| With the rapid development of economy,exhaust gas produced by coal burning contains large amounts of nitrogen oxides,which results in the hazards of NOx heavier and heavier in our air pollution.How to remove NOx efficiently has become the most important task in the field of environmental governance.NH3-SCR technology is the most widely used denitrification technology in the industry.but the problems like high cost of operations, catalyst poisoning caused by its corrosivity and secondary pollution caused by excessive NH3 also limit governance of nitrogen oxides.People tried to use solid reductant instead of NH3 to solve the defects of the traditional SCR technology.As an excellent adsorption and catalytic material,activated carbon is paid extensive attention by researchers,but the continuous oxidation consumption of activated carbon makes the catalyst cost increased and not be able to operate for a long time.It has become the research emphasis of SCR reaction used activated carbon as the carrier and reductant for how to solve the substantial consumption of activated carbon. With the development of microwave technology in the field of chemistry and chemical, it is recognized that the special "heating effect" and catalytic action existed in microwave action. Therefore, this study used activated carbon instead of gas reducing agent, loaded the active component on activated carbon to prepare catalyst and taking advantage of the microwave catalytic to develop a new technology of microwave selective catalytic reduction of nitrogen oxide (MW-SCR),in order to obtain an efficient, and environment-friendly denitrification technology.In this paper, microwave catalytic activated carbon reduction of NO was researched in the new microwave catalytic reactor,and compared with reduction of NO over activated carbon in conventional heating mode.The results show that the conversion rate of microwave catalytic reduction of NO over activated carbon increased from 62.9% to 99.82% when catalyst bed temperature was at 250℃ to 600℃,which was significantly higher than it of reduction of NO by conventional heating activated carbon.These results showed the microwave catalysis. The exhaust temperatures of reduction of NO by conventional heating activated carbon was up to 100℃,while the exhaust temperature of MW-SCR technology remained at room temperature,which reduced heat loss.In this paper, Mn2O3 was loaded on the activated carbon by impregnation method,the catalysts were characterized by XRD and TEM.Used Mn2O3/AC as the microwave catalyst and solid activated carbon as the reducing agent, denitrification efficiency of microwave selective catalytic reduction of NO over Mn2O3/AC was higher than it of microwave catalytic reduction reaction of NO over activated carbon, NO conversion rate reached 95.63% at 370℃ of the catalyst bed temperature,and was close to 100% at 400℃, which could remove nitrogen oxides efficiently.When the catalyst bed was at 400℃ and O2 concentration was increased from 0 to 13.51%,the activated carbon consumption of microwave catalytic reduction of NO over activated carbon was up from 15.89% to 42.3%,while activated carbon was loaded active component Mn2O3,the effect of O2 on NO conversion rate reduced,and the activated carbon consumption remained at 15% to 17%,which showed that oxidation resistance of Mn2O3/AC was better than AC.Microwave selective catalytic reduction of NO technology uses activated carbon as solid reductant instead of gas reducing agent used in the traditional SCR technology,which avoids the secondary pollution caused by the excessive NH3. Microwave catalyst Mn2O3/AC has good oxidation resistance and high efficiency of removal of nitrogen oxides over microwave catalytic,it can also reduce the consumption of reducing agent activated carbon.MW-SCR technology has a wide range of potential applications in the removal of nitrogen oxides. |
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