Effects of chemical fractionation analysis on physical andchemical structures of biomass char

doi:10.11949/j.issn.0438-1157.20150472

Abstract

Abstract:

Chemical fractionation analysis is widely used to study the effect of alkali and alkaline earth metal (AAEM) species on the reactivity of biomass char. The influence of chemical fractionation analysis on the physical and chemical structures of biomass char was investigated in this study. The physical structures of biomass char were studied by the mercury porosimetry and scanning electron microscopy (SEM). The results showed that the influence of chemical fractionation analysis on the porosity and surface morphology of the biomass char was apparent. However, the effect of chemical fractionation analysis on the specific surface area of biomass char could be ignored. X-ray photoelectron spectroscopy (XPS) and Raman were used to identify the O-containing functional groups and the aromatic ring structures in the biomass char, respectively. The results indicated that the changes of the oxygen containing functional groups were little during the chemical fractionation analysis. The influence of the chemical fraction analysis on the aromatic ring structures could be ignored. During the chemical fractionation analysis, both NH₄Ac and HCl could change the cross-linking structures of biomass char.

Key words: chemical fractionation analysis, pyrolysis, biomass, char, physical structure, alkali and alkaline earth metals, carbon and oxygen functional group, numerical analysis

摘要：

化学分析分馏过程广泛应用于碱金属及碱土金属对生物质焦炭活性影响的研究。针对化学分析分馏过程对生物质热解焦炭物理化学结构产生的影响展开深入研究。通过压汞仪、扫描电子显微镜(SEM)对化学分析分馏过程中焦炭的孔径分布、孔隙率、比表面积及颗粒表面形貌等物理结构的变化进行了分析,结果表明该过程对焦炭的孔隙率影响显著,对比表面积影响不大,对热解焦炭多孔状表面形貌影响较为突出。利用X射线光电子光谱法(XPS)和拉曼光谱法(Raman)对焦炭表面碳氧活性官能团结构及焦炭芳香环结构等化学结构特征展开了研究,结果表明化学分析分馏过程对生物质焦炭表面碳氧活性官能团结构的破坏作用较小,化学分析分馏对焦炭的芳香环结构影响不大,水洗过程对焦炭内部的交联结构影响不明显,醋酸铵溶液、盐酸对焦炭内部的交联结构破坏明显。

关键词: 化学分析分馏, 热解, 生物质, 焦炭, 物理结构, 碱金属和碱土金属, 碳氧官能团, 数值分析

CLC Number:

X382.1

FENG Dongdong, ZHANG Yu, LIU Peng, GUO Yangzhou, HUANG Yudong, SUN Shaozeng, WU Jiangquan, ZHAO Yijun. Effects of chemical fractionation analysis on physical andchemical structures of biomass char[J]. CIESC Journal, 2015, 66(11): 4634-4642.

冯冬冬, 张宇, 刘鹏, 郭洋洲, 黄玉东, 孙绍增, 吴江全, 赵义军. 化学分析分馏过程对生物质焦炭物理化学结构的影响[J]. 化工学报, 2015, 66(11): 4634-4642.

