Sulphur Cycle)

1. Zhang, P., et al., Overview of Nuclear Hydrogen Production Research through Iodine-Sulfur Process at INET, International Journal of Hydrogen energy, 35 (2010 ) 2883 – 2887. 2. IAEA Nuclear Energy Series, No. NP-T-4.2 Hydrogen Production Using Nuclear Energy, 2013 3. Status of HTTR Project in JAEA, Hirofumi OHASHI, Technical Meeting on the Safety of High Temperature Gas Cooled Reactors in the Light of the Fukushima Daiichi Accident, 8 - 11 April 2014, IAEA Headquarters, Vienna, Austria 4. Greg F. Naterer, Ibrahim Dincer, Calin Zamfirescu Hydrogen Production from Nuclear Energy, Springer, 2013

12.6 Hydrogen Production by Photo-electrochemical Water Splitting

1. Kudo, A., Miseki, Y. Heterogeneous photocatalyst materials for water splitting. Chem. Soc. Rev. 2009, 38, 253–278. 2. Kamat, P.V. Graphene-based nano architectures. Anchoring semiconductor and metal nano particles on a two-dimensional carbon support. J. Phys. Chem. Lett. 2010, 1, 520–527. 3. H. Matsushima, T. Nishida, Y. Konishi, Y. Fukunaka, Y. Ito and K. Kuribayashi, Electrochim. Acta, 48 (2003) 4119. 4. Guttman F and Murphy OJ, Modern Aspects of Electrochemistry. New York: Plenum Press, 1983.

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ANNEXURE

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ANNEXURE

13.0 Publications and Patents pertaining to Hydrogen Production through Thermochemical Routes (I-S & Cu-Cl)

13.1 Publications

1. G. D. Yadav, P.S. Parhad, A. B. Nirukhe and S. B. Kamble. Study of Hydrogen Generation using Copper and Hydrochloric Acid. Presented at Chemcon-2008, IIChE Annual congress held in Chandigarh, India during December 27-30, 2008. 2. D. Parvatalu, A. Bhardwaj and B.N. Prabhu.Technical challenges in generation of Hydrogen through thermo-chemical processes: ONGC perspective. Poster paper presented at PETROTECH-2009 held in Delhi, India during January 11-15, 2009.

3. A. Bhardwaj, D. Parvatalu, and B.N. Prabhu. Closed-loop Thermo- chemical Cycles for Hydrogen Production: Fuel for Tomorrow. Poster paper presented PETROTECH-2009 held in Delhi, India during January 11-15, 2009.

4. A. Bhardwaj, D. Parvatalu, and B.N. Prabhu. Hydrogen Production by Closed-loop Thermo-chemical Cycles: A Review of S-I Process. Paper presented at the National Conference on Energy held at Punjab University, Chandigarh, India during March, 2009.

5. V. Immanuel, K. U. Gokul, S. Sant and A. Shukla. Membrane Electrolysis of Bunsen Reaction. Presented at CHEMCON-2009, IIChE annual congress held in Visakhapatnam, India duringDecember 27-30, 2009,

6. D. Parvatalu, A. Bhardwaj and B. N. Prabhu. Electrochemical Routes Need Better Understanding in Managing Closed- loop Hybrid Thermo- chemical Hydrogen Generation Cycles. Paper presented at 15th National convention of Electrochemists held at VIT-University, Vellore, India during February18-19, 2010.

7. A. Bhardwaj, D. Parvatalu, and B.N. Prabhu. Study of the Alternate Route in Closed-loop Thermo-chemical Cycles for Hydrogen Production: fuel for tomorrow. Poster presentation at PETROTECH-2010 held in Delhi, India during October 31-November 4, 2010.

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8. A. Bhardwaj, D. Parvatalu, B.N. Prabhu and N.J. Thomas. Future Energy and Hydrogen. Oral presentation at 17th IORS, held in Mumbai, India during September 9-10, 2010.

