Western Kentucky University TopSCHOLAR® Masters Theses & Specialist Projects Graduate School Summer 2017 One-step Laser-Induced Hydrogen Generation from Coal Powders in Water Dovletgeldi Seyitliyev Western Kentucky University, [email protected] Follow this and additional works at: http://digitalcommons.wku.edu/theses Part of the Oil, Gas, and Energy Commons, and the Other Physics Commons Recommended Citation Seyitliyev, Dovletgeldi, "One-step Laser-Induced Hydrogen Generation from Coal Powders in Water" (2017). Masters Theses & Specialist Projects. Paper 2038. http://digitalcommons.wku.edu/theses/2038 This Thesis is brought to you for free and open access by TopSCHOLAR®. It has been accepted for inclusion in Masters Theses & Specialist Projects by an authorized administrator of TopSCHOLAR®. For more information, please contact [email protected]. ONE-STEP LASER-INDUCED HYDROGEN GENERATION FROM COAL POWDERS IN WATER A Thesis Presented to The Faculty of the Department of Physics and Astronomy Western Kentucky University Bowling Green, Kentucky In Partial Fulfillment Of the Requirements for the Degree Master of Science By Dovletgeldi Seyitliyev August 2017 I dedicate this thesis to my family and the teachers in my Turkmen-Turkish high school who dedicated their lives to my success. ACKNOWLEDGMENTS I would like to thank my advisor Dr. Ali Oguz Er for his expert advice, encouragement, and inspiration throughout this difficult project, as well as my group partners Khomidkhodzha Kholikov and Ilhom Saidjafarzoda for their assistance in the lab. I would also like to thank to all undergraduate students in our lab for their extraordinary help. Finally, this project would have been impossible without support of American Chemical Society Petroleum Research Fund (ACS PRF). iv PREFACE One of the greatest challenges facing humankind in upcoming future is the energy. Starting with the revolution of technology in eighteenth century, energy became one of the most important subjects in science. Fossil fuels such as coal, petroleum, and natural gas have been the main energy resources for everything vital for human society. However, they are not environmentally friendly and have several adverse effects such as global warming and air pollution. In order to solve some of these problems, alternative energy sources are required. One of the alternatives is hydrogen gas since it is abundant enough and has no adverse effect to the environment. However, it does not exist in its gas form, it must be produced from the other sources. In this project, we worked on generating hydrogen from fossil fuels and water using nanosecond laser pulses. Since both the fossil fuels and water are abundant and cheap, our goal was to generate hydrogen by the cheaper and simpler method. We have been working on this project for nearly 18 months in order to obtain and analyze the results to understand how laser affects fossil fuel in water yielding hydrogen. Outcomes and results will be discussed in several sections. First, importance of hydrogen energy will be introduced which will be followed by detailed information about laser-material interactions. After that, experimental methods, results, and outcomes based on our research will be provided. In Appendix section, supplementary information about experimental results and instruments will be included. All of the results in this thesis is a result of our hard work so we wish it would be valuable contribution to the state of science. v CONTENTS ABSTRACT vii Chapter 1. INTRODUCTION 1 1.1. Hydrogen 1 1.2. Hydrogen Production 3 1.3. Laser Material Interactions 6 Chapter 2. Materials and Methods 14 Chapter 3. Results and Discussion 16 3.1. Characterization of the Samples 16 3.2. Gas components and possible reactions 22 i. Graphite under air and argon atmosphere without water 25 ii. Graphite under air and argon atmosphere with water 25 iii. Coal samples under air and argon atmosphere without water 26 iv. Coal samples under air and argon atmosphere with water 28 v. Time dependency of generated gas 30 3.1. Laser-coal interactions: Simulation 34 CONCLUSION 37 APPENDIX A: Supplementary Information 38 APPENDIX B: Gas Chromatography 45 APPENDIX C: ND:YAG laser operation 57 Literature cited 63 vi ONE-STEP LASER-INDUCED HYDROGEN GENERATION FROM COAL POWDERS IN WATER Dovletgeldi Seyitliyev August 2017 66 Pages Directed by: Ali Oguz Er, Wieb Van Der Meer, and Steven Gibson Department of Physics and Astronomy Western Kentucky University This study presents a simple way of obtaining hydrogen gas (H2) from various ranks of coal, coke, and graphite using nanosecond laser pulses. Powder samples of coal and graphite with and without water were irradiated with 1064 nm and 532 nm pulses from an Nd: YAG laser for 45 minutes under air and argon atmospheres. It was observed that 532 nm laser pulses were more effective than 1064 nm pulses in gas