Control of transport phenomena in the interior of the reforming catalyst grain: A new approach to the optimisation of the reforming process

The aim of the study was to provide favourable conditions for the transport of the reagents by modifying the porous structure and shape of the reforming catalyst grain. The study entailed the analysis of the transport phenomena and reactions that occur in spherical, cylindrical and slab-shaped catalyst grains. To upgrade the efficiency of the catalyst, use was made of analytical equations that describe the changes in the concentrations of the reagents in the catalyst grain. The equations were derived from the mass balances and the kinetic scheme assumed for the reforming process. By virtue of the coefficients of reagent diffusion, the equations are a function of the porous structure parameters and can therefore define a more or less advantageous profile of concentrations. The modification of the profile by minimising the objective function proposed in the paper leads to the reduction in the influence of diffusion resistance on the course of the reforming process. The study demonstrates that after the porous structure of the experimental catalyst had been changed, it was possible to increase its specific surface area and mechanical strength and, at the same time, noticeably improve the conditions for the transport of reagents. (C) 2011 Elsevier B.V. All rights reserved.