Simultaneous Removing SO2 and NO by Ammonia-FeⅡ EDTA Solution Coupled with Iron Regeneration

Abstract

In this paper, the simultaneous absorption of SO2 and NO from the simulated sintering flue gas by ammonia-FeⅡEDTA complex solution was investigated in a pilot scale reactor. The experiment results showed that the maximum removal efficiencies of SO2 and NOx by ammonia-FeⅡEDTA complex solution scrubbing were 99% and 68.26%, respectively. However, the denitiration efficiency was gradually declined due to the oxidation of FeⅡEDTA into FeⅢEDTA. At the same time, FeⅢEDTA did not have the ability of binding NO. In order to keep the high denitration efficiency, FeⅢEDTA regeneration by iron and the surplus iron ion removal by the precipitation were proposed. Moreover, the optimum parameters of the surplus iron ion removal were also investigated, the experimental results showed that the optimum addition of ammonia carbonate was 0.4 g/L. After the regeneration and precipitation, the denitration efficiency by ammonia-FeⅡEDTA complex solution could be kept at 55%, and the desulfurization efficiency in the test was above 99%.