CN-118594290-B - Flexible hollow fiber composite membrane for oil-gas separation and preparation method thereof

CN118594290BCN 118594290 BCN118594290 BCN 118594290BCN-118594290-B

Abstract

The invention discloses a flexible hollow fiber composite membrane for oil-gas separation and a preparation method thereof, wherein the composite membrane relates to 2 layers, the inside of the composite membrane is a flexible matrix in a hollow fiber form, and the outside of the composite membrane is a functional layer for oil-gas separation, the preparation method comprises the steps of soaking and cleaning matrix materials such as polyamide imide, polyvinylidene fluoride, zirconia and the like in organic solvents such as isopropanol, normal hexane, absolute ethyl alcohol and the like, drying the materials in a blast drying oven after cleaning, then dissolving the materials in fluorinated solution according to a certain mass ratio by using amorphous fluorine-containing polymer Teflon AF2400, heating and uniformly mixing the materials by magnetic force to obtain a coating modified liquid, and preparing the flexible oil-gas separation composite membrane with the thickness of 0.2-2 mu m by a liquid phase dipping and pulling method. The hollow fiber flexible composite membrane prepared by the invention has high oil-gas separation efficiency, short oil-gas balance time and excellent stability, and can separate fault characteristic gas from insulating oil in oil-filled power equipment such as transformers.

Inventors

CHEN CHUAN
ZHANG WEI
Shen Leyu
Meng Yanzong
ZHU XIURAN
MA LIANGZHI
JU DENGFENG
GUO JINGHONG

Assignees

国网智能电网研究院有限公司

Dates

Publication Date: 20260512
Application Date: 20240521

Claims (10)

1. A preparation method of a flexible hollow fiber composite membrane for oil-gas separation is characterized by comprising the following steps: The method comprises the following steps: Step 1, preprocessing a matrix, namely soaking and cleaning the matrix material in an organic solvent according to a set proportion, and drying to obtain the matrix material with a clean surface; The set proportion is that the mass proportion of the matrix material and the organic solvent is (1-2) 5 (2-5) 15; step 2, preparing coating modification liquid, namely selecting amorphous fluorine-containing polymer Teflon AF2400, dissolving the amorphous fluorine-containing polymer Teflon AF2400 in fluorinated liquid, heating by magnetic force, stirring and mixing uniformly to obtain the coating modification liquid; Step 3, transferring the coating modified liquid obtained in the step 2 into a container, putting the substrate material obtained in the step 1 into the container filled with the coating modified liquid, vacuumizing the container to reach the negative pressure of a set range, taking out the composite film from the coating modified liquid by utilizing the dipping and pulling method, and vertically hanging the composite film in a blast drying box for drying treatment to obtain the oil-gas separation composite film; The setting range is that the vacuum negative pressure is set to be minus 0.2 to minus 0.8 Bar.
2. The method for preparing the flexible hollow fiber composite membrane for oil-gas separation according to claim 1, wherein the method comprises the following steps: In the step 1, the matrix material is any one of polyamide imide or polyvinylidene fluoride, the pore diameter range is 50-200 nm, and the organic solvent is any one of isopropanol, n-hexane and absolute ethyl alcohol.
3. The method for preparing the flexible hollow fiber composite membrane for oil-gas separation according to claim 1, wherein the method comprises the following steps: in the step 1, the cleaning time is 1-4 h, the drying treatment temperature is 40-60 ℃ and the time is 2-3 h.
4. The method for preparing the flexible hollow fiber composite membrane for oil-gas separation according to claim 1, wherein the method comprises the following steps: In the step 2, the concentration of the Teflon AF2400 in the prepared coating modified liquid is 0.3-1.0 wt%, the fluorinated liquid is at least one of FC-40 and FC-770, and the mass ratio of the Teflon AF2400 to the fluorinated liquid is 1 (2.5-3.5).
5. The method for preparing the flexible hollow fiber composite membrane for oil-gas separation according to claim 1, wherein the method comprises the following steps: in the step 2, the magnetic heating temperature is 60-80 ℃, the magnetic stirring rotating speed is 300-800 r/min, and the dissolution time is 6-12 h.
6. The method for preparing the flexible hollow fiber composite membrane for oil-gas separation according to claim 1, wherein the method comprises the following steps: the step 3 specifically comprises the following steps: step 3.1, transferring the coating modifying liquid into a glass container, sealing one end of a matrix material, and vertically placing the matrix material into the glass container filled with the coating modifying liquid; step 3.2, vacuumizing the glass container to reach the negative pressure of a set range, and enabling the coating modification liquid to enter the surface layer of the film hole of the matrix material to realize matrix coating modification; and 3.3, taking out the composite membrane from the coating modification solution by utilizing a dipping and pulling method after coating, and vertically hanging the composite membrane in a blast drying box for drying treatment to obtain the oil-gas separation composite membrane.
7. The method for preparing the flexible hollow fiber composite membrane for oil-gas separation according to claim 6, wherein the method comprises the following steps: in step 3.2, the dip coating time is 10-60 s, and the coating ambient temperature is 15-60 ℃.
8. The method for preparing the flexible hollow fiber composite membrane for oil-gas separation according to claim 1, wherein the method comprises the following steps: In the step 3.3, the drying treatment temperature of the composite film after coating modification is 100-140 ℃, the treatment time is 12-18 h, and the dipping and pulling speed is 30-60 cm/min.
9. The method for preparing the flexible hollow fiber composite membrane for oil-gas separation according to claim 6, wherein the method comprises the following steps: In the step 3.3, the oil-gas separation composite membrane which is coated and modified is repeatedly operated, so that the thickness of the modified layer reaches 0.2-2 mu m.
10. A flexible hollow fiber composite membrane for oil-gas separation, prepared by the preparation method of the flexible hollow fiber composite membrane for oil-gas separation according to any one of claims 1 to 9, characterized in that: the flexible hollow fiber composite membrane for oil-gas separation is characterized in that the inside of the flexible hollow fiber composite membrane is a flexible matrix in a hollow fiber form, and the outside of the flexible hollow fiber composite membrane is a functional layer for oil-gas separation and is used for separating dissolved gas in transformer oil.

