Study On Preparation And Properties Of Iron Containing SCR Catalyst For Denitrification

Nitrogen oxides are the major air pollutants, and also the main components of acid rain. In order to keep the sustainable development of science and technology and the improvement of people's living standard in a wider range, the annual discharge of NOx in China is becoming more and more. People's production and life will be seriously affected if a series of methods are not used to control the NOx emission. Selective catalytic reduction?SCR? technology is an important means of controlling NOx emission in industry, and the catalyst is the key of the whole SCR technology. Iron and its oxides have been widely concerned by the researchers in recent years because of their high catalytic activity, low cost and no toxicity. In this paper, a series of SCR de NOx catalysts containing iron were prepared by different methods. The main contents are as follows:Through the impregnation method, the TiO₂ sol was supported on the cordierite,then use the dip coating method, load Fe, Ce and other active ingredients,finally obtained supported cordierite monolithic honeycomb ceramic catalyst. With a variety of characterization methods XRD, BET, etc, the preparation process of the catalyst?substrate pickling concentration and time?the number and time of carrier sol coating?active component impregnation times and time? that influence the coating carrier and the active ingredient loading was studied in detail,the same to catalyst Structure and morphology?redox properties and catalytic activity.The effects of active components and calcination temperature on the catalytic activity of SCR catalyst for the preparation of supported monolithic honeycomb ceramics were investigated. And by using XRD, H₂-TPR, BET surface area measurement technology were used to characterize the catalyst.The experimental results show that during the coating process, the coating time can affect the coating of the titanium sol coated on the surface of the cordierite, and the sol particles can reach the adsorption saturation on the surface of the cordierite after 3 h. With the increase of the coating times, the total load of the active component on the carrier coating increased, but the load increment showed a gradual downward trend. After coating 3 times the load reaches saturation.The specific surface area of the 12 h was increased by the mass concentration of 10 % oxalic acid treatment.,it is indicated that the specific surface area of the supported honeycomb ceramics catalyst can be greatly increased by acid treatment. which is conducive to the active component in full contact with the gas molecules, increase the denitration effect,the prepared catalyst's denitration activity is excellent. Characterization and comparison of supported iron with different cerium monolithic cordierite ceramic honeycomb catalyst,we can found that the molar ratio of Ce/Fe catalyst for 4 has relatively high catalytic activity.For use with different content of manganese nitrate, cerium nitrate and iron nitrate in multi metal oxide catalysts for the denitrification activity test. Choose the best ratio of complex metal oxide catalysts for Mn-Ce-Fe molar ratio is 0.5:4:1; Composite metal oxide catalyst was prepared with the best ratio, the denitrification performance and sulfur resistant performance is excellent. Doped catalyst can be obtained greater specific surface area, the adsorption of ammonia gas to be carried out more fully, thus contributing to the SCR reaction, finally the whole denitrification activity can be improved, the denitrification activity temperature window can be widened.