Effect of Concentration by Thermal Swing Adsorption on the Catalytic Incineration of VOCs

Abstract

Among the different processes for elimination of volatile organic compounds (VOCs) from gaseous effluents (mainly air streams), the frequently employed catalytic oxidation is undertaken in this contribution. With the purpose of reducing the amount of catalyst needed for incineration and the surface of recuperative heat exchangers, thermal swing adsorption can be use as a previous step for VOC concentration. By means of simulating the behavior of a conventional packed bed reactor and using kinetic expressions recently developed for the incineration of mixtures of ethyl acetate and ethanol on a laboratory catalyst based on Mn/Cu oxides, it is shown in this paper that the reduction in catalyst volume is significantly larger than the concentration factor, due to the combined effect of the lower flow rate and temperature rise. A second aspect dealt with in this contribution concern the simulation of the packed bed reactor. The intraparticle mass-transfer limitations turn out to be very strong and, consequently, the mass conservation balances of three species inside the particles should be solved numerically and iteratively at each position inside the bed. A precise approximation to circumvent such procedure is developed and shown to reduce computing time in more than one order of magnitude and to avoid convergence troubles otherwise found with the numerical procedure.