Multilayer filter material for aviation fuel coalescing filter element

Abstract

The application discloses a kind of multilayer structure filter material for aviation kerosene coalescing filter element, the multilayer structure filter material for aviation kerosene coalescing filter element, according to the direction of aviation kerosene flow, from inflow surface to outflow surface, including the following material composition: (1) non-woven fabric prefilter layer;(2) precision glass fiber filter layer;(3) electrospinning-glass fiber composite demulsification coalescing layer;(4) wood pulp paper support layer;(5) non-woven fabric secondary coalescing layer.The above multilayer structure filter material, not only can play the interception effect to the particulate pollutants in aviation kerosene, has high pollution capacity, high filtration efficiency and low resistance, can also play the high-efficiency demulsification and coalescing effect to the polluted water in aviation kerosene, so that water droplet coalesces into large water droplet after passing through multilayer structure filter material, to realize automatic sedimentation separation.

Description

Technical Field

[0001] This invention belongs to the field of filtration and separation technology, and specifically relates to a multi-layer structure filter material for aviation kerosene coalescence filter cartridges. Background Technology

[0002] Particulate matter and moisture are the main contaminants in jet fuel. Excessive impurities can clog aircraft fuel filters, causing malfunctions in the aircraft fuel system, while moisture can cause corrosion and microbial growth, increasing electrostatic effects. Therefore, filter separators must be installed in fuel storage and transportation systems. The filter separator contains two sets of filter elements with different functions—a coalescing filter element and a separating filter element. Fuel first flows from the inside out through the coalescing filter element, which serves the dual purpose of filtering particulate contaminants and allowing water droplets to coalesce into larger droplets before gravity sedimentation. The separating filter element has excellent hydrophobic properties; a small number of smaller water droplets, unable to settle in time, flow with the fuel to the separating filter element and are intercepted on the outside, thus further separating moisture.

[0003] The jet kerosene coalescing filter element is a crucial component and a key technological challenge in jet kerosene filtration separators. Domestic research has primarily focused on the structural design methods of these filter elements. Currently, most jet kerosene coalescing separators utilize tubular structures for their internal coalescing filter elements. For example, the jet kerosene coalescing separators designed in Chinese patents CN202123426069.5, CN201821918232.5, and CN202110451949.3 all employ this structural form for their internal coalescing filter elements. This design allows the core filtration material to be fixed inside the central tube through pleating. Its most significant advantage is maximizing the filtration area of ​​the filter media within a limited space, thereby greatly increasing the processing flow rate of the jet kerosene coalescing filter element. However, there are very few reports on research regarding the key filtration materials within the central tube of jet kerosene coalescing separators. Previous domestic studies generally believed that the glass fiber filter paper inside the central tube of the coalescing filter element plays the role of filtering particulate pollutants, while the glass fiber felt on the outer layer of the central tube is the coalescing material. Therefore, the material design did not consider its effect on water droplet coalescence (Hua Guangsheng, Guo Donglei, Li Fangjun. Demulsification layer structure and material analysis of coalescing filter element [J]. Hydraulics and Pneumatics, 2010(11):16-18; Chen Huan, Liang Meng, Su Bingquan. Development history and suggestions of jet fuel filter separator standards [J]. Petrochemical Equipment, 2020,49(4):50-55). However, in reality, the pore structure of the glass fiber felt is too loose, and its ability to coalesce emulsion water droplets with very small particle size is poor. Therefore, the filter material inside the central tube must first play a certain role in demulsifying and coalescing the water in the fuel, so as to play an important role in reducing the free water content after filtration. In other words, the filter material inside the central tube must be able to simultaneously achieve filtration and coalescence separation of particulate pollutants and polluted water.

[0004] Clearly, a single-structure filter material cannot meet the complex functional requirements of aviation kerosene coalescing separators. Therefore, the key to solving the filter material problem lies in the targeted design of the filter material's pore structure and surface characteristics, as well as the effective combination of multiple layers. Based on the path of aviation kerosene through the coalescing separator filter element and the different removal mechanisms of the two different pollutants, this invention creatively designs the core filter material into a multi-layered filter material structure with different functions, ultimately achieving the removal of both pollutants by the coalescing separator filter element. Summary of the Invention

[0005] Because aircraft have extremely high requirements for the cleanliness of aviation kerosene, particulate contaminants and polluted water must be removed by a coalescing separator before it is added to the aircraft. The core filter material of the coalescing filter cartridge is key to achieving efficient removal of contaminants. The main objective of this invention is to provide a multi-layered composite filter material for coalescing separator cartridges. In addition to achieving high filtration efficiency, high dirt-holding capacity, and low resistance for particulate contaminants, it can also effectively demulsify and coalesce polluted water, forming large water droplets that then self-sedimentate and separate, achieving highly efficient water separation.

