Of Na <sub> 2 </ Sub> S Solution Absorption Of So <sub> 2 </ Sub> S Single Quality Of The Flue Gas System,

China is the major country all over the world in SO2 emissions.If these SO2 can be well recovered and mostly used,it will not only control environmental pollution,but also bring economic benefits. However, the desulfurization technologies which have been industrially applied at present,mainly focus on SO2 pollution's control and don't make full use of it. With economic development and the state putting forward higher requirements for environmental protection,new desulfurization technology for deeper desulfurization and effective use of resourses should be studied and developed.This issue studied the new technology that Na2S solution absorbs SO2 flue gas,and prepares elemental sulfur. The thermodynamic analysis of SO2-Na2S-H2O system,the effect of absorption conditions on the absoption process and the feasibility and optimal conditions of absorption solution's redox reaction were studied,which obtained the following results:(1) The thermodynamic analysis of SO2-Na2S-H2O system shows that:when the system reaches equilibrium,gas phase are SO2 and H2S,and liquid phase are S2O32- and HSO3- while pH value is during 2 and 9.(2) Na2S solution has good absorption for SO2 flue gas in the concentration form 0.01% to 15%,and the total absorption rate reaches higher than 99%. If the condition is different,the concentration of each species in absorption solution is different. So,controlling the concentration of SO2 in flue gas and the gas flow rate can adjust the ratio of NaHSO3 and Na2S2O3.(3)The use of absorption solution in first-stage from absorption process to prepare elemental sulfur is feasible,and the reduction rate of elemental sulfur is above 96%.In redox reaction,the molar ratio of NaHSO3 and Na2S2O3 is 2:1,the pH value is between 2 and 3,the reaction temperature is between 130℃and 140℃,and the reaction time is one hour. To ensure the reduction rate,the solution should contain Na2S in more than 0.03mol/L.