MICROKINETIC MODELING FOR WATERGAS SHIFT REACTION OVER NICKEL-BASED CATALYST

Abstract

This report presents the development and application of a microkinetic model of the watergas shift (WGS) reaction on a nickel catalyst. Based on a published mechanism consisting of initially 19 elementary steps that were reduced using sensitivity and principal component analysis to only 12 elementary steps and corresponding rate constants (k-values) which we calculated using E (kJ/mol) and A (mol cm s) values. Using the 12 elementary steps and pseudo-steady-state hypothesis (PSSH) the rate expressions for the reaction were solved. Our approach utilized reduced mechanism equations, where the rate of formation equaled the rate of consumption, ensuring steady-state conditions. These equations were solved alongside the site balance equation (summation of θ=1) to determine all surface coverages (θ values). Once the θ values were known, we computed the overall reaction rate for the formation of product.