Experimental Studies On Accelerating Effect Of Flue Gas Desulfurization Additives For Formation Of Sulfate

The principle of wet limestone scrubbing was reviewed. One of the key problems, oxidation of sulfite, was summarized as well. On the base of large number of literatures, the effect of additives on oxidation kinetics of sulfite was investigated. By use of self-designed intermittent reactors and bubbled ones in laboratory scales, the characterized oxidation kinetics and macroscopical ones of sulfite were studied respectively whether in presence of additives. The study was significant to look through the oxidation mechanism of sulfite, and explore the promoted oxidation technology of sulfite with low cost and energy consumed. The uncatalyzed characterized oxidation kinetics of sodium sulfite was studied respectively by using different water such as high pure water and distilled one. Effect of light was studied as well by using brown reactor and transparent one. It is shown that light and water quality have great effect on the oxidation, especially the latter. The uncatalyzed oxidation course is divided into two steps, which are rapid reaction in rich oxygen region and slow reaction in poor one. Mathematical models of the general oxidation of calcium sulfite were made under heterogeneous conditions, which included the dissolution of calcium sulfite from solid to liquid, diffusion of oxygen from gas to liquid, and chemical reaction in liquid. Integrated with the experimental results of characterized kinetics, the rate control step of macroscopical kinetics was inferred. In presence of manganese sulfate, the symbol of metal catalysts, characterized and macroscopical oxidation kinetics of sulfite were studied respectively. It is shown that manganese sulfate is effective. There is induced period in characterized reaction, which is shortened gradually with the increasing of manganese sulfate. It would accelerate characterized reaction, which leads to the acceleration of general oxidation of calcium sulfite. As a kind of organic acid, peracetic acid was used as catalyst firstly. The corresponding characterized and macroscopical oxidation kinetics of sulfite was studied respectively. It is shown that peracetic acid is effective, and it would accelerate characterized.reaction, which leads to the acceleration of general oxidation of calcium sulfite. The characterized and macroscopical oxidation kinetics of sulfite was studied respectively in presence of inhibitors, such as alcohols, phenols and hydroquinone. It is proved that these additives would inhibit characterized reaction, which leads to the retardment of general oxidation of calcium sulfite. The dissolution rule of calcium carbonate was studied. Integrated with mathematical models, the empirical equations were achieved for calculating the dissolved calcium carbonate. The study was helpful to explore effective promoted oxidation technology of sulfite and reduce invest and energy consume for wet desulfurization.