High Temperature Filter Material Modification And Catalyst Loading Based On Filter Efficiency Enhancement And Its Performance Study

Industrial production emits a large amount of high-temperature flue gas,and the dust particles(PM)and nitrogen oxides(NO_x)in the flue gas cause serious harm to air quality and human health.The bag-type dust removal technology with needle-punched felt as the core is currently the main dust removal technology in the high-temperature field,but the filtration efficiency of ordinary needle-punched felt for particles with small particle size is very low,and most of the existing needle-punched felt does not have the function of denitration,It is of practical significance to improve the filtration performance of needled felt and to develop filter materials with integrated functions of dust removal and denitrification.*Therefore,in view of the above problems,this paper takes polytetrafluoroethylene(PTFE)/polyphenylene sulfide(PPS)needle-punched felt(hereinafter referred to as NF)as the research object,according to the route of improving filtration performance and preparing denitration functional filter material,carried out The following works:First,in order to improve the filtration efficiency of NF,aramid nanofiber(ANF)dispersions with different mass fractions were introduced into the needle felt by coating to prepare NF/ANF composite needle felt with micro-nano structure.performance research.The results show that compared with the original felt,the thermal stability and mechanical properties of NF/ANF have almost no effect,and the filtration efficiency of particles with different particle sizes is significantly improved,especially the filtration efficiency of particles with a particle size of 1.25μm is increased by 37.9%,the filtration resistance increases only slightly.Through the electron microscope photos of the filtered samples,it is found that the nanofiber membrane plays a major role in the filtration process,and achieves the effect of high efficiency and low resistance.Secondly,in order to explore the effect of NF-supported catalysts under different processes,Mn-Ce-O_xcatalysts were supported by impregnation method using raw felt,impregnated felt and film-coated felt as substrates.Through experiments,it was found that the performance of the original felt supported by the catalyst has little effect;after the impregnated felt supported the catalyst,the bonding fastness is poor,the average pore size and air permeability are increased,and the filtration efficiency is significantly reduced.This is mainly because the presence of the catalyst destroys the PTFE emulsion,making the The PTFE emulsion is deactivated;the filtration resistance increases greatly after the catalyst is loaded on the membrane felt.Therefore,it is considered that the original felt is the best catalyst supporting substrate.In addition,in order to further improve the denitration rate,NF original felt was taken as the research object,and the mass ratio of catalyst to needle felt was selected as 0.8,1.0and 1.2,and a new type of ternary Mn-Ce-Fe-O_xcatalyst supported by redox coprecipitation method was prepared.Denitrification function filter material.The results show that the catalyst is distributed inside and on the surface of the needled felt.XRD results show that the catalyst exists in the form of weak crystals,and the mechanical properties of the composite filter material are reduced after the catalyst is loaded.Through the denitration test,it was found that the denitration rates of 0.8Mn-Ce-Fe-O_x/NF,1.0Mn-Ce-Fe-O_x/NF,and1.2Mn-Ce-Fe-O_x/NF were 76.43%at the temperature of 220℃,respectively,79.52%,82.6%,and the filtration performance of 1.2Mn-Ce-Fe-O_x/NF is weaker than that of1.0Mn-Ce-Fe-O_x/NF,so considering the cost and performance,it is determined that1.0Mn-Ce-Fe-O_x/NF is the optimal ratio of denitration filter material;meanwhile,in order to compare the denitration stability,the functional filter material prepared by redox coprecipitation method was found to have better load fastness and denitration after continuous operation at 220℃for 6 h.It also shows that the denitration effect of the three-way catalyst is better than that of the two-way catalyst.