Isothermal partial oxidative pyrolysis mechanisms of solid particles from biomass gasification
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摘要: 在固定床反应器中考察了不同气氛下PBG恒温热解特性的差异，结合XPS与13C NMR等技术手段分析了400 ℃恒温热解条件下PBG固相产物的化学结构变化。结果表明，PBG在400 ℃恒温热解时，生物质气化燃气（BAG）与N2气氛下更易生成焦油，其析出量分别为50.71与37.45 mg/g，而临氧燃气气氛（BAG+2% O2）下焦油析出量仅为11.96 mg/g，说明适量O2的存在可有效抑制焦油的生成。进一步进行化学结构分析表明，在燃气（BAG）恒温热解条件下，PBG主要发生以脱氢脱氧为主的芳香化缩聚反应，易形成焦油类的大分子多环芳烃；而在临氧燃气（BAG+2% O2）恒温热解条件下，PBG表面的有机基团易与O2发生表面氧化反应，生成表面含氧官能团，在一定程度上抑制了芳香环缩聚反应，进而有利于降低焦油类物质的产率。因此，在生物质气化燃气实际高温过滤过程中适当添加氧（如：2% O2），可有效降低PBG焦油收率，且不会形成大分子多环芳烃，有助于解决粗燃气过滤的过滤介质堵塞问题。Abstract: Isothermal pyrolytic characteristics of PBG at 400℃ under different reaction atmospheres in a horizontal tubular quartz reactor were investigated and compared. Meanwhile, chemical structures of PBG and its pyrolysis solid products were also analyzed with the help of XPS and 13C NMR methods. The results indicate that tar yields derived from PBG pyrolysis are 50.71 and 37.45 mg/g under biomass air gasification (BAG) and N2 atmospheres, respectively, while 11.96 mg/g under BAG+2%O2 atmosphere, which indicates that the presence of oxygen can inhibit the production of tar. Furthermore, the dominant reaction is characterized as the polycondensed aromatization involving dehydrogenation and deoxygenation in PBG under BAG atmosphere, tending to the formation of heavy organic compounds such as tar. While, surface oxygen-containing organic functional groups can be generated via the oxidation reaction between some surface functional groups of PBG and O2 in PBG under BAG+2%O2 atmosphere, inhibiting the aromatization of aromatic clusters and the formation of heavy organic compounds such as tar to some extent. Thus, the introduction of a limited amount of oxygen may be helpful for solving the pipe blockage during hot gas filtration of the raw BAG gas.
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图 2 不同反应气氛下PBG转化率和焦油生成量(a)、临氧气氛下气体组分浓度变化率(b)
Figure 2 PBG conversion rate and the tar yield under different reaction atmospheres (a) and the change rate of gas concentration under BAG+2%O2 atmosphere (b)
图 3 PBG及其在不同气氛下热解固体产物的C 1s谱图
Figure 3 C 1s XPS spectra of PBG and its pyrolysis solid products derived from different reaction atmospheres
(a): PBG; (b): BAG-solid product; (c): BAG+2%O2-solid product; (d): N2-solid product
图 4 PBG及其在不同气氛下热解固相产物13C NMR谱图
Figure 4 13C NMR curve fitting results for PBG and its pyrolysis solid products derived from different reaction atmospheres
(a): PBG; (b): BAG-solid product; (c): BAG+2%O2-solid product; (d): N2-solid product
图 5 PBG及其在不同气氛下热解固相产物13C NMR碳骨架分布
Figure 5 Distribution of carbon skeletons determined by 13C NMR in PBG and its pyrolysis solid products derived from different reaction atmospheres
图 6 PBG及其在不同气氛下热解固相产物芳香簇典型示意图
Figure 6 Typical aromatic clusters derived from NMR in PBG and its solid products under different reaction atmospheres
