Study On The Process Of Simultaneous Removal Of SO₂ And NO_x By Ammonia-Fe???EDTA

SO₂ and NO_x,as major air pollutants,are resulted from the combustion of fossile fuel,including stationary source?70%?and mobile source.In stationary sources,the pollutants are primarily from power stations,building materials manufacturing industries et.al.To meet the stringent regulation,many efforts have been made to reduce SO₂ and NO_x emission by using post combustion abatement technologies such as the combination of WFGD and SCR.However,the combined abatement technologies exhibit obvious disadvantages like large space requirement,complex flue gas pipeline,large disposable investment,and high cost for operation.Thus,development of new technology for simultaneous desulfurization and denitrification on base of the existing techniques and equipments was imperative.Ammonia-complexing simultaneous desulfurization and denitration technology can efficiently reduce the emission of SO₂ and NO_x in the present of complexing agent.It has attracted lots of interest in recent years,because of its smaller size and lower cost.Meanwhile,the simultaneous desulfurization and denitration technology can be integrated with existing system like WFGD and SNCR.However,most researches were carried out on the small bubble reaction device,which has significant difference with the practical industrial application.In this dessertation,a small spray-type system was set up The complexing agent,which was prepared by adding ammonia water into the mixed solution of FeSO₄ and EDTA-2Na,was characterized by IR and XRD as well as the complexing absorption product.The main research achievements are summed up as follows:The effect of experimental parameters such as pH value,initial concentration on the removal rate of SO₂ and NO were studied by orthogonal test.The results indicated that the pH value of solution has the greatest influence on the efficiency of complex denitration,and the optimum pH value range was 6-8.Fe???EDTA complex denitration reaction is exothermic reaction.The presence of SO₂ is helpful to prolong the effective denitrification time.The complexing agent powders were prepared by vacuum drying method and characterized by IR and XRD.The complexing agent of infrared absorption peak is mainly affected by Fe,the COO^-stretching vibration appears in from 1650cm^-1-1610cm^-1 and 1390cm^-1-1370cm^-1 position.The C-N stretching vibration appears in the 1091cm^-1 and 1047cm^-1 position.Fe???EDTA complex agent shows five strong diffraction peaks at low angle of 10°-17°and four continuous weak diffraction peaks at 28°-30°.The pH value of the absorption solution has strong influence on the efficiency of denitration because of the change Fe²⁺/EDTA complex forms.Under acidic condition,it is not conducive to the formation of Fe???EDTA.Meanwhile,high alkalinity will reduce the stability of complexing agent.