钙基添加剂对煤慢速和快速热解行为的影响

Effects of Ca-based additives on behaviors of slow and fast coal pyrolysis

在固定床反应器上对淮北煤(Hub)进行热解实验,测定了气体、焦油和焦炭的产率、主要气体的累积释放量以及苯、甲苯和二甲苯(BTX)产率,旨在考察2种常见钙基添加剂CaCO3和Ca(OH)2对煤慢速和快速热解的影响。在慢速热解情况下,无论CaCO3还是Ca(OH)2都使焦炭产率明显降低,气体产率上升,焦油产率有所下降,BTX产率增大,但Ca(OH)2的作用较强。在快速热解情况下,钙基添加剂使焦油产率略有下降,气体和焦炭产率略有增大,但增加不明显。由此表明,钙基添加剂在慢速热解时对焦油二次裂解及对煤焦分解的作用较大。

Experiments are performed in a fixed bed reactor to investigate the effects of two common Ca-based additives, CaCO3 and Ca （OH）2, on both slow and fast pyrolysis of Huaibei coal（Hub）. The yields of liquid and char, the cumulative amount of main gaseous products（ H2,CO, CH4, CO2 ） and the yields of BTX （benzene, toluene and xylene） are determined. In the case of slow pyrolysis,the addition of Ca-based additives to coal results in slight reduction of the tar yield,with a remarkable decrease in the char yield and an increase in the gas yield, and also results in a significant enhancement in the yields of BTX. Ca（OH） 2 shows a stronger effect than CaCO3. In the case of fast pyrolysis, Ca-based additives lead to only slight reduction of the tar yield ,with slight increase in the yields of char and gaseous product. It is suggested that Ca-based additives exhibit greater effect on the secondary cracking of tar and decomposition of char during slow pyrolysis.