TECHNICAL REPORT BEST AVAILABLE TECHNOLOGY ENHANCING PRODUCTIVITY IN THE INDIAN CEMENT SECTOR TECHNICAL REPORT – BEST AVAILABLE TECHNOLOGY Enhancing Productivity in the Indian Cement Sector
Copyright © United Nations Industrial Development Organization, 2017
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Designed by Athenea International/Omnilang (Mauricio Mondragon & Maria Grineva). 2017 Table of contents
List of abbreviations 6 Acknowledgements 7 Executive Summary 9 1 Introduction 11 1.1. Objectives of Workshop 12 2 Best Available Techniques (BAT) 15 2.1. General remarks 15 2.2. Regulatory Aspects 16 3 Emission 19 3.1. NOx Emission 19
3.2. SO2 24 3.3. CO and Organics 27 3.4. Mercury and heavy metals 32 4 Emission Management 39 5 Climate change and the cement industry 43
5.1. Strategies to reduce CO2 emissions in the cement industry 43 5.2. Paris Agreement and the cement sector 44 6 Process Impact (AF/ARM) 47 6.1. Combustion Properties 47 6.2. New auxiliary equipment 50 7 NCCBM Presentation 53 7.1. India experience - AF/ARM use and their impact on emissions 53 7.2. Emission management in India (compliance, monitoring, reporting and trends for future) 53 7.3. Energy efficiency in cement sector in India 54 8 Feedback from participants 57 8.1. General Feedback 57 8.2. Specific Content Feedback 58 9 NCCBM Status versus Sustainable Cement Industry (BAT + key issues) 61 10 Conclusions 65 Annexes 67 Annex 1. Presentations 67 List of abbreviations Acknowledgements
ACI Activated Carbon Injection HW Hazardous Waste The Technical Report – Best Available Technology was drafted in the context of project AF Alternative Fuels LCTPi Low Carbon Technology Partner- - Development and adoption of appropriate technologies for enhancing productivity in the cement sector - funded by the Government of India, Department of Industrial Policy & AFR Alternative Fuel Recovery ship Initiative Promotion (DIPP). AMS Automated Monitoring System LEILAC Low Emissions Intensity Lime And Cement APC Advanced Process Control The report was produced by UNIDO’s department of Trade, Investment and Innovation (TII), ARM Alternative Raw Material NOC Normal Operating Conditions under the directorship of Dr. Bernardo Calzadilla-Sarmiento, the project being managed by Dr. Anders Isaksson. AST Annual Surveillance Test NOx Nitrogen Oxides expressed as NO2 BAT Best Available Techniques OTNOC Other Than normal Operating Conditions The technical content is the work of the following UNIDO technical experts: Dr. Daniel BPAC Brominated Powdered Activated Lemarchand, Dr. Pieter Du Toit, Ms. Layse Harada, Ms. Cornelia Bauer and Dr. Harald Carbon PAH Polyaromatic Hydrocarbons Schöffmann. BTX (Benzene, Toluene, Xylene) PAT Perform Achieve Trade CCS Carbon Capture and Storage PCB Polychlorinated Biphenyls The results presented in this report, have been reviewed and edited by Dr. Ritin Koria, Mr. Vikas Kumar, and Ms. Shraddha Srikant. Cd Cadmium and its compounds PPE Personal Protective Equipment CEM Continuous Emission Monitoring PRTR Pollutant Release and Transfer Proof reading was undertaken by Ms. Lauren Cooke, and final layout and Design was Register CMA Cement Manufacturers Association undertaken by Mr. Mauricio Mondragon and Ms. Maria Grineva. Quality Assurance CO Carbon Monoxide QA Quality Assurance Level 1 Furthermore, we would like to extend thanks to the staff of the National Council for Cement and CO Carbon dioxide QAL1 2 Building Materials (NCCBM) and the Cement Manufacturers’ Association (CMA), in particular QAL2 Quality Assurance Level 2 CPAC Commercial Powdered Activated Mr. Sanjeev Kumar Chaturvedi and Mr. Shailendra Chouksey, respectively, for availing the Quality Assurance Level 3 Carbon QAL3 necessary logistical support for the hosting of technical workshops and seminars, for support CPCB Central Pollution Control Board SCR Selective Catalytic Reduction in data collection and active participation in the project. Cu Copper and its compounds SHC Specific Heat Consumption ECRA European Cement Research SNCR Selective Non Catalytic Academy Reduction EIS Energy Isolation Standard SOx Sulphur Oxides expressed as SO2 ETP Effluent Treatment Plant SPC Specific Power Consumption HCl Hydrogen Chloride STP Sewage Treatment Plant HF Hydrogen Fluoride Tl Thallium and its compounds Hg Mercury and its compounds WAH Work at Height
6 | Best Available Technology Best Available Technology | 7 Executive Summary
UNIDO has implemented a project titled ‘Development and adoption of appropriate technologies for enhancing productivity in the cement sector’, in collaboration with the Department of Industrial Policy and Promotion (DIPP), Ministry of Commerce and Industry, Government of India.
Under the aegis of the UNIDO International Centre for Inclusive and Sustainable Industrial Development (IC-ISID), New Delhi, the cement project aimed to support the Indian cement sector by strengthening the capacity and capability of the nodal technical institution for the sector – the National Council for Cement and Building Materials (NCCBM) - to provide management and technical support to the cement industry. The project looked to facilitate structured expert dialogue, transfer state-of-the-art technologies, and action a wide range of technical capacity building and knowledge sharing activities, and ultimately strengthen the global competitiveness of the Indian cement sector.
One of the six workshops organised in this direction, was on Best Available Technologies (BAT) in the cement sector. The workshop was designed to highlight modern technologies and techniques, as well as the main issues faced by plants and the cement sector during the implementation of new technologies and new auxiliary equipment. This technical report highlights the training provided with respect to the use of best available technologies within the Indian cement sector.
The report covers key aspects for the cement sector such as Major sources of emissions, SO2 emissions, CO and Organics, Mercury and Heavy Metals, highlighting the sources and con- trol methods for each. The report also details emissions management and tackling climate change with vis-à-vis the cement industry. The report also covers technical process impacts of using AF/ARM in the cement industry, covering combustion properties for various types of fuels/materials as well as auxiliary equipment for the same. Inputs from NCCBM regarding the status of AF/ARM in India have also been summarized.
The report concludes that the Indian cement sector clearly shows a high level of technology, process optimization and plant design of modern kiln lines with standard fuel, as 30 % of all Indian cement lines were built after 2010. At present, the cement sector intends to start with alternative fuels and raw materials to optimize utilization of resources and cost control. Due to the fact that the overall AF substitution rate is below 1.5 [%] in India, no experiences with higher AF substitution rates exist in the cement industry [exceptions are the big groups which can provide group internal support]. However, NCCBM’s technical capabilities and position- ing in the industry are found to be conducive to facilitating the adoption of new abatement techniques and suggested technologies by the industry, given some directed operational training and technical guidance to NCCBM’s staff.
8 | Best Available Technology Best Available Technology | 9 Introduction 1
UNIDO has implemented a project titled One of the six workshops organised in this ‘Development and adoption of appropri- direction, was on Best Available Technolo- ate technologies for enhancing productivity gies (BAT) in the cement sector. The work- in the cement sector’ in collaboration with shop was designed to highlight modern the Department of Industrial Policy and Pro- technologies and techniques, as well as the motion (DIPP), Ministry of Commerce and main issues faced by plants and the cement Industry, Government of India. sector during the implementation of new technologies and new auxiliary equipment. Under the aegis of the UNIDO International A summary of each topic has been pre- Centre for Inclusive and Sustainable Indus- sented, as well as an assessment of what trial Development (IC-ISID), New Delhi, the the main needs and next steps are to fulfil cement project aimed to support the Indian the objectives of the project. cement sector by strengthening the capacity and capability of the nodal technical institu- This report is structured as follows: tion for the sector – the National Council for Cement and Building Materials (NCCBM) - to »»Chapter 1 provides an introduction and provide management and technical support lists the objectives of the workshop. to the cement industry. »»Chapter 2 presents the general remarks of The project aimed to facilitate structured Best Available Techniques and its regula- expert dialogue, transfer of state-of-the-art tory aspects. technologies to the Indian cement sector, and a wide range of technical capacity-building »»Chapter 3 presents information for each and knowledge sharing activities to boost the pollutant about their environmental and technical and managerial capabilities of the health impacts as well as their sources, NCCBM and ultimately strengthen the global techniques to control them, and the end competitiveness of the Indian cement sector. of pipe technologies sustainably imple- To fulfil this objective, one of the activities of mented in other plants worldwide. the project was to conduct technical work- shops fort he scientists and engineers of the »»Chapter 4 presents the best practices for NCCBM in areas such as energy usage and emission management and monitoring. energy efficient solutions, waste derived fuels,
CO2 emissions and green technologies, patents »»Chapter 5 presents a summary of climate and intellectual property rights (IPRs), global change and the cement industry and on best practices and up-to-date technologies. going projects of carbon capture.
Best Available Technology | 11 Introduction
»»Chapter 6 presents information about pro- 1.1. Objectives of Workshop cess impacts on cement kiln operation, either due to alternative fuel or alternative The ‘Best Available Technologies and Pro- raw material use, as well as the installa- cesses’ Workshop was designed to inform tion of new abatement technologies or the NCCBM staff about the main issues new auxiliary equipment. faced by cement sector plants during the implementation of new technologies. »»Chapter 7 shows the outcomes and discus- sions with regard to the NCCBM presenta- The workshop had the following objectives: tions about emissions impacts due to the use of AF/ARM, how emissions are being »»To inform the NCCBM about the best avail- managed in the Indian cement sector and able technologies and techniques what the status of the Indian cement sec- tor is regarding energy efficiency. »»To inform the NCCBM about kiln operation when using AF/ARM »»Chapter 8 addresses the feedback from the participants, subdivided into general »»To identify business and strategy opportu- The project aimed to facilitate and content specific feedback. nities “ structured expert dialogue, »»Chapter 9 presents a first assessment of »»To identify potential gaps transfer of state-of-the-art what the status of the NCCBM is in regards BAT implementation and key issues for the technologies to the Indian cement sector. cement sector, and a wide
»»Chapter 10 finalizes and concludes the range of technical capacity- outcome of this workshop. building and knowledge
sharing activities to boost
the technical and managerial capabilities of NCCBM and “ ultimately strengthen the global competitiveness of the Indian cement sector. „
12 | Best Available Technology Best Available Technology | 13 Best Available Techniques (BAT) 2
2.1. General remarks »»‘Techniques’ includes both the technology used and the way in which the installation Current European practices were presented is designed, built, maintained, operated to the NCCBM in order to demonstrate the and decommissioned. implementation of best available technol- ogies. The full scope of the European ref- In Europe, BATs for a given industrial sector erence document, techniques, criteria for are described in BAT reference documents determining BAT and the enforcement of this (BREFs). BREFs are the result of an exchange criteria through EU regulation were outlined. of information between European Union Member States, the industries concerned, A definition of the best available techniques non-governmental organizations promoting can be summarized as follows: environmental protection and the European Commission. This exchange of information is »»‘Best Available Techniques’ or ‘BAT’ refers often called the Sevilla process. to the most effective and advanced stage in the development of a process and its There are a number of criteria for deter- methods of operation. mining BAT, such as: environmental bene- fits; cross-media effects; operational data; »»BAT also refers to processes and tech- applicability; economics; driving force for niques best suited to reducing emissions implementation; example plants and refer- and fulfilling other permit conditions. ence literature. These criteria are described in detail in BREF. The most important chapter »»The ‘Best’ techniques are those which aim of the BREF is the BAT conclusions; these will at protecting the environment be the reference point in setting down the permit conditions for large industrial instal- »»‘Available’ techniques refers to those tech- lations. These documents are freely accessi- niques which have been developed on a ble on the Internet. scale which allows for implementation in the relevant industrial sector under econom- It is also important to note that the BAT ref- ically and technically viable conditions, tak- erence document does not necessarily pro- ing into consideration the costs and advan- vide an exhaustive list of the techniques tages; whether or not the techniques are that could be applied in the sector. Other used or produced inside the member state techniques may exist, or may be developed, in question; and whether the techniques which could be considered in the determina- are reasonably accessible to the operator. tion of BAT for an individual installation.
