A coalescing element for testing water separation index and its preparation method

Abstract

The present invention discloses a coalescing element for a water separation index measuring instrument and a preparation method thereof, and belongs to the field of aviation fuel performance testing. The coalescing element of the present invention comprises a shell and a filter medium, the shell comprises an inlet and an outlet, the filter medium comprises a demulsification layer and a coalescing layer, and is located inside the shell; the demulsification layer is prepared from a hydrophilic glass fiber felt with a smaller wire diameter, and the coalescing layer is prepared from a hydrophobic glass fiber felt with a larger wire diameter, and by limiting the mass ratio and thickness of the two, the water separation effect of the coalescing element is improved, and the measurement error of the water separation index is reduced. The preparation method of the present invention achieves the purpose of the present invention by preparing hydrophilic fiber felt and hydrophobic fiber felt, and characterizing and determining qualified hydrophobic fiber felt. In addition, the preparation method also has the advantages of simple and convenient preparation and low manufacturing cost, and the prepared coalescing element also has the advantages of good performance and stable performance.

Description

Technical Field

[0001] The invention belongs to the field of aviation fuel performance testing, in particular to a coalescing element for water separation index testing and a preparation method thereof. Technical Background

[0002] The presence of water in fuel not only affects the performance of the oil, but also corrodes storage equipment, affecting its normal operation and, in severe cases, causing major safety accidents. Therefore, accurately evaluating the difficulty of separating water from fuel is crucial to ensuring the safe operation of equipment.

[0003] The water separation index (WSI) is a numerical value used to evaluate the ease with which jet fuel separates water when passing through coalescing elements. It is expressed on a scale of 0 to 100, with clean, transparent jet fuel receiving a value of 100. To assess the ability of jet fuel to release entrained free or emulsified water when passing through fiberglass coalescing materials, WSI instruments can be used in the field and in the laboratory to detect surfactants added or mixed into the fuel during production and transportation from production to use.

[0004] Oil-water separation filter media are typically composed of a composite material, including a demulsifier layer and a coalescing layer. As a key component of the coalescing element used in portable hydrocarbon fuel water separation index testers, oil-water separation filter media plays a vital role in aviation fuel performance testing. The oil-water emulsion passes through the filter media at the inlet of the coalescing element. The demulsifier layer adsorbs tiny water droplets dispersed in the fuel onto the fiber surface, breaking the emulsion. As the number of water droplets adsorbed on the fiber surface increases, they coalesce and, under the influence of fluid drag, enter the coalescing layer. During this process, the water droplets continue to coalesce and grow, eventually shedding the coalescing layer and being discharged from the outlet along with the fuel.

[0005] The current coalescing elements have the disadvantages of poor repeatability of water separation effect and large deviation in the measurement results of water separation index. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a coalescing element for a water separation index measuring instrument and a preparation method thereof.

[0007] To address the above technical issues, the present invention employs the following technical solution: According to coalescence theory, when an oil-water emulsion passes through a coalescing bed, water droplets typically undergo three processes within the bed: capture-attachment, collision-coalescence, and detachment-sedimentation. To ensure smooth detachment of water droplets from the coalescing bed, the present invention employs a hydrophilic glass fiber mat with a smaller diameter for the demulsification layer and a hydrophobic glass fiber mat with a larger diameter for the coalescing layer. This meets the requirements for water separation index measurement and achieves the present invention's objectives.

[0008] The present invention relates to a coalescing element for a water separation index measuring instrument, comprising a housing and a filter medium, wherein the housing comprises an inlet and an outlet, and the filter medium comprises a demulsification layer and a coalescing layer, and is located inside the housing, wherein the demulsification layer is close to the inlet of an inlet pipe of the housing, and the coalescing layer is close to the outlet; the demulsification layer is made of a hydrophilic fiber felt, and the coalescing layer is made of a hydrophobic fiber felt, wherein the fiber diameter ratio of the hydrophobic fiber felt to the hydrophilic fiber felt is 50-2, and the mass ratio is 5-1; and the housing limits the thickness of the demulsification layer and the coalescing layer to 1-3 mm.

