彭何欢, 徐佳佳, 吴有龙, 张文标, 马中青. 温度对纤维素半纤维素和木质素热解炭理化性能的影响[J]. 农业工程学报, 2018, 34(Z): 149-156. DOI: 10.11975/j.issn.1002-6819.2018.z.023
    引用本文: 彭何欢, 徐佳佳, 吴有龙, 张文标, 马中青. 温度对纤维素半纤维素和木质素热解炭理化性能的影响[J]. 农业工程学报, 2018, 34(Z): 149-156. DOI: 10.11975/j.issn.1002-6819.2018.z.023
    Peng Hehuan, Xu Jiajia, Wu Youlong, Zhang Wenbiao, Ma Zhongqing. Effect of pyrolysis temperature on physicochemical properties of biochar produced from cellulose, hemicellulose and lignin[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2018, 34(Z): 149-156. DOI: 10.11975/j.issn.1002-6819.2018.z.023
    Citation: Peng Hehuan, Xu Jiajia, Wu Youlong, Zhang Wenbiao, Ma Zhongqing. Effect of pyrolysis temperature on physicochemical properties of biochar produced from cellulose, hemicellulose and lignin[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2018, 34(Z): 149-156. DOI: 10.11975/j.issn.1002-6819.2018.z.023

    温度对纤维素半纤维素和木质素热解炭理化性能的影响

    Effect of pyrolysis temperature on physicochemical properties of biochar produced from cellulose, hemicellulose and lignin

    • 摘要: 生物质炭是由生物质在缺氧或无氧的情况下,经高温慢速热解产生的一类难熔的、稳定的、高度芳香化的、富含碳素的固态物质,在能源、农业、环境和材料领域有广阔的应用前景。该文以纤维素、半纤维素和木质素为原料,采用程序控温管式炉,在不同的热解温度条件下(250、350、450、550、650、750和850 ℃)制备生物质三组分炭材料,并利用元素分析仪、量热仪、傅里叶变换红外光谱仪(FTIR)、X射线衍射仪(XRD)、核磁共振波谱仪(13C NMR)、热重分析仪(TG)和扫描电镜(SEM)等仪器对其物理化学性能进行表征,研究热解温度对生物质三组分炭材料理化性能的影响。结果表明:随着热解温度增加,生物质三组分炭的质量产率和能量产率都呈下降的趋势,纤维素炭、半纤维素炭和木质素炭的质量产率分别从94.23%、63.06%和87.14%减少至17.01%、20.67%和41.40%,能量产率分别从94.23%、55.7%和77.82%减少至58.69%、12.91%和31.09%。随着热解温度增加,生物质三组分炭中C元素的含量逐渐增加,而H元素、O元素、H/C、O/C的含量逐渐减少,尤其在250~450 ℃范围内下降最为显著。随着热解温度增加,FTIR分析表明-OH、-CH3、-CH2、C=O、C=C、苯环骨架、C-O、C-H等官能团含量显著下降,并且在高温热解时红外曲线几乎变为直线。随着热解温度增加,XRD分析表明生物质三组分炭中的三斜晶系(Iα)和单斜晶系(Iβ)衍射峰的强度逐渐降低,而石墨化微晶碳的002衍射峰和101衍射峰的强度逐渐增加;13C NMR分析表明生物质三组分炭中的烷基碳、含氧烷基碳和羧基碳含量逐渐减少,而芳基碳的含量则显著增加,证明高温有利于类石墨化结构形成。随着热解温度的增加,纤维素炭和半纤维素炭的热失重率逐渐下降,而木质素炭的热失质量率逐渐增加,三组分炭的热失质量峰值往高温一侧移动。随着热解温度的增加,生物质三组分炭的颜色逐渐加深,其中纤维素炭发生皱缩现象,其直径不断减小,半纤维素炭发生熔融和发泡现象,变为薄片状的炭材料,木质素炭的孔结构变得更加发达,并且出现球状的金属结晶体。该文研究结果可为生物质炭的制备和应用提供基础数据。

       

      Abstract: Abstract: Biochar is produced from slow pyrolysis at high temperature in the atmosphere of limited or without oxygen, which is a infusible, stable, highly aromatic, and porous carbon-rich material. It could be widely used in the energy, agriculture, environment, and material industry. In this paper, the biochar, derived from biomass three major components (cellulose, hemicellulose, and lignin), was produced by the tube furnace with programmed temperature controlling. Then, the effect of pyrolysis temperature (250, 350, 450, 550, 650, 750, and 850 ℃) on the properties of biochar was investigated by several instruments, such as elementary analyzer, bomb calorimeter, Fourier transform infrared spectrometry (FTIR), X-ray diffractometer (XRD), Nuclear magnetic resonance spectrometer (13C NMR), Thermogravimetric analyzer (TG), and Scanning electron microscope (SEM). The results indicated that, as the pyrolysis temperature increased from 250 to 850 ℃, the mass yields of cellulose char, hemicellulose char, and lignin char were gradually decreased from 94.23%, 63.06% and 87.14% to 17.01, 20.67%, and 41.40%, respectively, and the energy yields cellulose char, hemicellulose char, and lignin char were gradually decreased from 94.23%, 55.7%, and 77.82% to 58.69%, 12.91%, and 31.09%, respectively. As the pyrolysis temperature increased, the content of C in biochar derived from biomass three major components all increased, while the content of H and O, the value of H/C and O/C all decreased, especially more remarkably in the temperature of 250-450 ℃. The FTIR analysis indicated that as the pyrolysis temperature increased, the absorbance of functional groups (-OH, -CH3, -CH2, C=O, C=C, benzene ring skeleton, C-O, C-H, etc.) on the biochar derived from biomass three major components all decreased. The XRD analysis indicated that as the pyrolysis temperature increased, the intensity of crystalline structure of the cellulose Iα(triclinic) and Iβ(monoclinic) in the cellulose char and hemicellulose char decreased, while the graphite structure of (002) and (101) in cellulose char, hemicelluloses char and lignin char increased. The 13C NMR analysis indicated that as the pyrolysis temperature increased, the content of alkyl-C, O-alkyl-C, and carboxylic-C all decreased in the biochar derived from three major components, while the Aryl-C all increased. As the pyrolysis temperature increased, the weight loss rate at peaks of DTG curves from cellulose char and hemicellulose char gradually decreased, while that of lignin char increased, meanwhile the temperature at peaks of DTG curves shift towards the side of high temperature. As the pyrolysis temperature increased, the shrinking of cellulose char occurred, and the diameter of cellulose char decreased; melt phase with substantial foaming formed in the hemicellulose char, the hemicellulose char became laminar structure material; the pore structure of lignin char became stronger, and spherical metallic crystal formed on the surface of lignin char. This study will provide basic data for the production and application of biochar.

       

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