The University of New South Wales School of Materials Science and Engineering of Masters Research Degree The Effect of Coal Properties on Carbonization behaviour and Strength of Coke Blends August 2012 Kyung Eun (Jake), JEE Supervisors Prof. Veena Sahajwalla Dr. Sushil Gupta ACKNOWLEDGEMENTS First and foremost I would like to sincerely acknowledge the people and organizations contributed to publish this thesis. I gives grateful thanks to the supervisor, Professor Veena Sahajwalla for her relentless guidance during the research of study and Dr. Sushil Gupta, co-supervisor for his suggesting research topic, discussing study procedures and solving experimental problems. Additionally many great advices from Dr. ByoungChul Kim and Mr. DongMin Jang, which are important for finishing thesis work, are also appreciated. I also would like to be grateful to Dr. WoonJae Lee for his whole support of experimental planning, Mr. YoungHa Bae, technology development team leader of the POSCO coke making department who provided all coal samples and all the following staff members of the coke making technology development team in Pohang Works for their all efforts in processing experiment: Mr. HeykJin Kim, Mr. TaeMan Kang, Mr. YongJin Kim, Mr. JongSu Heo, Mr. YongPyo Kim and Mr. BumDuk Han. Special thanks are given to Mr. JinKook Park and Mr. HyunJun Shin for entire collaboration involved in the preparation of the coal samples. I wish to give appreciation to the general manager of the POSCO coke making department in Pohang Works, Mr. DongWon Kim for his all care to accomplish this study, Mr. DongKi Son, Mr. Hyung-Ki Seong, Mr. JongYup Choi, Mr. SeaKyoung Oh, Mr. KiSeog Choi and Mr. SeungOh Yoon for their all instruction of the coke making technology, Mr. JaeHong Yu and Mr.SangDong Lee for their precious advise, Mr. JeongHoon Kim, Mr. SangWan Kim, Mr. JaeWon Hur and Miss SuJin Oh for filling the author’s absence in the cokemaking department of POSCO Pohang Works during this study. A sincere debt of gratitude is owed to POSCO executive members for their sponsoring, Mr. JoonYang Chung, Mr. JinIl Kim, Mr. BongRae Cho and KeeChang Lee. Additionally, YongOk Choi, Chief Executive Officer of POSFINE, without whom I never would have been able to come to the Australia and do this study. Finally, particular thanks to POSCO Australia members: Mr. SungWook Kang, Mr. JongHun Jong, and Mr. InHyunk Yeou for the supporting life in Australia. Mostly, I also would like to give my gratitude to my wife Ms. JiSong Yi who always take care of our family and YeWon Jee, my daughter continuously giving me power to finish thesis by million dollars of smile. Table of Contents 1 INTRODUCTION AND OBJECTIVE .........................................................1 1.1 Introduction ..................................................................................................................... 1 1.2 Objectives ....................................................................................................................... 6 2 LITERATURE REVIEW ...............................................................................7 2.1 Iron-making Process ....................................................................................................... 7 2.1.1 Blast-Furnace Process ............................................................................................. 7 2.1.2 Coke-Making Process ............................................................................................ 11 2.2 Coal Characterization ................................................................................................... 14 2.2.1 Coal Composition .................................................................................................. 14 2.2.2 Coal Classification ................................................................................................. 15 2.2.3 Physical Properties ................................................................................................ 19 2.2.4 Chemical Properties ............................................................................................... 29 2.2.5 Coal Petrography ................................................................................................... 29 2.2.6 Inorganic Matter .................................................................................................... 34 2.3 Carbonization Phenomena ............................................................................................ 36 2.3.1 Meta-plast Formation ............................................................................................ 36 2.3.2 Resolidification and Semicoke .............................................................................. 45 2.3.3 Carbonization in Industrial Oven .......................................................................... 49 2.4 Factors affecting Coke Properties................................................................................. 50 2.4.1 Coke Quality Parameters ....................................................................................... 50 2.4.2 Coal Rank .............................................................................................................. 57 2.4.3 Coal Maceral.......................................................................................................... 60 2.4.4 Coal Fluidity/Rheology ......................................................................................... 69 2.4.5 Coal Inorganic Matter ............................................................................................ 76 2.5 Coke Strength Prediction .............................................................................................. 79 2.5.1 Coke Strength Model ............................................................................................. 79 2.5.2 Effect of Blending ................................................................................................. 83 2.6 Summary ....................................................................................................................... 87 3 EXPERIMENTAL ...................................................................................... 89 3.1 Coal Samples ................................................................................................................. 91 3.2 Carbonisation Tests ....................................................................................................... 95 3.2.1 Carbonisation in 30 kg Operations ........................................................................ 97 3.2.2 Carbonisation in Industrial Oven ........................................................................... 97 3.2.3 Coke Strength Measurement ................................................................................. 98 3.2.4 Coke Texture ....................................................................................................... 100 3.2.5 Physical Structure (SEM/Optical Microscopy) ................................................... 101 4 ASSOCIATION BETWEEN COAL PROPERTIES AND COKE STRENGTH ..................................................................................................... 102 4.1 Effect of Coal Rank ..................................................................................................... 102 4.2 Effect of Coal Rheology .............................................................................................. 106 4.3 Effect of Coal Rank and Rheology on Coke Strength of Blends ................................ 109 4.4 Coke Micro-texture...................................................................................................... 111 5 EFFECT OF VITRINITE TYPES ON COKE STRENGTH.................... 117 5.1 Effect of Vitrinite Composition ................................................................................... 118 5.2 Effect of Sub-maceral on Coke Strength ..................................................................... 119 6 EFFECT OF BLENDING ON COKE STRENGTH ................................ 123 6.1 Vitrinite Composition and Coal Property .................................................................... 123 6.2 Vitrinite Composition and Coke Strength ................................................................... 124 6.2 Implication on Industrial Coke Strength ..................................................................... 126 7 CONCLUSIONS ....................................................................................... 129 List of Figures Figure 2.1 Schematic of blast furnace and movement of gas (Hutny, 1991) ........................... 7 Figure 2.2 Relationship between the blast furnace volume and adjusted coke strength (Nakamura, 1981) .................................................................................................. 10 Figure 2.3 Conventional Coke Making Process ..................................................................... 11 Figure 2.4 Non - recovery coke oven (Bertling, 1999) .......................................................... 13 Figure 2.5 Coalification Process ............................................................................................. 15 Figure 2.6 Estimators of coal rank (Esterle, 2007) ................................................................. 17 Figure 2.7 Correlation of the coal density with carbon contents (Huang, 1995) and Densities of coal macerals (Krevelen, 1993) ....................................................... 20 Figure 2.8 Microhardness index