[0009] Preferably, the fiber diameter of the hydrophilic fiber felt is 1 μm to 5 μm; the fiber diameter of the hydrophobic fiber felt is 10 μm to 50 μm.

[0010] Preferably, the hydrophilic fiber felt is made of asbestos or alkali-free glass fiber felt, and the hydrophobic fiber felt is made of alkali-free glass fiber felt.

[0011] Preferably, the shell is composed of coaxial inner and outer tubes and a fixing device, the inner and outer tubes both include an inlet end and an outlet end, and the outlet end of the inner tube is located inside the inlet end of the outer tube; the fixing device is used to fix the relative distance between the inner and outer tubes.

[0012] The preparation method of the coalescing element for the water separation index measuring instrument according to the present invention comprises the following steps:

[0013] 1) Preparation of hydrophilic fiber felt: Weigh an appropriate amount of fiber felt, heat it to remove organic matter on the surface, and make a hydrophilic fiber felt;

[0014] 2) Preparation of hydrophobic fiber felt:

[0015] i. Prepare an appropriate amount of hydrophobic reagent with a mass content of 1% to 10%;

[0016] ii. Weigh a fiber felt with a fiber diameter 50 to 2 times that of the hydrophilic fiber felt, dry it in an environment of not less than 120°C for not less than 2 hours, and then cool it;

[0017] iii. In accordance with the mass ratio of the hydrophobic agent and the fiber felt of 1:10~1:100, the dried and cooled fiber felt is immersed in the prepared hydrophobic agent and placed in a sealed container at an internal temperature of not less than 120 ℃ and heated for not less than 1h to form a hydrophobic fiber felt;

[0018] 3) Characterization of hydrophobic fiber felt: The prepared hydrophobic fiber felt is qualified if the water contact angle is not less than 130°;

[0019] 4) The prepared hydrophilic fiber felt and the qualified hydrophobic fiber felt are processed into a shape matching the inner diameter of the inlet end of the outer tube of the shell, and are prepared into a filter medium at a mass ratio of 5 to 1. The filter medium is placed inside the shell with a thickness of 1 to 3 mm. The hydrophilic fiber felt serves as a demulsification layer close to the inlet, and the hydrophobic fiber felt serves as a coalescing layer close to the outlet.

[0020] Preferably, the hydrophobic agent is prepared from toluene and fluorosilane.

[0021] More preferably, the fluorosilane is a mixture of one or more of heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane, and 4-methyl-tridecafluorodecyltriethoxysilane.

[0022] The present invention relates to a coalescing element for a water separation index measuring instrument. The demulsification layer is prepared using a hydrophilic glass fiber felt with a smaller wire diameter, and the coalescing layer is prepared using a hydrophobic glass fiber felt with a larger wire diameter. By limiting the mass ratio and thickness of the two, the water separation effect of the coalescing element is improved and the measurement error of the water separation index is reduced. The present invention relates to a method for preparing a coalescing element for a water separation index measuring instrument. By preparing hydrophilic fiber felt and hydrophobic fiber felt, and characterizing and determining qualified hydrophobic fiber felt, the prepared coalescing element achieves the purpose of the present invention. In addition, the preparation method has the advantages of simple and convenient preparation and low manufacturing cost. The prepared coalescing element also has the advantages of good performance and stable performance. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the embodiments, but they are not intended to limit the technical solutions of the present invention.

[0024] Example 1

[0025] The utility model discloses a coalescing element for testing water separation index, which consists of a shell and a filter medium.

[0026] The outer shell consists of coaxial inner and outer tubes and a fixing device. The inner tube has an inner diameter of 21mm, an outer diameter of 30mm at the inlet, and an outer diameter of 25mm at the outlet. The outer surface of the outlet is marked with a 0.1mm precision scale. The outer tube has an inner diameter of 25mm and an outer diameter of 30mm at the inlet, and an inner diameter of 1mm and an outer diameter of 5mm at the outlet. Through holes are opened at corresponding positions on the inner and outer tubes. The fixing device is a bolt, which is located in the corresponding through holes of the inner and outer tubes.

