Catalytic Oxidation Of Ammonium Sulfite Into Ammonium Sulfate Using Air

Flue gas desulfurizations are the key technologies in Chinese environmental protection markets. Catalytic oxidation of ammonium sulfite into ammonium sulfate by air is the afterwards of ammonia desulfurization technique. The effects of the initial concentration of ammonium sulfite(0.500 mol/L～1.50 mol/L), the reaction temperature(40℃～60℃), the air flow rate(100 L/h～400 L/h) and the concentration of catalyst of cobalt sulfate(0.0010 mol/L～0.020 mol/L) are investigated. Design the orthogonal experiment to find out the optimum reaction conductions, and the mechanisms of the catalytic oxidation reaction are studied. The main reactor in the experiment is a mechanically agitated thermostatic reactor. It has three necks for continuous feeding of gas, a speed stirrer and a tail gas absorber in the experiment.According to the experiment of result, the oxidation rates of the ammonium sulfite are higher when the ammonium sulfite concentrations are low. With the increase of the concentration, the oxidation rates of ammonium sulfite decrease; the optimal reaction temperature is 50℃, the oxidation rates increase with the air flow rate and the concentration of catalyst cobalt sulfate. According to the orthogonal experiment, the optimum reaction conditions are the initial concentration of ammonium sulfite 1.10 mol/L,the concentration of catalyst of cobalt sulfate 0.015 mol/L, the reaction temperature 50℃.In the liquid phase the mechanism of the reaction mainly is the catalyzed oxidation and the free radical responded unifies, the O2 existence makes the vital role regarding there spouse, the OH? free radical existence is the key factor. By using the salicylic acid as the capturer, we use the high performance liquid chromatography and the fluorescence to detect its main hydroxylation products 2, 3-dihydroxy benzoic-acid and 2, 5-dihydroxy benzoic-acid. The obtained data and the experiment data confirmed this response a free radical response.