Experimental Research On FGD With Alkali Absorption-microbial Reduction Regeneration

The biological flue gas desulfurization(BFGD)process has been adopted,simulated flue gas desulfurization devices have been designed and built personally,which uses Sulfate Reducing Bacteria(SRB)and Colorless Sulfur Bacteria(CSB)as the experimental bacteria to analyze the performance of the BFGD process.The enrichment culture of bacteria(SRB,CSB)was carried out in the experiment.The growth conditions of SRB were researched,and the required carbon source and sulfur source of SRB were chosen.Moreover,the factors affecting the sulfite removing capability of the SRB were studied.The experimental results indicated that the best growth conditions of SRB were initial pH value 7.0,culture temperature at about 30℃-35℃,and the strain can make use of sodium lactate,glucose and citric acid water as carbon source, can carry out the metabolic activity with sulfate and the sulfite as electron acceptor.Citric acid water was chosen as the carbon source of SRB.The optimum technological conditions for reducing sulfite were initial pH value 7.0,culture temperature at about 35℃,and the sulfite concentration was not over 500mg/L in the anaerobic reactor.Studies have been carried out on the influencing factors of converting sulfide directly by CSB.The results showed that the optimum parameters were obtained at pH=7.5-8.0 and the sulfide concentration was not over 300mg/L.With increasing of the dissolve oxygen(DO)concentration,the removal efficiency of sulfide increased,and the SO₄^2- concentration was increasing also.The series process of alkaline absorption of sulfur dioxide-sulfite-reducing-biological desulfurization was investigated,the whole system continuous operation 20d in order to study the change of all factors in anaerobic reactor and aerobic reactor.The results showed that the daily average removal efficiency of SO₂ was over 97%.After 5 days,the conversion efficiency of sulfite reached over 96%and the most of sulfite was reduced to sulfide,simultaneously produced a little H₂S.The daily average removal efficiency of sulfide was over 95%in the aerobic reactor and the daily average production efficiency of sulfur was about 24%.The SO₄^2-in effluent did not increase significantly.