Diffusion and Reaction in a stagnant Boundary Layer about a Carbon Particle. 6. Effect of Water Vapor on the Pseudo-Steady-State structure

The effect of modest amounts of water vapor on the combustion of a carbon particle surrounded by a stagnant boundary layer is investigated. Water vapor participates in the combustion by accelerating homogeneous oxidation of CO in the boundary layer and through the carbon-steam reaction. Small particles (<100 Mm) benefit very little from the presence of water vapor, while for large particles there is a significant enhancement in the rate of CO oxidation in the boundary layer. The qualitative features of the pseudo-steady-state structure are preserved lor a wide range of water vapor concentration. Model calculations suggest that there would be significant CO and H₂ oxidation in the combustion zone of the Lurgi gasifier.