Nonstationary operation of a system of catalytic monolithic reactors for selective NOx reduction

A mathematical model of thermally coupled monolithic catalytic reactors for selective NOx reduction is formulated, based on the evaluation of publishe d kinetic data. The effect of temperature profiles on the conversion of NO is systematically studied. It is shown that when inlet streams containing r eacting gas and cooling air are periodically switched between two thermally coupled monolithic reactors, one can achieve mean conversions of NO close to those corresponding to steady-state conditions with an optimal temperatu re profile. Operating parameters maximizing the NO conversion fdr a series of inlet gas conditions and catalyst types are obtained as a solution of a vector-optimization problem. Multiplicity of cyclic steady states is found in a certain parameter range under periodic operation. (C) 1999 Elsevier Sc ience Ltd. All rights reserved.