湿式烟气脱硫系统同时脱汞研究

研究表明，湿法烟气脱硫装置(WFGD)可去除烟气中绝大部分Hg²⁺，但对单质汞的吸收效果不明显，因此研究提高湿法烟气脱硫系统中单质汞的氧化率的方法对控制汞的排放具有重要意义。综述了WFGD及在此系统中各种添加剂的脱汞性能，认为在添加剂中，气态的臭氧、液态的次氯酸和氯化钠稀溶液、 黄磷乳浊液、氢硫化钠溶液及EDTA的汞去除效果较好，且不会被SO₂大量消耗，可在WFGD系统实现同时脱硫脱汞；而气态的氯气，液态的K₂S₂O₈溶液虽然也有较好的汞去除效果，但因易被SO₂或亚硫酸盐溶液消耗，当在WFGD系统中用其氧化单质汞时，需要对脱硫塔进行分层或其他改造，使烟气中的SO₂被吸收后再控制汞，提高经济性。

Study on simultaneous removal of SO2 and Hg in wet flue gas desulfurization

It was indicated that wet flue gas desulfurization (WFGD) system could remove a high percentage of mercury (II) from the flue gas but was ineffective at removing Hg⁰. So it is significant to study the method of increasing mercury oxidation rate to remove total mercury in WFGD. An overview of the mercury removal effectives of several additives in WFGD was presented. In these additives, ozone, chloric acid and sodium chlorate(NOXSORBTM) dilute solution, yellow phosphorus emulsion, sodium bisulfide solution and ethylenediaminetetracetic acid (EDTA) which would not be consumed largely by SO₂ were believed to have certain effects. Thus, simultaneous removal of mercury and SO₂ in WFGD system could be achieved. Additives such as Cl₂, and potassium persulfate solution (K₂S₂O₈) also had certain effects but they were easily consumed by SO₂ and sulfite solution, the scrubbing tower should be modified while these additives were used to oxidize the Hg⁰ in WFGD in order to reduce the capital and operation cost.