Modeling The Zeolite Based Separation And Catalytic Reaction Processes

Based on the adsorption and transport data of guest molecules diffusing in two zeolites, MFI and FAU, the Maxwell-Stefan (MS) equation was adopted to describe properties of surface diffusion, bulk diffusion and Knudsen diffusion. An one dimensional unsteady model was established in this thesis for processes of separation and catalytic reaction that are carried out in a single zeolite particle, zeolit membrane module or fixed bed packed with zeolite catalysts. Finite volume method and Fortran language were used to solve the model equations. Compared with the experimental or simulation results reported in the literature, the model was proved to reasonably predict the following properties:multicomponent adsorption and diffusion processes in a zeolite film or particle, multicomponent diffusion and permeation for guest molecules in a zeolite membrane module, and catalyst effectiveness factor for catalytic reactions coupled with adsorption and diffusion in a zeolite film or particle.Then the generalized model was used to investigate the diffusion of benzene molecules in a Na-Y zeolite membrane module, the separation of ethylene, propylene and butane mixture in MFI zeolite during FCC process, and the coupling effects of reaction and mass transfer in a catalyst or catalytic film using a reversible reaction, A(?)B+C, as a model reaction. It is observed that the effectiveness factor has an extremum value under transient state that is a new phenomenon not reported previously.