To inhibit deputy reaction of SO2-3oxidized into SO2-4during the process of limestone-gypsum wet flue-gas desulfurization

the basic aluminum sulfate solution with aluminum content of 30g/L and alkalinity 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 SO2-3from being oxidized to SO2-4and to improve the SO2 desorption rate.The blank test was also conducted to provide a reference.The concentrations of SO2-3and SO2-4in 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 SO2-3oxidation to SO2-4.The optimal hydroquinone concentration is about 4mmol/L

the reduced oxidatized SO2-3amount is about 54% higher than that in the blank test.The optimal ethanol concentration is about 7mmol/L

the reduced oxidatized SO2-3amount 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 4mmol/L hydroquinone or 7mmol/L ethanol

the SO2 desorption rate can be increased by at least 15%.If only considering the effect of inhibition oxidation

adding ethanol is better.