The Simultaneous Removal Of SO₂and NO From Sintering Flue Gas By Ammonia-Fe（Ⅱ）EDTA Absorption In A Pilot-scale Reactor

With issuing more strict emission standards of SO2and NOX, the reduce of SO2,NOXand other pollutants emissions form the sintering process has become urgent. Thesintering process is one of the most important part for preventing polluttant in steelindustry. In recent years, the simultaneous removal of SO2and NO by wet method haddrawn more attention because of its low investment, simple equipment and highremoval efficiency. In this paper, the ammonia WFGD(wet flue gas desulfurization)combined with Fe(II)EDTA absorption NO technology was proposed. At the same time,the experiment was investigated in a pilot-scale reactor. The experimental data wasuseful for industrial application of this technology.First of all, the influence of reactor structure on the denitration performance wasstudied, and the optimal structural parameters were: packed tower type, φ25mm Bauerring packing material, a packing height of900mm and a liquid-gas ratio of12L/m3.Secondly, the effects of gas properties and slurry properties on SO2and NOremoval efficiency were also studied. It was found that it had a negative effect ofabsorption of NO when the gas flow rate, the concentration of oxidation air quantityand the NO concentration were increased. When the slurry temperature was constant,the change of the flue gas temperature had a little influence on SO2and NO absorption.Meanwhile, the change of SO2concentration had no significant effect on SO2and NOabsorption.(NH4)2SO4concentration and slurry temperature increase suppressed SO2and NO absorption.. The initial NO removal efficiency decreased from90.63%to44.12%when the concentration of (NH4)2SO4increased from0.0to3.5mol/L. Withthe increase of Fe(II)EDTA concentration, SO32-concentration and the pH value, thecapacity of Fe(II)EDTA complex was increased. Especially, when SO32-existed, thelife of the complex agent was significantly improved. The denitration efficiency wasonly decreased by16.46%after30min at0.3mol/L SO32-. Cl-had no effect on SO2andNO absorption. Finally, Fe(II)EDTA complexes regeneration in regeneration tank and regenerationtower were compared. Meanwhile, the factors of regeneration parameters wereinvestigated. The regeneration tower was better for the regeneration, and the denitrationefficiency could remain above60%. Moreover, it was found that iron with a largerspecific surface area, less surface oxidation and no oil on the surface was best. Increasingthe quality and the bulk density of iron was advantageous to the regeneration. Although(NH4)2SO4was harmful for NO absorption, it could prevent the oxidation ofFe(II)EDTA.