[0006] To achieve this objective, this invention provides a multi-layered filter material preparation scheme based on the characteristics of the two pollutants in aviation kerosene and the related filtration mechanism. The multi-layered filter material consists of five stacked layers of materials, in the following order: The first layer is a non-woven pre-filtration layer, which mainly plays a preliminary filtering role for particulate pollutants in the fuel, capable of accommodating a large number of particulate pollutants and reducing resistance; the second layer is a precision glass fiber filter layer, which mainly further improves the filtration efficiency for particulate matter, and also has a certain dirt-holding capacity; the third layer is an electrospun-glass fiber composite demulsification and coalescence layer, which can further filter submicron-sized particulate pollutants and also demulsify submicron-sized emulsions in the system; together with the composite glass fiber filter material, it can effectively and initially coalesce emulsions of different sizes; the fourth layer is a wood pulp paper support layer, which provides support and facilitates the processing of multi-layered materials into filter cartridges; the fifth layer is a non-woven fabric coalescence layer, which plays a secondary coalescence role, causing polluted water to further coalesce into larger water droplets, which then settle into the collection tank, achieving sedimentation separation.

[0007] The objective of this invention is achieved through the following technical solutions:

[0008] A multi-layered filter material for aviation kerosene coalescing filter cartridges, wherein the multi-layered filter material for aviation kerosene coalescing filter cartridges is composed of the following materials arranged sequentially from the inlet surface to the outlet surface according to the direction of aviation kerosene flow: a non-woven pre-filter layer; a precision glass fiber filter layer; an electrospun-glass fiber composite demulsification coalescing layer; a wood pulp paper support layer; and a non-woven secondary coalescing layer.

[0009] Preferably, in the above-mentioned multi-layer filter material for aviation kerosene coalescing filter cartridges, the non-woven pre-filtration layer has an average pore size of 4.0-8.0 μm, a thickness of 1.0-2.0 mm, and a basis weight of 30.0-50.0 g / m³. 2 Further preferably, the nonwoven pre-filter layer has an average pore size of 5.0-6.0 μm, a thickness of 1.2-1.6 mm, and a basis weight of 30.0-40.0 g / m³. 2 .

[0010] Preferably, in the above-mentioned multi-layer filter material for aviation kerosene coalescing filter elements, the precision glass fiber filter layer has an average pore size of 1.0-2.0 μm, a thickness of 0.5-0.8 mm, and a basis weight of 65.0-85.0 g / m³. 2 Further preferably, the precision glass fiber filter layer has an average pore size of 1.2-1.6 μm, a thickness of 0.6-0.7 mm, and a basis weight of 70.0-80.0 g / m³. 2 .

[0011] Preferably, in the above-mentioned multi-layer filter material for aviation kerosene coalescing filter cartridges, the average pore size of the glass fiber substrate in the electrospun-glass fiber composite demulsification coalescing layer is 2.0-4.0 μm, the thickness is 0.6-1.0 mm, and the basis weight is 70.0-90.0 g / m³. 2 Further preferably, the average pore size of the glass fiber substrate in the electrospun-glass fiber composite demulsification and coalescing layer is 2.5-3.5 μm, the thickness is 0.8-1.0 mm, and the basis weight is 80.0-90.0 g / m³. 2 .

[0012] Preferably, in the above-mentioned multi-layer filter material for aviation kerosene coalescing filter elements, the electrospinning diameter of the electrospinning layer in the electrospinning-glass fiber composite demulsification coalescing layer is 80.0-180.0 nm. More preferably, the electrospinning diameter of the electrospinning layer in the electrospinning-glass fiber composite demulsification coalescing layer is 120.0-150.0 nm.

