在改性高岭土催化剂上甲醇脱水生成二甲醚的动力学考察

Study on Kinetics of Methanol Dehydration to Dimethyl Ether on Modified Kaolin

采用积分反应器 ,考察了常压下在改性高岭土 (MK)催化剂上甲醇脱水生成二甲醚的反应动力学 ,根据L angmuir均匀吸附理论 ,采用 R- E机理 ,推断吸附的甲醇分子与气相主体中的甲醇分子发生的表面反应为速率控制步骤 (RDS) ,得到双曲线型动力学方程为 :r=ksb Mp M2 /(1 +b Mp M+bp E) (r为反应速率 ,ks为反应速率常数 ,b M 为甲醇的吸附平衡常数 ,b为二甲醚和水的吸附平衡常数之和 ,p M、p E 分别为甲醇、二甲醚的分压 ) .在 MK上 ,表面反应的活化能为 79.1 k J/mol.数据处理和参数确定均用最小二乘回归法 .

Kinetics of methanol dehydration to dimethyl ether on modified kaolin catalyst was studied in an integral reactor under normal pressure. It is deduced that the surface reaction of methanol molecule adsorbed on the active site of catalyst with methanol molecule in gas phase is the rate determining step(RDS). The hyperbolic type kinetic equation r = k \-s b \-M p M 2/(1+ b \-M p M+ b p E) is obtained according to the theory of langmuir even adsorption and using the R\|E mechanism. The activation energy of surface reaction is 79.1 kJ/mol. Mean square regress was used in data processing and evaluation of parameters.