| The environmental problems are also increasingly prominent with the continuousdevelopment of Chinese heavy industry. Recently, the haze weather frequentlyhappened to many cities, air quality reduction day by day, which affects people’shealth. Air pollution has been a serious problem attracted wide attention. Bagfilter isan effective means of governance in the field of industrial gas pollution, because ofthe special working environment and industrial real production conditions, thematerial presented higher requirements, use of efficient low resistance the filtermaterial to strengthen the filtration of particulate matter in the air is an effective wayto solve the air pollution problem.They were a good choice for composite filter because of Basalt fiber and PPSfiber had excellent high temperature, acid and other properties. But in thepre-prepared Basalt/PPS composite filter acupuncture found that the performance ofthe composite filter media relative to other deep bed filtration materials, also has somegaps, needs to be further improved and enhanced.The research mainly divided into the following three aspects:(1)Basalt fiber, polyphenylene sulfide fiber and basalt fabric were used as themain raw material. The composite web was formed by opening and carding, and thenthe cross lapping, pre-needling and needling process was used to prepare thecomposite filter materials. Three main needling process parameters were studiedwhich involved acupuncture frequency, step size and acupuncture channel. Theuniversal material tester, thickness analyzer, filter material testboard was used tocharacterize and analysis their mechanical, thickness and filter properities,respectively. The acupuncture optimum process parameters was selected through theorthogonal experimental design which used the filter performance as main index. (2)The surface tension meter, rotational viscometer, dynamic light scatteringparticle size analyzer was used to characterize and analysis the surface properties,flow performance, and particle size of PTFE emulsion, respectively. The bestacupuncture Basalt/polyphenylene sulfide composite filter were finishing by PTFEemulsion. The surface properties and filtration performance may increased with thefinishing by PTFE emulsion. This paper focused on the filtration performance ofcomposite materials. The optimum finishing parameters was selected through theorthogonal experimental design which used the filter performance as main index.(3)The stereo microscope, Scanning Electron Microscope(SEM), universalmaterial tester, air permeability tester, Aperture Tester, filter material testboard wasused to characterize and analysis composite their structure, mechanical, airpermeability, mean pore size and distribution, filter properities of composite materialswhich finishing by PTFE emulsions with different concentrations, respectively. It mayprovide some guidance for composite material in actual production application.The results show that:(1)To filter performance index, the optimum acupuncture parameter was150frequency of acupuncture, step size4.5mm, acupuncture once in double sides. Underthe process conditions, the filtration efficiency of the composite filter (10μm particlesize lower) was89.992%, mean pore size was33.1μm.(2)With good surface properties of PTFE emulsion, surface tension of about32,is not good viscosity; viscosity of PTFE increased with increasing concentration ofthe emulsion, with the increase of temperature was firstly decreased and thenincreased; PTFE emulsion particle size distribution mainly concentrated in the150-200nm (low concentration) so, the particle size distribution was more uniform.(3)The optimum process parameters emulsion concentration of10%, dippingtime5min, curing temperature160℃, curing time3min; The mean pore sizedecreased from33.1μm to27.3μm and the filtration efficiency had been significantlyimproved from89.992%to97.229%with the increase of PTFE emulsionconcentrations. (4)The results showed that the gaps between the fibers were relatively reducedand the mean pore size decreased from30.4μm to23.7μm with increasing ofconcentrations of PTFE emulsions. While ensuring certain strength and filtrationresistance, the filtration efficiency had been significantly improved to98.363%. |
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