References 36

[1]	Basu P. Biomass Gasification and Pyrolysis: Practical Design and Theory [M]. Beijing: Science Press, 2011.
[2]	Sun Li (孙立), Zhang Xiaodong (张晓东). Biomass Pyrolysis Gasification Principle and Technology (生物质热解气化原理与技术) [M]. Beijing: Chemical Industry Press, 2013.
[3]	Zhang Lixin, Kudo S, Tsubouchi N, Hayashi J, Ohtsuka Y, Norinaga K. Catalytic effects of Na and Ca from inexpensive materials on in-situ steam gasification of char from rapid pyrolysis of low rank coal in a drop-tube reactor [J]. Fuel Processing Technology, 2013, 113: 1-7.
[4]	Jensen P A, Frandsen F J, Johansen K, Sander B. Experimental investigation of the transformation and release to gas phase of potassium and chlorine during straw pyrolysis [J]. Energy & Fuels, 2000, 14: 1280-1285.
[5]	Keown D M, Favas G, Hayashi J, Li Chunzhu. Volatilisation of alkali and alkaline earth metallic species during the pyrolysis of biomass: differences between sugar cane bagasse and cane trash [J]. Bioresource Technology, 2005, 96: 1570-1577.
[6]	Jordan C A, Aka G. Speciation and distribution of alkali, alkali earth metals and major ash forming elements during gasification of fuel cane bagasse [J]. Fuel, 2012, 91: 253-263.
[7]	Mourant D, Wang Zhouhong, He Min, Wang Xiaoshan, Garcia-Perez M, Ling Kaicheng, Li Chunzhu. Mallee wood fast pyrolysis: effects of alkali and alkaline earth metallic species on the yield and composition of bio-oil [J]. Fuel, 2011, 90: 2915-2922.
[8]	Chaiwat W, Hasegawa I, Kori J, Mae K. Examination of degree of cross-linking for cellulose precursors pretreated with acid/hot water at low temperature [J]. Industrial & Engineering Chemistry Research, 2008, 47: 5948-5956.
[9]	Quyn D M, Wu Hongwei, Hayashi J I, Li Chunzhu. Volatilisation and catalytic effects of alkali and alkaline earth metallic species during the pyrolysis and gasification of Victorian brown coal. (Ⅳ): Catalytic effects of NaCl and ion-exchangeable Na in coal on char reactivity [J]. Fuel, 2003, 82: 587-593.
[10]	Takarada T, Nabatame T, Ohtsuka Y, Tomita A. Steam gasification of brown coal using sodium-chloride and potassium-chloride catalysts [J]. Industrial and Engineering Chemistry Research, 1989, 28: 505-510.
[11]	Yamashita H, Yoshida S, Tomita A. Local structures of metals dispersed on coal (Ⅲ): Na K-edge XANES studies on the structure of sodium gasification catalyst [J]. Industrial and Engineering Chemistry Research, 1991, 30: 1651-1655.
[12]	Yamashita H, Nomura M, Tomita A. Local structures of metals dispersed on coal (Ⅳ): Local-structure of calcium species on coal after heat-treatment and CO2 gasification [J]. Energy & Fuels, 1992, 6: 656-661.
[13]	Ohtsuka Y, Tomita A. Calcium catalyzed steam gasification of Yallourn brown coal [J]. Fuel, 1986, 65: 1653-1657.
[14]	Clemens A H, Damiano L F, Matheson T W. The effect of calcium on the rate and products of steam gasification of char from low rank coal [J]. Fuel, 1998, 77: 1017-1020.
[15]	Gopalakrishnan R, Bartholomew C H. Effects of CaO, high- temperature treatment, carbon structure, and coal rank on intrinsic char oxidation rates [J]. Energy & Fuels, 1996, 10: 689-695.
[16]	Tyler R J, Schafer H N S. Flash pyrolysis of coals-influence of cations on the devolatilization behavior of brown coals [J]. Fuel, 1980, 59: 487-494.
[17]	Asadullah M, Zhang Shu, Min Zhenhua, Yimsiri P, Li Chunzhu. Effect of biomass char structure on its gasification reactivity [J]. Bioresource Technology, 2010, 101: 7935-7943.
[18]	Zevenhoven-Onderwater M, Backman R, Skrifavars B J, Hupa M. The ash chemistry in fluidised bed gasification of biomass fuels (Ⅰ): Predicting the chemistry of melting ashes and ash-bed material interaction [J]. Fuel, 2001, 80: 1489-1502.