[0013] Preferably, in the above-mentioned multi-layer filter material for aviation kerosene coalescing filter elements, the wood pulp paper support layer has an average pore size of 12.0-20.0 μm, a thickness of 0.6-1.0 mm, and a basis weight of 100.0-150.0 g / m³. 2 Further preferably, the wood pulp paper support layer has an average pore size of 15.0-18.0 μm, a thickness of 0.8-1.0 mm, and a basis weight of 120.0-140.0 g / m³. 2 .

[0014] Preferably, in the multi-layered filter material for the above-mentioned aviation kerosene coalescing filter element, the secondary coalescing layer of nonwoven fabric is polyester nonwoven fabric with an average fiber diameter of 20.0-30.0 μm, a thickness of 2.0-3.0 mm, and a basis weight of 30.0-50.0 g / m³. 2 Further preferably, the average pore size of the fibers in the secondary coalescing layer of the nonwoven fabric is 20.0-25.0 μm, the thickness is 2.0-2.5 mm, and the basis weight is 35.0-45.0 g / m³. 2 .

[0015] By stacking the above-mentioned materials in sequence, a multi-layered filter media for aviation kerosene coalescing filter elements can be obtained. If the multi-layered filter media is to be applied to devices, conventional support meshes can be added directly to the multi-layered filter media structure according to the device's standard manufacturing process requirements.

[0016] The design concept of this invention is as follows: based on the direction of jet fuel flow, the design of multi-layer materials achieves the removal of both pollutants by first filtering out particulate contaminants and then efficiently demulsifying and coalescing the polluted water. Firstly, by designing filter media with different pore sizes for particulate contaminants, it can efficiently filter out particulate impurities, possessing a high dirt-holding capacity while maintaining low resistance. Secondly, based on the trend of water droplet coalescence and the requirement for efficient demulsification of emulsified water on the filter media surface, further targeted design of the filter media pore structure and surface characteristics enables the rapid coalescence of tiny water droplets into larger droplets, allowing them to ultimately settle into the collection tank by gravity or be intercepted by the hydrophobic filter element, thereby achieving a highly efficient water droplet coalescence and separation effect.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] To address the two main contaminants in current aviation kerosene materials—particulate matter and moisture—this invention designs a filter material for coalescing filter cartridges, enabling rapid filtration and separation of these contaminants. This meets the application requirements of aircraft in scenarios with higher fuel cleanliness standards.

[0019] First, a combination of a non-woven fabric pre-filter layer and a precision glass fiber filter layer is used to filter particulate contaminants. The non-woven fabric pre-filter layer has a high dirt-holding capacity, which can accommodate a large number of particulate contaminants without forming a significant filter cake structure, thus preventing a significant increase in the filter media's filtration resistance; while the precision glass fiber filter layer provides high filtration efficiency, thereby achieving efficient separation of particulate contaminants.

[0020] Secondly, the electrospinning-glass fiber composite demulsification and coalescence layer can effectively demulsify submicron-sized emulsified water and initially coalesce into larger water droplets, laying the foundation for efficient separation of water droplets.

[0021] Finally, to address the issue of insufficient strength in nonwoven fabric and fiberglass materials, a wood pulp paper support layer is added to improve the structural stability of the filter material. Through the further coalescence effect of the secondary coalescence layer of nonwoven fabric, the polluted water can be effectively and completely formed into large water droplets, which then settle into the collection tank under their own gravity, thus achieving sedimentation separation. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the multi-layer filter material for aviation kerosene coalescing filter cartridges according to the present invention. The markings in the diagram are: 1. Non-woven pre-filter layer, 2. Precision glass fiber filter layer, 3. Electrospun-glass fiber composite demulsification coalescing layer, 4. Wood pulp paper support layer, 5. Non-woven secondary coalescing layer.

[0023] Figure 2 SEM images of each layer of filter media in Example 1 and cross-sectional views of the composite material.

[0024] Figure 3 Illustration of a performance testing device for multi-layer filter media used in aviation kerosene coalescing filter cartridges. Detailed Implementation

[0025] The present invention will be described below with reference to specific embodiments. Those skilled in the art will understand that these embodiments are for illustrative purposes only and do not limit the scope of the invention in any way.

[0026] Please see Figure 1 The present invention provides a technical solution:

[0027] A multi-layered filter material for aviation kerosene coalescing filter cartridges includes a non-woven pre-filter layer 1, a precision glass fiber filter layer 2 below the non-woven pre-filter layer 1, an electrospun-glass fiber composite demulsification coalescing layer 3 below the precision glass fiber filter layer 2, a wood pulp paper support layer 4 below the electrospun-glass fiber composite demulsification coalescing layer 3, and a non-woven secondary coalescing layer 5 below the wood pulp paper support layer 4.

