| Global mercury emission pollution problem has drawn great attention worldwide,based on the minamata convention mercury emission reduction commitment,developing economic and efficient coal-fired flue gas mercury technology has become one of hot topics in the study of coal-fired flue gas control in China.The paper conducted a simulated wet oxidation desulfurization of flue gas mercury experiment based on the oxidation method,the research results are as follows:1,The oxidants screening experiment about Hg0 oxidation for Hg2+were conducted.Through the theoretical analysis the properties of KMnO4,NaClO2,NaClO,K2S2O8,K2FeO4,H2O2 etc,it was found that KMnO4,NaClO2,NaClO have oxidation ability.In condition of mercury initial concentration 50.2?g/m3,oxidant concentration 4mmol/L,pH 6,temperature 50°C.The oxidation removal rate of Hg0 is around 70%.2,Based on oxidants screening experiment of chapter 3,the spray tower oxidant wet oxidation experiment research was carried on.The results showed that NaClO/NaClO2,H2O2/NaClO2 two groups of compound oxidant have good experiment effect of oxidizing Hg0.In conditions of mercury initial concentration50.2?g/m3,gas flow rate 10L/m3,the concentration ratio 6/4?mmol/L:mmol/L?,absorbing liquid volume 5L,pH 5,temperature 50°C,absorbing liquid flow rate0.15L/min,liquid gas ratio 15?L/m3?,lotus nozzle,the nozzle built in the top of the tower spray?top from down?.The compound oxidant NaClO/NaClO2,H2O2/NaClO2oxidation of Hg0 removal rate are 90%,85%respectively.3,Combined with wet limestone desulfurization technology,the researcher has carried out the experiment of oxidant synergy limestone simultaneous removal of SO2and Hg0.Found that NaClO/NaClO2,H2O2/NaClO2 two groups of compound oxidant have good experiment effect of oxidation Hg0 and absorption SO2.The orthogonal experiment results show that the optimal parameters of compound oxidant NaClO/NaClO2 is A4B1C4.Namely the concentration ratio 10/4?mmol/L:mmol/L?,initial pH 5,liquid gas ratio 18?L/m3?,desulfurization efficiency and mercury removal rate are 99.5%and 85.4%respectively.4,By characterization analysised the solid by-products of desulfurization and mercury removal,the results showed that the limestone desulfurization of solid by-products was mainly CaSO3,oxidant synergy limestone desulfurization and mercury removal of solid by-products was mainly CaSO4;Through analyzing the form of mercury occurrence,the results showed that 23%of the mercury in the form of mercury compounds exist in gypsum,77%of the mercury in the form of mercury ion present in the supernatant. |
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