Selective catalytic reduction of NOx over zeolite-coated structured catalyst packings

In this work, the performance of two configurations of in situ zeolite-coat ed structured catalyst packings is treated. Just to demonstrate the reactor concepts, the catalyst packings were tested on a bench scale in the select ive catalytic reduction of NO with excess ammonia. The performance of Cu-ZS M-5-coated ceramic slabs that were placed in a parallel passage array (PPR) was compared with a Cu-ZSM-5 monolith. Practical correlations are given fo r pressure drop, diffusion and the overall performance of the reactor. Acco rding to a simple model, the catalyst effectiveness factor of the PPR turne d out to be 17%, whereas that of the monolith was 95%. The plate thickness and the spacing of the parallel plates proved to be of paramount importance for optimum catalyst efficiency. For practical evaluation and comparison w ith known NOx reduction units, more realistic reaction conditions should be chosen. (C) 2001 Elsevier Science Ltd. All rights reserved.