[0027] The filter medium consists of a demulsification layer and a coalescing layer. The demulsification layer is a hydrophilic fiber felt made of quartz wool with a diameter of 1μm. The coalescing layer is a hydrophobic fiber felt made of alkali-free glass fiber felt with a diameter of 10μm.

[0028] When assembling the agglomeration element of this embodiment, the agglomeration layer and the demulsification layer are first placed in the inlet end of the outer tube of the outer shell in sequence, and then the outlet end of the inner tube of the outer shell is placed in the inlet end of the outer tube. External force is applied to the inner and outer tubes to squeeze the agglomeration layer and the demulsification layer. With the help of the scale at the outlet end of the inner tube, the thickness of the agglomeration layer and the demulsification layer is squeezed to 1.6 mm, and the thickness is fixed by bolts placed in the corresponding through holes of the inner and outer tubes.

[0029] The coalescing element of this embodiment is prepared by the following steps:

[0030] (1) Weigh 10 g of quartz wool with a fiber diameter of 1 μm to make a fiber felt, place it in a muffle furnace at 350°C for 1 h to remove surface organic matter, and obtain a hydrophilic fiber felt;

[0031] (2) Weigh 0.99 g of toluene and add 0.01 g of heptadecafluorodecyltriethoxysilane using a microinjector to prepare a 1% by weight fluorosilane solution as a hydrophobic reagent;

[0032] (3) Weigh 10 g of alkali-free glass fiber felt with a fiber diameter of 10 μm, place it in an oven at 120 °C for 2 hours, and then cool it naturally;

[0033] (4) The alkali-free glass fiber felt dried in step (3) is immersed in the hydrophobic reagent prepared in step (2), and then placed in a ceramic sealed container with an internal temperature of 120° C. and maintained at this temperature for 1 hour to obtain a hydrophobic fiber felt.

[0034] (5) The prepared hydrophobic fiber felt is characterized by its apparent contact angle with water, and a water contact angle greater than 130° is considered qualified.

[0035] (6) The hydrophilic fiber felt prepared in step (1) and the qualified hydrophobic fiber felt were cut into discs with a diameter of 25 mm, and 0.045 g of the hydrophilic fiber felt and 0.195 g of the hydrophobic fiber felt were weighed respectively to form a filter medium, which was placed in the inlet end of the outer tube of the shell, with the hydrophilic fiber felt as the demulsification layer located on the outside and the hydrophobic fiber felt as the coalescence layer located on the inside. The inner tube was placed, and the filter medium was squeezed into a thickness of 1.6 mm. The thickness was maintained by the fixing device bolts to assemble into a coalescence element.

[0036] The coalescing elements prepared in this example were subjected to performance and repeatability testing using a water separation index tester. The instrument's use and reference solution preparation followed the guidelines set forth in SH / T0616-1995, "Determination of the Water Separation Index of Jet Fuels (Handheld Separator Method)." The test results are as follows: at a reference solution concentration of 0.2 mL / L, the water separation indices for the coalescing elements in this example were 90 and 89, respectively; at a reference solution concentration of 0.4 mL / L, the water separation indices for the coalescing elements in this example were 85 and 83, respectively; at a reference solution concentration of 0.6 mL / L, the water separation indices for the coalescing elements in this example were 78 and 80, respectively; and at a reference solution concentration of 0.8 mL / L, the water separation indices for the coalescing elements in this example were 72 and 75, respectively. The deviation and repeatability of the water separation index measurements met standard requirements, demonstrating superior accuracy and repeatability compared to existing coalescing elements.

[0037] Example 2

[0038] The difference from Example 1 is that:

[0039] The inner diameter of the outer shell is 45mm, the outer diameter of the inlet is 60mm, and the outer diameter of the outlet is 50mm; the inner diameter of the outer tube at the inlet is 50mm, the outer diameter is 60mm, the inner diameter of the outlet is 2mm, and the outer diameter is 6mm.

