盐酸预处理对生物质热解特性和热力学特性的影响  

Effects of Hydrochloric Acid Pretreatment on Pyrolysis and Thermodynamic Properties of Biomass

作　　者：陈东雨[1] 黄顺朝 刘新月 牛卫生[1] 刘越洋 史国宏[2] CHEN Dongyu;HUANG Shunchao;LIU Xinyue;NIU Weisheng;LIU Yueyang;SHI Guohong(College of Engineering,Shenyang Agricultural University,Shenyang 110161,China;Biochar Engineering Technology Research Center,Shenyang Agricultural University,Shenyang 110161,China)

机构地区：[1]沈阳农业大学工程学院,沈阳110161 [2]沈阳农业大学生物炭工程技术研究中心,沈阳110161

出　　处：《农业机械学报》2020年第8期320-327,共8页Transactions of the Chinese Society for Agricultural Machinery

基　　金：辽宁省自然科学基金项目(20180550038);现代农业产业技术体系建设专项资金项目(CARS-01-46);辽宁省兴辽英才计划项目(XLYC1802094);沈阳市中青年科技创新人才支持计划项目(RC180204)。

摘　　要：为深入探讨盐酸预处理对生物质热解特性的影响,采用热重法对比分析了酸洗前后玉米秸秆和银中杨在低升温速率(10、20、30、40、50℃/min)下的热解特性,利用分布活化能模型(DAEM)计算了热解过程的动力学参数和相应的热力学参数,采用傅里叶变换红外光谱(FTIR)分析了酸洗前后生物质化学结构的变化。结果表明:生物质热解过程经历了失水、玻璃化转变、快速热解和碳化4个阶段;酸洗预处理提高了生物质热解的最大失重速率和最终失重率,减少了焦炭的产生。在转化率为20%~70%时,用DAEM模型计算得到酸洗前后玉米秸秆和银中杨热解活化能分别为218.27~340.08 kJ/mol、225.17~291.73 kJ/mol、227.35~254.76 kJ/mol、197.39~235.52 kJ/mol。盐酸酸洗预处理整体上降低了生物质热解过程中的活化能、焓变和熵变,增加了吉布斯自由能(ΔG),促进了热解反应。酸洗前后玉米秸秆和银中杨红外光谱图相似,但在相同吸收峰处存在明显的强度变化,说明酸洗预处理对不同生物质有机官能团的影响程度不同。In order to further explore the influence of hydrochloric acid pretreatment on the pyrolysis characteristics of biomass,the thermogravimetric method was used to compare and analyze the pyrolysis characteristics of corn straw and poplar before and after pickling under low heating rates(10℃/min,20℃/min,30℃/min,40℃/min and 50℃/min).The kinetic parameters and corresponding thermodynamic parameters of pyrolysis process were calculated by distributed activation energy model(DAEM),and Fourier transform infrared spectrometer(FTIR)was used to analyze the change of chemical structure of biomass before and after pickling.The results showed that the pyrolysis process of biomass experienced four stages:water loss(room temperature^120℃),glass transition(120~210℃),main pyrolysis(210~400℃)and carbonization(400~700℃).Pickling pretreatment increased the maximum weightlessness rate and the final weight loss rate of biomass pyrolysis,and reduced the generation of coke.Under the conversion rate of 20%~70%,it was calculated that the pyrolysis activation energy of corn straw and poplar before and after pickling were 218.27~340.08 kJ/mol,225.17~291.73 kJ/mol,227.35~254.76 kJ/mol and 197.39~235.52 kJ/mol,respectively.At the same time,theΔH of corn straw and poplar before and after pickling were 291.09~291.28 kJ/mol,249.68~249.82 kJ/mol,228.68~228.86 kJ/mol and 221.78~221.93 kJ/mol,respectively.TheΔG were 119.23~122.92 kJ/mol,118.57~125.09 kJ/mol,123.78~128.22 kJ/mol and 121.97~129.29 kJ/mol,respectively.TheΔS were 266.54~271.42 J/(mol·K),198.01~206.29 J/(mol·K),156.53~159.14 J/(mol·K)and 144.02~153.81 J/(mol·K),respectively,indicating that hydrochloric acid pickling pretreatment on the whole reduced the activation energy,enthalpy change and entropy change in the process of biomass pyrolysis,increased the Gibbs free energy(ΔG),promoted the pyrolysis reaction.The infrared spectrogram of the corn straw and poplar were similar before and after pickling,but there was a significant intensity change at the same absorpt

关 键 词：玉米秸秆 银中杨 热解 盐酸预处理 酸洗 动力学 

分 类 号：TK6[动力工程及工程热物理—生物能] S216.2[农业科学—农业机械化工程]