The Recycling Technology And Principle Of Novel Natrium-alkali FGD With Ion-exchange Membrane Electrolysis

SO2 produced by smoke from burning coal and oil makes air quality worse and acid rain more serious. The control of SO2 becomes an urgent demand. Due to the high capital cost and the lack of technology support, the study of desulfurization in China is left behind. A novel wet FGD (Flue Gas Desulfurization) process is presented on the base of study of sodium alkali FGD and membrane electrolysis, which utilizing traditional ion-exchange membrane electrolysis to regenerate sodium alkali fertile liquor and to reclaim sulfur dioxide as sulfuric acid. The equipments of different cells are studied with solution of NaHSO3-Na2SO3 as electrolysis solution. The aim is to illuminate and define the recycling principle, influencing factors of membrane electrolysis effect, membrane electrolysis models and influencing factors of the above three membrane electrolysis cell.The firstly, in the process of two cells anion-exchange membrane electrolysis, the current efficiency will be better with more current density, lower pH of cathode influent solution, higher H2SO4 concentration of anode solution and faster velocity of flow of electrolysis solution. The model is the relationship between theoretical sulfur dialysis ratio and acidity of cathode influent and effluent. The model is good agreement with the experiment results and reflects the dialysis ratio well and sulfur dialysis ratio should be less than 50%. The model has good stability in the stated range of influent solution pH.The secondly, in the process of three cells anion-cation-exchange membrane electrolysis, some factors can influence the current efficiency. The current efficiency of dialysis system decreases with the concentration of the dialysis solution increasing. But the current efficiency of dialysis system increases with the pH of the dialysis solution increasing. The current efficiency of dialysis system decreases with the current density increasing. The current efficiency of dialysis system decreases with the H2SO4 concentration of anode solution increasing. The current efficiency and sulfur transference ratio of dialysis system increases with the flow velocity of electrolysis solution increasing. But when the flow velocity exceeds the crisis point, the current efficiency and sulfur transference ratio of dialysis system will no longer increase. The theoretical model shows that the H+ concentration of influent and effluent hardly vary at pH=5.0~5.5. The pH of effluent solution increases at low pH of inflation solution but decreases at high pH.The thirdly, in the process of three cells cation-cation-exchange membrane electrolysis, some factors can influence the current efficiency. The concentration and pH can not evidently influence the current efficiency of the dialysis system. The current efficiency of dialysis system decreases with the current density increasing. The current efficiency of dialysis system increases with the H2SO4 concentration of anode solution increasing but the variation is not visible. The theoretical model shows that the pH of the effluent solution is lowest when the pH of influent solution is about 5.0. The membrane dialysis equipment can be designed through the Na+ transference quantity and the operation condition and membrane size of the membrane dialysis equipment can be optimized with the theoretical model.A novel wet FGD (Flue Gas Desulfurization) process is firstly presented in the research. The influence of membrane dialysis effect for two cells anion-exchange membrane electrolysis, three cells anion-cation-exchange membrane electrolysis and three cells cation-cation-exchange membrane electrolysis experiment research and theoretical model are studied through variation compose and concentration of the dialysis solution, current density, the H2SO4 concentration of anode solution and flow velocity of cathode-anode solution. The theoretical model is good agreement with the experiment research results. The membrane dialysis equipment can be designed, the operation condition and membrane size of the membrane dialysis equipment can be optimized, and membrane dialysis combination can be devised with the theoretical model.