乙苯和对二甲苯在EUO分子筛上吸附的蒙特卡罗模拟

ADSORPTION STUDY OF ETHYLBENZENE AND PARA-XYLENE ON EUO ZEOLITE BY MONTE CARLO SIMULATION

采用巨正则统计系综蒙特卡罗模拟方法研究了高温条件下,乙苯和对二甲苯在4种不同硅铝比EUO分子筛上的吸附行为,并结合工业样品的催化反应进行了验证。结果表明:对二甲苯在EUO分子筛内的吸附能略高于乙苯,对二甲苯主要吸附在直孔道内,而乙苯更多地吸附在侧笼内;Al原子产生的B酸位对吸附质的扩散具有阻滞作用,导致对二甲苯的吸附等温线出现更多的阶梯平台;在反应过程中,积炭导致的堵孔对对二甲苯的扩散影响更大,因此,副产物甲苯的生成比乙苯的转化衰减更快。

The adsorption behavior of ethyl benzene and para-xylene on four EUO zeolites with different Si Al ratio was studied under high temperature conditions by means of the macro-canonical statistics ensemble Monte Carlo simulation and validated by the catalytic reaction of industrial samples.GCMC simulation shows that the adsorption energy of PX in EUO zeolite is slightly higher than that of EB;PX is mainly adsorbed in the straight pore channel,while EB is adsorbed in the side cage,the Bronsted acid produced by Al atom can block the diffusion of adsorbed mass,which leads to more ladder platform in the adsorption isotherm of PX;the blockage caused by carbon deposition has a greater effect on PX diffusion,so the generation of by-product toluene will decay more rapidly than that of ethylbenzene.