Study On Limestone Wet Flue Gas Desulfurization Compound Additive

Coal is the main sources of energy in our country. Large amounts of SO2 produced in the combustion process pollute the atmospheric environment seriously. Flue gas desulfurization with wet limestone is widely used, but shortcomings still exist in this technology, for example, the solubility of limestone is small; the liquid-gas ratio of operation is large; and also the running cost is high. Adding some additives to the limestone slurry can promote the dissolution of the limestone, improve mass transfer and reaction performance, and improve the efficiency of flue gas desulfurization and limestone utilization.In this study, N2, O2 and 1% SO2 were used to simulate flue gas. A 500mL bubbling reactor was used as absorption equipment. The additives for wet limestone flue gas desulfurization were studied experimentally. Organic macromolecular substances A and B and inorganic substance C, which have non-toxic side effects, were selected as the additives. The removal efficiency of SO2, the pH value of slurry and the utilization of limestone showed that:A and B can promote the dissolution of the limestone, improve the performance of mass transfer and reaction in the slurry, and therefor effectively improve the removal efficiency of SO2 and the utilization of limestone. This effect is more clear with a higher additive concentration. For additive-enhanced process, the SO2 removal efficiency and the utilization of limestone decreased when the temperature increased, just like the process without additive. Compound additive, a, is composed of A and B at different proportion. Its enhancing effect is best when the ratio of A to B is 1:1. Another compound additive, b, is composed of C and the mixture of A and B, the ratio of A to B being 1:1. The enhancing effect of b is superior to compound additive a, and the enhancing effect increases when the concentration of C is increased.