(a): PBG; (b): BAG-solid product; (c): BAG+2%O2-solid product; (d): N2-solid product
表 1 PBG的工业分析及元素分析
Table 1 Proximate and ultimate analyses of PBG
Sample Proximate analysis wdb/% Ultimate analysis wdb/% M A V FC C H S Oa N PBG 2.51 19.58 16.84 61.07 56.88 3.64 0.93 18.28 0.69 a：calculation by difference 
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表 2 PBG原样及不同气氛下热解固体产物表面碳官能团的相对含量
Table 2 The relative amounts of carbon functionalities in PBG and its pyrolysis solid products derived from different reaction atmospheres
Sample Relative amount w/% Rb C-C & C=C C-H C-O C=O COOH total OFGsa PBG 8 72 13 1 6 20 0.11 BAG-solid product 39 46 10 1 4 15 0.85 BAG+2%O2-solid product 10 66 12 5 7 24 0.15 N2-solid product 10 74 8 4 4 16 0.14 a：total OFGs=the sum of oxygen-containing functional groups; b：R= the ratio of “C-C & C=C” to “C-H”
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表 3 PBG及其在不同气氛下热解固相产物13C NMR碳官能团分布
Table 3 Distribution of carbon functionalities determined by 13C NMR in PBG and its pyrolysis solid products derived from different reaction atmospheres
Skeletons
Moieties
δCarbonyls Aromatics Alkyls C=O
(202)COOH
(187, 178)Ar-O
(167, 153)Ar-C
(140, 126)Ar-H
(113, 101)R-O
(93, 76, 56)CH2
(40, 31)CH3
(20, 13)PBG 0.82 2.75 7.26 45.99 22.11 5.45 7.04 8.58 BAG-solid product 0.00 0.00 6.28 73.50 15.06 0.00 0.00 5.16 BAG+2%O2-solid product 0.00 1.58 8.49 59.27 21.83 6.57 0.00 2.26 N2-solid product 0.00 0.98 6.63 52.87 26.50 9.44 1.11 2.47 Ar-O: O attached to aromatics; Ar-C: C attached to aromatics; Ar-H: H attached to aromatics; R-O: O attached to aliphatics
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表 4 PBG及其在不同气氛下热解固相产物芳香度、芳香环边缘位点的碳原子占比、每个芳香簇所含最小碳原子数
Table 4 Aromaticity, fractions of aromatic edge carbons and minimum number of carbons per aromatic cluster in PBG and its pyrolysis solid products derived from different reaction atmospheres
Sample Aromaticity XAr-H Xedge, min Xedge, maX nC, min PBG 75.36 0.29 0.39 0.72 ＞12 C BAG-solid product 94.85 0.16 0.23 0.28 ＞77 C BAG+2%O2-solid product 89.59 0.24 0.34 0.45 ＞29 C N2-solid product 86.00 0.31 0.39 0.55 ＞20 C
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[1] HEIDENREICH S. Hot gas filtration-A review[J]. Fuel, 2013, 104:83-94. doi: 10.1016/j.fuel.2012.07.059 [2] WOOLCOCK P J, BROWN R C. A review of cleaning technologies for biomass-derived syngas[J]. Biomass Bioenerg, 2013, 52:54-84. doi: 10.1016/j.biombioe.2013.02.036 [3] SHARMA S D, DOLAN M, ILYUSHECHKIN A Y, MCLENNAN K G, NGUYEN T, CHASE D. Recent developments in dry hot syngas cleaning processes[J]. Fuel, 2010, 89:817-826. doi: 10.1016/j.fuel.2009.05.026 [4] ALVIN M A. Impact of char and ash fines on porous ceramic filter life[J]. Fuel Process Technol, 1998, 56:143-168. doi: 10.1016/S0378-3820(97)00088-X [5] SIMEONE E, SIEDLECKI M, NACKEN M, HEIDENREICH S, DE JONG W. High temperature