[0028] This invention provides a multi-layered filter material for aviation kerosene coalescing filter cartridges, wherein the materials for each layer are sourced from:

[0029] The nonwoven pre-filter layer 1 is a polyester or nylon nonwoven fabric, which is a commercially available material purchased from Shandong Taipeng Environmental Protection Materials Co., Ltd.

[0030] The precision glass fiber filter layer 2 is made by mixing glass wool and glass fiber and reinforcing it with thermosetting resin. The glass fiber filter material used in the precision glass fiber filter layer is provided by Guangzhou Huachuang Huagong Materials Technology Development Co., Ltd., and the thermosetting resin used is phenolic resin or epoxy resin commonly used in the market.

[0031] The electrospun-glass fiber composite demulsification and coalescing layer 3 is obtained by electrospinning glass fiber paper as the substrate. Electrospinning is performed by dissolving meta-aramid polymer (purchased from Teijin Aramid Trading (Shanghai) Co., Ltd.) in an N,N-dimethylacrylamide solution containing 1% lithium chloride, followed by electrospinning (using Shenzhen Tongli Micro-Nano Technology Co., Ltd., TL-20M-500). The electrospinning conditions are: spinning solution concentration 7-10%, electrostatic voltage 10-25KV, injection speed 0.3-0.5ml / h, and spinning distance 10-25cm. The glass fiber substrate (purchased from Guangzhou Huachuang Huagong Materials Technology Development Co., Ltd.) is prepared by papermaking of glass wool and chopped glass fiber, and reinforced with a reinforcing resin that has demulsification and coalescing functions.

[0032] The wood pulp paper support layer 4 is made from common plant fibers and reinforced with thermosetting resin. The precision glass fiber filter layer is provided by Guangzhou Huachuang Huagong Materials Technology Development Co., Ltd., and the thermosetting resin used is commercially available phenolic resin or epoxy resin.

[0033] The nonwoven fabric secondary coalescing layer 5 is made of polyester nonwoven fabric material, and the nonwoven fabric secondary coalescing layer is a commercially available material.

[0034] Figure 1 The invention also demonstrates the removal process of particulate pollutants and polluted water by the multi-layer filter material, which achieves the removal of both pollutants by intercepting particulate pollutants and agglomerating water droplets.

[0035] Example 1: A multi-layered filter media for aviation kerosene coalescing filter cartridges, composed of the following materials:

[0036] (1) Nonwoven pre-filter layer: Polyester nonwoven fabric is used, with an average pore size of 5.5μm, a thickness of 1.6mm, and a basis weight of 40.0g / m³. 2 .

[0037] (2) Precision glass fiber filter layer: The glass fiber filter layer used has an average pore size of 1.6μm, a thickness of 0.65mm, and a basis weight of 75.0g / m³. 2 .

[0038] (3) Preparation of electrospun-glass fiber composite demulsification and coalescence layer: The glass fiber substrate used has an average pore size of 3.0 μm, a thickness of 0.70 mm, and a basis weight of 85.0 g / m³. 2The demulsifying and coalescing reinforcing resin for glass fiber filter media was prepared according to Example 1 of invention patent CN110330586B. The electrospun layer was prepared by dissolving a meta-aramid polymer in a solution containing 1% lithium chloride N,N-dimethylacrylamide to obtain an electrospun polymer solution. Electrospun fibers were then applied to the surface of the glass fiber substrate under the following conditions: meta-aramid polymer concentration in the spinning solution was 8%, electrostatic voltage was 15KV, injection speed was 0.3ml / h, spinning distance was 12cm, and the average diameter of the resulting spun fibers was 135nm. This yielded the electrospun-glass fiber composite demulsifying and coalescing layer.

[0039] (4) Wood pulp paper support layer: The wood pulp paper used is filter paper reinforced with thermosetting phenolic resin, with an average pore size of 15.0 μm, a thickness of 0.87 mm, and a basis weight of 120.0 g / m³. 2 .

[0040] (5) Secondary nonwoven coalescing layer: Made of polyester nonwoven fabric with an average pore size of 24.0 μm, a thickness of 2.5 mm, and a basis weight of 42.0 g / m³. 2 .