generation and both were nonlinearly correlated with respect to the laser energy density. Mainly hydrogen (H2) and carbon monoxide (CO) were observed. The H2 to CO ratio shows that the highest efficiency rank was the anthracite coal, with an average ratio of 1.4 due to its high fixed- carbon content and relatively high hydrocarbon amount. Coal samples were characterized by scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, Thermogravimetric analyzer (TGA), and calorimeter. Graphite was used as a pure carbon source to study the possible reactions of gas yielded during irradiation process. The amount of H2 produced was negligible when graphite powder was exposed under the air and argon atmospheres. On the other hand, H2 was obtained from irradiation of graphite powder in the presence of water due to a possible carbon-water reaction. When coal powders were irradiated under air and argon atmosphere, the amount of produced H2 increased drastically compared to graphite due to the presence of hydrocarbons in coal. In addition, theoretical simulations by a standard finite difference method supported experimental observations. vii CHAPTER 1 INTRODUCTION 1.1.Hydrogen The energy crisis that is humankind is facing needs to be explained in order to understand why alternative energy sources like hydrogen are needed. Today, most of the energy consumed release carbon dioxide and other small particulate matters (such as dirt, liquid droplets emitted from the cars, factories etc.) that cause air pollution and global warming. On the other hand, fossil fuels, the most common energy source currently used, are a finite source and there is an urgent need for alternative energy sources such as hydrogen. Figure 1. Illustration of hydrogen gas molecule. Hydrogen gas is the simplest molecule consisting of two hydrogen atoms. It is a promising alternative to replace fossil fuels based on its characteristics such as being non- toxic, high in energy, and the most abundant element on Earth, along with having no adverse effect on the environment. One of the excitement about hydrogen is that it can be produced directly from the water which is one of our planet’s most common substances. Hydrogen require energy input to be produced, it is considered as an energy carrier and 1 readily can be generated from any type of energy available today [1]. The concept of hydrogen economy is based on the future where all of our energy needs will be met by hydrogen that is produced from renewables such as wind power or solar energy. Figure 2. Trend toward lower carbon fuels from the past (1850) to nowadays (2000) based on the market share percentage of energy sources [2]. Hydrogen is the ultimate goal in fuel industry to remove carbon emissions since burning hydrogen releases nothing but water. Figure 2 shows that from the past to the present days, emissions of carbon to hydrogen ratio decreases. In early history people used dry wood as their energy sources which has the carbon/hydrogen ratio of roughly 10:1. Later on the coal dominates as main energy source with even more less carbon to hydrogen ratio (from 2:1 up to 1:1). The oil slides further down the carbon scale with 1:2 ratio on average. And as you can guess, natural gas has even less carbon and more hydrogen than oil (a 1:4 ratio) [3]. It can be clearly seen that humankind made a progress to reduce carbon to hydrogen ratio, hence to reduce air pollution and global warming by reducing carbon 2 emissions. However, hydrogen will be the optimum point for humanity with 0 carbon emissions. Energy source must be cost effective in order to be accepted and used widely in society. The main drawback of hydrogen is that the cost is not as cheap as fossil fuels or natural gas (yet). For comparison cost of fossil fuel is $1 per million BTU, natural gas is $4 per million BTU which is considered as expensive in today’s energy economy. Hydrogen gas is even more expensive to generate with about $7 per million BTU [4]. However, as today natural gas gaining on oil’s market, it is a hope that one day, hydrogen will gain on natural gas market and the 0% carbon emission goal will be achieved. 1.2. Hydrogen Production Hydrogen does not exist naturally on Earth in its molecular form, instead it requires energy to be produced and must be generated from other sources such as natural gas, coal and renewable sources with input from renewable energies such as solar light, wind, and hydropower [5, 6]. Most hydrogen today is produced through natural gas (and/or coal) reforming at large refineries and by coal gasification, i.e. reacting coal with oxygen and steam under high pressures and temperatures to form synthesis gas-a mixture consisting primarily of carbon monoxide and hydrogen. Another most known conventional method of hydrogen production is electrolysis of water which breaks down water in its components releasing hydrogen and oxygen.