gas filtration with ceramic candles and ashes characterisation during steam-oxygen blown gasification of biomass[J]. Fuel, 2013, 108:99-111. doi: 10.1016/j.fuel.2011.10.030 [6] KAMIYA H, SEKIYA Y, HORIO M. Thermal stress fracture of rigid ceramic filter due to char combustion in collected dust layer on filter surface[J]. Powder Technol, 2011, 115(2):139-145. https://www.sciencedirect.com/science/article/pii/S0032591000003387 [7] HEMMER G, HOFF D, KASPER G. Thermo-analysis of fly ash and other particulate materials for predicting stable filtration of hot gases[J]. Adv Powder Technol, 2003, 14(6):631-655. doi: 10.1163/15685520360731954 [8] HURLEY J P, MUKHERJEE B. Assessment of filter dust characteristics that cause filter failure during hot-gas filtration[J]. Energ Fuel, 2006, 20(4):1629-1638. doi: 10.1021/ef050303k [9] 龚智, 苏德仁, 曾中华, 魏志国, 潘贤齐.堇青石陶瓷过滤器生物质燃气除尘实验研究[J].陶瓷学报, 2011, 32(3):347-352. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=tcxb201103002GONG Zhi, SU De-ren, ZENG Zhong-hua, WEI Zhi-guo, PAN Xian-qi. Experimental study on cordierite ceramic filter for biomass fuel gas filtration[J]. J Ceram, 2011, 32(3):347-352. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=tcxb201103002 [10] 郎林, 谢建军, 杨文申, 阴秀丽, 吴创之.改性陶瓷管高温净化生物质粗燃气的研究[J].工程热物理学报, 2014, 35(8):1665-1668. http://www.cqvip.com/QK/90922X/201408/71678266504849524856485252.htmlLANG Lin, XIE Jian-jun, YANG Wen-shen, YIN Xiu-li, WU Chuang-zhi. Hot gas filtration performance of modified ceramic candles for biomass gasfication[J]. J Eng Thermophys, 2014, 35(8):1665-1668. http://www.cqvip.com/QK/90922X/201408/71678266504849524856485252.html [11] 阴秀丽, 吴晋沪, 定明月, 郎林, 谢建军, 王树荣. 千吨生物质气化合成液体燃料关键技术与示范[R]. 455860816-3011BAD22B06/01, 2011.YIN Xiu-li, WU Jin-hu, DING Ming-yue, LANG Lin, XIE Jian-jun, WANG Shu-rong. The key technology and demonstration unit for 1000-ton synthol liquid fuel by biomass gasification[R]. 455860816-3011BAD22B06/01, 2011. [12] 郎林, 阴秀丽, 吴创之, 潘贤齐. 一种生物质粗燃气高温除尘除焦一体化净化工艺[P]. 中国, 201310590071. 7, 2014-3-5.LANG Lin, YIN Xiu-li, WU Chuang-zhi, PAN Xian-qi. An integrated high-temperature dust/tar purification technologyfor the crude biomass fuel gas[P]. Chinese Patent, ZL201310590071. 7, Mar. 5th, 2014. [13] 吴创之, 应浩, 李宗立, 阴秀丽, 潘贤齐, 周意. 生物质气化发电与热电联供系统研究[R]. 455860816-2012BAA09B03/01, 2012.WU Chuang-zhi, YING Hao, LI Zong-li, YIN Xiu-li, PAN Xian-qi, ZHOU Yi. The integrated systems for biomass gasification, power generation and CHP[R]. 455860816-2012BAA09B03/01, 2012. [14] 江俊飞. 生物质燃气中固体颗粒物的临氧燃烧研究[D]. 北京: 中国科学院大学, 2016.JIANG Jun-fei. The partial oxidation of the particulate matters in product gas[D]. Beijing: Chinese Academy of Sciences, 2016. [15] 陈亮. 有氧气氛下生物质热解特性的实验研究[D]. 上海: 上海交通大学, 2011. http://www.wanfangdata.com.cn/details/detail.do?_type=degree&id=D633171CHEN Liang. Experimental study on biomass pyrolysis characteristics in the presence of oxygen[D]. Shanghai: Shanghai Jiao Tong University, 2011. http://www.wanfangdata.com.cn/details/detail.do?