Research On The Cleaning Performance Of Non-woven Filtration Material

With the rapid development of China’s economy, the environmental problem has become more serious in recent years. Severe haze weather charged many cities in recent years, the bad weather could harm the health and common life, a part of the reason was the excessive emissions,therefore, emissions control needs to be focus on. Bag filter is the efficient dust removal equipment to control air pollution, filter bag is the core of the dust catcher, filters were mostly made by needled felt. The high-efficiency, low-resistance and easy dust cleaning filter material will be chose, they can reduce the operation cost and improve the service life. So study the dust cleaning performance of the filter is very important.The needle-punched non-woven felt made by polyphenylene sulfide(PPS) fibers has excellent high temperature resistance, chemical resistance. It is widely used as high temperature filtration material, but the filter material without post-processing has rough surface, so the post-processing is necessary before come to service.PPS filters having non-treated,singeing,dipping with PTFE emulsion and laminating with PTFE micro-porous membrane respectively were chosen to be the experimental samples and study the cleaning performance of the filter material with post-processing.The research mainly divided into the following three aspects:(1)Study the finish technology of PPS untreated filter, singeing filte, dipping with PTFE emulsion impregnated filter and PTFE micro-porous membrane filter. The fabric thickness gauge,apertometer, universal material testing machine, air permeability tester, scanning electron microscope and other instruments were used to test thickness,aperture changes, mechanical properties, permeability and surface morphology of the different post-processing filters.(2)The filter testing system accord with German VDI/DIN3926 standard( BHA Group QG061)was used to test the filtration and cleaning performance of the four filters. Study change of the residual pressure difference and cleaning cycle in the initial stage, the debugging stage and stable stage.(3)The four filters were made into filter bags, then put them into the imitation of industrialbag filter. In the clean condition, study the filter performance of different post-processing technology. In the dust stage, study the influence of filtration velocity, filtration time and filtration temperature on pressure drop, peek pressure, pressure rising rate and maximum opposite acceleration of filter bag.The results show that:(1)After post-processing technology, the thickness of filters was reduced, reducing range between 35% to 46%. The mean pore diameters of untreated filter, singeing filter, impregnated filter, membrane filter were 12.7μm、7.8μm、8.4μm and 4.4μm. The permeability of the three filters compared with untreated filter were reduced by 49.8%, 44.2% and 72.6%; The change of breaking strength after post-processing were not great, but breaking elongation receded. The surfaces of filters changed greatly, after post-processing, the surfaces became more smooth, the fibres became more tight.(2) In the initial stage, the cleaning cycles of the untreated filter, singeing filte, impregnated filter and membrane filter were 229, 393, 398 and 194 seconds, the residual pressure drops of the four filters were 53, 85, 69, 59 Pa. In the debugging stage, the residual pressure drop kept growing, the pressure drop of membrane filter was minimum. In the stable stage, membrane filter has minimum residual pressure drop, longest cleaning cycle, so it has best performance.(3) In clean condition, filtration velocity of filter and pressure drop had linear relationship,the pressure drop of filters became increasing after post-processing. The peak pressure decreased with the increase of filtration velocity, and the filters after post-processing had higher peak pressure. The pressure drop of filter increased with the augment of filtration time, the increase of membrane filter’s peak pressure was biggest. When the temperature increased, the peak pressure increased, but the pressure peak arrival rate reduced. The maximum opposite acceleration increased with the increase of filtration velocity and reduces with the increase of the augment of filtration time. The influence of the temperature on maximum opposite acceleration was little.