SOLVING LINEAR DIFFUSION-REACTION NETWORKS IN POROUS CATALYST PARTICLES USING BEM

Multiple diffusion reactions ave frequently encountered in the modelin g of heterogeneous catalytic reactors. Obtaining an accurate estimate of the yield and selectivity in such reactions is crucial for an optim al design of reactors. Due to the inadequacy of analytical techniques in handling nonuniform catalyst shapes and mixed boundary conditions, numerical techniques are often employed to compute these design parame ters. Among other numerical techniques, the boundary element method (B EM) is a superior method to solve linear diffusion reaction problems. The integral nature of the BEM formulation allows for boundary-only di scretization of the particle, thus reducing the computer execution tim e and the data preparation effort. A boundary element algorithm is dev eloped to solve a network of linear diffusion reactions in porous cata lyst particles in two dimensions. For this purpose a matrix of fundame ntal solutions is defined and derived. The developed algorithm is appl ied to complex reaction networks to obtain the yield of intermediates for nonregular catalyst shapes and nonuniform boundary conditions. The method can be used as a design tool to study particle scale modeling in detail and can be incorporated into an overall reactor model.