Study On Structure And Properties Of Coalescing Filter Media For Oil/Gas Separation

Oil mist is an aerosol consisting of submicron oil droplets,produced in crankcase ventilation,oil lubricated compressors and various other industrial processes.In order to protect the environment and our health,as well as to avoid problems with downstream equipment,coalescing filter media are usually used to remove this oil mist from the gas stream.The coalescence performance mainly depends on the oil/gas separation efficiency and pressure drop of the filter media.Efficiency is related to whether it can meet the requirements of use.The pressure drop is related to the cost of equipment.High efficiency and low resistance are the goals of coalescing filter media for oil/gas separation.This thesis focuses on the research on the evaluation of oil/gas separation performance,the selection of new oleophilic fibers,and the influence of filter media structure on oil/gas separation performance in the development of high-efficiency and low-resistance oil/gas separation filter media,and the preparation of new oil/gas separation media has great significance for the practical application of subsequent filters.1.According to the ISO12500-1 international standard,the oil/gas separation test bench for filter media is designed.It can measure the pressure difference in real time,the oil/gas separation efficiency is obtained by the counting method,and the test result of the test bench is reliable.The test bench provides the test conditions for the oil/gas separation performance of the filter media,solves the requirement that the existing test bench can not meet the oil/gas separation performance test of the filter media,and makes up for the blank of the domestic filter media oil/gas separation performance test.2.Using a high-speed camera,aerosol generator and self-made fiber placement device to build a coalescence observation micro-amplification system,observe the morphology of oily aerosol on the fiber,understand the oily aerosol capture mechanism,and prove that kapok fiber is better than glass wool in the oleophilic properties.It provides an important basis for the selection of oil/gas separation filter media.3.The oil/gas separation filter media containing kapok fiber was prepared,which solved the problem of sizing difficulty due to the hydrophobicity of kapok fiber.At present,there has been no report on the application of kapok fiber to gas/liquid separation,which further expands the application field of kapok fiber.4.The"jump-and-channel"model was used to analyze the pressure drop curve of the filter media,the oil concentration in gas and the influence of the content of kapok fiber on the oil/gas separation performance of the filter media under the different air permeability levels were investigated.As the oil concentration in gas increases from 302.7 mg/m³ to 2327.6mg/m³,the steady-state pressure drop of the filter media gradually increases,and the steady-state pressure drop time is gradually shortened;the channel pressure drop?P_channelhannel gradually increases,and its formation time gradually increases.The content of kapok fiber in the filter media has a great influence on the steady pressure drop and the formation process,and the measured oil/gas separation efficiency fluctuates between 62.28%and 77.78%.At the two different air permeability levels,the best oil/gas separation performance is the filter media with 60%kapok fiber content.This provides a reference for the development of oil/gas separation media.