Theoretical Analysis of Catalytic Combustion in a Monolith Reactor

Abstract

A theoretical model of catalytic combustion is developed which allows calculation of temperature and reactant/product distribution in a tubular duct with catalytic walls. Under adiabatic conditions, as prevail in the central ducts of a catalytic monolith combustor, and in the absence of heat conduction along the reactor walls, the model provides an analytic solution. It exhibits the existence of multiple steady states and, for gas mixtures with low Lewis number, temperature excursions in excess of the adiabatic reaction temperature, Gas-phase reactions are shown to increase the fuel consumption in a given length of catalytic duct but leave unchanged the relations between the temperature and species distributions. The model is applied to a series of experimental results obtained with different fuels in tubular reactors. Satisfactory agreement is found between theoretical and experimental data when account is taken of the effects of heat loss from the reactor to the environment.