| With the development of industrialization, the demand of coal and other fossil fuels is increasing. The flue gas produced by the combustion of fuels is contained large amounts of sulfur dioxide (SO2) and nitric oxides (NOx) which are one of the main air pollutants. The study, which regards the recirculation nutrient liquid of the biological trickling filter as its research object, is on the basis of desulphurization and denitrification from flue gas by biological method. The liquid catalyzed oxidation is combined with the biochemical process of microorganisms by adding small amount metal ions of Fe2+, Mn2+, Zn2+, Al3+. The system of simultaneous removal SO2and NOX from flue gas is established by using the liquid catalyzed oxidation-microbiological method. Some important conditions, such as the temperature, the sprinkling amount, the inlet concentration of SO2and NOx and the gas flow rate, had been optimized by our team in the previous exploratory test. In order to determine the optimal formula of nutrient solution, the experiments try to research the effect of different suitable nutrient solution on the efficiency of simultaneous removal SO2and NOx from flue gas from flue gas by the liquid catalyzed oxidation-microbiological method. The structure succession and characteristics of microbial films for removal SO2and NOX in biological trickling filter system could be analyzed by the molecular biology method. Finally, the study tries to do the mathematical simulation for the liquid catalyzed oxidation-microbiological flue gas purification system by adding the optimal nutrient solution. And the dynamical model of the liquid catalyzed oxidation-microbiological simultaneous removal SO2and NOx system will be analyzed preliminarily. The main results of this study are as follows:(1) To conduct the contrast test between three kinds of suitable nutrient solution, the results showed that the removal efficiency of SO2were still up to100%when added different microbial nutrient solution. The highest removal efficiency of NOx could reach74.76%when the formula of nutrient solution was S (Powdered sulfur), MgSO4·7H2O, K2HPO4·3H2O and KH2PO4. The concentration ratio of K2HPO4·3H2O and KH2PO4will be unified as a factor. The L9(34) table was also selected to conduct the orthogonal test. According to the result of the orthogonal test, it could be analyzed that the influence of the removal efficiency of NOx follows the sequence:S (0.45g/L), MgSO4·7H2O (0.30g/L),K2HPO4·3H2O:KH2PO4(0.75g/L:0.50g/L). In addition, the optimal proportion was verified to be credible through confirmatory test. Finally, the optimal proportion of components respectively was S (0.45g/L), MgSO4·7H2O (0.30g/L), K2HPO4·3H2O (0.75g/L) and KH2PO4(0.50g/L).(2) For the the biological trickling filter which had added the optimal nutrient solution, the domesticated microbes of packed tower would be sampled and compared with the original microbial samples when the purification efficiency of system was stable. The total DNA of the sample was extracted respectively and the16S rRNA gene amplification needed be conduct. The structural characteristic of biofilms within system was analyzed by using the denaturing gradient gel electrophoresis method. The results showed that the dominant bacterial community of liquid catalyzed oxidation-biological trickling filter system was Vibrionimonas magnilacihabitans, Nitrosomonas sp., Pseudomonas brenneri, Brocadia spp. and Haliangiaceae, The quantity of Nitrosomonas sp., Brocadia spp., Pseudomonas brenneri and Haliangiaceae were the largest in the bacterial community. The additive nutrient solution could promote the growth of these four bacterial species.(3) The dynamical model for the mechanism of the liquid catalyzed oxidation-microbiological simultaneous removal SO2and NOx system was validated and analyzed preliminarily. The results showed that the biochemical degradation reaction rate constant of about SO2and NOx, could be calculated on the basis of the biological trickling filter system in the test, respectively were833.3g/(m3·h) and588.2g/(m3·h). At the time, the Surface absorption coefficient of microbial films about SO2and NOx were0.019m3/g and0.018m3/g. The correlation between the experimental and calculated value of inlet concentration of SO2and NOx could respectively reach0.929and0.987in adsorption-microbial films theory system. It was showed that dynamical model had has a good adaptability. |
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