Study On Integration Process Of Desulfurization And Denitration Of Flue Gas By Ferrous Complex Wet Method

SOXand NOXproduced in coal burning are two kinds of main atmospheric pollutants,threatening the ecological environment and human health. Integration technology ofDesulfurization and Denitration of Flue Gas by Ferrous Complex Wet Method not only canhigh efficiently remove SOXand NOXat a low temperature in a device, but also cansignificantly decrease investment and operating costs. The technology has been concernedabout for decades, but has not been industrialized for the absorbent regeneration difficulties.Effects of adding Na2SO3,Na2S and urea respectively on the deNOx by Fe(II)EDTAsolution, were investigated; and effect of ultrasound-activated carbon on the deNOx wasinvestigated while the reducers were added to the adsorber solution; as well as regenerationmechanisms of reduction of Fe(III)EDTA and Fe(II)EDTA-NO by Na2SO3and Na2S, werestudied. On this basis, the integration of a process route is proposed, and the pilotexperiment of the desulfurization and denitration of model flue gas was carried out byFe(II)EDTA solution while the Na2SO3/Na2S was used as the reducing agent for theregeneration process, and the effect of the process conditions on desulfurization anddenitration was investigated on the pilot device, and the absorber life was tested. The majorexperimental results are as follows:(1) Reduction rate of Fe(III)EDTA and Fe(II)EDTA(NO) by Na2SO3is the fastest whenpH of the absorber solution is between6and7in the regeneration process, but NOabsorption capacity is the highest when the pH is between8and9in the absorption process.Activated carbon and ultrasound can promote the regeneration of the absorption liquid byNa2SO3.(2) In the acidic condition, Na2S can reduce Fe (II) EDTA (NO) to Fe (II) EDTArapidly, and its concentration increase can enhance the reduction rate. Urea has anunfavorable effect for the processes of both regeneration and absorption.(3) The absorber life test is carried out in the homemade packed tower. Under theoptimum process conditions, the process of desulfurization and denitrification of a simulated flue gas was carried out while Na2SO3/Na2S was used as reducers, SO2removalremained100%and NO removal was higher than94%when the absorption time reached300h.