Study On The Mechanism Of Oxidation Of Hg~0 And Poisoning Of The Vanadium-based SCR Catalysts

China's energy structure will be dominated by fossil fue ls for a long time,coal resources account for the largest proportion of fossil energy.Trace elements produced by burning coal are harmful to the environment and residents,such as mercury,arsenic,selenium,plumbum and cadmium.SCR Process can also remo ve mercury.vanadium-based catalysts are the most widely used commercial SCR catalysts.It is significative to study the mechanism and poison of the vanadium-based catalyst.Based on the density functional theory?DFT?and the B3LYP,the lowest energy structure of reactant,intermediate,transition state and final product is optimized.The V₂O₅ model was optimized by the quantum chemistry method,and the structure and chemical parameters of the model were analyzed.Based on this model,the reaction process of HCl and Hg is simulated.Three reaction paths are found.Analyze the data to get the path A as the most probable path?6 intermediates and 5transition states?.The energy barrier of the decisive step is 58.658 kJ/mol.The reaction of HBr with HgBr is simulated,three reaction paths are found.Analyze the data to get the path B as the most probable path?3 intermediates and 2 transition states?.The energy barrier of the decisive step is 89.267 kJ/mol.The effects of K,Na and Ca poisoning on the V₂O₅ model were simulated.The poisoned models are more stable and can no longer adsorbe HCl and HBr,reaction efficiency of Hg is affected.The V₆O₂₀H₁₀ and V₁₀O₃₁H₁₂ are optimized and the structure and chemical parameters are analyzed.Combined with the theory o f frontier molecular orbit and the surface electrostatic potential analysis,the V₆O₂₀H₁₀ model is more likely to adsorb electrophile chemicals in the middle of the four oxygen atoms.By putting Hg,Pb,K,Na and Ca in the middle of the four oxygen atoms to study the adsorption and poisoning of V₆O₂₀H₁₀ cluster models,the structure and chemical parameters of the catalysts before and after adsorption are analyzed.the adsorption ability and the influence of the parameters of Hg is much weaker than that of K,Na,Ca and Pb.the order of toxic effects is:K-doped>Na-doped>Ca-doped>Pb-doped>undoped.The adsorption energy of Pb,K,Na and Ca is much higher than that of HCl and HBr,and the poisoned models can no longer adsorb HCl and HBr.The reaction efficiency of Hg is affected to some extent by the other four elements.