β分子筛中苯分子扩散行为的KMC模拟  

Diffusivity of benzene in β zeolite: Kinetic Monte Carlo simulations

作　　者：张瑜[1] 张舟[1] 刘辉[1] 陈标华[1] 

机构地区：[1]北京化工大学可控化学反应科学与技术基础教育部重点实验室,北京100029

出　　处：《北京化工大学学报（自然科学版）》2006年第3期19-22,共4页Journal of Beijing University of Chemical Technology(Natural Science Edition)

基　　金：教育部科学技术研究重点项目(02017);国家'973'计划(2004CB217804)

摘　　要：采用动力学Monte Carlo(KMC)方法模拟研究了苯分子在β分子筛中的扩散行为,并将计算结果与描述多孔介质中表面扩散的Maxwell-Stefan(M-S)方程进行比较。在模拟过程中,通过引入反映扩散分子间相互作用的参数,计及扩散过程中被吸附分子之间的作用力,得到较常规的KMC方法更为准确的结果。结果表明:M-S方程可以很好地描述β分子筛中苯分子的扩散,尤其对于M-S扩散系数,由于KMC模拟和M-S方程均考虑了分子间的相互作用,因此模拟结果与理论结果符合良好;给出了具体的苯分子在β分子筛中扩散的相应相互作用参数值,初步揭示了大孔道分子筛中被吸附分子间相互作用的特征。Kinetic Monte Carlo （KMC） simulations were performed in order to study the diffusion behavior of benzene molecules in fl zeolite, and the simulation results were compared with those obtained using the Maxwell- Stefan （M-S） equations which describe surface diffusion in a porous matrix. During the simulations, various parameters were introduced in order to calculate the intermolecular interactions. The results show that the M-S equations can describe the diffusion behaviors in β zeolite very well. In particular, the occupancy dependencies of M-S diffusivities in the KMC simulation are consistent with the M-S equations given appropriate choice of the interaction factor f. Furthermore, the presence of an attractive effect on the adsorbate molecules in large pore zeolites is clearly demonstrated.

关 键 词：Β分子筛 扩散系数 Maxwell—Stefan方程 动力学蒙特卡罗(KMC) 

分 类 号：O414.2[理学—理论物理]