Heterogeneous reaction kinetics of catalytic coal gasification
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摘要: 以神木煤焦为研究对象,在小型加压固定床上考察了不同气化剂(水蒸气、二氧化碳、氢气)、催化剂负载量、水蒸气分压、氢气分压和一氧化碳分压对碳转化率和气化反应速率的影响。结果表明,对于非均相的催化气化反应来说,反应速率顺序为C-H2O >C-CO2>C-H2。H2和CO不同程度地抑制煤焦水蒸气气化反应,CO的抑制作用明显大于H2。在700 ℃,当添加5%的CO,碳转化率降低约50%。基于Langmuir-Hinshelwood(L-H)方程,结合随机孔模型,同时考虑催化剂负载量及气化产物分压的影响,建立了煤焦催化水蒸气气化动力学模型,模型预测反应速率常数与实验值误差在10%以内,说明建立的动力学模型可以较好地模拟煤焦的催化水蒸气气化反应过程。Abstract: The gasification tests of Shenmu coal char were carried out in a pressured fixed bed reactor to investigate the effect of gasification agents (H2O, CO2, H2), catalyst loading, and partial pressure of hydrogen and carbon monoxide on the carbon conversion and reaction rate. The results show that the heterogeneous reaction rate is in the order of C-H2O >C-CO2>C-H2. H2 and CO inhibit the steam gasification rate to some degrees. The inhibition of CO is much greater than that of H2. The carbon conversion decreases by about 50% with the addition of only 5% CO at 700 ℃. A kinetic model is developed combined Langmuir-Hinshelwood (L-H) with the random pore model, considering the effect of catalyst loading and the partial pressure of gasification product gases. The deviation between predication and experiment value is less than 10%, indicating that the derived kinetic model is appropriate for describing the catalytic coal gasification with steam.
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Key words:
- catalytic coal gasification /
- pressured fixed bed /
- kinetics /
- random pore model
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汪家铭, 蔡洁. 煤制天然气技术发展概况与市场前景[J]. 天然气化工, 2010, 35(1): 64-70. (WANG Jia-ming, CAI Jie. Technology development and market prospects of coal-based substitute nature gas[J]. Nature Gas Chemical Industry, 2010, 35(1): 64-70.) HIRSCH R L, GALLAGHER J E, LESSARD J R R, WESSELHOFT R D. Catalytic coal gasification: An emerging technology[J]. Science, 1982, 215(4529): 121-127. 王黎, 张占涛, 陶铁托. 煤焦催化气化活性位扩展模型的研究[J]. 燃料化学学报, 2006, 34(3): 275-279. (WANG Li, ZHANG Zhan-tao, TAO Tie-tuo. Study on active extending model of coal char catalytic gasification[J]. Journal of Fuel Chemistry and Technology, 2006, 34(3): 275-279. ) 王黎, 张占涛, 张丽. 煤焦催化气化的修正随机孔模型研究[J]. 西安交通大学学报, 2006, 40(3): 319-323. (WANG Li, ZHANG Zhan-tao, ZHANG Li. Study on modified random pore model of catalytic coal char gasification[J]. Journal of Xi'an Jiao Tong University, 2006, 40(3): 319-323.) 张泽凯, 王黎, 刘叶奎, 冯霄. 煤催化气化的修正缩核反应模型研究[J]. 西安交通大学学报, 2003, 37(11): 1190-1193. (ZHANG Ze-kai, WANG Li, LIU Ye-kui, FENG Xiao. Study of modified unreacted-core shrinking model of catalytic carbon gasification[J]. Journal of Xi'an Jiao Tong University, 2003, 37(11): 1190-1193.) ZHANG Y, HARA S, KAJITANI S, ASHIZAWA M. Modeling of catalytic gasification kinetics of coal char and carbon[J]. Fuel, 2010, 89(1): 152-157. SCHUMACHER W, MÜHLEN H J, HEEK K H V, JÜNTGEN H. Kinetics of K-catalysed steam and CO2 gasification in the presence of product gases[J]. Fuel, 1986, 65(10): 1360-1363. MEIJER R, KAPTEIJN F, MOULIJN J A. Kinetics of the alkali-carbonate catalysed gasification of carbon: 3. H2O gasification[J]. Fuel, 1994, 73(5): 723-730. 战书鹏, 王兴军, 洪冰清, 于广锁, 王辅臣. 褐煤催化加氢气化实验研究[J]. 燃料化学学报, 2012, 40(1): 8-14. (ZHAN Shu-peng, WANG Xing-jun, HONG Bing-qing, YU Guang-suo, WANG Fu-chen. Experimental study on catalytic hydrogasification of lignite[J]. Journal of Fuel Chemistry and Technology, 2012, 40(1): 8-14.) MÜHLEN H J, HEEK K H V, JÜNTGEN H. Kinetic studies of steam gasification of char in the presence of H2, CO2 and CO[J]. Fuel, 1985, 64(7): 944-949. FORMELLA K, LEONHARDT P, SULIMMA A, HEEK K H V, JVNTGEN H. Interaction of miners matter in coal with potassium during gasification[J]. Fuel, 1986, 65(10): 1470-1472. LEONHARDT P, SULIMMA A, HEEK K H V, JÜNTGEN H. Steam gasification of German hard coal using alkaline catalysts: Effects of carbon burn-off and ash content[J]. Fuel, 1983, 62(2): 200-204. KUBIAK H, SCHRÖTER H J, SULIMMA A, HEEK K H V. Application of K2CO3 catalysts in the coal gasification process using nuclear heat[J]. Fuel, 1983, 62(2): 242-245. WIGMANS T, HARINGA H, MOULIJN J A. Nature, activity and stability of active sites during alkali metal carbonate-catalysed gasification reactions of coal char[J]. Fuel, 1983, 62(2): 185-189. JÜNTGEN H. Application of catalysts to coal gasification process-incentives and perspectives[J]. Fuel, 1983, 62(2): 234-238. MEIJER R, LINDEN B V D, KAPTEIJN F, MOULIJN J A. The interaction of H2O, CO2, H2 and CO with the alkali-carbonate/carbon system: A thermogravimetric study[J]. Fuel, 1991, 70(2): 205-214. WALKER P L, MATSUMOTO J S, HANZAWA T, MUIRA T, ISMAIL I M K. Catalysis of gasification of coal-derived cokes and chars[J]. Fuel, 1983, 62(2): 140-149. MCKEE D W. Mechanisms of the alkali metal catalysed gasification of carbon[J]. Fuel, 1983, 62(2): 170-175. HAMILTON R T, SAMS D A, SHADMAN F. Variation of rate during potassium-Catalysed CO2 gasification of coal char[J]. Fuel, 1984, 63(7): 1008-1012. MATSUI I, KUNⅡ D, FURUSAWA T. Study of fluidized bed steam gasification of char by thermogravimetrically obtained kinetics[J]. J Chem Eng Jpn, 1985, 18(2): 105-113.
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