Study On Modified Fly-ash Catalyst By Plasma For Denitration Performance

Catalyst is the core part of the flue gas denitration process.However,the price is too expensive to implement fully in flue gas treatment.That not only because of the high price of raw materials,but also the complex preparation technology and the high energy consumption.Therefore,how to use simple,effective and energy-saving method to prepare a kind of high efficient denitration catalyst is one of the problems of domestic and foreign scholars’ research.The fly ash with low price as the main carrier of the catalyst and add a small amount of bentonite as a binder in the forming process to prepare a fly ash-based denitration catalyst.Therefore,the fly ash was modified in the plasma and loaded metal oxides respectively to prepare a series of different kinds of catalyst,such as modification fly ash catalyst,metal loading catalyst,and modification and metal loading catalyst.Then the catalyst combine with low temperature plasma technology to evaluate the catalyst activity.The different types of fly ash,carrier forming conditions,the modification conditions and loading conditions in the denitration process were studied.The catalysts characterized the element analysis,ICP,Boehm method,FTIR,BET,XRD,SEM and XPS techniques and further determined how the structure and properties affect the catalytic activity of catalyst.The results shown:The carrier of fly ash mixed with bentonite with 2:1 formed had a certain ability of denitration.Fly ash samples employed for this study were obtained by circulating fluidized bed combustion with the smaller C/N and the better performance of denitration compared with other two kinds of fly ash.The fly ash was modified with oxygen atmosphere can increase the quantity of the basic functional groups on the surface and obviously improve the effect of the denitration.The manganese metal and oxide metal were loaded in the catalyst successively by using the isometric impregnation method and then roasting in the low temperature plasma with oxygen.The two metals can have a synergistic effect forming P-type semiconductors which can significantly improve the performance of denitration.MnO2 and CeO2 play a main role of the oxide forms in the denitration processing.The fly ash-based catalyst with the preliminary modification and then loaded metal oxides not only can maintain effective denitration performance,but also obviously improve the sulfur resistance and had a positive effect to extend the service life of catalyst.