Support-pore architecture optimization in FCC catalyst particles using designed pore networks

SEM images of FCC catalyst particles reveal the internal pore space to consist of massive networks of randomly interconnected pores of varying sizes and orientation. Until recently, design of catalyst particles has been restricted mainly to composition, particle size and pore size distribution with little attention paid to pore architecture. With recent advances in computing technology and catalyst characterization techniques it is now possible to move from these 'jumbled' configurations towards more structured controlled pore architectures that could greatly enhance effective utilization of catalyst pore space. In this paper, an application of 2D stochastic networks to investigate the direct influence of pore assembly on diffusion and reaction in FCC catalyst particles is described. Coke burn-off in heavily coked particles was used. Various pore architectural structures were tested including random, positively spiralled, negatively spiralled, structured and interspersed 2D networks. The interspersed network exhibited fastest burn-off kinetics relative to other structures while the random configuration, which probably characterizes most current catalyst particles, showed results better only than the negatively spiralled network. This can be: attributed to enhanced reactant accessibility resulting from absence of transport inefficient micro- and macro-pore clusters and an increase in direct micro-macro pore links characteristic of the designed interspersed network. (C) 1999 Elsevier Science Ltd. All rights reserved.