9. D. Parvatalu, Anil Bhardwaj and B.N. Prabhu. Impact of Electrochemical Routes on thermochemical Hydrogen Generation Technologies. Poster presentation at ISAEST-9, held in Chennai, India during December 2- 4, 2010.

10. V. Immanuel, K. U. Gokul and A. Shukla. Membrane Electrolysis of Bunsen Reaction for the Iodine-Sulfur Process for Water Splitting. Presented at ISAEST-9, held in Chennai, India during December 2-4, 2010.

11. P. K. Sow and A. Shukla. Investigations on Electro-electrodialysis Cell

for Concentration of HIx. Presented at ISAEST-9, held in Chennai, India during December 2-4, 2010.

12. G. D. Yadav, A. B. Nirukhe and P.S. Parhad. Kinetic Study of Hydrolysis of Cupric Chloride in Cu-Cl Thermochemical Hydrogen Production. Presented at CHEMCON-2010, IIChE annual congress held at Annamalai University, Chidambaram, India during December 27-29, 2010.

13. G. D. Yadav, P.S. Parhad and A. B. Nirukhe. Study of Electrolysis of Cuprous Chloride. Presented at CHEMCON-2010, IIChE annual congress held at Annamalai University, Chidambaram during December 27-29, 2010.

14. P. K. Sow, S. Santand A. Shukla. EIS Studies on Electro-electrodialysis Cell for Concentration of Hydroiodic Acid. Int J Hydrogen Energy, 2010; 35: 8868–8875. 15. D. Parvatalu, Anil Bhardwaj and B.N. Prabhu. Development of thermochemical Hydrogen Production by Closed-loop Cycles: ONGC initiatives. Oral presentation at ICRE-11 held at CNRE, Univ. Rajasthan, Jaipur, India during January 17-21, 2011.

16. D. Parvatalu, A. Bhardwaj and B.N. Prabhu. Gearing up for Large Scale Thermochemical Hydrogen Generation Technologies: ONGC Initiatives. Oral presentation at ICSN 2011 held at Univ. Mumbai, Mumbai, India during February 14-16, 2011.

17. D. Parvatalu, A. Bhardwaj and B.N. Prabhu. Opportunities and Challenges Associated with Thermochemical Hydrogen Generation Technologies: A Perspective in Indian Context. Presented at ICAER

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2011 held at IIT-Bombay, Mumbai, India during December 9-11, 2011.

18. D. Parvatalu, A. Bhardwaj and B.N. Prabhu. Application of Electrochemical Technologies in Establishing Closed-loop Thermochemical Hydrogen Generation Cyclic Processes: ONGC Initiatives. Oral Presentation at NCE-16 (National Convention of Electrochemists) held at P.S.G.R.K. College, Coimbatore, India during December 15-16, 2011.

19. K. Kondamudi, P. Kotari and S. Upadhyayula. Numerical Study of SulfurtriOxide Decomposition over Complex Catalyst Shapes and Sizes in S-I Cycle for Hydrogen Production. Presented at Europacat X held at University of Glasgow, Glasgow, UK during August 28 – September 2, 2011.

20. K. Kondamudi, A.N. Bhaskarwar, S. Upadhyayula, B.N. Prabhu, Anil Bhardwaj and D. Parvatalu. Kinetic Studies of Sulfuric Acid Decomposition over Alumina Supported Iron (III) Oxide Catalyst in the SI Cycle for Hydrogen Production. Presented at ICRE-2011, held in Jaipur, India during January 17-21, 2011.

21. K. U. Gokul, V. Immanuel, S. Sant and A. Shukla. Membrane Electrolysis for Bunsen Reaction of S-I Cycle. J. Membr. Sci., 2011, 380, 13-20.

22. V. Immanuel, K. U. Gokul and A. Shukla. Membrane Electrolysis of Bunsen Reaction in the Iodine – Sulfur Process for Hydrogen Production. Presented at ICRE-2011 held in Jaipur, India during January 17-21, 2011

23. P. K. Sow and A. Shukla. Electro-Electrodialysis for Concentration of Hydroidic Acid. Presented at ICRE-2011 held in Jaipur, India during January 17-21, 2011.

