CFD MODELING OF GAS PHASE CATALYTIC PACKED BED REACTOR

Abstract

Catalysis has important application in the field of chemical industries one of the example of the catalysis is Fischer-Tropsch synthesis (FTS) of Gas to Liquid technology (GTL). In a Fischer—Tropsch process, mixture of carbon monoxide & hydrogen is converted into liquid hydrocarbons. FTS is a very useful technology as liquid hydrocarbon forms a great part of world's energy source (gasoline, kerosene and diesel). In the present work computational fluid dynamic (CFD) code ANSYS FLUENT 13 has been utilized to model the reactions for FTS that are taking place inside a single catalyst pellet representing a catalytic packed bed reactor. Diffusion, chemical reaction and heat & mass transfer are modelled in combined manner over a single catalyst pellet and simulations are performed, finite volume method of discretization is used for the solution of partial differential equations. In the first part of this work hydrodynamic study of pellet model is conducted and velocity coloured contours of propane and propane air mixture are obtained at different porosity values. For the validation purpose radial concentration profile of propane at Z0 axis has been generated also coloured contours of concentration of propane & contours of temperature has been generated for catalytic combustion of propane at 500 K and 600K the results are found to be in good agreement with those present in literature. Finally, the validated model of the pellet is applied for Fischer-Tropsch synthesis of GTL technology and performance of reactor in tenis of conversion of reactants (CO + 1-12) is evaluated again by using CFD the conversion of CO is found to around 87% and conversion of H2 is around 72%