Short-channel structured reactor for catalytic combustion: Design and evaluation

Abstract

Emission control of hazardous air pollutants, including volatile organic compounds (VOC), is one of the priorities for environmental catalysis. Metallic structured short-channel reactors of various geometries are regarded as an alternative to ceramic monoliths. The paper presents the coupled results on reactor structure modelling and the catalyst testing. It is expected, that mass transfer coefficients for laminar flow partially developing in short-channels can be increased up to 10 times comparing to standard monoliths, but the increased transfer properties involve elevated pressure drop. Therefore, performance evaluation criteria (PEC) have been developed to properly estimate the structure performance. The criteria derived cover both the general case for the comparable mass transport and kinetics of the process and the restricted case for the diffusional process limitation. In comparison with monoliths, the best structures (sinusoidal and triangular) seem to be from 1.5 times upto 4 times more efficient. Chromium–aluminium (CrAl) steel was surveyed in terms of its applicability for carrier manufacturing and catalyst depositing. Alumina washcoat and cobalt catalyst were deposited as organic precursors using Langmuir–Blodgett method (LB). Additional noble metal promoters were deposited by chemisorption. Catalytic tests have proved that the small amounts of highly dispersed Co 3O 4 are sufficiently active in combustion of diluted n-hexane with 100% selectivity to CO 2.