Experimental Research on Effect of Acids as Additives on Wet Flue Gas Desulfurization with Ethylenediamine

Experiments were performed on a bubbling system to study the effect of additives such as hydrochloric acid, sulfuric acid, phosphoric acid, citric acid and boric acid on wet flue gas desulfurization, using ethylenediamine as the absorbent. Experimental results show that the tribasic weak acid additives can improve SO₂ removal efficiency, and buffer pH fluctuation. It suggests that phosphoric acid, boric acid and citric acid are good for ethylenediamine as an absorbent. By changing the temperature, initial pH value of the solvent and the ethylenediamine concentration, the impacts on the SO₂ removal efficiency were investigated. The results indicate that the appropriate absorption conditions of ethylenediamine/phosphoric acid solvent are following: the initial pH of the absorbent is 6.5~7.5, absorption temperature is 328 K, and the ethylenediamine concentration is 0.3 mol·L^-1.