NITROUS-OXIDE FORMATION AND DESTRUCTION BY INDUSTRIAL NO ABATEMENT TECHNIQUES, INCLUDING SCR

A kinetic investigation of nitrous oxide formation from selective catalytic reduction (SCR) of NO has been made. It is shown that catalytic decomposition of ammonia yields both NO and nitrous oxide, the former as a primary product and the latter as a secondary product. Both nitrogen oxides subsequently undergo catalytic decomposition. In the presence of molecular oxygen, another NO formation process (from oxygen and adsorbed ammonia) occurs at somewhat higher temperatures, creating an optimum temperature window. Comparative tests conducted on a number of metal oxides show that high efficiency for NO decomposition is often related to high production rates of nitrous oxide within the temperature window.