Experimental Study of Flue Gas Desulfurization Using Landfill Leachate

摘要

Because of the complexity of landfill leachate's composition, the reaction mechanism of SO_2 in flue gas with landfill leachate was studied. The experimental results indicated that the factors influencing SO_2 absorption efficiency using landfill leachate as the scrubbing medium were, in decreasing order of importance, pH, Fe~(2+), Mn~(2+), and Cl~- as catalysts and the concentration of toluene and ethanol. Experiments showed that the pH of landfill leachate was the key factor governing both SO_2 absorption and ammonia stripping. With the initial pH of 8.5, the terminal pH 6.0 and L/G ratio 3 L/m~3, experimental results showed that average absorption efficiency of SO_2 and the stripping efficiency of ammonia were 85 and 44%, respectively. The use of catalysts such as Fe~(2+) and Mn~(2+) was important for SO_2 absorption when the pH value was below 7.0. The catalytic activity of Mn~(2+) was greater than that of Fe~(2+) although the reaction steps were very similar. Ethanol inhibits HSO_3~-/SO_3~(2-) oxidation. The HSO_3~-/SO_3~(2-) oxidation process improves the solubility of organics such as toluene in the leachate. The solute products of organics were water-soluble and biodegradable and could be used as substrates for bacteria in the post biotreatment. The factorial experiment results showed the effect of Cl~-, Fe~(2+), and Mn~(2+) as catalysts on the HSO_3~-/SO_3~(2-) oxidation has a greater positive impact than ethanol's inhibitory effect on the HSO_3~-/SO_3~(2-) oxidation.