[0041] like Figure 2 As shown in the figure, (a) to (e) are SEM images of the nonwoven pre-filter layer, precision glass fiber filter layer, electrospun-glass fiber composite demulsification and coalescing layer, wood pulp paper support layer, and nonwoven secondary coalescing layer of Example 1, respectively, showing the pore size of the filter material fibers in each layer; (f) is a cross-sectional view of the material after the above layers are stacked sequentially, with a flat cross-section and good contact between the layers without obvious defects. The layers are directly stacked to form an integrated structure, thus obtaining the multi-layer structure filter material for the aviation kerosene coalescing filter element.

[0042] Example 2: A multi-layered filter media for aviation kerosene coalescing filter cartridges, composed of the following materials:

[0043] (1) Non-woven pre-filter layer: Nylon non-woven fabric is used, with an average pore size of 5.0 μm, a thickness of 1.5 mm, and a basis weight of 40.0 g / m³. 2 .

[0044] (2) Precision glass fiber filter layer: The glass fiber filter layer used has an average pore size of 1.6μm, a thickness of 0.67mm, and a basis weight of 71.0g / m³. 2 .

[0045] (3) Preparation of electrospun-glass fiber composite demulsification and coalescence layer: The glass fiber substrate used has an average pore size of 3.3 μm, a thickness of 0.74 mm, and a basis weight of 83.0 g / m³. 2The demulsifying and coalescing reinforcing resin for glass fiber filter media was prepared according to Example 1 of invention patent CN110330586B. The electrospun layer was prepared by dissolving a meta-aramid polymer in an N,N-dimethylacrylamide solution containing 1% lithium chloride to obtain an electrospun polymer solution. Electrospun fibers were then applied to the surface of the glass fiber substrate under the following conditions: a meta-aramid polymer mass concentration of 8%, a static voltage of 15 kV, an injection speed of 0.3 ml / h, a spinning distance of 12 cm, and an average fiber diameter of 139 nm. This yielded the electrospun-glass fiber composite demulsifying and coalescing layer.

[0046] (4) Wood pulp paper support layer: The wood pulp paper used is filter paper reinforced with thermosetting phenolic resin, with an average pore size of 17.6 μm, a thickness of 0.86 mm, and a basis weight of 134.0 g / m³. 2 .

[0047] (5) Secondary nonwoven coalescing layer: Made of polyester nonwoven fabric with an average pore size of 25.0 μm, a thickness of 2.6 mm, and a basis weight of 44.0 g / m³. 2 .

[0048] By setting the above-mentioned materials into a structure of sequential stacking, and forming an integrated structure by directly stacking the layers, the multi-layer structure filter material for aviation kerosene coalescing filter element can be obtained.

[0049] Example 3: A multi-layered filter material for aviation kerosene coalescing filter cartridges, prepared according to the following method:

[0050] (1) Non-woven pre-filter layer: Nylon non-woven fabric is used, with an average pore size of 6.0 μm, a thickness of 1.8 mm, and a basis weight of 44.3 g / m³. 2 .

[0051] (2) Precision glass fiber filter layer: The glass fiber filter layer used has an average pore size of 1.3μm, a thickness of 0.58mm, and a basis weight of 70.3g / m³. 2 .

[0052] (3) Preparation of electrospun-glass fiber composite demulsification and coalescence layer: The glass fiber substrate used has an average pore size of 3.8 μm, a thickness of 0.87 mm, and a basis weight of 86.3 g / m³. 2The reinforcing resin with demulsification and coalescence function used for reinforcing glass fiber filter media was prepared according to Example 2 of invention patent CN110330586B. The electrospun layer was prepared by dissolving a meta-aramid polymer in an N,N-dimethylacrylamide solution containing 1% lithium chloride to obtain an electrospun polymer solution. Electrospun fibers were then applied to the surface of the glass fiber substrate under the following conditions: a meta-aramid polymer mass concentration of 10%, a static voltage of 15 kV, an injection speed of 0.4 ml / h, a spinning distance of 12 cm, and an average diameter of 149 nm for the resulting spun fibers. This yielded the electrospun-glass fiber composite demulsification and coalescence layer.

[0053] (4) Wood pulp paper support layer: The wood pulp paper used is filter paper reinforced with thermosetting phenolic resin, with an average pore size of 17.8 μm, a thickness of 0.89 mm, and a basis weight of 138.0 g / m³. 2 .