Best Available Technology | 15 Best Available Techniques (BAT)
As reported, the NCCBM supports the Min- directive, the Industrial Emissions Directive istry of Environment, Forest and Climate 2010/75/EU, published in 2010. Change (MoEF&CC) in India in the develop- ment and implementation of new regula- According to the Industrial Emissions Direc- tions. A reference document was created by tive, emission limit values and the equiva- the NCCBM in conjunction with the Cement lent parameters and technical measures in Manufacturers Association (CMA) and other permits will be based on the BAT, without industry sectors and released in 2015. prescribing the use of any specific tech- However, the document is internal, and is niques or technology. restricted to the use of the Ministry. The original BAT reference document (BREF) 2.2. Regulatory Aspects for the production of cement and lime was adopted by the European Commission in ‘Best Available Techniques’, sometimes 2001. The review commenced in March 2005. referred to as ‘Best Available Technology’, As a result of IED implementation within the was first introduced in Europe in 1984, as EU, the Commission Implementing Decision part of Directive 84/360/EEC. This initial (2013/163/EU) on the BAT conclusions, BREF directive applied to air pollution emissions was adopted on 26th March 2013 and pub- from large industrial installations. lished on 9th April 2013.
In 1996, the Integrated Pollution Preven- Figure 1 presents the regulatory aspects of tion and Control directive (IPPC) applied applying BAT within European installations. the framework concept of BAT to the inte- grated control of pollution to the three Permit revision is carried out every four years. mediums of air, water and soil. The con- cept was also part of the directive’s recast- ELVs (Emission Limit Values) for each pollut- ing in 2008 (2008/1/EC) and its succeeding ant will be presented in the next chapter.
Figure 1: Application of BAT Document within a normal permitting procedure - EU
BAT Committee BAT Document 20 Industry Sectors: Incineration, Power Generation, Steel, Petrochemistry, etc. Technical Working Group
Permit Permit Application Facility Facility Applicants (Emission Impact Installation Operation Analysis)
Application Review Objection (if necessary)
Permit Review Permit Report & Permit Permit (Professional Decision Approval Reconsider- Authority Review, Information (including (for Starting of Disclosure) emission limit) Operation) ation
16 | Best Available Technology Best Available Technology | 17 Emission 3
3.1. NOx Emission emissions in Europe. The cement industry accounts for approximately 2-3% of the 3.1.1. Impact on health and emissions. environment BAT conclusions set the Emission Limit In the cement sector, NOx is the term for Values (ELVs) for cement kilns, as shown emissions containing nitrogen oxide (NO) in Table 1 (below). and nitrogen dioxide (NO2). NO2 in high con- centration becomes a red or orange/brown Primary measures such as: flame cooling; gas with a sharp, pungent odour. low-NOx burners; mid-kiln firing; addition of mineralizers and process optimization; Long-term exposure to concentrations above staged combustion and SNCR (Selective Non 40µg/m3 causes adverse health problems, Catalytic Reduction) are considered BAT for mainly respiratory problems. Environmen- the cement industry. SCR (Selective Catalytic tally, NOx contributes to acid rain, ground Reduction) is not yet considered BAT for the level ozone formation, smog formation and cement sector. SCR is subject to appropri- the greenhouse effect. ate catalyst and process developments in the cement industry. When applying SNCR, Traffic and industry are the main contribu- ammonia slip has a limit of 30 mg/Nm3 but tors to NOx emissions. Industry is respon- can in actual fact, be as high as 50 mg/Nm3 sible for approximately 30% of the NOx depending on initial levels and efficiency.
Table 1: BAT conclusions set the Emission Limit Values (ELVs) for cement kilns
BAT-AEL Kiln Type Unit (daily average value) Preheater kilns mg/Nm3 <200 – 450(2) (3)
Lepol and long rotary kilns mg/Nm3 400 – 800(1)
(1) Depending on initial levels and ammonia slip 3 3 (2) BAT AEL is 500 mg/Nm , where after primary measures, the initial NOx level is > 1000 mg/Nm (3) Existing kiln system design, fuel mix properties including waste, raw material burnabilitz can influence the ability to be in the range. Levels below 350 mg/Nm3 are achieved in kilns with favourable conditions. The lower value of 200 mg/Nm3 has only been reported as a monthly average for three plants (easy burning mix used)
Best Available Technology | 19 Emission
3.1.2. Sources 3.1.2.1. Thermal NOx 3.1.2.2. Fuel NOx 3.1.3.1. Primary measures Thermal NOx is formed in the main flame of This NOx type is predominantly found in Primary measures for reducing NOx are those NOx emissions in the cement industry are the rotary kiln burner, where the cement pro- low temperature combustion, which takes which take place within and act directly upon created in the combustion process and as cess reaches its highest temperature. The place in a calciner. The total level is directly the combustion process. Some of these
yet there is no method to completely avoid rate of formation (→ Zeldovich Mechanism), related to the N2 content of the fuels being actions do not require investment; such
this. There are, however, actions that can be and ultimately the emission level, is influ- used (e.g. petcoke has a higher N2 content actions do not however guarantee reach- undertaken at the moment of creation that enced by two main factors: than standard coal) ing the requested emission limits. Emission can reduce the formation of the emissions. limits can be kept if the actual emissions »»O2 There are three different types of formation 3.1.2.3. Prompt NOx and limits are not far away from each other. mechanism active, see figure 2. »»Temperature This NOx type is formed by the breaking of
Figure 3 shows the influence of these two N2 bonds by “CH” hydrocarbonaceous rad- List of successfully implemented primary factors on the formation of NOx. icals. These radicals are released primarily measures:
by the fuel, as opposed to by O2 radicals Figure 2: NOx formation mechanism [mg/m³] vs. process Temperature [°C] [→ Feminore Mechanism]. The radicals 1. Kiln feed stabilization contribute to the emission of NOx at the rate of KBE, < 100 ppm. 2. Burnability improvement (mineralizers)
3. Reduction of excess air (measure KBE) 3.1.3. Control 4. Clinker cooler stabilization ] 3 NOx emissions can be controlled by in-pro- cess actions, so-called ‘primary measures’. 5. Sinterzone temperature (no overburning,
[mg/m Unfortunately, however, the three main e.g.: free lime target in clinker ~ 1.5 [%]) gaseous pollutants are interconnected. fuel NOx Thermal NOx This is shown in figure 4. The universal 6. Low nitrogen fuels at the calciner message of this diagram, valid for all three Prompt NOx main gaseous pollutants in the combus- 7. Reduce primary air on the main burner tion, is that optimizing one (NOx → reduce (switch from direct to indirect firing;
O2/SO2+CO increase) will result in a higher reduce burner momentum as far as quality emission on the other. and volatilisation allows)
Figure 3: Formation of NOx related to T and O level (measured at kiln back end) 2 Figure 4: SO2, CO and NOx interdependency.
