To inhibit deputy reaction of SO2 -3 oxidized into SO2 -4 during the process of limestone-gypsum wet flue-gas desulfurization,the basic aluminum sulfate solution with aluminum content of 30 g/L and alkalini-ty of 26% was prepared to carry out desulfurization tests.Two antioxidants,hydroquinone and ethanol, were added into the basic aluminum sulfate solution to prevent the SO2 -3 from being oxidized to SO2 -4 and to improve the SO2 desorption rate.The blank test was also conducted to provide a reference.The concentra-tions of SO2 -3 and SO2 -4 in the solution were measured by indirect iodimetry and EDTA titration method. The results show that,both the hydroquinone and the ethanol have an inhibition effect on SO2 -3 oxidation to SO2 -4 .The optimal hydroquinone concentration is about 4 mmol/L,the reduced oxidatized SO2 -3 amount is about 54% higher than that in the blank test.The optimal ethanol concentration is about 7 mmol/L,the reduced oxidatized SO2 -3 amount is about 63 % t higher than that in the blank test.Adding hydroquinone and ethanol can both improve the SO2 desorption rate.Compared with the blank test,adding 4 mmol/L hy-droquinone or 7 mmol/L ethanol,the SO2 desorption rate can be increased by at least 15%.If only consider-ing the effect of inhibition oxidation,adding ethanol is better.%为了研究抑制石灰石-石膏湿法烟气脱硫中 SO2－3氧化为 SO2－4的不利副反应,配制了铝质量浓度为30 g/L、碱度为26％的碱式硫酸铝溶液,分别进行不添加阻氧剂(空白)、添加2种阻氧剂(对苯二酚、乙醇)的 SO2吸收及解吸效应试验,并分别采用间接碘量法和 EDTA 滴定法对溶液中的 SO2－3和 SO2－4浓度进行测定。试验结果表明：添加对苯二酚或乙醇均对 SO2－3氧化为 SO2－4具有抑制作用；添加对苯二酚的最佳浓度约为4 mmol/L,SO2－3的氧化量较空白试验减少54％以上；添加乙醇的最佳浓度约为7 mmol/L,SO2－3的氧化量较空白试验减少63％以上；添加对苯二酚与乙醇均具有提高 SO2解吸率效应,与空白试验相比,添加4 mmol/L对苯二酚或7 mmol/L 乙醇时,SO2解吸率至少提高15％；就抑制氧化效应而言,添加乙醇的效果更好。
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