24. K. Kondamudi and S. Upadhyayula. Kinetic Studies of Sulfuric Acid

Decomposition over AL–Fe2O3 Catalyst in the Sulfur-iodine Cycle for Hydrogen Production. Int. J. Hydrogen Energy, 2012, 37(4), 3586– 3594.

25. P. K. Sow and A. Shukla. A Chronopotentiometry based Identification of Time-varying Different Transport Resistances of Electro-electrodialysis Cell used for Concentration of HIx Solution. Int. J. Hydrogen Energy. 2013, 38, 3154-3165

26. P.K. Sow, D. Parvatalu, A. Bhardwaj, B. N. Prabhu and A. N. Bhaskarwar. Impedance spectroscopic determination of effect of temperature on the transport resistances of an electro-electrodialysis cell

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used for concentration of Hydroidic Acid. J. Applied Electrochem, 2012, 43 (11) 31-41.

27. P. K. Sow and A. Shukla. Effect of Asymmetric Variation of Operating Parameters on EED Cell for HI Concentration in I-S Cycle for Hydrogen Production. Int. J. Hydrogen Energy, 2012, 37(19), 13958-13970.

28. V. Immanuel, D. Parvatalu, A. Bhardwaj, B. N. Prabhu, A. N. Bhaskarwar and A. Shukla. Properties of Nafion 117 in Highly Acidic Environment of Bunsen Reaction of I-S Cycle. J. Membr. Sci., 2012, 409-410, 137-144.

29. V. Immanuel and A. Shukla, “Effect of Operating Variables on Performance of Membrane Electrolysis Cell for Carrying Out Bunsen reaction of I-S Cycle” Int. J. Hydrogen Energy, 2012, 37, 4829-4842.

30. P. K. Sow and A. Shukla. Electro-electrodialysis for Concentration of Hydroidic Acid. Int. J. Hydrogen Energy, 2012, 37, 3931-3937.

31. V. Immanuel, K. U. Gokul and A. Shukla. Membrane Electrolysis of Bunsen Reaction in the Iodine-Sulfur Process for Hydrogen Production. Int. J. Hydrogen Energy, 2012, 37, 3595-3601.

32. P. K. Sow and A. Shukla. A Chronopotentiometry based Identification of Time-varying Different Transport Resistances of Electro-electrodialysis Cell Used for Concentration of HIx Solution. Int. J. Hydrogen Energy, 2013, 38(8), 3154-3165. 33. D. Parvatalu, S. Banerjee and B.N. Prabhu. Envisaged Technical Barriers in Converting Electrochemical Solutions to Hybrid- Thermochemical Technologies: ONGC Perspective. Paper presented at ISAEST-10held in Chennai, India during January 28-30, 2013.

34. A.B. Nirukhe, P.S. Parhad, A. Bhardwaj, D. Parvatalu and G. D. Yadav. Hydrogen Production by Non-Catalytic Decomposition of Hydroidic Acid. Paper accepted for presentation at the International Conference on Advances in Chemical engineering (ICACE-2013)to be held at NIT, Raipur, India during March, 8-9, 2013.

35. S. Kamini, S. Banerjee, D. Parvatalu and B.N. Prabhu. Hydrogen Production by Thermochemical Iodine-Sulfur Cycle: Process Simulation Studies of Bunsen Section. Paper presented at the International Conference on Advances in Chemical engineering (ICACE- 2013)held at NIT, Raipur, India during April 5-6, 2013.

36. K. Kondamudi and S. Upadhyayula, “Decomposition of Sulfuric Acid over Mixed Metallic Oxides - A Comparative Study for Oxygen Evolving

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Step in S-I Cycle for Hydrogen Production”, EUROPACAT XI Conference, LYON, France, September 1-6, 2013.