CO o ppm n NOx
temperature [0c]
20 | Best Available Technology Best Available Technology | 21 Emission
8. Low-NOx burner (attention when high sul- install; however, they have a low efficiency. The Operational differences to the SNCR are: »»Clean Dust SCR( → after raw mill) phur fuels are used, e.g. pet coke) only available comparable data set is one case • High cost for reheating with UREA prills where the efficiency of the solid »»Temperature level → 300 - 400 [°C] • No cleaning or poisoning issues 9. Water injection (flame cooling) injection is 5 times less, compared to all instal-
lations with either liquid Urea or NH3 solution. »»Clean atmosphere (no dust) The issues with dust and poisoning threat 10. High volatile fuel in an in-line-calciner kept the SCR from being recommended as a (with a reducing zone) Subtopic: “High Efficiency SNCR” The practical implementation in the cement BAT, but after the realization of several pro- An important topic is the ‘high efficiency plant can be applied to three types of systems: jects in cement plants showing the applica- 3.1.3.2. Technologies SNCR’. This development is initiated by more bility and usability of an SCR system, this sit- The two main NOx reduction technologies stringent limits; a lot of existing SNCR instal- »»High dust SCR( → after preheater) uation will change. rely on the same chemical reaction: lations are experiencing a high NH slip or 3 • Temperature level is good do not reduce below the new legal limits. • Intensive dust cleaning 3.1.3.3. Summary 4 NO + 4 NH + O → 4 N + 6 H O In table 2, an overview of achievable results 3 2 2 2 • Danger of poisoning (thallium/ammoni- High efficiency SNCR combines a standard of primary measures and end of pipe tech- CO(NH ) + 2 NO + 0.5 O → 2 N + CO + 2 H O umsulphates) 2 2 2 2 2 2 nozzles system but with more injection points, nologies is given, including: achievable
Reducing NOx requires the addition of NH3; in order to be able to utilize the advantage of a »»Medium Dust SCR( → after preheater + reduction efficiencies and operating and this can take different forms but it is mainly complicated control system trying to optimize pre-dedusting ESP) investment costs. The wide range of the as an NH -solution or UREA-solution. the injection amounts, reagent mixture (pos- reduction efficiency of one method (excep- 3 • Temperature level is god sible) and location. The optimization is based • Reduced dust cleaning on the catalyst tion: SCR/SNCR which are well defined) is an 3.1.3.2.1. SNCR: Selective Non Catalytic on a complicated control programme using (but additional ESP) indication that local tests have to be done Reduction process values, temperature values form the • Danger of poisoning (thallium / ammoni- separately at every cement kiln before being In the selective non-catalytic reduction, the riser duct and trying to make an online sim- umsulphates) able to evaluate all impacts (cost, NOx Level,
reagent is injected in a temperature range ulation to evaluate the temperature profile in NH3 emission, reduction efficiency). between 800 [°C] - 1150 [°C]. The optimum riser duct and adapt the mentioned parame- place for this injection is the riser duct; ters to avoid an inefficient injection of reagent. today, however, additional firing locations, Table 2: Summary table of NOX reduction methods: expected reduction efficiencies/cost: by-pass extractions and meal feeds interfere 3.1.3.2.2. SCR Selective catalytic reduction primary measures and end of pipe technologies. with possible feeding points. In principle, the SCR is based on the same reac- tion as the SNCR with the difference that the (15) (3) Kilns Reduction Emission Data Cost Data Low retention times, CO / CO formation reaction is supported by a catalyst (see figure 5). Measure/ 2 systems efficiency Technique Investment Operating and a non-temperature optimized location applicability (%) mg/Nm3(1) Kg/t(2) (EUR Million) (EUR/t clinker) reduces the efficiency of the installation. An injection system for NH3 or Urea solution Primary This inefficiency can result in a NH3 slip, is required. Due to the required efficiency, a especially when reducing the NOx level perfect distribution in the gas stream is neces- Flame Cooling(5) All 0-35 reduced to 1.15-2.3 Up to 0.2 Up to 0.50 <500-1000(9) below 500 [mg/Nm³](10% O2, dry). sary so that only liquid solutions are allowed. Low NOx Burner All 0-35 500-1000 1.15-2.3 Up to 0.45 0.07 Primary Techniques 1400 reduced Main reagents Figure 5: Honeycomb catalyst with reaction All 25 2.4 0.25 0.056 EGTEI 2003(4) to 1050 Ammonia solution (NH3 in water, e.g. 25%) principle Mid kiln firing Long 20-40 No information - 0.8-1.7 No information Urea solution (CH4N2O in water, e.g. 25 - 40%) Mineralised clinker All 10-15 No information - No information No information Others Precalciner 0.1-2 Ammonium salt solutions (e.g. (NH ) SO in water) (9) 4 2 4 NOx N Staged combustion 10-50 <450-1000 1.04-2.3 No information Liquid photo wastes 2 Preheater 1-4 Urea prills Preheater and <200(10) (11)- 30-90(10) 0.4-1.15 0.5-1.2 0.1-1.7 Precalciner 500(14) SNCR(4) (5) (6) (12) Urea Prills (solid urea) Grate Urea prills are a special case used in the begin- 35 <500(10)-800(5,6) 1.15-1.84 0.5 0.84 NH H O preheater ning of the NOx reduction. Urea prills are solid Possibly all, Urea pressed into prills (small balls). The SCR(7) preheater and 43(13)-95 <200(8)-500 0.23-1.15 2.2-4.5 0.33-3.0 advantage of these is that they are simple to precalciner
22 | Best Available Technology Best Available Technology | 23 Emission
Special provisions for cement kilns co-incin- SO formed in the top stages is mainly released »»Watch molar ratio because it also impacts 3.2. SO2 2 erating waste are set for SO emissions. The by the presence of FeS (Pyrite), which oxidizes clinker quality, and has a significantly pos- 2 2 3.2.1. Impact on health and competent authority may grant derogations between 350 - 600 [°C]. Sources of this pyrite itive impact on process environment for emission limit values set out in this point are raw materials (limestone, marl, clay, etc.). Definition: Molar Ratio in cases where SO do not result from the In any case, not all the sulphur from the fuel 2 In the cement industry, SOx is expressed in co-incineration of waste. or pyrite entering the kiln or preheater leaves %SO3 / 80 SO (sulphur dioxide). Sulphur dioxide is a the kiln as emission; process conditions have 2 %Na2O / 62 + %K2O / 94 colourless, penetrating, smelling gas highly 3.2.2. Sources a significant impact on the possible emission. soluble in water. From this list, the three highlighted actions
In the cement industry there are roughly Typical trapping ratios for SO2 are: significantly reduce the SO2 emission. In any
Long term exposure at a concentration above three sources of gaseous SO2 emissions: case, it is recommended that with SO2 emis- 40µg/m3 causes adverse health problems, »»Kiln/pre-heater 40 - 85% sion, the primary measures should be tuned mainly respiratory problems and eye irrita- 1. Combustion of the main burner to the maximum reduction rate in order to
tion. On the environmental side, SO2 is well »»Conditioning tower 20% reduce absorbent costs, before any active known to contribute to acid rain (e.g. forest 2. Evaporation in the sinter zone of the kiln measurement is set. damages and stone building damages). »»Raw mill shop 40 - 85% Almost all emissions are linked to pyrite sul- 3. Combustion of pyritic sulphur (top stages 3.2.3.2. Technologies phur present in the raw materials. pre-heater kiln) 3.2.3. Control At present, mainly three active methods to
reduce SO2 are used:
Table 3: parameter SO2 Due to the situation that in India, 99% of the SO2 is a gaseous pollutant whose emission installed cement kilns are pre-heater/pre-cal- levels are strongly controlled by the pro- 1. Absorbent addition (dry) [→ absorbent
(1) (2) ciner kilns, we concentrate on this kiln type. cess conditions. Also here, we differentiate limehydrate Ca(OH) ] BAT-AEL 2 Parameter Unit (daily average value) between primary measures, more or less opti-
Figure 6 shows the situation of modern kilns mizing the SO2 absorption with the kiln line 2. Wet scrubber [ → limestone solution] SO expressed where SO only leaves the system if it is operation. The second action is the instal- x mg/Nm3 <50 – 400 2 as SO2 evaporated in the top stages. lation of additional reduction equipment. 3. Activated carbon (not really used, but possible) (1) The range takes into account the sulphur content in the raw material. This behaviour is proven, and only when 3.2.3.1. Primary measures (2) For white cement and special cement clinker production, a kiln bypass is installed can a part of the The following list is a summary of opera- 3.2.3.2.1. Absorbent addition (Ca(OH)2, dry) the ability of clinker to retain fuel sulphur might be evaporated/burned sulphur in the kiln be tional actions that avoid high investment Opposite to the NOx reduction, the addition significantly lower leading to higher SO emissions. x released into the environment. and operating costs: of dry absorbents into the preheater exit proved to be successful enough to suggest it »»Raw mix management (includes quarry) Figure 6: Inner/outer sulphur cycle in a pre-heater/-calciner kiln. for SO2 reduction. Achievable reduction effi- »»Low temperatures (~90 °C) + high mois- ciencies are between 60-80%. Raw ture in raw mill material The installation can be very simple; addition »»Temperature profile in preheater to the kiln feed at top stage cyclone or via a » CaO and SO combines readily at Raw mill » 2 pneumatic feeding into the downcomer short 800C-1000C Pre-heaters/-calciners trap Sulphide before the ID fan. The only requirement for Oxidation almost all SO2 from kiln (but not the pyritic this dosing is a reliable control of the amount. Preheater and SO ) Watch! - High trapping efficiency might Precalciner 2 cause riser build-up or kiln sulphur rings Precalciner fuel 3.2.3.2.2. Wet Scrubber The wet scrubber is the state-of-the-art SO »»Keep compound operation 2 reduction method used in power stations, Control your burning zone with oxidizing »» and also in the cement industry. Achievable atmosphere (and short flame) to avoid vol- Fuel main bumer reduction efficiencies are above 90 % and atilization of sulphur Clinker Sulphate the resulting stack emission level can be Rotary kiln »»Watch for SO2 trapping vs. NOx formation below 10 [mg/Nm³] (dry, 10% O2).
24 | Best Available Technology Best Available Technology | 25 Emission
The basic principle can be seen in figure 7. 3.2.4. Summary 3.2.4.2. Comparison table of BAT »»Fuel types and physical properties of fuels technologies (too coarse, or real lumps) - E.g. whole A solution of water/lime is pumped to the Table 4 summarizes the 3 mentioned reduc- tyres kiln back end 3.2.4.1. Ca(OH)2 addition vs. wet spray heads from the recycle pumps. The scrubber tion methods with the limitation that acti- lime slurry is sprayed either co-current (here) Figure 8 shows the typical operating val- vated carbon is not the only realistic reduc- »»TOC in raw materials (cases with CO emis-
or counter-current into the flue gas stream, ues of lime hydrate addition in compari- tion method for SO2. sions appearing in the top stages) which passes through the flue gas-stream. son to the typical operating areas of wet scrubbers. This gives a good overview of »»SNCR (with Urea) is a possible source of CO
In the absorber vessel, the SO2 is captured when to use lime hydrate, or when a wet 3.3. CO and Organics emission and converted into gypsum, which can be scrubber is required. used in cement production. 3.3.1. CO 3.3.1.3. Control The CO emission can be controlled by the Figure 7: Wet scrubber process 3.3.1.1. Description and impact on health following actions: Carbon monoxide (CO) is a colourless, odour-
less, and tasteless gas that is slightly less »»O2 level dense than air. It is toxic to hemoglobic animals • Combustion is very sensitive to the avail- (including humans) when encountered in con- able reaction partners and if enough O2 centrations above about 35 ppm, although it is is not available, CO is formed. also produced in normal animal metabolism • An increase in the O level of the kiln/ in low quantities, and is thought to have some 2 calciner will help, but might lead to a normal biological functions. In the atmosphere, production limit. it is spatially variable and short-lived and has a role in the formation of ground-level ozone. »»Fuel preparation • Coarse fuels do not mix properly with the 3.3.1.2. Sources combustion air → CO In the cement process, CO is mainly produced • Counter-actions improved preparation/ in incomplete combustion. The following list is increase O level a summary of possible situations in combus- 2 tion (with one exception) with CO formation: »»Raw material control • Check alternative raw materials »»Under stoichiometric combustion, O2 level • Quarry investigations (clay/marl) »»Incomplete mixing of combustion air and fuel Figure 8: Input Level vs. Emission achieved with lime hydrate or wet scrubber
Table 4: Overview end of pipe SO2 reduction systems
Kilns Reduction Emission Data Cost Data Measure/
) systems efficiency 2 Technique Investment Operating applicability (%) mg/Nm3(1) Kg/t(2) Ca(OH)2 Addition (EUR Million) (EUR/t) Absorbent addition All 60-80 <200-400(5) 0.23-0.92 0.2-0.3 0.1-0.4 - emissions Wet Scrubber All >90 <10-300(4) 0.02-0.69 5.8-23(6) 0.5-2(6) ](dry,10% o Activated Carbon Dry Up to 95 <50 <0.11 15(3) No information 1.) Wet Scrubber (1) Normally refers to daily averages, dry gases, 273K, 101.3 kPa and 10%O2 [mg/nm (2) Kg/tonne clinker: based on 2300m3/tonne clinker
clean gas so (3) This cost also includes an SNCR process, referring to a kiln capacity of 2000 tonne clinker/day and initial emissions of 3 2.) 50-600 mg SO2/Nm , cost data from 1997
(4) The final achievable emission level is dependent on the initial SO2 value prior to the installation of the wet scrubber and could be higher 3 (5) For an initial SOx level of 1200mg/Nm input so Level [mg/nm ](dry,10% o ) (6) 2008
26 | Best Available Technology Best Available Technology | 27 Emission
