Experimental Study Of Activities And Anti-SO₂ Performance Of The Fast SCR Of NO_x Over V₂O₅-WO₃/TiO₂

Nitrogen oxides (NOx) is one of the main air pollutants generated by coal-fired power plants and can cause a series of environmental problems such as acid rain, haze photochemical pollution and eutrophication. As an improved process of the Selective Catalytic Reduction (SCR), Fast SCR reaction is attracting widespread attention at home and abroad due to its advantages of fast reaction rate, low temperature demand and high N2 selectivity. In this work, a benchtop experimental apparatus of catalytic activity evaluation was set up. Experiments focused on activities and anti-poison performance of the Fast SCR of NOx over V2O5-WO3/TiO2 were conducted in the temperature range of 50℃-500℃. The effect of reaction conditions on the performance of the Fast SCR of NOx over V2Os-WO3/TiO2 was studied and reaction kinetics of catalytic oxidation of NO over V2O5-WO3/TiO2 was analyzed. Poisoning mechanism of sulfur dioxide (SO2) on the catalyst was studied preliminarily by specific surface area (BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR). This work will provide experimental basis for the industrial applications of the Fast SCR DeNO* process.The results show that the addition of NO2 can improve NOx removal efficiency effectively, especially when reaction temperature is low. Denitrification efficiency can be increased from 61% to 87% when the ratio of NO2 to NO is 1:1 in the temperature range of 250℃-400℃. Analysis of reaction kinetics shows that reaction order of NO is 1.181, reaction order of NO2 is 1.3495 and reaction order of NH3 is 0 in the case of removing influence of internal and external diffusion and the molar ratio of NH3 to NO is higher than or equal to 1. The adsorption-desorption experimental result showes that the catalyst has little adsorption capacity of NO, but the adsorption capacity of NO2 is very strong and the active site of NO2 adsorption has high thermal stability. The anti-sulfur experimental result shows that SO2 can weaken the catalytic performance significantly. The main reasons are formation of (NH4)2SO4 and NH4HSO4, competitive adsorption of SO2 and NOx and the lead chamber reaction of SO2 and NO2.