3种农业生物质的燃烧特性及动力学特征

Combustion Properties and Kinetics Characteristics of Three Agricultural Biomass

采用热重分析法研究了稻壳、小麦秸秆和玉米秸秆3种农业生物质的综合燃烧特性,同时采用Coats-Redfern非等温积分法探究了其燃烧动力学特征。结果表明,3种生物质的燃烧过程可分为水分蒸发、挥发分析出燃烧、残余挥发分释放燃烧、焦炭燃烧和燃尽5个阶段,其中挥发分析出燃烧是燃烧过程的主要失重阶段。3种生物质的综合燃烧特性指数有所差异,以玉米秸秆的燃烧特性最好,其次为小麦秸秆和稻壳。Coats-Redfern分析表明,稻壳、小麦秸秆和玉米秸秆的燃烧反应分别遵循4、5和4级反应动力学模型,主要燃烧过程的平均活化能从高到低依次为小麦秸秆129.5 kJ/mol、玉米秸秆117.5 kJ/mol和稻壳105.5 kJ/mol。

This paper studies the combined combustion characteristics of rice husk,wheat straw and corn straw by thermogravimetric analysis and investigates their combustion kinetics by the Coats-Redfern non-isothermal integration method.The results showed that the combustion process of three kinds of biomass could be divided into five stages:evaporation of water,precipitation and combustion of volatile matter,combustion of residual volatile,coke combustion and burnout,in which the precipitation and combustion stage of volatile matter was the main weight loss stage.The combined combustion characteristics indices of the three biomasses differed,with corn straw having the best combustion characteristics,followed by wheat straw and rice husk.Coats-Redfern analysis showed that the combustion reactions of rice husk,wheat straw and corn straw followed order 4,5 and 4 reaction kinetics models respectively。The average activation energies of the main combustion processes were 129.5 kJ/mol for wheat straw,117.5 kJ/mol for corn straw and 105.5 kJ/mol for rice husk in descending order.