MCM-22型分子筛中纯的和混合的轻烃的吸附行为的Monte Carlo模拟研究

Grand canonical Monte Carlo simulation of pure and binary components sorption equilibria of light hydrocarbons in MCM-22 zeolite

用巨正则MonteCarlo方法模拟了轻烃 (甲烷、乙烷和丙烷 )及其混合物在MCM 2 2中的吸附。模拟中 ,采用全原子力场模型和CVFF力场参数得到了甲烷、乙烷和丙烷的纯组分的吸附等温线。考察了轻烃的二元混合物的选择性吸附 ,结果表明 ,甲烷 丙烷体系最易采用吸附分离 ,其选择性高达 2 70 ,而乙烷 丙烷体系吸附分离难度较大。甲烷 乙烷体系选择性的结果与理想吸附理论预测的结果吻合较好。同时还计算了三种纯组分的吸附热 ,以及三种混合体系中各个组分的吸附热。甲烷和丙烷吸附热相差较大 ,而乙烷和丙烷吸附热相差较小。以上结果均是由于丙烷与MCM 2 2作用最强而甲烷与其作用最弱产生。

Adsorption of methane, ethane and propane, and adsorption separation of their binary mixture in MCM-22 zeolite were simulated by using a grand canonical Monte Carlo (GCMC) method. The all-atom forcefield of the Consistent Valence Forcefield (CVFF) was used in simulated. The simulated results show that it is easy for the system of methane-propane to be separated in MCM-22 (its selectivity can reach 270). The simulated results of methane-ethane mixtures agree well with the predictions of using the Ideal Adsorbed Solution (ISA) theory. In addition, the result is also found that the difference of isosteric heats of pure component leads to the deviation of the binary adsorption behaviour.