木质类生物质催化热解动力学研究

【作者】 杜海清；

【导师】 白雪峰；

【作者基本信息】 黑龙江大学 ， 化学工艺， 2008， 硕士

【摘要】 本文采用非等温热重分析法,对松树、杨树、椴树和白桦等四种木质类生物质的热解特性进行了系统研究。考察了氮气气氛下升温速率、催化剂以及与煤共热解对生物质热解过程的影响。生物质的热解过程经历水分析出,挥发份析出和炭化三个阶段。挥发份析出是生物质热解的主要过程,通常在200~400℃之间进行。选用Coats-Redfern法对实验数据进行反应动力学研究表明,生物质的热解反应为一级反应。随着生物质热解过程的升温速率(10、20、40和60℃/min)逐渐提高,热解峰值温度提高34~40℃,最大失重速率呈线性增大,活化能增大4.14~6.86 kJ/mol。Na2CO3和K2CO3催化生物质热解实验结果表明,当催化剂的加入量从0增加到10%时,生物质的热解峰值温度降低52.2~69.8℃,活化能下降3.8~7 kJ/mol,最大失重速率增大了16.8~25.6%。生物质与二种煤(烟煤与褐煤)混合共热解实验结果表明,在生物质与烟煤进行共热解的反应中,没有出现协同作用,热解结果只是生物质与烟煤各自热解过程的简单叠加;在生物质与褐煤进行共热解的反应中,有协同作用发生,生物质与褐煤各自单独的热解峰消失,在生物质与褐煤的热解峰值温度之间出现了一个新的热解峰。更多还原

【Abstract】 Iso-thermogravemetric analysis was used in this paper to investigate the pyrolysis characteristics of four kinds of lignocellulosic biomass (pine, poplar, bass and birch) under N2 atmosphere with different conditions. The influences of heating rates, catalysts and co-pyrolysis with coal were discussed.The whole process of pyrolysis of biomass could be divided into three stages, dehydration, devolatilization and carbonation. Devolatilization was the main process which occurred mainly between 200~400℃. The result of dynamic study by Coats-Redfern method showed that the pyrolysis of biomass could be described as first order reaction. The peak temperature increased by 34~40℃, the peak weight loss rate exhibited linear increment and the activation energy increased by 4.14~ 6.86 kJ/mol along with the increasing of heating rate(10、20、40 and 60℃/min). The investigation of pyrolysis catalyzed by Na2CO3 and K2CO3 indicated that the peak temperature decreased by 52.2~69.8℃, the activation energy decreased by 3.8~7.0 kJ/mol and the peak weight loss rate increased by 16.8~25.6% with the increasing of catalyst content from 0 to 10%. The co-pyrolysis of the blend of biomass with coal was investigated. The results showed that biomass and soft coal did not interact chemically under inert conditions, whereas biomass and lignite seemed to interact on each other for the disappearing of the original peak of lignite and biomass and the appearing of a new peak between the peak temperature of biomass and lignite.更多还原