Study On The Activity Of Limestone In Wet Flue Gas Desulfurization Of Thermal Power Plants

As the wet FGD absorber,limestone have an important impact on the process and results Of the flue gas desulfurization。In the limestone/gypsum wet desulphurization system, the dissolution of limestone restricts the speed of the entire system of sulfur dioxide absorption rate, which an important parameter used as measuring the performance of dissolved limestone is the activity of the limestone. Experiments have proved that under certain conditions, the solution to the addition of limestone chemical additives can significantly increase the rate of dissolution of limestone.In order to understand the additive's impact on limestone dissolution rate, the researcher collected natural limestone from autonomous regions and different parts, analyzed its chemical composition, choosed the 3 different quality limestones as the absorbent, then sulfuric acid was used as titration agent to test temperature, grain Drive, organic, inorganic compound additives'impact on sulfuric acid dissolved their properties. Experiments in the application of inorganic additives for MgSO₄,Na₂SO₄,Na₂CO₃, and so on; organic additives for citric acid, adipic acid, acetic acid, sodium acetate, sodium citrate and sodium oxalate, and so on; compound additive for adipic acid, acetic acid, respectively combinated with MgSO₄,Na₂SO₄. Simulation of wet flue gas desulfurization slurry, in determining the pH value, the study of different concentrations of sulfuric acid dissolved the limestone on the additive effects of characteristics, as well as to maintain a certain acceleration of the acid droplets, the pH value of the absorbent research and utilization over time CaCO₃ Trend.Analysis of experimental data, obtained pH value of sulfuric acid dissolved the limestone rate plays an important role, pH value, the lower the better it is for the dissolution of limestone; pH value of 5.0, the conversion rate of limestone in the 45℃hours at room temperature than when the high - About 10%; over 300 purpose than 200 limestone purpose of the sulfuric acid dissolved the high rate of about 20%; add 0.2343 percent of the limestone on the fly without too much impact on the conversion rate; Na₂SO₄ limestone on the conversion rate of no effect; Na₂CO₃ on Limestone conversion with the added impediment of the increased concentration and decreased; MgSO₄ on the limestone into obstacles with the added role of increasing the concentration of the increase; salts and organic compound additives can promote the dissolution of limestone, and With the pH value, the better the effect of increasing the promotion, the promotion of organic acids is the best adipic acid, followed by acid, organic salt is the best promotion of sodium acetate; compound additives, the effect of promoting the best Acetic acid is satisfied with the combination. Were the source of materials and co-market prices, acetic acid, acetic acid and sodium acetate and a combination of Na₂CO₃ is the most prospects for the development of desulfurization additives.