大型海藻浒苔热解特性与动力学研究

Study on Pyrolysis Characteristics and Kinetics of Green Seaweed Enteromorpha clathrata

以2005年10月采自江苏如东海区的条浒苔(Enteromorpha clathrata)为研究材料,用热重分析法对其热解过程及其动力学规律进行了研究。采用10、20、30℃/min等升温速率分别对0.18、0.28、0.45mm等粒径样品进行热解,结果表明样品非等温失重过程主要为脱水、保持、剧烈失重和缓慢失重4个阶段,且热解失重区为190～520℃之间范围;通过对最大失重率Dmax、失重率峰值温度θmax、挥发等参数分析,可以得出温度Ts和r值都随升温速率的增加而增加,升温速率越高,反应时间越短,热解特性指数增加;当样品粒径为0.28mm以上时,颗粒粒径越大对热解过程影响较大。用Coats-Redfern方法计算出样品的热解动力学参数,发现其热解反应机理函数不同于木质类生物质,求得的活化能E与频率因子A之间存在动力学补偿效应。

The pyrolysis characteristics and kinetics of green seaweed Enteromorpha clathrata(a marine biomass)were studied with thermogravimetric analysis method.The pyrolysis was carried out at different heating rates(10,20,30℃/min)and particle sizes(0.18,0.28,0.45mm).The results showed that there were four stages(dehydration,holding,rapid weight-loss and slow weight-loss)during the non-isothermal weight-loss process of samples.The weight-loss temperature in pyrolysis was between 190～520℃.The changes of the main components of sample were analyzed by Fourier transform infrared spectrum(FTIR).The characteristic parameters of pyrolysis at different heating rates were compared,and the releasing index of pyrolysis was calculated as well,showing that the higher the heating rate,the quicker the pyrolysis reaction.The effect of particle size on the pyrolysis was negligible when particle size was more than 0.28mm.The kinetic parameters were calculated by using the Coasts-Redfern method,indicating that the reaction function of pyrolysis mechanism was different from the woody biomass.There was a kinetic compensation effect between the activation energy and the frequency factor.