A Two Scale Model For The Diffusion-reaction Process On The Catalyst Of Ethylbenzene Synthesis

Gas phase alkylation and liquid phase alkylation are the most widely used technology for ethylbenzene synthesis. The gas phase method is approached by introducing ethane alkylation with benzene on ZSM-5as catalyst. As a typical kind of zeolite, ZSM-5is structured with regular and complex pore, which does much effect on the diffusion and reaction on it. However, the pore size effect of ZSM-5was not considered in traditional models for the diffusion-reaction process, and also the mechanism of reaction on ZSM-5could not be described through empirical power law for reaction. So it will be of great meaning to build up a new two-scale model, which contains the diffusion and reaction mechanism on the zeolite, to describe the diffusion-reaction process on catalyst particles.In this research, a two scale model for diffusion-reaction process in zeolite particles is proposed by modifying traditional model with more accurate subprocedures, and the new model is compared with traditional models.Comparison of different traditional models for the alkylation process is made to find out the mechanism of diffusion on the large scale, and the result showed that Knudsen diffusion was among one of the diffusion mechanism in the particles. A model of minor scale is built by introducing IAST as absorption model and M-S theory as diffusion model, with a quite good verification of their suitability.The large scale model and the minor scale model are correlated by the effective factor on the minor scale. The two-scale model is found to be less sensitive to pressure while more sensitive to temperature.