Description

Flexible hollow fiber composite membrane for oil-gas separation and preparation method thereof Technical Field The invention belongs to the technical field of oil-gas separation, and particularly relates to a flexible hollow fiber composite membrane for oil-gas separation and a preparation method thereof. Background When thermal or electrical faults occur in the oil-filled power equipment, the insulating oil and the insulating paper in the equipment can age and decompose to generate seven characteristic gases such as hydrogen, methane, ethane, ethylene, acetylene, carbon monoxide and carbon dioxide. At present, analysis of Dissolved Gas (DGA) in oil is the most effective means for monitoring and judging faults of oil-filled equipment, and the fault type and fault degree of the oil-filled equipment can be objectively and accurately described by utilizing characteristic information of the dissolved gas in the oil. The analysis technology of dissolved gas in oil generally needs to perform oil-gas separation firstly, and then detect and analyze the separated oil-dissolved gas to obtain components and contents. The oil-gas separation is a vital link, and influences or even determines the accuracy of the detection of the rear-end fault gas, thereby influencing the whole test result. The current methods adopted for oil-gas separation mainly comprise a dynamic headspace degassing method, a vacuum complete degassing method and a permeable membrane degassing method. The dynamic headspace degassing method and the vacuum complete degassing method are easy to generate vaporization oil, the vaporization oil enters the detection cavity and pollutes the rear-end gas detection unit, so that detection data are inaccurate, and the two methods are mechanical structures, so that the failure rate is high and the maintenance amount is large. And the oil-gas separation membrane degassing method utilizes a Teflon membrane to realize oil-gas separation, and when the oil-gas separation reaches balance, the concentration of dissolved gas in oil can be obtained through the concentration of separated gas according to Henry's law. The membrane can prevent vaporized oil from entering the detection cavity, and has the advantages of simple structure, strong potential adaptability, low energy consumption, low maintenance cost and the like, thereby having great prospect in the future. However, the conventional single-layer Teflon film is very thin and is easy to break. The composite Teflon film of the ceramic hollow fiber matrix has application, but the ceramic is a brittle material, so that the reliability of transportation and long-term application is difficult to ensure. Therefore, development of a non-brittle material as a skeleton support body to be compounded with Teflon to form a flexible oil-gas separation membrane for application is needed. The prior art document 1 (CN 116328550A) discloses a preparation method of an oil-gas separation membrane for online detection of a transformer, which comprises the steps of firstly spreading liquid fluorine silicon rubber on a flat plate, solidifying to form a film, secondly mixing and dispersing Hyflon AD60 and perfluoropolyether heat conduction liquid uniformly, adding alpha-phase nano alumina powder, dispersing uniformly to obtain a casting membrane solution, thirdly coating the casting membrane solution on the film, standing, covering a pressing plate, heating to 180-220 ℃ in a drying oven, keeping the temperature for 3-10 h, fourthly standing at high pressure, and then keeping the temperature in the drying oven for 6-12 h again when the temperature reaches 24-48 h, and cooling to obtain the oil-gas separation membrane. However, the prior art has the defects that the preparation technology is only suitable for a flat membrane, is not suitable for a hollow fiber membrane, the oil-gas separation membrane prepared by the technology does not show the stability of a casting membrane liquid separation layer and the stability of long-term operation test, and in addition, the oil-gas separation membrane prepared by the technology does not carry out professional mechanical strength test, and the oil leakage test of membrane rupture is carried out only by adding oil pressure to 500 kPa. Disclosure of Invention In order to solve the defects in the prior art, the invention provides the flexible hollow fiber composite membrane which takes polymer materials such as polyamide imide or polyvinylidene fluoride as a matrix and is compounded with a Teflon material to prepare a flexible oil-gas separation membrane and promote industrial application, thereby providing a high-reliability oil-gas separation flexible hollow fiber composite membrane and a preparation method thereof. The invention adopts the following technical scheme. The first aspect of the invention provides a preparation method of a flexible hollow fiber composite membrane for oil-gas separation, which comprises the following steps: Step 1, prepro