A method of extending the useful life of the aged SCR catalyst layer in the exhaust system of the fixed source of NOx

摘要

(NO) in the presence of a nitrogen reducing agent in the exhaust gas after the treatment system of the fixed source of NO _x so that the exhaust gas discharged from the system to the atmosphere continues to meet the forbidden limits for both NO _x and ammonia emissions. _x) a dissimilar bovine (a method for N ₂₎ extending the useful life of the aging selective catalytic reduction (SCR) catalyst bed to catalyze the conversion to, the ammonia in the aged SCR catalyst downstream, the exhaust gas also contains oxygen, nitrogen And an additional honeycomb substrate comprising a catalyst for conversion to water (ASC), wherein the catalyst for converting ammonia in the exhaust gas also containing oxygen to nitrogen and water and kNO _x of the honeycomb monolith substrates, including at least at 300 to 400 ℃ 80 m / hr, where a 10% H ₂ O (steam in air ) KNO _x of a sample of catalyst aging at 450 ℃ for 48 hours in the 50 ppm CO, 30 ppm NO, 36 ppm NH 3, 15% O 2, 8% water, 3% CO ₂ and the balance N ₂ gas composition Is determined by the SCR activity test in a laboratory scale reactor.