Study On The Property And Preparation Of The Catalysts For PCDD/Fs Degradation

With the rapid development of the society, resources of the urban land are decreasing, and the traditional way of landfill treatment is becoming unsuitable to meet the demand of modern urban waste treatment. Nowadays, the dominant way of waste disposal is turning into waste incineration. In order to reduce the pollution hazard of pollutants, especially the chlorinated organic compounds, in flue gas to the surrounding environment, and eliminate the potential threat of incineration plants to the surrounding residents, in recent years, developing and improving the advanced technology of pollutants emission control method has become one of the major problems to be solved and been more attractive to the public than ever. Catalytic degradation technology has been considered as the most potential technology to control pollutant emission, because of its advantages of overcoming the drawbacks of traditional active carbon adsorption method and degrading the organic compounds completely without causing secondary pollution. In combination with the prior laboratory research of our group, this paper demonstrates the preparation and properties of PCDD/Fs, and promotes the industrial applications of PCDD/Fs.In order to select the appropriate calcination temperature, calcination atmosphere and resources of catalytic carrier TiO2, this paper prepares a series of V2O5-WO3/TiO2 catalysts by impregnation method, and then preforms the thermal catalytic degradation experiments of dichlorobenzene by using these catalysts. Through analyzing catalyst removal efficiency with the catalyst characterization results, the following conclusions are obtained:1.When the calcination temperature is over 450℃, with the increase of the calcination temperature, the partial microporous structure of the catalysts would collapse, causing the decrease of specific surface area and pore volume and the increase of average pore diameter, which finally leads to the decreased catalytic activity of the catalyst.2. The microstructure of TiO2 greatly affects the surface structure of the catalyst. The catalyst, with higher specific surface area and smaller particle size, are more effective. Therefore, improving the microstructure of TiO2 will help to increase the low-temperature activity of the catalyst.3.Although different calcination atmosphere does not affect the surface structure of catalyst, but the increasing of O2 content in calcination atmosphere could not only improve the average oxidation state of V element on catalyst surface, but also increase the proportion of V5+of V element. Besides, the increasing of O2 content would increase the concentration of active oxygen on catalyst surface. All these effects work in combination and enhance the oxidizing ability and catalytic activity of the catalyst.Referring to the above results, this paper prepared the honeycomb catalysts for PCDD/Fs using nano-TiO2 as catalytic carrier, 1wt% V2O5 and 6wt% WO3 as catalytic active component with corresponding additives. This paper researched the additive formulations and the moisture content during the preparing process of the honeycomb catalyst. Finally, based on the experimental system, which was built in incineration plant, for degrading dioxin, experiments and analysis of the catalytic activity of the above honeycomb catalysts were preformed.