Preparation And Performance Evaluation Of Catalysts For N₂O Catalytic Decomposition

N₂O is one of the important atmospheric pollutants,which not only has a strong greenhouse effect,but also seriously damages the ozone layer.Adipic acid,nitric acid and circulating fluidized bed can discharge to the atmosphere of different concentrations of N₂ O.In the existing N₂ O removal technology,direct catalytic decomposition method has the advantages of simple process,high decomposition rate and does not produce secondary pollution,which has become the most promising N₂ O removal technology,whose core is the direct decomposition catalyst.N₂ O emissions from industry has a large number of exhaust gas,high speed,high resistance and other characteristics,so the catalyst decomposition activity and mechanical strength requirements are very high.In order to meet the requirement of industrial flue gas emission,it is urgent to develop an efficient and stable direct decomposition N₂ O catalyst.In this paper,the decomposition efficiency of N₂ O is compared with different transition metal oxides,the optimal active components are selected,and the content of active components,the carrier of catalyst,the content of metal additives and additives are selected.Catalysts for N₂ O decomposition were developed within Cu O as the active component,ZnO as the promoter,and ?-Al2O3 as the carrier.Experiments were performed to investigate the effects of active component and promoter on the activities on N₂ O decomposition and resistance to O₂ and H2 O of the catalysts.Moreover,the performance of the catalysts under different flue gas conditions was also studied.The results indicated that the catalyst with 15% CuO possessed the highest N₂ O decomposition activity,and the addition of Zn O could promote the catalytic activity remarkably.The N₂ O decomposition efficiency of the 15Cu-30ZnO/?-Al2O3 catalyst held steady over 90% after 100 hours stability test in presence of O₂ and H2 O at the temperature of 650? and space velocity of 21000 h-1.In addition,the catalyst exhibited favorable resistance to the deactivation of O₂ and H2 O under high temperatures.The removal of N₂ O by the modified SCR denitration catalyst was studied.Firstly,the effect under the conditions without the use of a catalyst of ammonia atmosphere on N₂ O decomposition efficiency is studied.The modification process was modified by adding additives in the catalyst formulation.Mechanical mixing of intermediate temperature catalysts and composite metal oxides and their decomposition properties were investigated.The results showed that the modified SCR catalyst with the addition of metal oxide can significantly improve the decomposition performance of N₂ O,At 360?,the decomposition efficiency increased from the original 6% to 69%,and had a good adaptability to the complex flue gas condition.