3.3.1.4. Technologies are classified as potential human carcino- Table 5: BAT Applicability and Technique If CO emissions reach the stack, and no pro- gens, and are considered toxic, persistent cess action helped, they can be reduced by and bio accumulative. Organic HAP also a re-design of the combustion area → e.g. includes compounds such as: benzene; Technique Applicability calciner, requiring a significant investment. methane; propane; chlorinated alkanes and Carefully selecting and controlling of kiln alkenes; phenols; and chlorinated aromat- inputs (raw materials), i.e. chlorine, copper Generally applicable The most modern technology is the instal- ics. Adverse health effects of HAPs include a and volatile organic compounds lation of an RTO (“regenerative thermal oxi- damage to the immune system, as well as Carefully selecting and controlling kiln inputs dation”), described in chapter 3.3.2.4.2, in neurological, reproductive, developmental, b Generally applicable the “Organics” section, with the advantage respiratory and other health problems. (fuels), i.e. chlorine and copper that not only CO, but all organic emissions Limiting/avoiding the use of wastes which c Generally applicable are eliminated. Non-Methane Volatile Organic Compounds contain chlorinated organic materials (NMVOC): these compounds are identical Avoid feeding fuels with a high content of Generally applicable 3.3.2. Organics to volatile organic compounds (VOCs), but d halogens (e.g. chlorine) in secondary firing exclude methane. Quick cooling of kiln flue-gases to lower than Applicable to long wet kilns and 3.3.2.1. Definitions and their impact 200°C and minimising residence time of flue long dry kilns without preheating. In on health and environment 3.3.2.2. BAT aspects e gases and oxygen content in zones where the modern preheater and precalciner There are different definitions with regard to There are no BAT AELs (Associated Emission temperatures range between 300 and 450°C kilns, this feature is already inherent organics. They are classified according to their Levels) established for TOC but there are Stop co-incinerating waste for operations such use, chemical composition, impact or origin. AELs for dioxins. The BAT-AEL for the emis- Generally applicable f as start-ups and/or shutdowns The common characteristic is a C-H bond. sions of PCDD/F from the flue-gases of the kiln firing processes is <0,05 – 0,1 ng PCDD/ Total hydrocarbon (THC): refers to the organic F I-TEQ/Nm 3 as the average over the sam- Figure 9: Organics evaporation/cracking compounds present in a given medium pling period (6 – 8 hours). in gaseous form. Another term frequently Breakdown used for this is VOC, mainly in the US, but it In order to keep the TOC emissions low from Fractions includes methane and ethane. the flue-gases of the kiln firing processes, the BAT is to avoid feeding raw materials A → Fraction of original Total Organic Carbon (TOC): historically refers with a high content of volatile organic com- material that forms char or coke to non-gaseous substances (analysed in sol- pounds (VOC) into the kiln system via the E HAPs ids or liquids), however could be used in the raw material feeding route. D B → Volatile fraction of regulation as an equivalent to VOC or THC. B C organic material R e a c In order to prevent emissions of PCDD/F or
28 | Best Available Technology Best Available Technology | 29 Emission
The hydrocarbons that are evolved from the information could be: an estimation of the Table 6: Acceptable points of organics’ injection in cement kilns different raw materials that constitute the amount to be disposed of; suitability as an cement-kiln feed typically contribute the alternative raw material; what the usage Raw Mill Calciner Riser Duct Kiln inlet Main burner greatest portion to the overall stack of organic experience is; analysis of the organic main Not Materials with relevant Acceptable Acceptable Acceptable Acceptable emissions (assuming the kiln is operated components; and the determination of the organic content acceptable properly from a combustion standpoint). maximum input quantity. Generally Materials with relevant Not not Acceptable Acceptable Acceptable toxic/halogen organic acceptable The organic matter associated with most To determine the environmental analysis, compounds acceptable sedimentary materials typically consists of one must consider carrying out the analy- Temperature range Up to two fractions: one fraction that is soluble, sis of moisture, such as content, trace ele- 50-120°C 850-900°C 1000-1200°C 1100-1200°C (gas phase) 2000°C or extractable by an organic solvent such as ments, chlorine and sulphur when there is benzene; and an insoluble fraction, which is reasonable suspicion; analysis of VOC/TOC not extractable. The soluble fraction is com- when there is reasonable suspicion; and the Quality Control 3.3.2.4.2. Technologies monly referred to as bitumen and the insolu- analysis of toxic organic compounds. In regards to quality control, it is important to There is some evidence that SCR is able to oxi- ble fraction is referred to as kerogen. constantly safeguard the quality and low fluc- dize heavier fractions of organics. Activated It is important to select a safe, suitable stor- tuations of composition. This means that it is Carbon Injection has no visible effect on VOC The organic material found in the shale or age facility and consider its environmental recommendable to do: delivery inspections; emissions abatement. Regenerative thermal limestone used in cement manufacturing protection (if necessary, ground water pro- correct declarations (shipping order); visual oxidation (RTO) is an emerging technique that often contains both. Some anthropogenic tection, enclosure and active ventilation), inspections; probe sampling; development destroys organic compounds. RTO is an end- material (e.g. lubricants, oils, etc.) can also fire and explosion prevention and make sure of a sampling plan; analysis on a regular of-pipe technology placed after the main filter, be found in the raw mix. Organics can also that workers adhere to proper safety guide- basis, according to the legal requirements, where the gas is heated up to the oxidization be formed as a result of the incomplete com- lines (PPE, SOPs, etc.). technical standards, guidelines and official temperature of ~ 900°C. At this temperature, bustion of fuel within a pyro processing sys- directives. Reasonable assessment verifi- organic carbon components are oxidized to
tem (oxygen, residence time, temperature In case pre-treatment (grinding, drying) is cation, determination of actions in cases of CO2. This technology is not yet a BAT for the and turbulence). necessary, the selection of suitable pro- non-adequate delivery, application of exist- cement industry, but tests have proven its cesses must be made; in cases of feeding ing quality and environmental management efficiency although the Capex needed is high. 3.3.2.4. Control via raw mill only it must be ensured that no systems are also recommended. The main techniques and technologies will be (toxic) organic substances are released / Table 7: RTO installation at an Austrian plant. explained in the following sections. In sum- emitted, and last but not least, it is recom- Emission Control mary, in order to control organics, several steps mended to select suitable transport and In order to assess emission impact and ensure Austrian Case shall be taken into consideration such as: dosing systems. emission control, it is advisable to conduct: RTO-regenerative thermal oxidizer in the Austrian cement plant »»Raw material /ARM input control Injection points 1. Trials and pre-tests (when first using alter- It is generally not recommendable to native raw materials) »»Ceramic honeycomb: 15x15x30 cm »»Injection points inject organics-containing material and/ »»25 x 40 honeycombs per layer »»Quality control or halogen organic compounds at the 2. Emission control of an external measuring »»5 layers per chamber » 5 chambers »»Emission control raw mill, as there is limited suitability if institute (optional) » specific abatement technologies are in • 25,000 ceramic honeycombs »»End of pipe technologies place. To inject organics containing mate- 3. Long-term operation • 145,000 m² heat exchange surface rial at the calciner is however, acceptable »»Start up: summer 2011 3.3.2.4.1. Primary measures in cases where there is sufficient temper- 4. Continuous measurements, according to »»Emission limits (yearly average) Raw Material /ARM Input Control ature and residence time to destroy the legal requirements and national guidelines »»CO: 330 mg/m3 Prior to the utilization of any new material in harmful compounds. On the other hand, »»TOC: 33 mg/m3 the process, it is highly recommended to do toxic/halogen organic compounds are not 5. Spot measurements, according to legal »»Reduction of TOC and CO > 95% possible a qualification of the material. Information acceptable in this injection point. Toxic/ requirements and national guidelines »»Operational availability near to 100% with respect to origin, type, quantity and its halogen organic compounds are accept- »»Thermal efficiency 95% classification (“hazardous/non hazardous”) able at the riser duct or kiln inlet only if 6. Additional measurements of (toxic) »»Electric power demand +8 kWh/t clinker (fan, will determine its first requirements with sufficient temperature and residence time organic substances and / or more frequent air pressure) regard to sampling and analysis. Additional are in place. (See Table 6.) measurements, on a voluntary basis »»Energy cost ~ 1 €/t clinker additionally
30 | Best Available Technology Best Available Technology | 31 Emission
3.4. Mercury and heavy metals branes. At high concentrations it causes cell contributes. Primary natural sources are those ing and smelting, in which thallium is a trace death and destruction of tissues, however at where mercury of geological origin is released contaminant of the raw material. Heavy metals, also called trace elements, are low concentrations damage is reversible. via natural processes such as volcanoes or essential elements for living organisms with geothermal processes or evasion from natural 3.4.2. Emission Limits a relatively low necessary daily intake dose All alkylmercury compounds are thought surfaces geologically enriched in mercury. In (<1 mg). They are not metabolized as elements, to be rather similar with respect to toxicity, addition to these source types, the distribu- In Europe, the Emission Limits set for heavy but in the form of different compounds, while other organic mercury compounds (e.g. tion of mercury is affected by its remobiliza- metals are present in Table 8 below. which can be found in almost everything. phenylmercury) have similar toxicity levels tion and re-emission pathways. They do have an impact on living beings - up as inorganic mercury compounds. The most Table 8: Emission limits set for heavy metals to toxic behaviour, when in excess. Some real dangerous mercury compounds are alkylmer- One of the least volatile metals of concern trace elements together with (Hg, Cd, Tl and cury and, more particularly, dimethylmercury. is chromium, considered as non-volatile BAT-AEL Pb) are commonly called “trace elements” The latter compound can be found in the food metal in the kiln system. The main con- (average over the Metals Unit sampling period (spot or “heavy metals” when talking about envi- chain through bioaccumulation, reaching cern is that its presence of Cr in clinker will meaurements for at ronmental concerns in the cement industry. high concentrations among some species, lead to content in finished cement that can least half an hour)) especially in fish such as tuna or swordfish. cause cement eczema. Hg mg/Nm3 <0.05(2) Mercury is a heavy metal that can exist in the It causes impairment of the central nervous 3 (1) environment in a large number of forms. The system. Methylmercury is distributed in all Lead and cadmium are both low-volatile met- Σ (Cd, TI) mg/Nm <0.05 Σ (As, Sb, Pb, Cr, main groups of mercury species (the differ- tissue, including the brain, and is more dan- als. Lead is known for wide-ranging health mg/Nm3 <0.5(2) ent forms in which mercury exists) are ele- gerous for pregnant women, as prenatal dam- effects associated with the nervous system and Co, Cu, Mn, Ni, V) mental or metallic mercury, inorganic and age occurs in all parts of the brain unlike in blood. Cadmium can also have severe health (1) Low levels have been reported. (2) Low levels have been reported. Values higher than organic mercury forms. adults where the damage is local. effects and is considered to be carcinogenic. 0.03 mg/Nm3 have to be further investigated. Values close to 0.05 mg/Nm3 require consideration of additional Mercury can exist in three different oxida- Inorganic mercury compounds, such as salts, Thallium is a heavy metallic element that measures/techniques. tion states: primarily affect the gastro-intestinal tract. exists in the environment mainly combined Kidneys are a target tissue for retention of with other elements (oxygen, sulphur, and 3.4.3. Cement Industry Levels »»Metallic-Hg(0) or Hg0, this form of mercury. This form cannot pass halogens); it is a semi-volatile metal. Humans »»Mercurous-Hg(I) or Hg+, the blood-brain barrier easily. Mercury salts may be exposed to thallium by ingestion, skin Primarily, the main concern of all the heavy occur in both mercury forms (Hg22+ and contact and inhalation of dust or fumes; it is metals for the cement industry is mercury. »»Mercuric-Hg(II) or Hg2+. Hg2+) with both oxidation states. Mercuric highly toxic. Major releases to the environ- Figure 10 shows the levels of mercury in sev- Mercurous and mercuric mercury form salts are usually more toxic than their mercu- ment are from processes such as coal burn- eral plants in Europe. numerous inorganic and organic chemical rous counterparts because their solubility in compounds, but Hg+ mercury is rarely stable water is greater. The inorganic mercury com- Figure 10: Mercury Levels (Source: CEMBUREAU CSI enquiry 2009) under ordinary environmental conditions. pounds are principally excreted in urine.
