Experimental Study Of Denitration And Sulfur Resistance Over Mn Based Catalyst With Dielectric Barrier Discharge Assisted

Nitrogen oxide is one of the major pollution from coal-fired power plant,which has caused serious problem to both human health as well as industrial growth.Dielectric barrier discharge(DBD)and low-temperature selective catalytic reduction(SCR)have been paid more attention as a NOx removal technique in recent years,though the experiment and mechanism of low-temperature SCR assisted by plasma on NO removal are not well studied yet,with the ambiguous interaction of plasma and catalyst as well as SO2 and H2O resistance properties.The effect of support materials with different mass ratio over Mn catalyst for NO removal was firstly studied in this paper,here we choose multi-walled carbon nanotubes(MWCNTs)and titanium dioxides as support materials.After carrying out a series of experiments and characterizations,the result show that catalyst with higher mass ratio of MWCNTs(MWCNTs:TiO2=4:1)have larger surface area,more active metal oxides(MnO2)and superior reduction potential,therefore a better low-temperature SCR activity(the maximal efficiency of NO removal is 72.4%at ambient temperature).Base on that,MWCNTs were choosen as the main support materials of catalyst,Mn-Ce with different mass ratio were supported on MWCNTs/ZSM-5.From the comparison of activity experiments and characterizations,we found that the optimal Mn/Ce mass ratio of 1:1 with superior SCR activities(84.6%at ambient temperature)at minimum input energy.The interaction of Mn-O-Ce physicochemical structure and valence variation of Mn and Ce cations not only provide oxygen vacancies,but more importantly,directly affect the formation and consumption of Lewis acid sites in whole reaction process.Subsequently,an increased number of Lewis acid sites coordinate NH3 molecules with Mn and Ce atoms,then contribute to ammonia adsorption and rob electrons directly from gaseous NO or nitrate anions as following Eley-Rideal pathway.At last,cerium modification inhibit further speciation of ammonium and manganese sulfates species on the catalyst surface,thereby promoting low temperature catalytic activity and sulfur durability.Through the study of this paper,we established some experimental bases of plasma combined with catalyst for SCR reaction,provided a strategy and theoretical guidance for further study of industrial application and resistance of gas poisoning.