第10 卷 第9 期 Vol.10 No.9 2017 年 5 月 May 2017 基于不同热分析法的稻草木质素热解反应 动力学研究 娄 瑞 1 ,武书彬 2 ,赵红霞 1 ,张 斌 1* (1. 陕西科技大学机电工程学院,西安 710021; 2. 华南理工大学制浆造纸工程国家重点实验室,广州 510640) 摘要:采用热失重(thermal gravimetric,TG)技术在非等温体系对稻草类木质素的热稳定性和热解特性进行 研究。在氮气气氛下,采用不同升温速率对稻草木质素热解行为的影响进行分析,并通过单一升温速率法 (Coats-Redfern 法)、多重升温速率法(Kissinger 法和 Ozawa 法)、分布活化能模型(distribute activation energy model,DAEM)等多种热分析方法对木质素热解动力学方程进行模拟并对其反应热力学参数进行计算。研究 结果表明,随着升温速率的提高,稻草木质素热解反应过程逐渐向高温区移动,但其最大失重速率均发生在 250~450℃温区。此外,基于不同动力学模拟方法所求算的稻草木质素热力学参数有差异,Coats-Redfern 法 拟合的热解反应动力学方程可用一级反应进行描述。 关键词:林产化学加工学;稻草;酶解/酸解木质素;热解;动力学 中图分类号:TS724 文献标识码:A 文章编号:1674-2850(2017)09-1011-08 Study on pyrolysis kinetics of lignin derived from rice straw by means of several thermoanalysis methods LOU Rui 1 , WU Shubin 2 , ZHAO Hongxia 1 , ZHANG Bin 1 (1. College of Mechanical and Electrical Engineering, Shaanxi University of Science and Technology, Xi’an 710021, China; 2. State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China) Abstract: The pyrolysis characteristics and thermostability of lignin isolated from rice straw was studied by thermal gravimetric (TG) analysis under the nitrogen and non-isothermal system. The mechanism and kinetics of the thermal decomposition reaction of rice straw lignin were studied by means of the single heating rate method (Coats-Redfern method), multiple heating rate method (Kissinger method and Ozawa method), and distribute activation energy model (DAEM), and through that to obtain the fitted lines of kinetic equations and thermodynamic parameters. The research results showed that the temperature intervals of the volatile release in the pyrolysis process shifted towards high-temperature region as the heating rates increased, while the maximum rate of weight loss occurred at the temperature range of 250-450℃. Moreover, the values of thermodynamic parameters had a greater difference by means of the different model approaches, and the pyrolysis kinetic of rice straw lignin was described as a first-order reaction model based on Coats-Redfern method. Key words: chemical processing of forest products; rice straw; enzymatic/acidolysis lignin; pyrolysis; kinetics 基金项目:高等学校博士学科点专项科研基金(20136125120003);陕西省自然科学基础研究计划面上项目(2016JM5008);陕西省教育 厅专项科研计划(16JK1093);陕西省教育厅省级重点实验室科研计划(14JS011) 作者简介:娄瑞(1983—),女,讲师,主要研究方向:木质纤维生物质预处理及其生物质基化学品和材料的转化. E-mail: [email protected]
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Study on pyrolysis kinetics of lignin derived from rice straw by means of several thermoanalysis methods
LOU Rui1, WU Shubin2, ZHAO Hongxia1, ZHANG Bin1
(1. College of Mechanical and Electrical Engineering, Shaanxi University of Science and Technology, Xi’an 710021, China;
2. State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China)
Abstract: The pyrolysis characteristics and thermostability of lignin isolated from rice straw was studied by thermal gravimetric (TG) analysis under the nitrogen and non-isothermal system. The mechanism and kinetics of the thermal decomposition reaction of rice straw lignin were studied by means of the single heating rate method (Coats-Redfern method), multiple heating rate method (Kissinger method and Ozawa method), and distribute activation energy model (DAEM), and through that to obtain the fitted lines of kinetic equations and thermodynamic parameters. The research results showed that the temperature intervals of the volatile release in the pyrolysis process shifted towards high-temperature region as the heating rates increased, while the maximum rate of weight loss occurred at the temperature range of 250-450℃. Moreover, the values of thermodynamic parameters had a greater difference by means of the different model approaches, and the pyrolysis kinetic of rice straw lignin was described as a first-order reaction model based on Coats-Redfern method. Key words: chemical processing of forest products; rice straw; enzymatic/acidolysis lignin; pyrolysis; kinetics