Study Of Removing The Multicomponent Industrial Waste Gas Pollutants By Combinged Catalysts

Atmospheric pollution problem has been attracted much attention in recent years.This article is focused on the dealing with acrylonitrile absorption tower exhaust.Two main methods(AOGI and AOGC)has been applied to purify the exhaust gas.This paper has put forward a new kind of method for the tail gas treatment scheme.We call it step by step integration processing system.We make full use of the physical and chemical properties of each catalyst and the principle of catalytic reaction to purify the exhaust gases with a variety of targeted catalyst in one reactor.The composition of tail gas are mainly hydrocarbons(C3H6,C3H8,C2H6),Cyano material(C3H3N,C2H3N)and nitrogen oxides(NO,N20,N02).First the nitrogen oxides was reduced to nitrogen by the hydrocarbons through the first staged catalyst and then the acrylonitrile was eliminated by the second staged catalyst,finally the remaining hydrocarbons was completely oxidized to carbon dioxide and water by the third staged catalyst.The third chapter of this article is mainly on the first staged catalyst.This chapter examines the influence of different catalyst supportors including Zr02,Ti02,ZSM-5,Beta,SBA-15 and different active ingredients including(Co,Mn,Cu,Ag,Pt)on the catalytic activity.We screen out Ag-Al2O3 as the best catalyst and then the loading of active components and preparation methods of catalysts were investigated.We found that the catalyst of Ag-Al2O3 made by impregnation method has excellent catalytic activity.Finally we have carried on the exploration of catalysts in different catalytic environment,including the different amount of oxygen concentration,space velocity,reducing agent and so on.We hope to explore the best condition for the catalyst through these experiments.In this paper,the fourth chapter is mainly focus on the second staged catalysts.A series of experiments have been conducted in order to screen out the best catalyst supporter and active component.The experiments results show that the activity of Cu-ZSM-5 zeolite catalyst is higher than other catalysts,It has better nitrogen selectivity,almost no by-products generated.The catalyst can achieve the purpose of tail gas purification in different reaction conditions.Finally the catalysts have been characterized by XRD,H2-TPR and XPS,we hope to have a better understanding of the catalyst through the above characterization technique.In this paper,the fifth chapter is focus on the hydrocarbons oxidation by the third staged catalyst.Precious metals has been favored by researchers due to its strong oxidizing,high activity and renewable advantages.Ethane gases has been used as the research object of tail gas treatment to be eliminated by the palladium catalysts.We have discussed the effect of palladium loading and catalyst supporters.At last,we found that the optimization loading of Pd is 0.05%.The experiments also prove that adding a second metal did not raise the transformation rate of ethane while increasing palladium loading can.But taking the economy into consideration,the catalyst with 0.05%palladium metal loading can achieve the purposes of exhaust purification.In the sixth chapter of this article we did a lot of experiment on the combined catalysts.In the past three chapters,we have found out three best catalysts corresponding to each catalytic reaction,but how to make full use of these three catalysts to achieve the best effect is still remains to explore.This section we combine with the characteristics of each catalyst and focus on the application effect of composite catalyst.