[0054] (5) Non-woven secondary coalescing layer: Polyester non-woven fabric material with an average pore size of 24.6μm, a thickness of 2.4mm, and a basis weight of 45.0g.

[0055] By setting the above-mentioned materials into a structure of sequential stacking, and forming an integrated structure by directly stacking the layers, the multi-layer structure filter material for aviation kerosene coalescing filter element can be obtained.

[0056] Example 4: A multi-layered filter media for aviation kerosene coalescing filter cartridges, prepared according to the following method:

[0057] (1) Non-woven pre-filter layer: Nylon non-woven fabric is used, with an average pore size of 4.3μm, a thickness of 1.2mm, and a basis weight of 36.4g / m³. 2 .

[0058] (2) Precision glass fiber filter layer: The glass fiber filter layer used has an average pore size of 1.8μm, a thickness of 0.78mm, and a basis weight of 79.4g / m³. 2 .

[0059] (3) Preparation of electrospun-glass fiber composite demulsification and coalescence layer: The glass fiber substrate used has an average pore size of 3.2 μm, a thickness of 0.77 mm, and a basis weight of 83.0 g / m³. 2The demulsifying and coalescing reinforcing resin for glass fiber filter media was prepared according to Example 2 of invention patent CN110330586B. The electrospun layer was prepared by dissolving a meta-aramid polymer in an N,N-dimethylacrylamide solution containing 1% lithium chloride to obtain an electrospun polymer solution. Electrospun fibers were then applied to the surface of the glass fiber substrate under the following conditions: a meta-aramid polymer mass concentration of 10%, a static voltage of 20 kV, an injection speed of 0.35 ml / h, a spinning distance of 14 cm, and an average fiber diameter of 149 nm. This yielded an electrospun-glass fiber composite demulsifying and coalescing layer.

[0060] (4) Wood pulp paper support layer: The wood pulp paper used is filter paper reinforced with thermosetting phenolic resin, with an average pore size of 14.5 μm, a thickness of 0.79 mm, and a basis weight of 128.0 g / m³. 2 .

[0061] (5) Secondary nonwoven coalescing layer: Made of polyester nonwoven fabric with an average pore size of 28.0 μm, a thickness of 2.9 mm, and a basis weight of 41.0 g / m³. 2 .

[0062] By setting the above-mentioned materials into a structure of sequential stacking, and forming an integrated structure by directly stacking the layers, the multi-layer structure filter material for aviation kerosene coalescing filter element can be obtained.

[0063] Comparative Example 1: Comparative Example 1 is basically the same as Example 1, except that it lacks the first layer of nonwoven pre-filter material compared to Example 1.

[0064] Comparative Example 2: Comparative Example 2 is basically the same as Example 2, except that it lacks a precision glass fiber filter layer material compared to Example 2.

[0065] Comparative Example 3: Comparative Example 3 is basically the same as Example 3, except that it lacks the electrospinning layer material and is only a single glass fiber demulsification and agglomeration layer compared to Example 3.

[0066] Comparative Example 4: Comparative Example 4 is basically the same as Example 3, except that it lacks a nonwoven secondary coalescing layer compared to Example 3.

[0067] Comparative Example 5: Comparative Example 5 is basically the same as Comparative Example 2, except that the reinforcing resin used in the electrospinning-glass fiber composite demulsification and coalescence layer of Comparative Example 2 is a common thermosetting resin, rather than the resin with excellent demulsification and coalescence function prepared according to Example 1 of Patent CN110330586B.

[0068] Comparative Example 6: The composition of the multi-layer filter media is as follows:

[0069] (1) Non-woven pre-filter layer: Nylon non-woven fabric is used, with an average pore size of 7.3 μm, a thickness of 2.2 mm, and a basis weight of 56.4 g / m³. 2 .

[0070] (2) Precision glass fiber filter layer: The glass fiber filter layer used has an average pore size of 0.9 μm, a thickness of 0.58 mm, and a basis weight of 69.4 g / m³. 2 .

[0071] The remaining electrospun-glass fiber composite demulsification and coalescence layer, wood pulp paper support layer, and nonwoven fabric secondary coalescence layer are the same as in Example 1.

