Study On The Flue Gas Desulphurization By Microorganism

With simple process,low investment and operation costs,no coal loss andrepeated pollution,flue gas desulfurization techniques bybioreactor(BIO-FGD) havea lot of advantages for society, environment and economy.This study aimed atresearching and developing a new fluegas desulfurization technique with moreefficiency and low cost. Two bio-tricklings were adopted to remove the SO2 ,thebio-trickling of sulfate reducing bacteria and the bio-trickling of thiobacillusdenitrificans connect in series.The bioreactor we adopted is bio-trickling, the material of the tower is glass andthe inner diameter of the tower is 80mm, the height of the packing layer (SRBbio-trickling) is 1.5m and the height of the packing layer (T.D bio-trickling)is 1m.Thepacking of the two tower ia all cascade ring (16×8.9×1.1), the material of the cascadering is polypropylene plastic. At the beginning, the sulfate reducing bacteria andthiobacillus denitrificans grow on the surface of the packing separately, the colour ofthe sulfate reducing bacteria bio-film is black and the colour of the thiobacillusdenitrificans bio-film is yellow.When the bio-film of SRB is very good, we reduce theSO42- concentration of the nutrient solution and at the same time, we input the SO2(N2 as the balance air) to domesticate the SRB until theycan removel the SO2.At 30℃, in the range of 0～1800ppm(SO2 inlet concentration) ,the SO2removalefficiency is all over 99%,and the SO2removal efficiency is all over 99% with theinput time.Firstly, The SO2 molecules enter the liquid from the gas, and become theSO32- in the loquid ,then the SRB use SO32- as the E-receptor ,so SO2 is removed atall.The outcome of the reaction is sulfide .The outcome of the SRB bio-trickling (H2S)is removed at the T.D bio-trickling.We also study the effect of operating conditions on the SO2 removalefficiency,as a result,we found that the pH of nutrient solution and the Liquid gas ratiohas little effect on the SO2 removal efficiency,in the range of 6～8(pH), the SO2removal efficiency is all over 99%, in the range of 19.09～39.81 m3/h·m2(spraydensity), the SO2 removal efficiencyis all over 99%.