Study On The Process Of Regeneration Of Natrium-alkali FGD Liquor Via Ion-exchange Membrane Electrolysis

On the basis of study on sodium alkali regeneration via ion-exchange membrane electrolysis, this paper focuses on the anode oxidation and membrane in two-compartment membrane electrolysis where the sodium sulfite and sodium bisulfite solution are treated. The oxidation characteristic of the cationic membrane, anionic membrane and anionic membrane in electrodialys equipment whose anodal broad attached by a piece of film are analyzed.Then an electrolysis device is designed in order to choose optimal membrane by analyzing the distribution of voltage and ion migration rate.In the process of electrolysis, with the voltage increasing, the current and the pH of cathodal export liquor go up, the oxidation rate of sulfite and bisulfite root increase but the proportion of sulfite and bisulfite root oxidative consumption in the total power consumption declines. When the voltage is lower than 6V, there are no bubbles produced on anode borad in sodium sulfite and sodium bisulfite solution, water electroanalysis is virtually non-existent.Sulfate root is concentrated, which confirms that sulfite or bisulfite is fundamental oxidized into sulfate.When the anodic board is attached a piece of film, with the voltage increasing, the oxidation rate of sulfite and bisulfite root goes up, the proportion of sulfite and bisulfite root oxidative consumption in the total power consumption declines ,which is lower than no film attached on anodic board, that shows anodal surface membrane with film can effectively controls the oxidation of sulfite and bisulfite root, but the resistance of membrane increases and the current falls down in the same voltage. For example when the sodium Concentration is the same, pH=2~7and the voltage is 4V, the highest oxidation rate is 2% without a piece of film on anodal broad, but when anodal broad is attached by a piece of film, the highest oxidation rate is 0.9%, the proportion of sulfite and bisulfite root oxidative consumption in the total power consumption falls about ten percents and the current falls about forty percents.In the electrolysis process, the voltage distribution changes according to the equipment structure and operation conditions, the resistance of the membrane changes with its material and structure. By the three difference pieces of films study, it indicates that the resistance of flat glass fiber membrane capability is close to ion exchange membrane, but the vitriol root transference is higher at the same voltage or same current density. It also shows that the membrane resistance is largest in sodium bisulfite solution than in other solution.