Study On Reactivity Of The Limestone In Wet Flue Gas Desulfurization

The reactivity of limestone for limestone-gypsum wet flue gas desulfurite system in fire power plant was on study. The content of CaCO₃ and MgCO₃ could be gained by X fluorescence spectral analysis, which contained in eight samples of limestones from different sources in China. At a fixed pH value, a series of experiments were carried out by titration with sulfuric acid to investigate the factors affecting the limestone dissolution rate. The research results shows that the desulfurite efficiency of the different limestone is distinct between 20% and 30%. A lower pH value is favorable for the limestone dissolution rate which increases 10% when pH decreases 0.5. But a lower pH value make against the increase of the desulfurize efficiency, and the formation of the pH amortize environment. So the pH value should be controlled between 5.0 and 5.5. And the smaller particle size the grain has the higher the dissolution rate is, especially when the particle size decreases from 200 mesh to 325 mesh. Agitation has little influence on the limestone dissolution.The effect of Cl^-, Na⁺and formic acid on the limestone dissolution rate is favorable. It is obvious that Na⁺ has an advanced effect on the dissolution rate while Cl^- is reversed, especially when pH value is high. Formic acid promotes the limestone dissolution extremely, as to reach a high dissolution rate in a short time. At a fixed flux of sulfuric acid, a series of experiments were carried out by MET to investigate the desulfurite reactivity. The research indicates that the pH flat of sample one,two,four,five,seven and eight are higher than five,so they can be used in limestone-gypsum wet flue gas desulfurite system.