High temperature catalytic combustion of CO−O 2−N 2, Ar, He, CO 2−H 2O mixtures of platinum

Abstract

In a steady flow reactor, using a platinum-coated honeycomb catalyst with channel diameter of 1.4 mm and length of 76 mm, measurements were made of substrate temperature at ten axial locations, exhaust concentrations of CO, CO 2, O 2 and pressure drop with CO-air mixtures at 600 K inlet temperature, 110–200 kPa pressures, 10–70 m s −1 inlet velocities, 0.013–0.32 equivalence ratios, and 0.54 mol % water content. Also employed were CO-CO 2, N 2, Ar, He-O 2 mixtures at 600–700 K, 110 kPa, 11–13 m s −1, and 0.031–0.56 equivalence ratios. The gas processes within a channel were then computed with a 2-dim. steady state model that includes axial and radial convection, laminar diffusion of mass, momentum and energy, a homogeneous single step irreversible reaction and, initially, a finite-rate surface reaction. Comparison of computed and measured quantities is satisfactory. Under the conditions tested, oxidation of CO is mostly diffusion-controlled. Homogeneous reactions are important only for the lowest velocities and highest equivalence ratios. It would appear that the presence of water increases the rate of high temperature catalytic oxidation of CO.