摘要
利用热重分析技术,分析了棉秆在分子筛、金属氧化物催化条件下的热解过程;比较了不同催化剂对棉秆挥发分热解和灰分产量的影响.研究表明,除纯棉秆外,棉秆催化热解过程均由失水区、活化热解区和消极热解区构成,纯棉秆热解的消极热解区不明显.催化剂加入后,活化热解区挥发分累积转化率减小,而消极热解区挥发分累积转化率显著增大,且消极热解区温度窗口往低温方向转移.催化剂显著促进了木质素的热解,但对纤维素和半纤维素热解的促进作用相对较弱.催化剂的加入使灰分增多,且金属氧化物催化时的灰分产量高于分子筛.Na_2CO_3催化时灰分主要产生于活化热解区,而MCM-41、ZSM-5、USY催化时则主要产生在消极热解区.
The influences of zeolites and metal oxides on the pyrolysis of cotton stalk have been studied by thermogravimetric analysis （TGA）. Performance of different catalysts for pyrolysis of volatile and yield of ash was also compared. The results showed that the catalytic pyrolysis experienced three stages： water losing stage, activated pyrolysis stage, passive pyrolysis stage. The passive pyrolysis stage for pure cotton stalk was small. Due to the addition of the catalysts, the percent of volatile conversion for activated pyrolysis stage decreased, while for passive pyrolysis stage the percent of volatile conversion increased and the temperature range shifted to low temperature region. These catalysts promoted the pyrolysis of lignin, but showed less performance to the pyrolysis of cellulose and hemicellulose. The yield of ash increased in the presence of catalysts, and the yield was higher when catalyzed by metal oxide than by zeolite. The ash for cotton stalk catalyzed by Na2CO3 was derived from activated pyrolysis stage, but for MCM-41, ZSM-5 and USY, the ash was mainly derived from passive pyrolysis stage.
出处
《南开大学学报（自然科学版）》
CAS
CSCD
北大核心
2009年第5期25-31,共7页
Acta Scientiarum Naturalium Universitatis Nankaiensis
基金
国家重点基础研究发展计划(2007CB210202)
作者简介
曹新新（1985-），男，山东临沂人，硕士研究生．