[0072] Performance testing

[0073] The cleanliness requirements for filtered aviation kerosene are: free water content less than 15 mg / L and solid impurity content less than 0.26 mg / L. Furthermore, the pressure must not exceed 315 kPa during the particulate matter and free water tests. Performance tests were conducted on the multi-layered filter media used in the aviation kerosene coalescing filter elements of Examples 1-4 and the filter media of Comparative Examples 1-6. A laboratory testing apparatus was constructed according to the test methods specified in GB / T 21358-2008. The oil volume and the content of added particulate contaminants and polluted water were calculated based on the area of ​​the test filter media. Figure 3 The jet fuel coalescing filter element shown is used for performance testing and evaluation using a multi-layer structure. The specific test process is as follows: (1) The purified jet fuel is passed into the filter media loading fixture and the air inside the fixture is discharged. The jet fuel containing particles is evenly dispersed, and the oil is regulated to flow into the fixture at a surface flow rate of 16 cm / min using a flow meter. A particle filtration experiment is conducted. Then, referring to the standard test method of ASTM D2276-22 for determining particulate impurities in aviation fuel using linear sampling, the downstream oil after particle filtration is sampled, and the change in filter paper weight is compared to obtain the particle content of the filtered fuel. The particulate pollutant filtration performance test is completed. The jet fuel with a water content of 30,000 ppm (with additives added as required) is emulsified using a high-speed disperser to obtain an oil-water emulsion. Then, the flow rate is adjusted to 16 cm / min. -1 The emulsion was pumped into a fixture containing the sample after particulate filtration testing at a surface velocity. The total water content downstream was measured using a Karl Fischer moisture analyzer (C20 model, METTLER TOLEDO, Switzerland). Measurements were taken every 15 minutes, and the average value was taken as the total water content downstream. Subtracting the dissolved water in the oil, the free water content of the filtered fuel was obtained.

[0074] Examples 1-4 and Comparative Examples 1-6 were tested according to the above method, and the test results are shown in Table 1.

[0075] Table 1 Performance test results of each embodiment and comparative example

[0076]

[0077] As can be seen from the test results in Table 1, after the multi-layer filter media used in Examples 1-4 passed the full-cycle test for particulate pollutants and polluted water, the content of midstream particulate matter in the filtered fuel was far below 0.26 mg / L, and the content of downstream free water was below 15 mg / L. This indicates that the multi-layer filter media can achieve efficient filtration and separation of particulate pollutants and effectively demulsify and aggregate polluted water, causing it to form large water droplets and achieve self-sedimentation and separation, so that the coalescing separation filter element meets the application requirements.

[0078] In Comparative Example 1, due to the lack of nonwoven pre-filter material, only the precision filter layer plays a role in intercepting and filtering particulate pollutants. As a result, a large number of particulate pollutants form a filter cake structure on the surface of the filter layer, which leads to a sharp increase in the system resistance. In addition, it also affects the function of the coalescing layer material, which in turn leads to a significant increase in the water content of the filtered fuel.

[0079] In Comparative Example 2, due to the lack of precision glass fiber filter layer material, the non-woven pre-filter layer alone could not achieve a high filtration efficiency. As a result, some particulate pollutants were intercepted by the electrospun-glass fiber demulsification and coalescence layer, which led to a decrease in the demulsification performance of the electrospun-glass fiber demulsification and coalescence layer. Furthermore, the clogging of the oil filter by high particulate pollutants caused a sharp increase in system resistance, resulting in a significant decrease in overall performance.

[0080] In Comparative Example 3, due to the lack of an electrospinning layer, only the glass fiber demulsifier layer effectively demulsified the emulsified water. Because the additives in the aviation fuel system lead to the formation of very small-sized emulsified water, the isolated glass fiber demulsifier layer was unable to effectively demulsify and aggregate these very small-sized emulsified water, resulting in the filtered free water content failing to meet the required standards.

[0081] Comparative Example 4, lacking the nonwoven secondary coalescing layer material, could not completely demulsify and coalesce the small-sized emulsion water into emulsion water that could spontaneously settle by relying solely on the electrospun-glass fiber demulsifying layer material, thus resulting in a significant increase in the content of free water after filtration.

[0082] Although Comparative Example 5 meets the requirements of a multi-layered structural material, it uses ordinary thermosetting resin as the glass fiber material instead of a reinforcing resin with excellent coalescence breaking function. Therefore, it fails to perform the original design function of the electrospinning-glass fiber coalescing layer, resulting in poor performance of the free water content index after filtration and failing to achieve good results.

