Optimization Of Low Temperature SCR Denitration Catalyst And Its Denitration Performance

The main components of NO_X in coal-fired flue gas are NO and NO₂.It is not only a precursor of acid rain and ozone,but also one of the main causes of haze,which will bring great harm to human health.Selective Catalytic Reduction?SCR?denitrification technology is one of the widely used NO_X pollution control technologies.However,for the current working conditions of the power industry,research and development of new,low-temperature SCR denitrification technology has attracted much attention,so the development of low-cost and high-efficiency Low temperature catalysts have become the focus of research.Many domestic and foreign scholars have shown that the addition of metal auxiliaries such as iron,bismuth,chromium and cobalt have a significant effect on the activity of the catalyst.This article focuses on the optimization of commercial catalysts and their metal modification.This paper firstly aimed at three commonly used commercial SCR denitrification catalysts,tested them at low temperature?100-300??to investigate their low temperature catalytic performance.Then,the three catalysts were tested for sulfur resistance,and the suitable ones-A catalyst which has comprehensive performance under low temperature conditions.For the preferred A catalyst,the existing problems in the low temperature SCR catalytic reaction are analyzed.On this basic,an improved method for improving its low temperature performance is studied.In the experiment,the effect of different metal component additions?Fe,Ce,Co,Cr?,preparation methods?citric acid method and impregnation method?,active component addition ratios and calcination temperature on the activity denitrification of the catalyst were investigated to select the optimal modification conditions of catalyst A.Thus determining the optimal modification conditions of the catalyst,that is,when the citric acid method was adopted with iron and chromium acting as the active component and the molar ratio was Fe/Cr=1:2.Calcination at a temperature of500°C.The A-4-3 catalyst prepared under these conditions exhibited the best low temperature activity.Then the effect of SO₂ on the denitration efficiency of A-4-3catalyst was investigated,and the characterization and comparison of A catalyst and the A-4-3 catalyst were carried out.The surface morphology of catalyst was observed by scanning electron microscopy?SEM?,the qualitative analysis of valence states of related species was applied by X-ray photoelectron spectroscopy?XPS?,and the crystal structure of the catalyst was analyzed by X-ray diffraction?XRD?.These provide a guidance for the development of low-temperature catalysts in the future.