Adsorption characteristics of SO2 and NO in a simulated flue gas over the steam activated biomass chars
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摘要: 以麦秆和稻壳生物质为研究对象,在不同的热解温度、热解速率以及蒸汽活化温度条件下制备了生物质焦,采用比表面积与孔隙度分析仪测定生物质焦的比表面积和孔隙结构参数。利用固定床吸附装置,研究了热解温度、热解速率、活化温度和模拟烟气中SO2和NO浓度等因素对生物质焦吸附SO2和NO性能的影响。结果表明,蒸汽活化可以显著提高生物质焦的BET比表面积、D-R比表面积、D-R微孔容积和总孔容,降低其平均孔径,并显著增加蒸汽活化生物质焦对SO2与NO吸附的起始穿透时间和吸附量。快速热解下制得的蒸汽活化焦对SO2和NO的吸附效果优于慢速热解,热解温度为873 K的蒸汽活化焦的吸附性能明显好于热解温度为673与1 073 K的蒸汽活化焦。在973~1 173 K下,随着蒸汽活化温度的提高,蒸汽活化生物质焦对SO2和NO的吸附量呈现先上升后下降的趋势。随着模拟烟气中SO2与NO浓度的降低,蒸汽活化生物质焦对SO2与NO吸附的起始穿透时间延长,但相应的SO2和NO吸附量下降。在873 K、快速热解和1 073 K条件下制得的蒸汽活化麦秆焦对SO2和NO吸附量最大,其值分别为109.02和21.77 mg/g。Abstract: Biomass chars were prepared under different pyrolysis temperatures, pyrolysis rates (rapid and slow pyrolysis) and steam activation temperatures from wheat straw and rice husk; their surface area and pore structure parameters were measured by nitrogen sorption at 77 K. The effects of pyrolysis temperature, pyrolysis rate, steam activation temperature as well as the concentration of SO2 and NO in a simulated flue gas on the adsorption characteristics of SO2 and NO over the biomass chars were carried out in a fixed-bed adsorber. The results indicated that the steam activation can significantly increase the surface area, micropore volume and total pore volume of biomass chars, while decrease their average pore sizes; as a result, the breakthrough time and adsorption capacities of SO2 and NO over the activated biomass chars are increased. Moreover, rapid pyrolysis gives the biomass chars better adsorption characteristics than slow pyrolysis. A pyrolysis temperature of 873 K is superior to 673 and 1 073 K to get biomass chars of high adsorption performance for SO2 and NO. Similarly, there also exists an optimum steam activation temperature between 973 and 1 173 K to prepare activated biomass chars of high adsorption performance. The breakthrough time increases but the adsorption capacities of SO2 and NO decrease with the decrease of the concentration of SO2 and NO in the simulated flue gas. The wheat straw char prepared under the conditions of rapid pyrolysis, pyrolysis temperature of 873 K, and steam activation temperature of 1 073 K performs best for the adsorption of SO2 and NO; over it, the adsorption capacities of SO2 and NO reach 109.02 and 21.77 mg/g, respectively.
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Key words:
- biomass char /
- steam activation /
- adsorption characteristics /
- SO2 /
- NO
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SENNECA O. Kinetics of pyrolysis, combustion and gasification of three biomass fuels[J]. Fuel Process Technol, 2007, 88(1): 87-97. DEMIRBAS A. Potential applications of renewable energy sources, biomass combustion problems in boiler power systems and combustion related environmental issues[J]. Prog Energy Combust Sci, 2005, 31(2): 171-192. 付鹏, 胡松, 向军, 孙路石, 张安超, 杨涛, 江龙. 生物质颗粒孔隙结构在热解过程中的变化[J]. 化工学报, 2009, 60(7): 1793-1799. (FU Peng, HU Song, XIANG Jun, SUN Lu-shi, ZHANG An-chao, YANG Tao, JIANG Long. Evolution of pore structure of biomass particles during pyrolysis[J]. CIESC Journal, 2009, 60(7): 1793-1799.) 任海君, 张永奇, 房倚天, 王洋. 煤焦与生物质焦共气化反应特性研究[J]. 燃料化学学报, 2012, 40(2): 143-148. (REN Hai-jun, ZHANG Yong-qi, FANG Yi-tian, WANG Yang. Co-gasification properties of coal char and biomass char[J]. Journal of Fuel Chemistry and Technology, 2012, 40(2): 143-148.) MEDIC D, DARR M, SHAH A, POTTER B, ZIMMERMAN J. Effects of torrefaction process parameters on biomass feedstock upgrading[J]. Fuel, 2012, 91(1): 147-154. ARIAS B, PEVIDA C, FERMOSO J, PLAZA M G, RUBIERA F, PIS J J. Influence of torrefaction on the grindability and reactivity of woody biomass[J]. Fuel Process Technol, 2008, 89(2): 169-175. 林木森, 蒋剑春. 生物质快速热解技术现状[J]. 生物质化学工程, 2006, 40(1): 21-26. (LIN Mu-sen, JIANG Jian-chun. A review on fast pyrolysis of biomass[J]. Biomass Chemical Engineering, 2006, 40(1): 21-26.) 吴创之, 周肇秋, 阴秀丽, 易维明. 我国生物质能源发展现状与思考[J]. 