37. D. Parvatalu and B.N. Prabhu. Material Issues Dictate Hydrogen Generation by Thermochemical Water Splitting Technologies: ONGC Energy Center Perspective. Presented at CORCON-2013, New Delhi.

38. D. Parvatalu, S. Banerjee and B.N. Prabhu. Recent Developments in Hydrogen Generation using Iodine- Sulfur Thermochemical Water Splitting Cycle: ONGC Energy Center efforts, PETROTECH-2014held in Delhi, India during January 12-15, 2014. 39. D. Parvatalu. Development of Thermochemical Hydrogen Generation Technologies using Water Splitting Processes: ONGC Energy Center Perspective. Invited lecture at National workshop on “Fuel Cell Technology: Basic science to Application” held at MANIT, Bhopal during March 24-25, 2014

40. D. Parvatalu. Hydrogen is the Key to Success of Renewable Energy Campaign: ONGC Energy Centre perspective. Invited talk at the National Seminar during 17-18th November 2014 at Univ. Kerala, Trivandrum organized by Indian Association for Hydrogen Energy and Advanced Materials

41. Kamini Shivakumar, S. Banerjee and D. Parvatalu. Simulation studies on HI Decomposition in Thermochemical Iodine-Sulfur Cycle. Paper presented at CHEMCON-2014, the 67th Annual Session of the Indian Institute of Chemical Engineers to be held at Punjab University, Chandigarh, from 27th – 30th December, 2014.

42. D. Parvatalu, An Overview of Material Requirements for Copper-Chlorine Thermochemical Cycle: ONGC Energy Centre Perspective. Paper published in Society for Materials Chemistry Quarterly Bulletin issued by BARC, 2014

43. D. Parvatalu. Development of Closed-loop Thermochemical Water splitting Processes for Hydrogen Generation: ONGC Energy Centre Initiatives. Presentation at 3rd International Conference on Hydrogen and Fuel Cell during 7-9 December 2014 at Udaipur.

44. D. Parvatalu. Role of Catalysts in the Development of the Iodine- Sulfur and Copper-Chlorine Thermochemical Hydrogen Generation Technologies. Presented at 22nd National Symposium on Catalysis (CATSYMP 22) during 7-9.01.2015 at CSMCRI Bhavnager.

45. N. Sathaiyan, V. Nandakumar, G. Sozhan, J. Ghandhiba Packiaraj, E.T. Devakumar, D. Parvatalu, Anil Bhardwaj and B.N. Prabhu. Hydrogen

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Generation through Cuprous Chloride-Hydrochloric Acid Electrolysis. International Journal of Energy and Power Engineering, 27 January 2015. [Pages 15-22]

13.2 Details of Patents Sl. Patent title Institutions Patent Details No.

1 Hydrogen Production Method by OEC and ICT, National and Multi-Step Copper-Chlorine Mumbai International* Thermochemical Cycle 2 Electrochemical Cell Used for the OEC and ICT, National and Production of Copper Using Cu-Cl Mumbai International* Thermochemical Cycle 3 Effect of Operating Parameters on OEC and ICT, National and the Performance of Mumbai International* Electrochemical Cell in Copper- Chlorine Cycle 4 High Performance Supported OEC and IIT, National* Metallic/Mixed Metallic Catalyst Delhi for Sulfuric Acid Decomposition in Sulfur-Iodine (SI) Cycle for Hydrogen Production 5 Process for Catalytic OEC and IIT, National* Decomposition of Sulfuric Acid Delhi over High Performance Supported Metallic/Mixed Metallic Catalyst in SI Cycle 6 Highly active supported bimetallic OEC and IIT, National* (Ni-Pt) catalyst for hydrogen Delhi iodide (HI) decomposition and synthesis procedure thereof 7 Vanadia supported Pt catalyst OEC and IIT, National* and use thereof for hydrogen- Delhi iodide decomposition in sulfur- iodine (I-S) cycle for hydrogen production.

The US and Japan patents on “Hydrogen Production Method by Multi-Step Copper - Chlorine Thermochemical Cycle” have been granted. *********

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