3.4.1. Environmental Impact on In the environment, the primary anthropogenic Health and Environment sources are those where mercury of geologi- cal origin is mobilized and released into the Liquid metallic mercury is poorly absorbed environment. The two main source categories by ingestion and skin contact but mercury of this type are mining (either for mercury or vapours are hazardous. In fact, inhaled mer- where mercury is a by-product or contaminant cury is absorbed in the lungs and enters in the mining of other minerals) and extrac- the bloodstream. It can easily cross blood- tion of fossil fuels where mercury is present mg/Nm³ brain placenta barriers due to its high lipid as a trace contaminant. The secondary anthro- solubility. Intestinal absorption of elemen- pogenic sources are those where emissions tal mercury is low. Dissolved mercury is occur from the intentional use of mercury e.g. oxidized into the inorganic divalent form in industry, products or for artisanal gold mining. body tissues (red cells, brain, liver, lung and In both these source types, emissions to the other tissues) where it may inhibit the activ- environment can occur via direct exchanges ity of some enzymes with thiol groups. It can of exhaust gases and effluents, although the Measurement number denature proteins and damage cell mem- generation of mercury containing waste also
32 | Best Available Technology Best Available Technology | 33 Emission
3.4.4. Sources The main sources of chromium are slag or and are reintroduced into the hot zone once mercury input that is too high. A dedicated iron sources such as raw materials and coal, again. A major part of the cadmium and quality assurance system is recommended. Mercury can be found as a native metal (rarely) oil and tyres when used as fuels. lead will be incorporated into clinker. The or in cinnabar and other possible host miner- remaining part will precipitate with the kiln »»Selective mining may be an option in order als. Cinnabar (HgS) is the most common ore. 3.4.5. Heavy Metals Behaviour in dust and be collected in the filter systems. to control and avoid mercury input peaks Natural sources of mercury include volcanoes, Cement Kilns into the kiln system. evaporation from soil and water surfaces, »»Volatile metals, such as mercury and thal- degradation of minerals and forest fires. Trace elements, such as heavy metals, are lium, are more easily volatilised and con- »»Mercury emissions are typically higher naturally present in low concentrations in dense on raw material particles at lower in kiln operations with the raw mill-off Mercury enters the cement manufacturing the raw materials and fuels used for the temperatures in the kiln system (thallium (“direct” operation) due to the missing process as a trace element with the raw mate- manufacturing of cement clinker. The behav- at approximately 300-350°C, mercury adsorption capacity of the freshly ground rials and the fuels. The mercury content of iour of these metals in the burning process at 120-150°C). While thallium is nearly particles in the raw mill. natural raw materials varies between individ- depends largely on their volatility and the completely precipitated onto the kiln dust ual raw material deposits and even within the volatility of their compounds. particles, not all of the mercury will be »»Periodic purging (dust removal) of cement same deposit. In fuels, the amount of mer- collected within the filter system. Volatile kiln dust from the system is an efficient way cury can vary in a similar way, depending on »»Non-volatile metals remain completely metals are only retained in the clinker min- to control and reduce mercury emissions. the fuel type and the fuel source. Depending within the product and leave the kiln system erals to a very small extent. Adsorption of mercury is favoured due to on their origin, alternative raw materials and fully incorporated into the mineral structure the very high dust loadings present in the fuels may have higher or lower mercury con- of the clinker (similar to the main elements). 3.4.6. Control raw gas streams from preheater-precalciner tent than the ordinary materials they replace. Most of the common metals are non-volatile. kilns. This technique is more efficient in the 3.4.6.1. Primary measures mill-off mode than in the mill-on mode due Thallium is found in many raw materials and »»Semi-volatile elements, such as cadmium or Mercury input control is the most important to the higher mercury concentrations in the fuels at trace concentration. lead, may, in part, be volatilised with the high measure for the responsible operation of a dust. The efficiency of this measure depends, temperature conditions in the sintering zone kiln. The best environmental practice is to in part, on the quantity of dust removed from Cement plants may introduce cadmium primar- of the kiln system. They condense on the raw conduct a careful selection and control of all the system, and on the temperature prevail- ily via fuels like coal, plastic waste and bio-fuels. materials in cooler parts of the kiln system substances entering the kiln in order to avoid ing in the air pollution control device.
Figure 11: Schematic of Heavy Metals behaviour on clinker process. Figure 12: Mercury Reduction by dust removal
Pathway of heavy metals in cement kilns with preheaters (dry pro cess)
Distribution of
the heavy metals ) in the process
Raw material
Pre-heater Secondar y Drying/ filter raw material grinding Regular Calciner fuels
Rotary kiln Clinker Seco ndary
fuels mercury emission reduction (% Mineral addi tives Cement Secondar y baghouse Dust removal (%) mineral additives Source: [89, ERFO, 2005]
34 | Best Available Technology Best Available Technology | 35 Emission
3.4.6.2. Technologies are at laboratory or pilot stage. However, This technology works but it is very costly, sorbent capture requires disposal and the Other techniques to reduce mercury air most of the test programmes completed in approximately 20M€. The cement plant is bag sizes of this type of installation differs emissions are available in other indus- those industries cannot be extrapolated to required to install an additional filter, fan in greatly from a normal bag filter. Hg removal tries such as waste incinerators and coal- the cement industry. Therefore, those tech- addition to the sorbent installation because performance is stable up to 260°C. fired power stations. Some, such as carbon niques cannot be considered as best envi- adsorption, are well proven, whilst others ronmental practice in the cement industry.
Figure 13: Schematic Activated Carbon CPAC Installation Figure 14: Schematic Activated Carbon BPAC Installation
Hg Activated Carbon Polishing Bag House b-PAC TM Hg BAGHOUSE POlISHING
RAW MATERIALS bAGHOUSe
RAWMILL FUELS
KILN CLINKER Cement Kiln with no Mercury Control CEMENT NON-leACHING CARbON PRODUCT WITH MeRCURy TO DISPOSAl C-PAC TM Hg kIlN bAGHOUSe BAGHOUSE RAW MATeRIAlS RAW MATERIALS
RAWMIll RAWMILL FUELS fUelS
KILN CLINKER kIlN ClINkeR SHUTTLED DUST & C-PAC TM CEMENT PRODUCT CeMeNT Cement Kiln C-PACTM Mercury Control cement kiln with b-Pac tm mercury control PRODUCT
36 | Best Available Technology Best Available Technology | 37 Emission Management 4
Emission management represents an impor- feedback on the performance of abatement tant and critical issue for the assessment of systems by continuous monitoring systems the environmental performance of industrial installations. In Europe, emission manage- »»To determine the relative contribution of ment also supports the verification of the different sources to the overall emissions emission levels associated with the imple- mentation of best available techniques »»To provide measurements for safety checks (BAT-AELs) under the Industrial Emissions Directive (IED, 2010/75/EU). »»To report emissions for specific invento- ries (e.g. local, national and international, The objective of presenting this topic at the such as E-PRTR) BAT workshop was to present the impor- tance of having reliable monitoring to »»To provide data for assessing environmental assess the environmental performance of impacts (e.g. for input to models, pollutant installations. There are several reasons why load maps and assessment of complaints) monitoring is important beyond the appli- cation of BATs, such as: The proximity of the emission source to the sensitive environmental receptor, the pres- »»To assess whether industrial installations ence of natural hazards, the past performance are operating according to BATs of the installation and/or its management and the degree of public concern can be relevant »»To assist in finding the optimal balance in defining what parameters need to be mon- between process yield, energy efficiency itored. Besides these, the size of installation, and resource input and associated emis- the complexity of the process, how frequently sion levels optimising the process, for it switches, the possible hazardous use in the more efficient operation and to mini- production, possible related environmental mise emissions and health effects resulting from emissions, the risk of breaching emission limits and »»To provide help in analysing the causes of ambient air quality standards are risk factors certain types of emission behaviour (e.g. to that influence the choice of what parameters detect reasons for variations in emissions need to be monitored, and in what frequency under normal operating conditions (NOC) they need to followed up, are also important. or other than normal operating conditions (OTNOC)); after operational conversions, The frequency of monitoring can be determined operational breakdowns or an increase in several different ways. One simple way is in capacity; installation, e.g. to provide to use the schematic diagram (See figure 15).
Best Available Technology | 39 Emission Management
For each parameter, there is a more appro- parameters to be monitored continuously, Figure 16 below summarizes each step of the data to serve as background information to priate method to use to measure it. Direct periodically and occasionally: standard mentioned above and the time- the yearly report. or indirect measurements have their advan- frame that each step has to be performed in tages and disadvantages. The method An important aspect of monitoring is the to comply with legal requirements. Reports are credible when: selected should take into account: reliabil- quality assurance of continuous emission ity; representativeness and results compar- monitoring. Because of the general increase One last important aspect of monitoring »»Data is consistent, transparent and credible ativeness; the availability of the method; in legal requirements on continuous meas- is reporting. It is good practice to report »»Data is presented in a clear, standard format cost and environmental benefits. urement equipment, the European stand- measurement results on a daily, monthly » Data meet quality assurance (QA) ard 14181 “Quality assurance of automated and/or yearly basis, depending on the spe- » requirements measuring systems” was presented, which cific requirements set by the local author- For the cement industry, the best availa- indicates the maximum requirement for ity. It is important to note that daily and/or »»Data allows emissions to be reported in ble techniques recommend the following quality assurance of CEMs. monthly reports should contain sufficient absolute as well as specific terms
Figure 15: Frequency of monitoring determination Figure 16: Quality Assurance Implementation
High 3 4 4 1. Occasional - periodic measurements once every three years up to once per year, possibly accompanied by approval test Medium 2 3 4 indicative monitoring between measurements. iso 14956
L ikehood 2. Regular (to frequent) - periodic measurements once -Calculation of total uncertainty Low 1 2 3 per year up to twice per year, possibly accompanied by indicative monitoring between measurements. en 14181 1. Occasional Low Medium High 3 3. (Regular to) Frequent - continuous or periodic -Calibration with SRM 2. Regular measurements (several times per year). -Uncertainty check 3. Frequent Severity of 4. Intensive Consequences 4. Intensive - continuous measurements, where available en 14181 en 14181 -Uncertainty check
Table 9: Parameters to be monitored continuously, periodically and occasionally.
r qaL 3 CONTINUOUSLY PERIODICALLY OCCASIONALLY 1 1 2 2 » Exhaust volume » Metals and their compounds » BTX (benzene, toluene, xylene)
» » » ast ast qaL qaL qaL
»» Humidity »» TOC* »»PAH (polyaromatic hydrocarbons), and Manufacture Test labs Test labs Test labs Test labs time »» Temperature »» HCl* »»Other organic pollutants (e.g. chloroben- 1 year 1 year »» Dust »» HF* zenes, PCB, (polychlorinated biphenyls) »» O »» NH *, and including coplanar congeners, chloro- Comissioning 2 3 at customer site »» NOx »» PCDD/F naphthalenes, etc.). At least every 5 years » SO , and or major change in plant operation » 2 or major changes or repairs of the AMS2 »» CO or violation of calibration curve *can be measured continuously
40 | Best Available Technology Best Available Technology | 41 Climate change and the cement industry 5
The global climate is projected to continue The cement industry has always been to change over this century and beyond. The among the largest CO2 emission sources. magnitude of climate change, beyond the Cement plants cause almost 5–7% of next few decades, depends primarily on the global CO2 emissions. Global strategies and amount of heat-trapping gases emitted glob- potentials toward mitigation of CO2 emis- ally, and how sensitive the Earth’s climate is sions in cement plants were discussed dur- to those emissions. ing the workshop.
