Modelling of internal diffusion inside a catalyst particle with non-uniform radial activity profile for parallel reactions

Abstract

Numerical solution of the system of diffusion equations which describe a system of parallel reactions under the conditions of internal diffusion in a non-isotropic spherical catalyst particle was carried out in this paper. The solution of the problem was sought for various radial activity profile corresponding to the concentration profile of active component in a particle of supported catalyst and for various values of the Thiele modulus of both parallel reactions. Further, the effect of reaction order of single reactions (zeroth or first) with respect to the effectiveness factor of the internal diffusion and to the selectivity of the main reaction was investigated. It is evident from the results that the change of the activity profile in the particle has a great effect on the selectivity and on the effectiveness factor of the internal diffusion.