苯与乙烯在ZSM-5分子筛内吸附行为的Monte Carlo研究

Adsorption of benzene and ethylene in ZSM-5 zeolite by grand canonical Monte Carlo simulation

采用巨正则统计系综蒙特卡罗模拟方法研究了ZSM-5分子筛上苯与乙烯分子的吸附行为。由分子筛内吸附质粒子云分布可知,在200 kPa时,乙烯在分子筛上的吸附量要远远大于苯的吸附量。由吸附相互作用能分布来看,乙烯与分子筛之间相互作用能要高于苯与分子筛之间的相互作用能,这就使苯分子的吸附相对于乙烯分子稳定。相对而言,温度变化对乙烯吸附影响远大于对苯吸附的影响。ZSM-5分子筛上存在着苯和乙烯的竞争吸附,并且吸附分子之间存在相互作用使二者与分子筛之间的相互作用能分布改变。苯与乙烯在分子筛内吸附等温线的模拟结果表明,在较高温度、较低压力下乙烯的吸附量要小于苯的吸附量。

The adsorption behaviors of benzene and ethylene in ZSM-5 zeolite have been studied by grand canonical Monte Carlo （GCMC） simulations. From the mass clouds of GCMC simulations, it can be found that the benzene and the ethylene molecules show different adsorption behavior in the zeolite cavities. The loadings of ethylene are significantly larger than those of benzene at 200 kPa. From the potential energy distribution, it can be seen that the potential energy of ethylene is higher than benzene, so benzene can adsorb more steadily than ethylene. When the temperature rises from 298 K to 473 K, the numbers of ethylene reduce clearly, while benzene changes little. When benzene and ethylene adsorb in zeolite at the same time, there are competitive adsorption, the potential energy distribution can be changed obviously. The adsorption isotherms of benzene and ethylene at different temperatures and （1×10^-3-5.0） kPa show at low pressure and high temperature, the loadings of ethylene are significantly lower than those of benzene.