[0040] The demulsification layer is made of alkali-free glass fiber felt with a diameter of 5μm.

[0041] The coalescing layer is made of 50 μm diameter alkali-free glass fiber mat.

[0042] When preparing coalescing elements:

[0043] (1) Weigh 50 g of alkali-free glass fiber felt with a fiber diameter of 5 μm and place it in a muffle furnace at 350°C for 1 h to remove surface organic matter to obtain a hydrophilic fiber felt;

[0044] (2) Weigh 0.95 g of toluene and add 0.05 g of heptadecafluorodecyltriethoxysilane using a microinjector to prepare a 5% by weight fluorosilane solution as a hydrophobic reagent;

[0045] (3) Weigh 50 g of alkali-free glass fiber felt with a fiber diameter of 50 μm, place it in an oven at 120 °C for 2 hours, and then cool it naturally;

[0046] (4) The alkali-free glass fiber felt dried in step (3) is immersed in the hydrophobic agent prepared in step (2), and then placed in a ceramic sealed container with an internal temperature of 120° C. and maintained at this temperature for 1 hour to obtain a hydrophobic fiber felt.

[0047] (5) The prepared hydrophobic fiber felt is characterized by its apparent contact angle with water, and a water contact angle greater than 130° is considered qualified.

[0048] (6) The hydrophilic fiber felt prepared in step (1) and the qualified hydrophobic fiber felt are cut into discs with a diameter of 50 mm, and 0.1 g of the hydrophilic fiber felt and 0.5 g of the hydrophobic fiber felt are weighed respectively to form a filter medium, which is placed in the inlet end of the outer tube of the shell. The hydrophilic fiber felt is located on the outside as the demulsification layer, and the hydrophobic fiber felt is located on the inside as the coalescence layer. The inner tube is placed, and the filter medium is squeezed into a thickness of 3 mm. The thickness is maintained by the fixing device bolts to assemble into a coalescence element.

[0049] The coalescing elements prepared in this example were subjected to performance and repeatability testing using a water separation index tester. The instrument's use and reference solution preparation followed the guidelines set forth in SH / T0616-1995, "Determination of the Water Separation Index of Jet Fuels (Handheld Separator Method)." The test results are as follows: at a reference solution concentration of 0.2 mL / L, the water separation indices for this example were 92 and 90, respectively; at a reference solution concentration of 0.4 mL / L, the water separation indices for this example were 82 and 81, respectively; at a reference solution concentration of 0.6 mL / L, the water separation indices for this example were 85 and 86, respectively; and at a reference solution concentration of 0.8 mL / L, the water separation indices for this example were 75 and 72, respectively. The deviation and repeatability of the water separation index measurements met standard requirements, demonstrating superior accuracy and repeatability compared to existing coalescing elements.

[0050] Example 3

[0051] The difference from Example 2 is that:

[0052] The inner diameter of the inner tube of the outer shell is 8mm, the outer diameter of the inlet end is 15mm, and the outer diameter of the outlet end is 10mm; the inner diameter of the inlet end of the outer tube is 10mm, the outer diameter is 15mm, the inner diameter of the outlet end is 1mm, and the outer diameter is 5mm.

[0053] The demulsification layer is made of quartz wool with a diameter of 5 μm.

[0054] The coalescing layer is made of 10 μm diameter alkali-free glass fiber mat.

[0055] When preparing coalescing elements:

[0056] (1) Weigh 10 g of quartz wool with a fiber diameter of 5 μm to make a fiber felt, place it in a muffle furnace at 350°C for 1 h to remove surface organic matter, and obtain a hydrophilic fiber felt;

[0057] (2) Weigh 0.95 g of toluene and add 0.05 g of tridecafluorooctyltriethoxysilane using a microinjector to prepare a 5% by weight fluorosilane solution as a hydrophobic reagent;

[0058] (3) Weigh 10 g of 10 μm alkali-free glass fiber felt, place it in a 120°C oven and bake for 2 hours, then cool naturally;

[0059] (4) The alkali-free glass fiber felt dried in step (3) is immersed in the hydrophobic agent prepared in step (2), and then placed in a ceramic sealed container with an internal temperature of 120° C. and maintained at this temperature for 1 hour to obtain a hydrophobic fiber felt.