The increase in global temperature is signifi- cantly altering our planet’s climate, resulting 5.1. Strategies to reduce CO2 in more extreme and unpredictable weather. Changes in the greenhouse gas concentra- emissions in the cement tions and other drivers alter the global cli- industry mate and bring about a myriad of human health consequences. Changes in precipi- There are four main levers that the cement tation, for instance, are creating changes in industry can apply to mitigate CO2 emis- the availability and quantity of water, as well sions and increase the clinker substitution as resulting in extreme weather events such in cement production. Firstly, the use of as intense hurricanes and flooding. Climate additives in cement can be used to develop change can be a driver of disease migration, a large range of products according to as well as exacerbate health effects result- their application, but it is dependent on ing from the release of toxic air pollutants local markets (e.g. marketing and national in vulnerable populations such as children, standards). Secondly, having more thermal the elderly, and those with asthma or cardi- and electric efficiency, by increasing energy ovascular disease. efficiency through process optimization and modernizing factories (e.g. Waste Heat Environmental consequences of climate Recovery-WHR). Thirdly, as far as alternative change, such as extreme heat waves, rising materials are available, utilizing waste-de- sea levels, changes in precipitation result- rived fuel (WDF) and industrial by-products, ing in flooding and droughts, intense hurri- instead of conventional fuels and materi- canes, and degraded air quality, directly and als, results in significant emission mitiga- indirectly affect the physical, social, and tion. Finally, carbon capture and storage psychological health of humans. (CCS) is also considered as an effective way
Best Available Technology | 43 Climate change and the cement industry
to avoid the release of CO2 by capturing it 5.2. Paris Agreement and the before it is released into the atmosphere and storing it safely. However, economi- cement sector cal and technical challenges still present a remarkable obstacle against implementing During COP21 in Paris, in December 2015, the such processes in the cement plant. cement industry presented its plan to tackle climate change. It launched the LCTPi (Low Several CCS projects were presented during Carbon Technology Partnership Initiative) that
the workshop and are listed below: comprises a 25% reduction in CO2 emissions in comparison to business-as-usual levels by 1. NORCEM (first big, pilot scale project): 2030. LCTPi considers the following aspects: where 4 technologies have been tested. »»Enhancing the coverage of the sector’s CO2 a. Aker Solution’s 1st generation amine and energy database, with a specific focus technology on China (representing about 60% of the b. RTI’s 3rd generation solid sorbent worldwide cement production) technology »»Enhancing the energy efficiency of the c. Alstom’s 2nd generation calcium loop- cement manufacturing process ing process d. The consortium DNV GL/ NTNU & »»Scaling up the collection, availability and Yodfat Engineers’ 3rd generation mem- usage of good quality alternative fuels and brane technology raw materials, including waste from other sectors in a circular economy concept 2. ECRA - Oxyfuel project; where there are 3 »»Further reducing clinker content in new technologies being tested. cement to minimize the share of the energy-intensive part of the process a. Cooler prototype b. Burner prototype »»Developing new cement with lower energy c. Calciner prototype and calcination requirements 3. LEILAC – CO separation at calcining »»Engaging the full building and infra- 2 structure value chain in local markets to 4. Sweden – Degerhamn micro-algae identify and maximize the avoided emis- sions by usage of cement and concrete products; promoting for instance con- 5. Joule - exhaust-gas CO2 to produce ethanol by modified bacteria crete pavements »»Evaluating cross-sectoral initiatives, par- 6. Accelerated Carbonation Technology (ACT) ticularly on the opportunity to capture, use to produce light aggregates and store carbon at scale
Due to economic, technical and legal barri- Existing CO2 roadmaps will be updated and ers, widespread cost-effective deployment reviewed with the new considerations in of CCS is not foreseen before 2020. mind, as set by the Paris Agreement 2015.
44 | Best Available Technology Best Available Technology | 45 Process Impact (AF/ARM) 6
6.1. Combustion Properties »»Fuel properties stable, and only 1 fuel per burner 6.1.1. Combustion facts »»Dry; moisture content < 1% In the first step, a short reminder on the requirements of good combustion is presented. »»Particle size: reference value e.g. R90µm • General rule: R90µm ~ 0.5 Volatile Figure 17 shows the different phases of the matter [%] combustion process. • Difficult fuels: e.g. high sulphur petcoke even lower To guarantee continuous combustion and the complete burnout of the fuels, These parameters are not exhaustive, but by the following parameters were followed experience, they have a high impact on the and optimized: combustion process in the kiln line.
Figure 17: Combustion phases
combustion of volatiles and radiation and radiation thermal decomposition convection
Gaseous phase High temperature
Combustion at particle surface heating by radiation increasing particle temperature Thermal decomposition: (light gases, tars, liquid HC’s, soot) Vaporization (liquid)
Unburnt coal ignition and combustion heating Phase of solid residue (1 to 2 s)
Best Available Technology | 47 Process Impact (AF/ARM)
6.1.2. Alternative raw materials has to deal with the following fuel types, Major issues of fuel quality are: In most existing plants, the gas retention (ARM) see figure 18. time in the calciner is too short as they would »»Locally reducing conditions. have been designed with a 2-3[s] gas reten- In most cases ARMs do not directly impact These are only a few examples of the availa- • Caused by coarse fuels; particles that tion, with coal or oil as fuel. Modern calciner the combustion situation; the exception is ble qualities of AF used in cement kilns, and aren’t fully burned fall into the clinker design recommends a retention time of at when they contain a significant amount of due to the development of the waste mar- and burn there in under-stoichiometric least 5 - 7 [s] with alternative fuels. Choosing TOC. Depending on the nature of the TOC, ket the physical properties are expected to conditions; Can be controlled by FeO the right location can optimize the mixing it burns either in the upper stages (CO and become worse. content in clinker and clinker core colour quality of the fuel and the combustion air VOC emission) or moves down to the cal- ( → brown). from the tertiary air duct. This is, however, ciner/riser duct and actively contributes to The first challenge is the selection of the difficult and today, attempts to solve this »»LSF target not reached. the clinker production. The ratio between optimized feeding point (lumpy → calciner, problem are with the help of CFD. heating the pre-heater exit gases and con- KBE) the others can be tried on the main • This occurs when the LHV of the fuel mix tributing to the clinker process has to be burner. Even the better ones like biomass, on the main burner is too low. There is The consequences of these design limita- determined case by case. The major impact such as SSW or animal meal are far from a clear recommendation not to allow the tions are: therefore is already discussed in the section being prepared to the optimum required for LHV of the fuel mix, on a weight basis, to » Formation of CO and, on organic emissions. the main burner. The fuel just burning in the be lower than 21.000 [kJ/kg Fuel mix]. » kiln it is not enough, for clinker quality rea- »»Unburned material entering the kiln via 6.1.3. Alternative fuels (AF) sons, a certain flame temperature and flame Both effects can be overcome or improved hot meal. shape must be achieved. by the following actions: Chapter 6.1.1 describes the situation in the Another important aspect is the danger of fall A new high momentum burner past with the standard fuels (coal, coke) 6.1.3.1. Main burner »» through of coarse particles from the alterna- used in the cement industry. Clinker quality must be the main parameter »»Reduce fuel size tive fuels into the kiln. Achieving the right level to follow and must lead to control actions on of entrance speed can help to reduce or even » Improve moisture Today the situation has completely changed the AF. Strict SOPs have to be developed and » solve this phenomena and the recommen- and a cement plant fighting with fuel costs followed to avoid clinker quality problems. »»Change substitution rate dation is an entrance speed above 35 [m/s] with adaptations (even higher speeds) to the Figure 18: Fuel types Comment: In the case of alternative fuel, the specific situation. On the other hand, this fall word “improvement” must always be used through cannot be avoided 100% and there- SSW (Solid shredded waste) Biomass with fuel properties and substitution rate. fore a SLC is not the recommended solution Depending on the targeted substitution rate, for a high substitution with coarse AF. If a the fuel properties have to be adapted and new calciner is designed, an inline calciner the higher the substitution target, fuel prop- should be chosen to reduce the problem of erties can become the limiting factor. Another fuel or impurities fall through. aspect of “improvement” is the total cost eval- uation. High substitution rate with a lower 6.1.4. Build-up formation/control quality fuel might reduce the clinker produc- tion of the kiln, so an overall cost evaluation Another effect of the alternative fuels com- has to be done and the balance between fuel bustion properties is the increased ten- Shredded tyres Whole tyres costs and production targets has to be found. dency to form build-ups in the whole kiln line, but specifically in the pre-heater tower. 6.1.3.2. Calciner Besides the quality parameter of AF (→ high The main two challenges of alternative fuel chlorine content) the combustion param- combustion in the calciner are: eters, even if under control, increase the
volatilization of SO3 and chloride and thus »»Gas retention time (calculated with the enhance the formation of build-up. An opti- combustion gases/calciner volume) mized combustion (as good as possible »»The mixing quality of the combustion air with AF) is required to keep clinker quality,
with the fuel such as SO3 content, and build-up formation
48 | Best Available Technology Best Available Technology | 49 Process Impact (AF/ARM)
under control. However, in most kilns with in the extraction point and problems with Figure 19 shows the assumed limits of chlo- Both show similar performance, but a slight
increased AF rates, the improvement of the the dust transport. The higher the chloride ride/SO3 in the hot meal some years ago. In advantage is seen on the flash dryer by following points is required (see also 6.2.3): content in the by-pass dust, the stickier the the meantime, the mentioned improvements keeping the combustion properties of the material, and it is recommended not to use (see figure 19, but not the gas by-pass) have SSW more stable in online concept. Both »»Setting up strict Standard Operating Proce- pneumatic transports. plants enabled to push their operational lim- systems can be operated with cooler exit dures (SOP) based on clinker quality and its. At present, it can be argued that a plant air; the belt dryer can even be conditioned build-up tendency. In the design phase of a gas by-pass, many can operate at the following hot meal levels down to 80 [°C] and the flash dryer will assumptions have to be taken into account without gas by-pass: operate at an entrance temperature of 150 »»Improved cleaning procedures (new tools, (e.g. all components are equally distrib- [°C]. A belt dryer can be equipped with an high water pressure lances) uted in the kiln exit gas) that might not be »»Chloride ~2.5 [%] intermediate storage before the burner, to true in the actual installation. For this rea- smooth out fluctuations. »»SO3 ~3.0 [%] »»Introduce/improve automatic cleaning son, by-pass installations require a higher with big blasters during operation amount of contingency in the project phase 6.2.4. SSW dryer Another advantage of the flash dryer is a pre to be able to react. treatment of the material in the way that fuel Drying the moist SSW is mostly important particles are separated in the hot air flow → 6.2. New auxiliary equipment 6.2.2. Meal curtain for the main burner. The moisture reduction additional advantage in the main flame. improves the combustion properties in the 6.2.1. By-pass The “meal curtain” occurs in plants with main flame. This improvement is mostly used a long experience of pet-coke firing a to further increase the substitution rate. From A gas by-pass is not novel, but in plants with standard installation at the kiln back end an operational point of view, experience has increasing SSW as alternative fuel, the chlo- to reduce the build-up formation in the been had with two drying systems: ride input is increasing. In the cement indus- riser duct. try, a limit of 300 [ppm] chloride input per »»Flash dryer ton of clinker is used as the maximum bear- Developed for operational success proven »»Belt dryer able amount. It is assumed that above this with petcoke, it has also shown its opera- level kiln operation deteriorates dramati- tional advantages with alternative fuels. Figure 19: Hot meal chloride SO3 relation and build-up problems cally. A gas by-pass is installed to extract the surplus chloride and treat it separately in There is only one problem, the optimum order to control the chloride level in the kiln. location of the gas by-pass and meal curtain is at the same place and it might occur that a Another aspect not to be forgotten is that the compromise (by-pass or meal curtain) has to extracted chloride dust is hazardous waste, be chosen. By experience, it is often better and in most plants it is added to the cement to compromise on the meal curtain. Chlorine bypass production. Here the limit of the cement standards has to be followed to avoid corro- 6.2.3. Optimized cleaning Cleaning (CARDOX blaster); sion problems or loss of market. procedures and cleaning Plant A Preheater design; equipment Plant b Installations for treating chloride input into meal curtain kilns from alternative fuels are designed for This paragraph does not deal with new Plant C a size of 5-10% of the kiln exit gases, which equipment (except the recommendation to is enough to reduce the chloride level and increase the numbers of big blasters) and it Plant D Combustion optimzation, keep the chloride content (overall balance) shall not describe the actual situation with Plant f burner, sulphur/alkali ratio in the cement below the standard of exam- very low average TSR substitution rates. Plant e ple EN197, 0.1 [%]. Instead, the topic is that due to increased Plant I Plant G experience with alternative fuels the opera- Plant H Plant J A gas by-pass installation, in operational tional limits have been pushed. This is best terms, is an additional piece of equip- expressed in the known relation between
ment with additional build-up formation chloride and SO3 in the hot meal.
