选用松木、杨木、玉米秸秆和稻壳4种生物质为原料,采用3%（体积分数）乙酸溶液进行洗涤除灰后,进行快速热解实验,对比研究酸洗预处理对4种生物质热解焦物理化学特性的影响。结果表明：乙酸酸洗可有效去除松木、杨木、玉米秸秆和稻壳灰分中的大部分无机元素,从而促进热解过程中挥发分的释放、显著改善热解焦的表面化学特性。酸洗可促进热解焦孔隙结构的形成,提高比表面积和总孔容积,但会使平均孔径减小,这表明酸洗主要提高微孔率,对微孔的形成有较大的促进作用。同时,酸洗使得更多的含氧官能团保留在生物质热解焦表面,这种影响对玉米秸秆和稻壳尤为明显。气化焦油的吸附实验结果表明酸洗后热解焦的吸附能力有所增加。
Abstract
Four biomass including pine, poplar, maize straw and rice husk were selected as raw materials. After washing and ash removal with 3 vol.% acetic acid solution, a fast pyrolysis experiment was conducted to compare the effects of acid washing pretreatment on the physical and chemical properties of char during pyrolysis of the four biomass. The results show that the acetic acid can effectively remove the pine, poplar, maize straw and rice husk ash content of inorganic elements, so as to promote the release of volatile matter in the process of pyrolysis, significantly improve the surface chemistry characteristic of the bio-char. Acid washing can promote the formation of pore structure of bio-char and improve the specific surface area and total pore volume. However, the average pore size decreased, indicating that acid washing can improve the micropore rate and promote the formation of micropores. At the same time, the acid washing keeps more oxygen containing functional groups in the surface of bio-char, which is especially significant for maize straw and rice husks. The adsorption experiment results of gasified tar showed that the adsorption capacity of pyrolysis char increased after washing.
关键词
生物质 /
热解 /
吸附 /
酸洗 /
热解焦 /
物理化学特性
Key words
biomass /
pyrolysis /
adsorption /
acid washing /
bio-char /
physical and chemical properties
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 张蓓蓓. 我国生物质原料资源及能源潜力评估[D]. 北京: 中国农业大学, 2018.
ZHANG B B.Assessment of biomass resources and energy potential in China[D]. Beijing: China Agricultural University, 2018.
[2] 陈涛, 张书平, 李弯, 等. 酸洗-烘焙预处理对生物质热解产物的影响[J]. 化工进展, 2017, 36(2): 506-512.
CHEN T, ZHANG S P, LI W, et al.Effect of acid washing and baking pretreatment on biomass pyrolysis products[J]. Chemical industry and engineering progress, 2017,36(2): 506-512.
[3] 张书平. 稻壳热解多联产及其产物改性应用的基础研究[D]. 南京: 东南大学,2018.
ZHANG S P.Basic research on rice husk pyrolysis polygeneration and its product modification application[D]. Nanjing: Southeast University, 2018.
[4] SU Y H, ZHANG S P, LIU L Q, et al.Combination of acid washing and torrefaction on Co-production of syngas and phenoli-riched bio-oil via low-temperature catalytic pyrolysis[J]. Energy, 2020, 210: 118633.
[5] 张志昊. 生物质热转化过程中碱金属元素迁移的研究[D]. 北京: 清华大学, 2014.
ZHANG Z H.Study on alkali metal element migration during biomass thermal conversion[D]. Beijing: Tsinghua University, 2014.
[6] KABADAYI C A, KANTARLI I C, YANIK J.Effects of spent liquor recirculation in hydrothermal carbonization[J]. Bioresource technology, 2017, 226: 89-93.
[7] DENG L, ZHANG T, CHE D F.Effect of water washing on fuel properties, pyrolysis and combustion characteristics, and ash fusibility of biomass[J]. Fuel processing technology, 2013, 106: 712-720.
[8] KARI S, WAHAB M.Fate of alkali and trace metals in biomass gasification[J]. Biomass and bioenergy, 1998, 15(3): 263-267.
[9] SU Y H, LIU L Q, ZHANG S P, et al.A green route for pyrolysis poly-generation of typical high ash biomass, rice husk: effects on simultaneous production of carbonic oxide-rich syngas, phenol-abundant bio-oil, high-adsorption porous carbon and amorphous silicon dioxide[J]. Bioresource technology, 2020, 295: 122243.
[10] ZHANG S P, SU Y H, DING K, et al.Effect of inorganic species on torrefaction process and product properties of rice husk[J]. Bioresource technology, 2018, 265: 450-455.
[11] ZHANG Z B, LU Q, YE X N, et al.Selective production of levoglucosenone from catalytic fast pyrolysis of biomass mechanically mixed with solid phosphoric acid catalysts[J]. Bioenergy research, 2015, 8(3): 1263-1274.
[12] SU Y H, LIU L Q, XU D, et al.Syngas production at low temperature via the combination of hydrothermal pretreatment and activated carbon catalyst along with value-added utilization of tar and bio-char[J]. Energy conversion and management, 2020, 205: 112382.
[13] PANDEY K K, PITMAN A J.FTIR studies of the changes in wood chemistry following decay by brown-rot and white-rot fungi[J]. International biodeterioration & biodegradation, 2003, 52(3): 151-160.
[14] 茹斌. 基于复杂组分的生物质热裂解行为及影响机制研究[D]. 杭州: 浙江大学, 2016.
RU B.Study on pyrolysis behavior and influence mechanism of biomass based on complex components[D]. Hangzhou: Zhejiang University, 2016.
[15] KUMAR S, LOGANATHAN V A, GUPTA R B, et al.An assessment of U(VI) removal from groundwater using biochar produced from hydrothermal carbonization[J]. Journal of environmental management, 2011,92(10): 2504-2512.
基金
国家重点研发计划（2019YF1100602）
PDF(1929 KB)