_type=degree&id=D633171 [16] NISHIMIYA K, HATA T, IMAMURA Y, ISHIHARA S. Analysis of chemical structure of wood charcoal by X-ray photoelectron spectroscopy[J]. J Wood Sci, 1998, 44(1):56-61. doi: 10.1007/BF00521875 [17] 张娜. 污泥热解过程中氮的迁移特性研究[D]. 沈阳: 沈阳航空航天大学, 2012. http://cdmd.cnki.com.cn/Article/CDMD-10143-1013174096.htmZhang Na. Study on the transformation characteristics of nitrogen during pyrolysis of sewage sludge[D]. Shenyang: Shenyang Aerospace University, 2012. http://cdmd.cnki.com.cn/Article/CDMD-10143-1013174096.htm [18] SULIMAN W, HARSH A J B, ABU-LAIL N I, FORTUNA A, DALLMEYER I, GARCIA-PEREZ M. Modification of biochar surface by air oxidation:Role of pyrolysis temperature[J]. Biomass Bioenerg, 2016, 85:1-11. doi: 10.1016/j.biombioe.2015.11.030 [19] CHENG C H, LEHMANN J, THIES J E, BURTON S D, ENGELHRAD M H. Oxidation of black carbon by biotic and abiotic processes[J].Org Geochem, 2006, 37(11):1477-1488. doi: 10.1016/j.orggeochem.2006.06.022 [20] BOEHM H P. Surface oxides on carbon and their analysis:a critical assessment[J]. Carbon, 2002, 40(2):145-149. doi: 10.1016/S0008-6223(01)00165-8 [21] 王永刚, 周剑林, 陈艳巨, 胡秀秀, 张书, 林雄超. 13C固体核磁共振分析煤中含氧官能团的研究[J].燃料化学学报, 2013, 41(12):1422-1426. http://manu60.magtech.com.cn/rlhxxb/CN/abstract/abstract18307.shtmlWANG Yong-gang, ZHOU Jian-lin, CHEN Yan-ju, HU Xiu-xiu, ZHANG Shu, LIN Xiong-chao. Contents of O-containing functional groups in coals by 13C NMR analysis[J]. J Fuel Chem Technol, 2013, 41(12):1422-1426. http://manu60.magtech.com.cn/rlhxxb/CN/abstract/abstract18307.shtml [22] 宋昱, 朱炎铭, 李伍.东胜长焰煤热解含氧官能团结构演化的13C NMR和FT-IR分析[J].燃料化学学报, 2015, 43(5):519-529. http://manu60.magtech.com.cn/rlhxxb/CN/abstract/abstract18619.shtmlSONG Yu, ZHU Yan-ming, LI Wu.Structure evolution of oxygen functional groupsin Dongsheng long flame coal by 13C-NMR and FT-IR[J]. J Fuel Chem Technol, 2015, 43(5):519-529. http://manu60.magtech.com.cn/rlhxxb/CN/abstract/abstract18619.shtml [23] BREWER C E, SCHMIDT-ROHR K, SATRIO J A, BROWN R C. Characterization of biochar from fast pyrolysis and gasification systems[J]. Environ Prog Sustain, 2009, 28(3):386-396. doi: 10.1002/ep.v28:3 [24] SOLUM M S, PUGMIRE R J, GRANT D M. 13C solid-state NMR of Argonne premium coals[J]. Energ Fuel, 1989, 3(2):187-193. doi: 10.1021/ef00014a012 [25] THOMAS S, LEDESMA E B, WORNAT M J. The effects of oxygen on the yields of the thermal decomposition products of catechol under pyrolysis and fule-rich oxidation conditions[J]. Fuel, 2007, 86(16):2581-2595. doi: 10.1016/j.fuel.2007.02.003 [26] THOMAS S, WORNAT M J. The effects of oxygen on the yields of polycyclic aromatic hydrocarbons formed during the pyrolysis and fuel-rich oxidation of catechol[J]. Fuel, 2008, 87(6):768-781. doi: 10.1016/j.fuel.2007.07.016 -
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