50 | Best Available Technology Best Available Technology | 51 NCCBM Presentation 7
7.1. India experience - AF/ for micro pollutants in most of the cement units that were using hazardous waste on a ARM use and their impact regular basis. Moreover, standard reference on emissions methods for each parameter that is required to be monitored, are not indicated in the Waste availability, its potential use in the guidelines for co-processing. cement industry and a summary of trials were presented. According to the presenta- tion, India has limited use of alternative 7.2. Emission management in fuel and alternative raw material. There is a guideline for co-processing given by the India (compliance, mon- Central Pollution Control Board (CPCB). itoring, reporting and This document covers a number of topics like: handling of waste; feeding points for trends for future) co-processing; list of wastes recommended & not recommended; operating conditions A summary of environmental regulation appli- & specification of HW for use as AFR; APC cable to the cement sector was presented. It requirements; emission standards and mon- included the existing co-processing require- itoring; and procedure & protocol for trial ments and new emission limits that will come run & approval for utilization. A detailed and into force in 2017. Some comments, with regard comprehensive presentation on the impacts to the content presented, are described below. of AF use on emissions was not covered. Specification criteria for ARM and hazardous As reported, analyses were carried out dur- waste for energy recovery are quite wide- ing normal operation, during co-processing ranged (e.g. Hg<10ppm; Cd+Tl+Hg<100ppm; and immediately after co-processing. Also, PCB<5ppm (ARM); PCB<50 Best Available Technology | 53 NCCBM Presentation It is also recommended that wastes or alter- Table 10: Specific heat consumption and native materials inserted to the secondary power consumption, India vs. world firing require qualitative limitations for input and process parameters. This is very Electrical Thermal Energy Country Energy important for materials containing relevant (kCal/kg clinker) amount of organics. In regard to persis- (kW/t cement) tent pollutants like PCBs, these materials India 82 725 should be fed via the main firing system to ensure their reliable destruction. If there World Average 100-110 850-860 are doubts about the feed point selection Best level Achieved by in the individual case, reference measure- 66 687 ments should be performed -with and with- Indian Cement Industry out using wastes. In the forthcoming years, it is expected to The NCCBM offers all services to plants so implement Continuous Emission Monitor- that they can optimize the heat and power ing (CEM) connected directly to the author- consumption; it was not presented as to how ities (most of plant is already connected). much the NCCBM staff is integrated in the As reported, to date, there are no calibra- realization of the suggested optimizations. tion standards to follow in order to assure The NCCBM staff knows the latest technol- the quality of data measured by AMS (Auto- ogies, but it could not be determined as to mated Measurement System). Apart from how much they are involved in constructing that, other reduction targets are expected and practical optimization of the latest tech- regarding CO2 emissions and energy effi- nologies in cement plants. A request from ciency that will most probably be tackled by NCCBM for training on the optimization of a PAT (Perform Achieve Trade) scheme. new equipment (e.g. modern coolers) indi- cates a dearth in the practical application. 7.3. Energy efficiency in On the one hand, tests with alternative fuels were conducted by the NCCBM, but cement sector in India with a continuous average substitution rate of < 1.5 [%] in the Indian cement industry, This presentation showed the status of the the long term operational experience of the Indian cement industry, where most of the consequences of AF substitution is missing. existing production capacity was built after On the other hand, we see the need for a 1990 (and 30% after 2010). Consequently, change in the mind set of the Indian cement 99% of the cement plants are dry lines. industry and the NCCBM because the intro- There are no numbers on the situation of duction of alternative fuels will lead to an grinding or percentages of mill types, but increase of the specific values, SHC and the numbers and the age of the plants indi- SPC, which is against the development of cate that they will be mostly vertical roller the last years. However, the government has mills and ball mills with roller presses. already reacted on this and the PAT (Perform Achieve Trade) scheme responsible for the There is much lower specific heat con- efforts to reduce SHC and SPC is adapted sumption and power consumption, than and the energy input from AFs is not counted the average values of the rest of the world; for in the SHC in the PAT scheme. Concern- see Table 10. ing power, no information was collected. 54 | Best Available Technology Best Available Technology | 55 Feedback from participants 8 This chapter summarizes the feedback of speech and response to questions asked; received from participants during the three- and if the workshop objectives were met and day workshop. Participants were requested results were useful for their activity. to give feedback on a general overview of the workshop as well as feedback on the On a scale 1 to 5, participants were asked to technical topics discussed. rate the above-mentioned topics as: 1- Strongly disagree or the lowest most 8.1. General Feedback negative impression Figure 20 below presents the overall satisfac- 2- Disagree or bad impression tion of participants concerning: whether the material covered was useful/relevant to their 3- Neither agree nor disagree needs and interests; whether the sessions were well organized; how effective group 4- Agree or good impression activities were; whether the visual aids were useful; whether the presenters had a good 5- Strongly agree or the highest positive subject knowledge, presentation style, clarity impression Figure 20: Overall Rate of Participant’ Satisfaction Overall satisfaction w ith WS Covered useful material Relevant to my needs and interests Well organised sessions Effective group activities Useful visual aids Subject knowledge of presenters Presentation style Clarity of talk Responses to questions asked Workshop objectives were met Results are useful for my activity Best Available Technology | 57 Feedback from participants 8.1.1. Additional Feedback »»Most of these data are general for the For emission monitoring, there is no stand- more process impact and operational details particular area of working and could be ard available to do the quality assurance of in regards to these technologies (SNCR/SCR). Every participant was given the option of improved by presenting detailed informa- CEMs. As reported, continuous monitoring adding comments to the feedback sheet, tion and technology analyses have never been calibrated. There The NCCBM engineering staff shows a high split in the topics “What did you like best is a need to set compliance with monitoring interest in operational experiences with new about this workshop” and “Comments or Comments are individual statements and do and respective standards to be followed. equipment (e.g. new cooler technologies: eta suggestions for improvements”. These addi- not represent the overall feedback received cooler, crossbar, polytrack) this topic was not tional comments are listed below. from the participants. To date, emissions of CO, organics, mercury covered in the workshop approach. Moreo- and heavy metals are not regularly moni- ver, the implementation of primary measures What did you like best about this workshop? tored in the Indian cement sector but they was discussed intensively, especially the 8.2. Specific Content Feedback may be required with the AF use. The NCCBM way to avoid expensive end of pipe technol- »»Openness of discussion environmental lab lacks appropriate meas- ogies. There is a high interest, but also some »»Faculty shared their experience of the Participants were requested to use the urement equipment to perform this emis- doubts, in the efficiency of these methods. international cement industry following scale in regards the specific con- sion monitoring (e.g. DF, heavy metals). tent of Workshop: Discussions were guided by the concerns »»Discussion on process parameters The strong need of SO2 abatement technology on the implementation of primary measures »»Details on process and emissions 1- No need of additional knowledge implementation may come from the fact that in existing and old cement plants, without the quality of raw materials in India is low and modern equipment. Another topic was that »»Topics were appropriate, well conducted, well presented and had a good outcome 2- Have sufficient knowledge as reported, sometimes contains sulphur pyrite. most of the Indian cement plants (or even all) are pushed over the designed capacity, »»WS was quite informative, had good time 3- Need for additional knowledge There was an interest in carbon capture by 10-20%. This way of operation is good for management and shared their practice technologies being studied, although their energy KPIs but leads to a high standard emis- experiences 4- Strong need for additional knowledge implementation in the cement industry is sion level (e.g. a plant was mentioned with still uncertain and this topic is outside the 2000 [mg/Nm³] (dry, 10% O ) NO at the stack). »»Presenter interaction with participants and 2 X knowledge sharing was very good Figure 21 below shows the views of partic- scope of the NCCBM. ipants for each topic discussed during the Finally, it must be reiterated that the imple- »»Dissemination of various topics selected workshop as a percentage. When the new emission regulation comes into mentation of the recommended primary to global practices force in 2017, most of plants will have to imple- measures is a universal advantage. Even if the »»Coverage of topics, such as, issues that General comment ment some abatement technologies to comply emission limits are not kept, primary meas- have become very important for the pres- The audience was a mix of participants with with new emission limit values (i.e. NOx lim- ures play a big role in reducing the operating ent and future of the cement industry different backgrounds. More than 75% of the its), therefore, there is a strong interest to know costs of the final emissions control equipment. participants reported having a need and/or » Knowledge on operating parameters for » strong need to get more detailed information SNCR/SCR were very helpful Figure 21: Summary of Workshop Specific Content Feedback of SOx, CO, organics, kiln operation - new aux- Comments and suggestions for improvement iliary equipment and emerging techniques. topics "Strong need" for »»More case studies to be discussed Around 60% of the participants reported a need additional k nowledge [%] to get more information on the remaining topics. "Have Sufficient »»Hard copies of presentations to be shared knowledge" [%] Better presentation data, question answer "Need" for additional »» Half of the participants’ feedback shows inter- knowledge [%] solutions, and communication est or need to get more information on climate "No need" for l l t y r g t t additional k nowledge [%] change and CO reduction alternatives. ts ro ro s ls n tr M e R n n 2 c t t n a e s R b C in e e »»Presenters/expert level should be e n n io t u A b S b m m p o o s e m d / u / b p e s C C is M e n F r R u i t A d d y g I A c C cr u a enhanced so as to cover a larger number y n n m v a t s S N q b r a a E a n n t S S e A to s e a e tie e - ry y g Specific Content Comments a s s ic H M m r W n r H of topics in an effective way l e e n e e - o D ia / u rc rc a d n p ti - il g u u g n io C ro n a n x TO For BAT regulatory aspects, the Indian Min- e o o r a s d P io r u R S S O y s n t e tio a R T - r i a n ra p a - A - d u m e io e O r w s »»Presentations should include videos and istry of Environment, Forest and Climate B x x n rc E g t p e e e O O a e n s O ln p N u N S O M a u i O - iq C h b n K n n n contact details should be shared so the par- C m il il o h change (MoEF&CC) has a similar approach o K K ti c te C a e a r T ticipants can ask them at a later date; videos, m e g to the application of BAT in the elaboration li p n C O i n rg more graphs and pictures (which are self il e of new regulations. The proposed document K m E explanatory) could form part of presentations will come into force in 2017. 