Influence Of Alternate Filtration Of Dusts And Droplets On Pressure Drop Characteristics By Natural Gas Filter

In the process of natural gas exploitation,transportation and purification,due to the influence of geological conditions,exploitation methods and operation conditions,impurities in natural gas are numerous and irregular,which makes it difficult to predict the working state of natural gas filter,and there will be many problems such as filter element congestion,failure and instrument misalignment,which pose a great threat to natural gas pipeline system.In order to better predict the pressure drop trend of filters,this thesis mainly takes the physical properties of filter elements and particles as reference variables,and explores the variation law of pressure drop in alternate filtration of dust and droplets.The results show that:In the process of gas-solid filtration of liquid-containing filters,the pressure drop rises faster than clean filters,and the pressure drop at the end is higher when the amount of dust is the same.Improving the accuracy of filters and reducing the size of dusts will accelerate the pressure drop rising rate of gas-solid filtration of liquid-containing filters,while increasing the viscosity of liquid will make the rate decrease at first and then increase,among which improving the accuracy of filters has the most obvious influence,which can increase the pressure drop rising rate of gas-solid filtration to 54.6 times that of clean filters.Therefore,the liquid-containing filters is easier to intercept dusts.At the same time,it will cause the filters to reach the limit pressure drop in advance and broken,which is not conducive to the long-term safe operation of the filters.The gas-liquid filtration process of solid-containing filters can be divided into flushing stage and filling stage.In flushing stage,the pressure drop decreases exponentially,and the rate depends on the density of dust layer in filters.The pressure drop increases exponentially in the filling stage until the filters reach the gas-liquid saturation state,and the rate depends on the density of the filter cake layer at the end of the flushing stage.Moreover,the gas-liquid saturation time of solid-containing filters is longer than that of the clean filters.And improving the accuracy of filters,increasing the size of dusts,increasing the liquid viscosity and increasing the accumulated amount of dusts will all prolong this time,among which improving the accuracy of filters is the most obvious,and it can be extended to 121.4% of the clean filters.Therefore,the solidcontaining filters have a stronger trapping effect on droplets,which can effectively avoid the secondary entrainment of droplets.In a word,in the three-phase filtration process of alternating dusts and droplets,the accumulation of dusts and droplets in the first stage can enhance the trapping effect of the filters on droplets and dusts,improve the filtration efficiency,and at the same time lead to the filters being blocked more easily,thus shortening the service life of the filters.