Study On Development Of Flue Gas Renewable Desulfurizer In Power Plant

With the continuous improvement of national environmental awareness,The sulfur emission standards for flue gas in power plants become more stringent.Reconstruction of desulphurization system in power plant is imperative.However,for the renewable desulfurization technology,Absorbent performance is the most critical.The main contents of this paper:(1)The desulfurization and regeneration effect of hydrochloric acid,sulfuric acid and citric acid was studied by using piperazine solution as the main absorbent.The results showed that the mixture of piperazine-citric acid was the best.When the molar ratio of piperazine/citric acid was 1:0.6,the desulfurization rate was 98%and the saturated loading was 1.28 mol/mol.The regeneration rate increased from 46.8%to 81.68%,and the effective desulfurization was increased from 0.85 mol/mol to 1.05mol/mol,the regeneration effect is obvious.The results showed that the desulfurization rate of the mixed system was 98%after 40 min,the molar concentration of piperazine was 0.3 mol/L,the molar concentration of SO2 was 1%and the absorption temperature was 40 ?.Regeneration temperature of 101.3 ?,50min can be completed desorption.After 6 times of saturated absorption regeneration cycle,the desulfurization rate of the solution decreased from 98.24%to 95.08%,the regeneration rate decreased from 80.52%to 78.62%,and the effect of absorption and regeneration was excellent.(2)The electrochemical corrosion of metal in the absorbent system was studied.The results show that the corrosion resistance of 304 stainless steel is excellent.The corrosion resistance of 304 stainless steel is weakened by the presence of SO42-in the solution.The metal corrosion of the absorbent system is proportional to the ambient temperature and SO2 loading.At 40 ?,The corrosion rate of the rich liquid(20 gSO2/L)is twice that of the lean liquid(6.9 gSO2/L).At 80?,the corrosion rate of the rich liquid is six times that of the lean liquid.(3)The absorption/desorption performance of the absorbent system was studied by using the absorption/regeneration cycle pilot plant under the condition of simulated flue gas(SO2 mole fraction 0.125%).If the liquid-to-gas ratio is greater than 0.5 and the lean liquid load is less than 3.7 g SO2/L,the outlet SO2 concentration is less than 30 ppm.For the regeneration tower,when the spray density is less than 0.6,the regeneration rate exceeds 70%.After 12 double-column cycle experiments,the sulfur content of the rich and poor liquid did not change significantly,the outlet SO2 concentration rose from 8.3 ppm to 14.53 ppm,the system cycle stability is better.The desulfurization energy consumption shows that the sulfur content in the lean liquid is 2.71?4.04 gSO2/L,the sulfur content in the rich liquid is 11.72?17.14 gSO2/L,the energy consumption can be reduced to 3.34 kg steam/kgSO2,much lower than Cansolv regeneration desulfurization process energy consumption(9.0 kg steam/kgSO2).