[0060] (5) The prepared hydrophobic fiber felt is characterized by its apparent contact angle with water, and a water contact angle greater than 130° is considered qualified.

[0061] (6) The hydrophilic fiber felt prepared in step (1) and the qualified hydrophobic fiber felt are cut into discs with a diameter of 25 mm, and 0.01 g of hydrophilic fiber felt and 0.01 g of hydrophobic fiber felt are weighed respectively to form a filter medium, which is placed in the inlet end of the outer tube of the shell, with the hydrophilic fiber felt as the demulsification layer located on the outside and the hydrophobic fiber felt as the coalescence layer located on the inside. The inner tube is placed, and the filter medium is squeezed into a thickness of 1 mm. The thickness is maintained by the fixing device bolts to assemble into a coalescence element.

[0062] The coalescing elements prepared in this example were subjected to performance and repeatability testing using a water separation index tester. The instrument's use and reference solution preparation followed the guidelines set forth in SH / T0616-1995, "Determination of the Water Separation Index of Jet Fuels (Handheld Separator Method)." The test results are as follows: at a reference solution concentration of 0.2 mL / L, the water separation indices for the coalescing elements in this example were 91 and 89, respectively; at a reference solution concentration of 0.4 mL / L, the water separation indices for the coalescing elements in this example were 84 and 85, respectively; at a reference solution concentration of 0.6 mL / L, the water separation indices for the coalescing elements in this example were 72 and 75, respectively; and at a reference solution concentration of 0.8 mL / L, the water separation indices for the coalescing elements in this example were 70 and 71, respectively. The deviation and repeatability of the water separation index measurements met standard requirements, demonstrating superior accuracy and repeatability compared to existing coalescing elements.

[0063] Example 4

[0064] The difference from Example 3 is that:

[0065] The demulsification layer is made of quartz wool with a diameter of 1 μm.

[0066] The coalescing layer is made of 50 μm diameter alkali-free glass fiber mat.

[0067] When preparing coalescing elements:

[0068] (1) Weigh 10 g of quartz wool with a fiber diameter of 1 μm to make a fiber felt, place it in a muffle furnace at 350°C for 1 h to remove surface organic matter, and obtain a hydrophilic fiber felt;

[0069] (2) Weigh 0.9 g of toluene and add 0.1 g of tridecafluorooctyltriethoxysilane using a microinjector to prepare a 10% by weight fluorosilane solution as a hydrophobic reagent;

[0070] (3) Weigh 10 g of 50 μm alkali-free glass fiber felt, place it in a 120°C oven and bake for 2 hours, then cool naturally;

[0071] (4) The alkali-free glass fiber felt dried in step (3) is immersed in the hydrophobic agent prepared in step (2), and then placed in a ceramic sealed container with an internal temperature of 120° C. and maintained at this temperature for 1 hour to obtain a hydrophobic fiber felt.

[0072] (5) The prepared hydrophobic fiber felt is characterized by its apparent contact angle with water, and a water contact angle greater than 130° is considered qualified.

[0073] (6) The hydrophilic fiber felt prepared in step (1) and the qualified hydrophobic fiber felt were cut into discs with a diameter of 25 mm, and 0.015 g of the hydrophilic fiber felt and 0.08 g of the hydrophobic fiber felt were weighed respectively to form a filter medium, which was placed in the inlet end of the outer tube of the shell, with the hydrophilic fiber felt as the demulsification layer located on the outside and the hydrophobic fiber felt as the coalescence layer located on the inside. The inner tube was placed, and the filter medium was squeezed into a thickness of 1.2 mm. The thickness was maintained by the fixing device bolts to assemble into a coalescence element.

