Studt On Catalytic Oxidation Absorption Of Various Pollutants In The Combustion Flue Gas Of Sinter By Micro-nano Bubbles

Since the 18th National Congress,China has been paying more and more attention to environmental protection issues,and the control of pollutants has become stricter.However,sintering process is one of the most polluting links in the production process of steel works,and the treatment of sintering fume has become the primary task for the major iron and steel enterprises to achieve environmental protection standards.In the past,sintered flue gas was mostly desulfurized by wet desulfurization technology and denitrification by SCR technology,and integrated control technology such as activated coke（carbon）desulfurization and denitrification integrated technology,circulating fluidized bed multi-pollutant co-purification technology,O₃multi-pollutant co-purification technology.Recently,there have been many researches on advanced oxidation processes,especially the integrated oxidation absorption of micro-nano bubbles.However,there are still few studies on the flue gas containing various pollutants generated by the actual sintering material combustion.Therefore,on the basis of the research on the integrated desulfurization,denitrification and mercury removal of micro-nano gas-liquid dispersion system,this study focuses on the effects of micro-nanometer bubble absorption on the purification of actual sintered flue gas,catalytic oxidation on the absorption of composite pollutants from sintered material and sludge,sintered material and PVC combustion,and the effects of various factors on the removal of composite pollutants from flue gas by micro-nanometer gas-liquid dispersion system to obtain the best removal conditions,and preliminarily analyzed the reaction mechanism of micro-nano bubbles.The conclusions are as follows:（1）Individual sintered material and NaNO₂ burned at 850°C for 20 min to obtain the flue gas through the micro-nano gas-liquid dispersion system.In the treatment,the absorption efficiency of NO_X could reach 59.3%and SO₂ was almost completely absorbed.under the condition of pH 5 of the feed water,if the metal ion Mn²⁺is added as a catalyst,the absorption efficiency of NO_X can be greatly enhanced,and the absorption efficiency of NO_X can reach the maximum 71.69%when Mn²⁺’s molar concentration is 2mmol/L.（2）Nano bubble system was used to absorb and treat the actual flue gas produced by the mixed combustion of sintering material and sludge.By comparing the promotion efficiency of NO_X absorption efficiency of NaCl and NaBr,NaCl>NaBr was obtained.When NaCl concentration was 0.5g/L,the absorption efficiency of NO_X in the system was increased by 3.09%higher than that without NaCl.By comparing the enhanced NO_X absorption efficiency of Fe²⁺and Mn²⁺,Mn²⁺>Fe²⁺was obtained.When the concentration of Mn²⁺was 2mmol/L,the absorption efficiency of NO_X in the system was increased by 9.41%compared with that without Mn²⁺.Under the optimal reaction conditions,namely pH=5,NaCl concentration of 0.5g/L,SDS’concentration of 8mg/L,and Mn²⁺concentration of 2mmol/L,the removal rate of NO_X and SO₂ was 83.12%and100%respectively.（3）The actual flue gas produced by the mixed combustion of sintered material and PVC is absorbed by the micro-nano bubble system:under the optimal reaction conditions,namely pH=5,SDS’concentration is 4mg/L,Mn²⁺concentration is 2mmol/L,NaBr concentration is 0.5g/L,the removal rate of NO_X is 85.20%,the removal rate of SO₂ is 99%,and the Cl^-content in the absorption solution is 0.31mg.The absorption effect of HCl increases first and then decreases with the increase of SDS’,Fe²⁺and Mn²⁺concentrations,and increases with the increase of pH and NaBr concentrations.（4）Preliminary studies show that the reason why micro-nano bubbles can promote desulphurization and denitrification is that a large amount of·OH will be produced when the micro-nano bubbles burst.·OH has strong oxidation property and can oxidize water-insoluble NO into water-soluble NO₂ and N₂O₅,thus improving the absorption efficiency.The addition of surfactant SDS’will improve the surface tension and increase the potential of the bubble surface,so that more·OH will be generated when the bubble bursts,further increasing the absorption efficiency.