58 | Best Available Technology Best Available Technology | 59 NCCBM Status versus Sustainable Cement Industry (BAT + key issues) 9 As a result of the workshop, the NCCBM reported to date, biodiversity and health & status with regard to the key issues of safety are out of the scope of the NCCBM. the cement sector was assessed by the experts. Following figure 22, the main find- The various scoring categories (5 excellent: ings and recommendations are presented. 0 unacceptable) are: It is important to note that the NCCBM has the means to support the cement sector »»Category E from 0 to 1.0 (red) for the existing technologies and well- »»Category D from 1.0 to 2.0 (orange) known process optimization for operation » Category C from 2.0 to 3.0 (yellow) without alternative fuels. There is how- » ever a need to improve its capacity for »»Category B from 3.0 to 4.0 (blue) the forthcoming issues of the sector. As »»Category A from 4.0 to 5.0 (grey) Figure 22: NCCBM status versus BAT and key issues of the cement sector emission Management kiln Operation with Af energy efficiency biodiversity Climate change Sustainability Health & Safety with Concrete Water Best Available Technology | 61 NCCBM Status versus Sustainable Cement Industry (BAT + key issues) Emission Management (Category B → 3.1) Climate Change (Category C → 2.9) Kiln Operation with AF (Category C → 2.5) [%] is missing. In the discussion, there was Emissions management, measurement, The NCCBM experts know the main levers Similar to energy efficiency, the Indian a strong request from the NCCBM for further monitoring and reporting contribute to to reduce CO2 emissions in the cement cement sector is on a high level of education on this topic. understanding, documenting and improving industry. The AF use is still limited and the operational experience with modern the industry’s environmental performance. NCCBM should be prepared to support the pre-heater/-calciner plants with standard Besides the alternative fuels experience, the A lack of emissions information can lead to sector to boost the AF use in India. Analysis fuels (petcoke, coal). The NCCBM experts interest to gain additional operating expe- local concerns about plant operation. The of biogenic content in fuels can enlarge the also have a high level and are acknowl- riences with the most modern equipment NCCBM is knowledgeable about the main NCCBM portfolio of services. Cementitious edged as partners for operator training. The technology (e.g. optimization of modern pollutants generated during cement produc- use is also a lever that the NCCBM can con- NCCBM has developed its own kiln simula- coolers) was expressed. tion. However, there is a need to build capac- tribute in by defining new cements with low tor for training purposes. ity of its experts with regard to monitoring. carbon content and last but not least, get Not just periodic monitoring (SRM and minor prepared to support pilot projects of carbon Due to the fact that the AF substitution rate elements monitoring), but continuous moni- capture and storage in the country. in India is below 1.5 [%], the practical long toring (calibration, certification of CEMs, etc.) term experience with AF firing at rates > 30 is also necessary. It is also important to make Sustainability with Concrete (Category C → 2.5) the NCCBM experts capable to support the The NCCBM experts are knowledgeable in sector with regard to new abatement tech- assessing concrete quality and performance nologies and their implementation in order as well as concrete mix design. It is necessary to comply with new regulatory limits (that to develop the NCCBM’s capacity to support will come into force in 2017). In addition, the other key issues related to concrete use like: NCCBM experts will also be able to support concrete recycling; green concrete; recycled the implementation of primary measures aggregates and sustainable resourcing. onsite to control the emission levels. If this is not enough to keep the limits, it can help Water (Category B → 3) reduce the operating costs of the new abate- The NCCBM experts know the aspects of ment technologies that can be significant. water management (footprint, optimization of water consumption, etc.). The design of Energy Efficiency (CategoryB → 3.0) STP/ETP (Effluent Treatment Station) and In the last few years, energy efficiency both in water quality analysis can enlarge the port- SHC and SPC, was a main target of the Indian folio of services of the NCCBM. cement industry, which was supported by the PAT scheme that gives energy efficient Health & Safety (Category E → 0) plants a financial advantage. The Indian To date, healthy and safety is out of the scope cement sector is on a high level of energy of the NCCBM. However, it is a key topic of efficient operation of modern dry lines. Nev- the sector and it could be an opportunity ertheless, it is recommended to change the to enlarge the NCCBM portfolio of services. approach to energy efficiency as the future of Risk assessments, health management, and fuel mix is an increase of the AF substitution operational standards (PPE, WAH, EIS, etc.) rate, and from experience, this will lead to an are in the scope of healthy and safety. increase in the SHC but also in the SPC, due to additional equipment. AFs not only have a Biodiversity (Category E → 0) cost advantage, but are also not counted, or To date, biodiversity is out of the scope of the only to a certain percentage, as CO2 emitters NCCBM. However, it is a key topic of the sector (climate change). The NCCBM experts will be and it could be an opportunity to enlarge the able to support the main target of future opti- NCCBM portfolio of services. The rehabilita- mization to be switched from the lowest pos- tion of quarries and biodiversity management sible SHC to the lowest possible total fuel mix plans as well as KPIs (e.g. bio-indicators) are costs (supported by the new PAT scheme). in the scope of biodiversity. 62 | Best Available Technology Best Available Technology | 63 Conclusions 10 The NCCBM staff’s interest on Best Available control) and RTO (CO and organics reduc- Technologies and Process Workshop was tion) were presented, but are not currently substantial, highlighted by the fact that the applicable to India’s scenario. workshop had more participants than offi- cially planned. India ranks third in the list of the main emit- ters of CO2 emissions (IEA, 2015), and the BAT implementation in India follows a sim- cement sector represents approximately 7% ilar approach as in Europe, whereas reg- of total country emission. The NCCBM can ulation reinforcement pushes the sector support the sector to offset its contribution to implement abatement technologies in to climate change. Reduction of direct and order to comply with more stringent emis- indirect emissions, promotion and improve- sion limits. In order to better support the ment of building energy efficiency (e.g. high cement sector in India, the NCCBM needs to performance concretes) are levers that the enhance its capacity on specific pollutant NCCBM could assist with. management (e.g. organics, heavy metals and mercury), their monitoring techniques The Indian cement sector clearly shows a as well as the continuous emission moni- high level of technology, process optimiza- toring follow up. tion and plant design of modern kiln lines with standard fuel, as 30 % of all Indian Participants showed knowledge on the cement lines were built after 2010. The main emission pollutants of the sector and NCCBM can offer all energy optimization respective technologies to minimize their services in the area of heat and power con- impacts. The NCCBM participants were very sumption. Some discussions indicate that attentive to forthcoming abatement tech- the NCCBM process staff does not have niques, especially NOX reduction and their enough operational experience on the lat- process related impacts. More stringent lim- est equipment. Operational training on the its will come into force in 2017. optimization of this equipment (e.g. mod- ern cooler types: ETA cooler, polytrack, The NCCBM is also aware of the topic of SO2 crossbar,etc.) was requested. emissions caused by raw materials and its reduction with dry absorption or a wet scrub- At present, the cement sector intends to ber. In parallel to these end-of-pipe tech- start with alternative fuels and raw materi- nologies, quarry studies are also done to als to optimize utilization of resources and control raw material induced SO2 emission. cost control. Due to the fact that the over- Activated carbon injection (heavy metal all AF substitution rate is below 1.5 [%], Best Available Technology | 65 Conclusions no experiences with higher AF substitu- opportunities to enhance the NCCBM port- tion rates exist in the cement industry folio of services, but are currently out of the Annexes [ → exceptions are the big groups which NCCBM scope. Their inclusion shall be sub- can provide group internal support] nor in ject to further discussion. the NCCBM. Further development is recom- mended and requested in this area during The actual NCCBM structure, team expertise workshops, as the NCCBM wants to remain and its relationship with the Department Annex 1. Presentations an acknowledged partner for the Indian of Industrial Policy and Promotion (DIPP) cement industry. and the Cement Manufacturers Association # Presentation (CMA) put the NCCBM ahead of its compet- Water, biodiversity and health and safety itors to boost the implementation of new 1 BAT - Regulatory aspects topics were not discussed in detail during abatement techniques and for the required NOX – Sources and Control the workshop though they are key issues changes in the mind set of the Indian cement 2 for the sector. There are some potential sector in a sustainable manner. 3 SOX – Sources and Control 4 CO and organics 5 Mercury and Trace Elements 6 Emission Management 7 Climate Change and the Cement Industry 8 Combustion properties - AF/ARM 9 Kiln operation - New abatement technologies and new equipment- Wet scrubber 10 Kiln operation - New abatement technologies and new equipment- SNCR/SCR 11 Kiln operation - New abatement technologies and new equipment- Dry scrubbing Kiln operation - Impacts of new auxiliary equipment (by-pass, burner modifications, 12 SSW dryer) 13 India experience – AF/ARM use and their impact on emissions 14 Emission management in India (compliance, monitoring, reporting and trends for future) 15 Energy efficiency in the cement sector in India 66 | Best Available Technology Best Available Technology | 67 Notes Images and illustration copytights © iSTOCK: Shuoshu. Shutterstock: B Brown; beerpoj012; GSK919; Banana Republic images; Rehan Qureshi; muratart. AETHEREAL SOLUTIONS: otherwise. TECHNICAL REPORT BEST AVAILABLE TECHNOLOGY ENHANCING PRODUCTIVITY IN THE INDIAN CEMENT SECTOR Vienna International Centre · P.O. Box 300 · 1400 Vienna · Austria Tel.: (+43-1) 26026-o · [email protected] www.unido.org