Experimental Study On Degradation Of Natural Gas Filter Performance

In the compressed air station of the natural gas long transmission pipeline,the filter element’s filtration efficiency and service life are deteriorated due to the high gas transmission pressure(7MPa ～10MPa),various impurities and complex components in the gas,and the quality of the filtered gas cannot meet the requirements of relevant standards.For this reason,this paper uses the performance evaluation device of natural gas filter elements to test the filtration performance of the filter elements after use in a certain pressure gas station with clean filter elements as a reference,and to clarify the difference in the filtration performance of the filter elements before and after use in the actual condition.At the same time,the filter element is disassembled into the filter material,and the reason for the filter element’s filter performance degradation is explored through the measurement of the filter material’s physical parameters.With A2 fine dust as the experimental medium,a set of horizontal filter element performance evaluation device is used to compare the gas-solid filtration performance of filter elements before and after the actual use.The results show that the particle penetration rate of the filter element with particle diameter of 1μm and above is 30% of that of the clean filter element,but the pressure drop of the former is 1.8 times of the latter.Through the measurement of the filter material parameters,it is found that the above results are caused by the fact that the high gas transmission pressure reduces the thickness of the filter material,the resistance of the gas increases greatly when it passes through,and the change of the thickness causes the average pore diameter to decrease,so that the filter element penetration rate decreases slightly.With DEHS as the experimental medium,a set of vertical filter element performance evaluation device is used to compare the gas-liquid filtration performance of coalescing filter elements before and after use.The results show that the particle penetration rate at0.3μm and above is 17 times higher than that of the clean filter,and the steady-state pressure drop of the filter is 1.3 times higher than that of the latter.Through the measurement of filter material parameters and the comparison experiment of filter material,it is found that the above results are caused by,on the one hand,the increase of the average pore size of the coalescence layer,which leads to the increase of the penetration rate of droplets with small particle size.On the other hand,the reduction of drainage layer thickness and average pore size makes it impossible for the liquid to be discharged from the filter material smoothly,resulting in the increase of pressure drop.At the same time,the fluid trapped inside the filter increases the saturation of the filter material,leading to an increase in the penetration rate.The experimental results reveal the reason of filter performance degradation after the filter element is used in complex working conditions,and provide some reference for the design and performance improvement of the filter element.