Investigation on Catalytic N2O Conversion to NO for Potential Nitric Acid Production from Industrial Waste Gas

Abstract

It is well known that N2O has a very significant impact on the greenhouse effect. Although N2O is not the major contributor to the global warming, while it could stay in atmosphere for about 150 years, and its global warming potential (GWP) is about 2.5 and 310 times as that of CH4 and CO2, respectively. The main source of N2O emission from chemical industries is originated from the process of adipic/nitric acid production. The emission of N2O due to adipic acid production in China is about 0.48∼0.72 million tons per year based on the mass ratio between N2O emission and adipic acid production, which is equivalent to 150∼250 million tons CO2 emission. However, there are few reports on economically reusing N2O from flue gas by direct oxidation method. Therefore, a series of catalysts applied on catalytic N2O conversion to NO for potential production of nitric acid from flue gas have been prepared by co-precipitation method. The basic property of catalysts was characterized by BET, laser particle size analyzer, FT-IR, TG/DTA, and CO2-TPD, etc. The catalyst’s performance was evaluated in a fixed-bed reactor with mixture of 40%(v)N2O+40%(v)N2+20%(v)O2 under 3000 h −1 space velocity and 0.1MPa system pressure. Results showed that catalysts of Pt/Cu-Zn-O and Pt/Zr-Zn-O have good selectivity on NO production, which was about 10% and 15%, respectively, in the temperature range from 550°C to 650°C. The basic experimental results show that it is a promising method to be applied for N2O reuse in adipic acid production and nitric acid industries and also provide the basis for further relative theoretical and experimental studies.