Research On Performance Of Catalytic Hydrolysis Of Cu/γ-Al₂O₃ Catalyst Toward Hydrogen Cyanide

Hydrogen cyanide (HCN) is one of poisonous and harmful gaseous pollutant which widely exists in the industry emissions and exhaust fumes of metallurgy, coal chemical industry, oil refining, synthetic ammonia, synthetic fiber, phosphorus chemical industry, chlor-alkali industry and chemical pharmacy. Its typical sources are the process of gasification and pyrolysis, high temperature carbon reduction, combustion of fossil fuel and the processing and use of chemical products containing cyanide. HCN has highly toxicity and corrosiveness, not only can be directly harmful to human health, but also easy to cause corrosion of raw material gas pipeline, reduce the service life of equipment, cause the poisoning of the downstream catalysts, affecting the yield and quality of the final products seriously. The catalytic hydrolysis of HCN not only can satisfy the needs of industrial gas purification to prevent the pollution of HCN and the harm to human health, but also realize the resource utilization of industrial waste gas. It has a good application prospect.In order to research the effects of the preparation conditions and reaction conditions on the catalytic hydrolysis performance of Cu/γ-Al2O3 catalyst toward HCN, a Cu/γ-Al2O3 catalyst was prepared by impregnation method to study the rules of precursor species of copper salt, concentration of precursor solution, dipping time and calcination temperature on the catalytic hydrolysis activity performance toward HCN. And the influence of different reaction conditions such as volume space velocity, water vapor content, reaction temperature and HCN content on the removol of HCN are investigated effects of discuss. The catalysts were characterized by FT-IR、BET、SEM、 XRD and XPS. The main results and conclutions are as follows:(1) In 4 kinds of copper salt precursors, Cu/γ-Al2O3 catalyst prepared by using copper acetate precursor had the best performance because of its larger surface area(256 m2/g) and higher CuO content (1.48%);(2) The Cu/γ-Al2O3 catalyst had the best catalytic activity with the optimum conditions of preparation:precursor copper acetate solution, concentration 0.05mol/L, dipping time 30min, calcination temperature 400℃;(3) The optimum reactions of volume space velocity, water vapor content, reaction temperature and HCN content were 17500h-1,1.25%,400℃, and 100ppm (120.5mg/m3)respectively;(4) Characterization analyses by XRD and XPS indicate that CuO on the surface of the Cu/γ-Al2O3 catalysts was in the amorphous phase;(5) Characterization analyses by XPS and BET indicate that with the increase of CuO, the HCN removal efficiency was better; with the decrease of surface area, the HCN removal efficiency was worse;(6) Characterization analyses by FT-IR indicates that the existence of CO32- is probably one of factors that make Cu/γ-Al2O3 catalyst being prepared by using copper acetate precursor have the best performance. However, the content of CO32- does not significantly affect the efficiency of the catalysts for purifying HCN.