Direct catalytic decomposition of nitric oxide; Quarterly technical progress report No. 9, October--December 1993

Abstract

This project investigates a suitable catalyst system for the direct nitric oxide decomposition in post-combustion gas streams. This process does not use a reductant, such as the ammonia used in the Selective Catalytic Reduction (SCR) of NO{sub x} to nitrogen. Therefore, it is a greatly simplified process basically involving passing the flue gas through a catalytic converter. A systematic study of water vapor effects on the structure and Cu{sup 2+} ion exchange capacity of parent ZSM-5 zeolites and on the catalytic activity of the Cu-ZSM-5 and metal ion (mg{sup 2+} and Ce{sup 3+}) modified Cu-ZSM-5 catalysts for NO decomposition has been performed during this quarter. Mg{sup 2+} and Ce{sup 3+} cocations in copper ion-exchanged ZSM-5 zeolites display a positive effect on the decomposition of nitric oxide to nitrogen and oxygen. The catalytic activity of a Cu-ZSM-5 catalyst was examined after it was exposed to different inert and oxygen-containing gas streams. The results show that the steady-state catalyst activity is not sensitive to three treatments.