Comparison of the performances of different catalytic reactor types for the water-gas shift reaction using computer simulations

Abstract

The low temperature water-gas shift reaction is mathematically modeled for packedbed and monolith reactors by applying mass, energy and momentum balances at steadystate. One-dimensional pseudo-homogeneous and heterogeneous models are applied to the packed-bed reactor, while only one-dimensional pseudo-homogeneous model is applied to the monolith reactor. Kinetic rate expressions of the Cu-ZnO-Al2O3 and Pt-CeO2-Al2O3 catalysts and the required data sets are taken from the literature. The modeling equations are developed on the basis of catalyst mass and the catalyst mass required to keep the downstream carbon monoxide concentration less than 1 mole per cent is calculated for desired methane conversion levels in a fuel processor feeding hydrogen to a 1.5 kW polymer electrolyte membrane fuel cell. The changes in temperature, pressure, methane conversion, carbon monoxide concentration in outlet and as well as molar flow rates of the components are simulated as a function of the calculated catalyst mass. The catalyst masses calculated by different mathematical models applied to the same type of the reactor are compared as well as the catalyst amounts calculated by using the same model for different types of reactors. The results of the water-gas shift reaction simulated over two different catalysts in the monolithic reactor are also compared.