| Currently,the flue gas emission of heavy industry such as metallurgy,steel,power generation,carbon black,cement,garbage incineration is the main cause of environmental pollution in our country.With the progress of science and technology and the enhancement of people's environmental protection consciousness,the environmental problem has become a problem to be solved in our country,the demand of filter materials also appears more urgent.Bag filter is an effective device in heavy industrial field to control air pollution,but due to the special working environment for industry and the actual production conditions,higher requirements have been put forward for the performance of the filter materials which are the core parts of the bag filter,so developing high-performance with low-cost filter materials has significant importance to our country's environmental protection causes.Now there exist three kinds of filter materials: woven fabric,needle fabric and BFI-TEX,Needle cloth has the biggest dosage used for air and gas filter materials.That's because compared with woven fabric,most of this kind of materials are three-dimensional structure with small pore,large porosity and high filtration efficiency;So they are widely used.Although BFI-TEX can hold back small dust,yet the running resistance is very big,and the demand for facility is very strict,it's being monopolized by abroad.So,the development of filter materials with high precision,reasonable price is the urgent requirement of the current dust removal market.Polyimide fiber(P84)as an ideal filter material,its cross section is 3 leaf disc shape,it has a larger specific surface area,high filtration efficiency,good thermal performance and high temperature resistant performance,but the price is expensive;Superfine glass fiber is the refinement of common glass fiber,not only has the common glass fiber's all excellent properties such as high temperature resistant,resistant to acid and alkali corrosion,high tensile fracture strength,but also has larger surface area,high gas adsorption rate,high filtration precision and high cost performance.The main research content are using superfine glass fiber and P84 fiber to needle in glass fiber cloth scrim to prepare composite needle-punched filter material,then testing and characterization the various properties of the filter materials,discussing the effect of the mixing parameters on the performance of the filter materials and optimizing the cost performance;Comparing with available P84/ordinary glass fiber composite needle-punched filter materials,through calculating quality factor,deeply studying the influence of the fibers' fineness on the filtering performance of the composite needle-punched filter materials;Researching the influence of the dipping treatment with PTFE emulsion on the performance of composite needle-punched filter materials: through the orthogonal experiment design to study PTFE emulsion finishing process,through the range analysis to choose the best process parameters;Through the general acid and alkali to etch the composite needle-punched filter materials which have been modified for a certain time,to study its corrosion resistance performance for acid and alkali.It turned out that: the composite needle-punched filter materials showed an obvious echelon structure,what's more,it had achieved the traditional deep filtering mechanism to surface filtering mechanism,effectively solved the contradiction between the filtration efficiency and the filtration resistance.The best mixing parameter is 60/40;The PTFE emulsion finishing process improved the filtration efficiency significantly,at the same time,enhanced the efficiency of pulse ash removal and the cost performance;The composite needle-punched filter materials with good resistance to acid and alkali corrosion,was suitable for the actual working environment. |
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