New Limestone-Gypsum Flue Gas Desulfuization Technology

A new wet FGD processes which SO₂ was absorbed in the spray tower using granular limestone simultaneously adding acetic acid had been proposed. The main difference compared to conventional wet FGD process was to utilize granular limestone directly as a desulphurization reagent simultaneously adding acetic acid. Thus, the pulverizing of limestone, which causes power consumption, can be saved. Only using granular limestone 210 ¿m directly as absorbent without acetic acid, SO₂ removal efficiency and limestone utilization were too low respective 60.7% and 44%. Adding 10-30 mmol/L acetic acid, degree of desulphurization was increased to 95% and the limestone utilization was enhanced to 93.5%, comparison with fine limestone, the desulphurization efficiency and limestone utilization were respective 88% and 92.9% at the same operating conditions. Adding organic acid, buffer capacity of system was enhanced. And the influent factors such as the concentration of acetic acid, limestone slurry and SO₂, residence time of flue gas were tested. The mechanism of acetic acid promoting SO₂ absorption was suggested.