农业机械学报, 2009, 40(1): 91-99. (WU Chuang-zhi, ZHOU Zhao-qiu, YIN Xiu-li, YI Wei-ming. Current status of biomass energy development in China[J]. Transactions of the Chinese Society for Agricultural Machinery, 2009, 40(1): 91-99. 马隆龙. 生物质能利用技术的研究及发展[J]. 化学工业, 2007, 25(8): 9-14. (MA Long-long. Process technology of bio-energy utilization and its development[J]. Chemical Industry, 2007, 25(8): 9-14.) LIU Y, BISSON T M, YANG H, XU Z. Recent developments in novel sorbents for flue gas clean up[J]. Fuel Process Technol, 2010, 91(10): 1175-1197. SΦRENSEN C O, JOHNSSON J E, JENSEN A. Reduction of NO over wheat straw char[J]. Energy Fuels, 2001, 15(6): 1359-1368. 张军, 林晓芬, 印佳敏, 范志林, 徐益谦. 生物质焦脱硫性能实验研究[J]. 工程热物理学报, 2005, 26(3): 537-539. (ZHANG Jun, LIN Xiao-fen, YIN Jia-min, FAN Zhi-lin, XU Yi-qian. Experimental research on the desulphurization performance of biomass char[J]. Journal of Engineering Thermophysics, 2005, 26(3): 537-539.) CARVALHO M F, DUQUE A F, GONCALVES I C, CASTRO P M L. Adsorption of fluorobenzene onto granular activated carbon: Isotherm and bioavailability studies[J]. Bioresour Technol, 2007, 98(18): 3424-3430. GONZALEZ J F, ROMAN S, ENCINAR J M, MARTINEZ G. Pyrolysis of various biomass residues and char utilization for the production of activated carbons[J]. J Anal Appl Pyrol, 2009, 85(2): 134-141. LIU W, ZENG F, JIANG H, ZHANG X. Preparation of high adsorption capacity bio-chars from waste biomass[J]. Bioresour Technol, 2011, 102(17): 8247-8252. SCHRODER E, THOMAUSKE K, WEBER C, HORNUNG A, TUMIATTI V. Experiments on the generation of activated carbon from biomass[J]. J Anal Appl Pyrol, 2007, 79(1-2): 106-111 李勤, 金保升, 黄亚继, 仲兆平, 李斌, 孙宇. 水蒸气活化制备生物质活性炭的实验研究[J]. 东南大学学报(自然科学版), 2009, 39(5): 1008-1011. (LI Qin, JIN Bao-sheng, HUANG Ya-ji, ZHONG Zhao-ping, LI Bin, SUN Yu. Preparation of biomass activated carbon by steam activation[J]. Journal of Southeast University (Natural Science Edition), 2009, 39(5): 1008-1011.) CETIN E, MOGHTADERI B, GUPTA R, WALL T F. Influence of pyrolysis conditions on the structure and gasification reactivity of biomass chars[J]. Fuel, 2004, 83(16): 2139-2150. BIAGINI E, SIMONE M, TOGNOTTI L. Characterization of high heating rate chars of biomass fuels[J]. Proc Combust Inst, 2009, 32(2): 2043-2050. ZANZI R, SJOSTROM K, BJORNBOM E. Rapid high-temperature pyrolysis of biomass in a free-fall reactor[J]. Fuel, 1996, 75(5): 545-550. SHARMA R K, WOOTEN J B, BALIGA V L, LIN X, CHAN W G, HAJALIGOL M R. Characterization of chars from pyrolysis of lignin[J]. Fuel, 2004, 83(11/12): 1469-1482. STAVROPOULOS G G, SAMARAS P, SAKELLAROPOULOS G P. Effect of activated carbons modification on porosity, surface structure and phenol adsorption[J]. J Hazard Mater, 2008, 151(2-3): 414-421. TSUJI K, SHIRAISHI I. Combined desulfurization, denitrification and reduction of air toxics using activated coke: 1. Activity of activated coke[J]. Fuel, 1997, 76(6): 549-554. CARRASCO-MARIN F, ULTRERA-HIDALGO E, RIVERA-UTRILLA J, MORENO-CASTILLA C. Adsorption of SO2 in flowing air onto activated carbons from olive stones[J]. Fuel, 1992, 71(6): 575-578. 李兰廷, 解炜, 梁大明, 孙仲超, 徐振刚. 活性焦脱硫脱硝的机理研究[J]. 环境科学与技术, 2010, 33(8): 79-83. (LI Lan-ting, XIE Wei, LIANG Da-ming, SUN Zhong-chao, XU Zhen-gang. Mechanism of removal of SO2 and NO on activated coke[J]. Environmental Science & Technology, 2010, 33(8): 79-83.) LU P, WANG Y, HUANG Z, LU F, LIU Y. Study on NO reduction and its heterogeneous mechanism through biomass reburning in an entrained flow reactor[J]. Energy Fuels, 2011, 25(7): 2956-2962. SERRE S D, SILCOX G D. Adsorption of elemental mercury on the residual carbon in coal fly ash[J]. Ind Eng Chem Res, 2000, 9(6): 1723-1730. 唐强, 张智刚, 樊越胜, 曹子栋. 活性炭选择性吸附烟气中SO2和NO的实验研究[J]. 热力发电, 2003, (12): 53-56. (TANG Qiang, ZHANG Zhi-gang, FAN Yue-shen, CAO Zi-dong. Experimental study on selective adsorption by activated carbon for SO2 and NO in the flue gas[J]. Thermal Power Generation, 2003, (12): 53-56).
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