REMOVAL OF NITRIC-OXIDE BY ITS REDUCTION WITH HYDROCARBONS OVER ALUMINA UNDER LEAN CONDITIONS

The objective of this; study is to investigate the removal of nitric o xide (NO) from a net oxidizing gas mixture using hydrocarbons (HC) as reductants over alumina. Studies were conducted to investigate the eff ect of operating variables such as catalyst temperature, space velocit y, and HC concentration on NO conversion. The durability of the cataly st was also investigated. Propane (C3H8) and propylene (C3H6) were use d as reductants during the flow reactor experiments, The study shows t hat the removal of NO over Al2O3 occurs in the 500-700-degrees-C tempe rature range when either C3H6 or C3H8 is used as reductant. Maximum NO conversion is observed around 600-degrees-C. The NO conversions obser ved using C3H8 and C3H6 are comparable when NO is being removed from a NO-HC-O2-SO2-CO-H-2-H2O stream at space velocities lower than 38570 h -1. At space velocities higher than 38 570 h-1, higher NO conversion i s observed when C3H6 is used as reductant. Durability investigations c onducted on the pulse flame combustor show that the durability of Al2O 3 is better than that of the zeolite-based catalysts for removing NO u nder oxidizing conditions.