[0074] The coalescing elements prepared in this example were subjected to performance and repeatability testing using a water separation index tester. The instrument's use and reference solution preparation followed the guidelines set forth in SH / T0616-1995, "Determination of the Water Separation Index of Jet Fuels (Handheld Separator Method)." The test results are as follows: at a reference solution concentration of 0.2 mL / L, the water separation indices for the coalescing elements in this example were 93 and 90, respectively; at a reference solution concentration of 0.4 mL / L, the water separation indices for the coalescing elements in this example were 82 and 83, respectively; at a reference solution concentration of 0.6 mL / L, the water separation indices for the coalescing elements in this example were 72 and 71, respectively; and at a reference solution concentration of 0.8 mL / L, the water separation indices for the coalescing elements in this example were 68 and 70, respectively. The deviation and repeatability of the water separation index measurements met standard requirements, demonstrating superior accuracy and repeatability compared to existing coalescing elements.

Claims

1. A coalescing element for a water separation index measuring instrument, comprising a housing and a filter medium, the housing including an inlet and an outlet, the filter medium comprising a demulsification layer and a coalescing layer located within the housing, the demulsification layer being adjacent to the inlet of the housing inlet pipe and the coalescing layer being adjacent to the outlet, characterized in that: The demulsification layer is made of hydrophilic fiber felt, and the coalescing layer is made of hydrophobic fiber felt. The fiber diameter ratio of the hydrophobic fiber felt to the hydrophilic fiber felt is (2~50):1, and the mass ratio is (1~5):

1. The hydrophilic fiber felt is made of asbestos or alkali-free glass fiber felt, and the fiber diameter is 1μm~5μm; the hydrophobic fiber felt is made of alkali-free glass fiber felt, and the fiber diameter is 10μm~50μm. The outer shell limits the thickness of the demulsification layer and the coalescing layer to 1~3mm. The outer shell is composed of coaxial inner and outer tubes and a fixing device. Both the inner tube and the outer tube include an inlet end and an outlet end, and the outlet end of the inner tube is located inside the inlet end of the outer tube. The fixing device is used to fix the relative distance between the inner and outer tubes.

2. A method for preparing a coalescing element for a water separation index measuring instrument according to claim 1, characterized in that: Here are the steps: 1) Preparation of hydrophilic fiber felt: Weigh an appropriate amount of fiber felt, heat it to remove organic matter on the surface, and make a hydrophilic fiber felt; 2) Preparation of hydrophobic fiber felt: i. Prepare an appropriate amount of hydrophobic reagent with a mass content of 1% to 10%; ii. Weigh a fiber mat with a fiber diameter 2 to 50 times that of the hydrophilic fiber mat, dry it in an environment of not less than 120°C for not less than 2 hours, and then cool it; iii. The hydrophobic agent and the fiber felt are immersed in the prepared hydrophobic agent in a mass ratio of 1:10 to 1:100 after drying and cooling the fiber felt, and heated in a sealed container at an internal temperature of not less than 120°C for not less than 1h to form a hydrophobic fiber felt; 3) Characterization of hydrophobic fiber felt: The prepared hydrophobic fiber felt is qualified if the water contact angle is not less than 130°; 4) The prepared hydrophilic fiber felt and the qualified hydrophobic fiber felt are processed into a shape that matches the inner diameter of the inlet end of the outer tube of the shell, and are prepared into a filter medium at a mass ratio of (1-5):

1. The filter medium is placed inside the shell with a thickness of 1-3 mm. The hydrophilic fiber felt serves as a demulsification layer close to the inlet, and the hydrophobic fiber felt serves as a coalescing layer close to the outlet.

3. The method for preparing the coalescing element for the water separation index measuring instrument according to claim 2, characterized in that: The hydrophobic agent is prepared from toluene and fluorosilane.

4. The method for preparing the coalescing element for the water separation index measuring instrument according to claim 3, characterized in that: The fluorosilane is a mixture of one or more of heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane, and 4-methyl-tridecafluorodecyltriethoxysilane.