| Nitrogen oxides is one of the major atmospheric pollutants. It will not only cause a series of questions such as acid rain, photochemical smog and so on, but also have a serious harm to human’s health. Because of its high conversion effect and good selectivity, the Selective Catalytic Reduction (SCR) de-NOx technology is widely used in practical engineering. Adoption of low temperature SCR catalyst can avoid the reheat of flue gas, which is necessary for the operation of high temperature using industrial catalysts. Then the energy consumption is reduced, and the poisoning effect of soot on catalyst is avoided to extend catalyst life. Therefore, it is urgent to research the low-temperature SCR catalyst and low temperature SCR technology process.In recent years, the fine particle pollution, especially emission of PM2.5attracts more and more reseacher’s attentions, and our country has begun the monitor for PM2.5emission. Especially, installation of bag filter is necessary to achieve the2011Atmospheric Environmental Standards for power plant. If the integration of bag filter and low-temperature denitration is realized, not only the dust removal and denitrification at the same time can be achieved, but it will save the space and investments. Also, the life of catalyst and bag filter cloth is basically the same, then it can reduce the amount of solid wastes generated, thus the study of integration of bag filter and low-temperature denitration is important。For this aim, the MnOx catalyst was prepared for low-temperature SCR reaction with citric acid in the present study, and the analyses of BET surface area, thermogravimetric differential thermal analysis, X-ray diffraction, scanning electron microscopy and other means were carried out for the catalyst’s characterization, then the suitable catalyst at low temperature NH3-SCR de-NOx performance is choosed. After that, the effects of reaction temperature, ratio of n(NH3)/n(NO), O2content, and flue gas inlet flow rate on removal of NO were researched on a fixed-bed reactor, using NH3as a reducing agent. It is found that at experimental temperature of 120℃-150℃, the O2content accounted for5vol.%in flue gas, n(NH3)/n(NO) is1, NO removal rate can reach90%.On the basis of the above experiments, the MnOx catalyst was loaded on the bag filter cloth and the de-NOx experimental study was carried out. The effects of reaction temperature, ratio of n(NH3)/n(NO), O2content, and flue gas inlet flow rate on removal of NO were researched. In order to sduty the actual situation in power station, the amount of dust added, methods of dust added and other facts on the effect of de-NOx were investigated and it is found that the integration of catalyst de-NOx and dust removal is feasible, but its efficiency is slightly reduced. In addition, the mechanism of catalyst poisoning in high dust conditions is also discussed.The idea of combination of bag cloth and low-temperature de-NOx catalyst is first proposed in this subject, and the simultaneous removal of nitrogen oxides and dusts of flue gas can be realized, which not only reduces the costs of denitrification and dust removal, but also reduces the space. Through this study, it can provide experimental references for integration of denitration and dust removal for industrial applications. However, this study is lack of a small-scale industrial test validation. In addition, the performance of dust removal after supportting catalysts and the resistance characteristicsis are lack of study in-depth. Also, the catalyst stability on cloth when cloth is backflushed is lack of appropriate research. |
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