Abstract:

Experimental research on the desulfurization of flue gas simulated with 0.3 mol/L amine solutions prepared with ethanolamine, ethylenediamine and so on. Desulfurization efficiency was studied by iodometry titration. Absorption capacity of SO₂, oxidation of absorbed SO₂ and desorption efficiency of SO₂ were researched via ion chromatography. Meantime, cycles on the desulfurization efficiency and SO₂ content of rich absorbent were studied. The results show that the desulfurization efficiency of all the absorbents were maintained 99 % for 30 min. After 60 min, the desulfurization efficiency of ethylenediamine solutions reached 99 %, but the desulfurization efficiency of alcohol amine solutions decreased significantly. The absorption capacity of the ethylenediamine solution for SO₂ was 455 mg/L, much higher than that of the alcohol amine solution. Boric acid was added to the ethylenediamine solution, the absorption capacity of the solution for SO₂ was slightly lower(450 mg/L), but oxidation efficiency of absorbed SO₂ reduced from 1.14 % to 0.29 %. At the same time, the desorption efficiency of SO₂ increased from 38.0 % to 59.0 %. Absorption-desorption cycle experimentals indicated that the average desulfurization efficiency of the ethylenediamine/boric acid solution reached above 99 %, and SO₂ content of rich absorbents decreased from 0.44 mol/L to 0.40 mol/L. The results suggest the desulfurization effect of the ethylenediamine/boric acid solution is excellent as the flue gas absorbent.

Key words: alcohol amine, ethylenediamine, ethylenediamine/boric acid, flue gas desulfurization