催化剂积炭对甲醇制低碳烯烃效果的影响  

The Effect of Coke Deposition of Catalyst on the Reaction of Methanol to Olefins

作　　者：张同旺[1] 武雪峰[1] 侯拴弟[1] 

机构地区：[1]中国石化石油化工科学研究院,北京100083

出　　处：《石油学报（石油加工）》2011年第6期891-896,共6页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：中国石油化工集团公司课题项目(合同号:S107029.2)资助

摘　　要：采用热重法、NH3-TPD和低温氮静态容量吸附法(BET)对不同积炭量的甲醇制低碳烯烃(MTO)催化剂分析表征,发现随着积炭量增加,催化剂上的强酸量逐渐减少,而弱酸量变化较小,表明积炭优先在强酸位上生成;微孔比表面积、微孔体积随积炭量增加而线性降低,对其线性回归发现积炭在催化剂上为单分子层孔内吸附。催化剂积炭量增加,MTO反应的甲醇转化率先基本保持不变,然后急剧下降,而低碳烯烃选择性先增加后降低。综合分析酸表征结果与甲醇转化效果表明,催化剂的中酸和弱酸即可使甲醇有效转化,过高的酸强度对甲醇转化率影响不大,还会导致积炭量快速增加及低碳烯烃发生二次反应,但过低的酸强度又无法使甲醇有效转化,因此适宜的积炭量可实现最高的低碳烯烃选择性。TG,NH3-TPD and BET methods were used to characterize the coked methanol to olefins（MTO） catalyst.With the increase of coke deposition amount,strong acid sites decreased while the weak acid sites almost maintained on the catalyst.Micropore specific surface area and volume of MTO catalyst declined with the growth of coke deposition.The regression of micropore specific surface area and volume showed that the coke was intra-pore monolayer adsorbed on catalyst.With the increase of coke amount,the methanol conversion kept constant first,then decreased sharply,and the selectivity of lower olefins increased first,then decreased gradually in MTO reaction.It is shown from the comprehensive analysis of acid characteristics results and methanol conversion of MTO reaction that the moderate and weak acid sites in catalyst did make methanol conversion efficiently.Although the strong acid sites could not affect methanol conversion,they could lead to unwanted secondary reactions of lower olefins.There existed an appropriate coke amount on MTO catalyst to help obtaining the maximum selectivity of lower olefins and to keep the certain methanol conversion.

关 键 词：低碳烯烃 转化率 碳基选择性 积炭 

分 类 号：TQ032.41[化学工程]