[0083] In Comparative Example 6, the pore structure of the pre-filter layer and the precision glass fiber filter layer materials, which are mainly used for filtering particulate pollutants, exceeded the scope defined by this invention. As a result, the filter layer materials failed to perform well in filtering particulate pollutants, causing blockage of the electrospun glass fiber coalescing layer. This led to a significant increase in resistance, and the electrospun glass fiber coalescing layer failed to perform its original design function. Therefore, the resistance and the free water content after filtration were both poor, and the desired effect was not achieved.

Claims

1. A multi-layered filter material for aviation kerosene coalescing filter cartridges, characterized in that, The aviation kerosene coalescing filter element uses a multi-layered filter material, which, according to the direction of aviation kerosene flow, consists of the following materials arranged sequentially from the inlet surface to the outlet surface: a non-woven pre-filter layer; a precision glass fiber filter layer; an electrospun-glass fiber composite demulsification and coalescing layer; and a wood pulp paper support layer. Non-woven secondary coalescing layer; The nonwoven pre-filter layer has an average pore size of 4.0-8.0 μm, a thickness of 1.0-2.0 mm, and a basis weight of 30.0-50.0 g / m³. 2 ; The precision glass fiber filter layer has an average pore size of 1.0-2.0 μm, a thickness of 0.5-0.8 mm, and a basis weight of 65.0-85.0 g / m³. 2 ; The electrospun-glass fiber composite demulsification and coalescing layer is obtained by electrospinning a glass fiber substrate. The glass fiber substrate is reinforced with a reinforcing resin that has demulsification and coalescing functions. The average pore size of the glass fiber substrate in the electrospun-glass fiber composite demulsification and coalescing layer is 2.0-4.0 μm, the thickness is 0.6-1.0 mm, and the basis weight is 70.0-90.0 g / m³. 2 ; The average pore size of the wood pulp paper support layer is 12.0-20.0 μm, the thickness is 0.6-1.0 mm, and the basis weight is 100.0-150.0 g / m³. 2 ; The average pore size of the secondary coalescing layer of the nonwoven fabric is 20.0-30.0 μm, the thickness is 2.0-3.0 mm, and the basis weight is 30.0-50.0 g / m³. 2 .

2. The multi-layer structure filter material for aviation kerosene coalescing filter elements according to claim 1, characterized in that, The nonwoven pre-filter layer is a polyester or nylon nonwoven fabric.

3. The multi-layer structure filter material for aviation kerosene coalescing filter elements according to claim 1, characterized in that, The precision glass fiber filter layer is made by mixing glass wool and glass fiber and reinforced with thermosetting resin.

4. The multi-layered filter medium for marine fuel coalescer cartridges of claim 1, wherein, The electrospun-glass fiber composite demulsification and polymerization layer is obtained by electrospinning a glass fiber substrate. The electrospinning is carried out by dissolving meta-aramid polymer in an N,N-dimethylamide solution containing 1% lithium chloride, and then electrospinning. The electrospinning conditions are as follows: spinning solution concentration of 7-10%, static voltage of 10-25 KV, injection speed of 0.3-0.5 ml / h, and spinning distance of 10-25 cm.

5. The multi-layered filter medium for marine fuel coalescer cartridges of claim 1 wherein, The fiberglass substrate is prepared by mixing and forming glass wool and chopped glass fibers.

6. The multi-layered filter medium for marine fuel coalescer cartridges of claim 1, wherein, The electrospinning diameter of the electrospinning layer in the electrospinning-glass fiber composite demulsification and coalescence layer is 80.0-180.0 nm.

7. The multi-layered filter medium for marine fuel coalescer cartridges of claim 1 wherein, The wood pulp paper support layer is made from plant fibers and reinforced with thermosetting resin.

8. The multi-layer structure filter material for aviation kerosene coalescing filter element according to claim 1, characterized in that, The secondary coalescing layer of the nonwoven fabric is a polyester nonwoven fabric.

9. The multi-layered filter medium for marine fuel coalescer cartridges of claim 1, wherein, The materials are stacked in sequence, and the layers are directly stacked to form an integrated structure.

10. The application of the multi-layer structure filter material for aviation kerosene coalescence filter element as described in claim 1 in filtering contaminants in aviation kerosene.

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