Study On Property Influences Of Filtration Media Against Fiber Shape Changing Under Thermal Shocks

The background for this research is that there are instant high temperature shocks during most industrial wasted gas filtration processes,and the properties of filtration medias changes due to the shape changing of the filtration medias under thermal shocks.The target of this research is to seek the changing rules of filtration efficiency and resistance of the filtration medias under thermal shocks,in order to guide the handing method for the filtration machineries in the thermal shock situations.This research aims to analyze the influences of filtration properties through the angle of filtration medias sharp charging under thermal shocks,in terms of the following fours aspects.(1)The paper analyzed the thermal shock effects made by high temperature dust and gas to the filtration media.The thermal transmittance theory has been employed to analyze the thermal shock impacts caused by three main factors as “dust”,“dust & gas”,and “gas”.This paper analyzed those three thermal shocks effects on the filtration medias respectively.The research conclusion shows: in the filtration system,the most appreciable impact factor among the three thermal shock factors is the “dust” thermal shock.The gas thermal shock impact on the whole filtration media instantly;and the change of the heat gas temperature is the key fact.The effect from heat dust to filter media shows a contacting affection;and it shows that the bigger temperature difference between dust and filter media the longer thermal shock effect time.The paper also conduces the calculation module for the heat dust running time in the filtration system.(2)This paper analyzed the effects on filtration fiber's tenacity caused by the factors of fiber diameter,thermal shock temperature,and thermal shock time through the angel of filtration fiber properties.The research made thermogravimetric analysis(TGA)on three filtration fibers in order to identify the temperature affections on the fiber itself.The research has made the fiber tenacity property tests with thermal shocks with 10 fibers for those 3 kinds fiber.With None-dimensional Method,the data analysis indicated the significant factors under thermal shocks on the filtration fibers.Based on the research of this part,the paper built up the Model of Thermal Shocks to the Fiber Tenacity Property.(3)The research analyzed thermal shocks cause the filtration media tenacity properties in the microscopic view.It analyzed the mechanical property tendency of Polyester filter media with a simulative thermal shocks environment with tensile pressure with three different testing conditions,in terms of tensile pressure,thermal shocks,and thermal shocks with tensile pressure.It employed SEM,XRD,and DMA tools for the above analysis to discover the mechanisms.The research shows that the tenacity of the filter media changing is increasing firstly and then dropping afterwards.The tenacity changing under thermal shock caused the three microscopic factors in terms of the increase of degree of crystallinity(tan?),glass transition temperature(Tg),and storage modulus(E').(4)This paper has analyzed the filtration properties changes of the filtration medias under the thermal shocks.The research employed the numerical simulation method to analyze the fiber diameter changing's effect on the filtration efficiency and resistance of the filtration media;secondly,it has analyzed the filtration efficiency and resistance changes due to the shrink of the filtration media due to the thermal shocks,with the proven of experimental tests.The conclusion as follow: in the same weight filtration media condition,the filtration efficiency and resistance will increase significantly if the thinner fiber is employed.Also,the paper discover the rules of the rate of filtration efficiency increase per unit increased filtration resistance according to the fiber diameter changing.At the meantime,the paper analyzed the effect of dust collection factors in terms of the distance between fibers in vertical direction,parallel direction,and filtration fiber diameter,under the thermal shock in order to shows the appreciable impact factors and the influence rules.It shows that the thinner fiber is better for the stabilization of the filtration efficiency and resistance for the filter media.