The Experiment Research Of Oxidation Kinetics Of Sulfite In The Process Of Wet Magnesium Flue Gas Desulfurization (FGD)

Sub-magnesium sulfate and magnesium sulfate were the mainly by-products in the process of the magnesium desulfurization. the purpose of choosing the strong reducing agent which added into the Desulfurization by-product solution was to enhance the reaction of strong reducing agent with the DO in water, but not the oxidation of Sub-magnesium sulfate with DO, then as much as Sub-magnesium sulfate would be gotten.Papers selected the distilled water, high pure water, tap water and deionized water as the test water, and all the water were oxygen saturated. the rate of oxygen consumption basically in the same order of magnitude. Sodium sulfite reaction order were 1.54,2.07,1.50 and 2.02; the part reaction order of DO were 0.14,0.03,0.51 and 0.24, respectively; activation energy were 149.6kJ/mol,139.6kJ/mol,100.4kJ/mol and 68.2kJ/mol.Papers selected four kinds of strong reducing agent, such as sodium thiosulfate, ethanol, phenol and resorcinol as the inhibitors, added into the sodium sulfite solution, experiments confirmed that the addition of inhibitors can significantly slow down sodium sulfite oxidation reaction rate, the inhibitory effect of sodium sulfite descending order is:resorcinol> phenol> sodium thiosulfate> ethanol, sodium sulfite oxidation kinetics of the intrinsic reaction order of 1.50.In the macro-kinetics experiments, Sodium thiosulfate as the inhibitor, the macro sub-magnesium reaction rate was:fn (Cj)=k·[Na2S2O3]-0.3; the magnesium oxidation was affected by the dissolution rate R1, sulfite oxidation reaction rate R2, dissolved oxygen from gas to liquid mass transfer rate R3 and so on, the total reaction rate R= Rmin (R1, R2, R3); the relationship between pH and the macro-reaction rate of Sub-magnesium sulfate can be divided into three sections:pH= 4.5-5.5 the reaction rate R= 1.37 x 10-5-0.17×10-pH; pH= 5.5-6.5 R=2.383×10-5-3.33×10-pH; pH= 6.5-7.5 R= 8.6×10-6+44.2×10-pH.