[19]	Pettersson A, Åmand L-E, Steenari B-M. Chemical fractionation for the characterisation of fly ashes from co-combustion of biofuels using different methods for alkali reduction [J]. Fuel, 2009, 88: 1752-1772.
[20]	Wu Wenguang (吴文广). Experimental investigation of homogeneous conversion and char heterogeneous decomposition of pyrolytic biomass tar [D]. Shanghai: Shanghai Jiao Tong University, 2012.
[21]	Mangun C L, Benak K R, Daley M A, Economy J. Oxidation of activated carbon fibers: effect on pore size, surface chemistry, and adsorption properties [J]. Chemistry of Materials, 1999, 11: 3476-3483.
[22]	Figueiredo J L, Pereira M F R, Freitas M M A, Órfo J J M. Modification of the surface chemistry of activated carbons [J]. Carbon, 1999, 37: 1379-1389.
[23]	Banyasz J L, Li S, Lyons-Hart J L, Shafer K H. Cellulose pyrolysis: the kinetics of hydroxyacetaldehyde evolution [J]. Journal of Analytical and Applied Pyrolysis, 2001, 57: 223-248.
[24]	Tong Jianhui, Han Xiangxin, Wang Sha, Jiang Xiumin. Evaluation of structural characteristics of Huadian oil shale kerogen using direct techniques (solid-state 13C NMR, XPS, FT-IR, and XRD) [J]. Energy & Fuels, 2011, 25: 4006-4013.
[25]	Müller J O, Su Dasheng, Wild U, Schlögl R. Bulk and surface structural investigations of diesel engine soot and carbon black [J]. Physical Chemistry Chemical Physics, 2007, 9 (30): 4018-4025.
[26]	Cuesta A, Dhamelincourt P, Laureyns J, Martinez-Alonso A, Tascon J M D. Raman microprobe studies on carbon materials [J]. Carbon, 1994, 32: 1523-1532.
[27]	Qian Lin (钱琳). Research on devolatilization and nitrogen conversion of lignite based on its chemical structure [D]. Harbin: Harbin Institute of Technology, 2013.
[28]	Xu Xiufeng (徐秀峰), Zhang Pengzhou (张蓬洲). The study of carbon structure by solid 13C NMR and XPS [J]. Coal Conversion (煤炭转化), 1995, 18 (4): 57-62.
[29]	Kelemen S R, Afeworki M, Gorbaty M L, Cohen A D. Characterization of organically bound oxygen forms in lignites, peats and pyrolyzed peats by X-ray photoelectron spectroscopy (XPS) and solid-state 13C NMR methods [J]. Energy & Fuels, 2002, 16: 1450-1462.
[30]	Xiang Jun (向军), Hu Song (胡松), Sun Lushi (孙路石), Xu Minghou (徐明厚), Li Peisheng (李培生), Su Sheng (苏胜), Sun Xuexin (孙学信). Evolution of carbon and oxygen functional groups during coal combustion [J]. Journal of Chemical Industry and Engineering (China) (化工学报), 2006, 57 (9): 2180-2184.
[31]	Lin-Vien D. The Handbook of Infrared and Raman Characteristic Frequencies of Organic Molecules [M]. London: Academic Press, 1991.
[32]	Tuinstra F, Koening J L. Raman spectrum of graphite [J]. Journal of Chemical Physics, 1970, 53: 1126-1130.
[33]	Li Xiaojiang, Hayashi J I, Li Chunzhu. FT-Raman spectroscopic study of the evolution of char structure during the pyrolysis of a Victorian brown coal [J]. Fuel, 2006, 85: 1700-1707.
[34]	Wang Yan, Alsmeyer D C, McCreery R L. Raman spectroscopy of carbon materials: structural basis of observed spectra [J]. Chemistry of Materials, 1990, 2 (5): 557-563.
[35]	Li Xiaojiang, Li Chunzhu. Volatilisation and catalytic effects of alkali and alkaline earth metallic species during the pyrolysis and gasification of Victorian brown coal (Ⅷ): Catalysis and changes in char structure during gasification in steam [J]. Fuel, 2006, 85: 1518-1525.
[36]	Li Xiaojiang, Hayashi J, Li Chunzhu. Volatilisation and catalytic effects of alkali and alkaline earth metallic species during the pyrolysis and gasification of Victorian brown coal (Ⅶ): Raman spectroscopic study on the changes in char structure during the catalytic gasification in air [J]. Fuel, 2006, 85: 1509-1517.