Coatings and coatings formed therefrom and low temperature gathering and processing oil and gas equipment including the coatings

Abstract

This invention provides a coating, a coating formed therefrom, and a cryogenic gathering and transportation oil and gas processing device including the coating. The coating comprises component A and component B. Component A includes an aqueous binder matrix and fillers dispersed therein; the fillers include an iron oxide core and a silica layer covering its outer surface, and the surface of the silica layer has hydroxyl groups; component B includes a curing agent. The coating formed by this coating has better oleophobic properties, higher mechanical properties, higher substrate adhesion, and can better adapt to high water content conditions.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field surface engineering technology, and in particular to a coating and a coating formed therefrom, and an oil and gas gathering and transportation equipment including the coating. Background Technology

[0002] In recent years, significant progress has been made in the unheated oil gathering of high water-cut oil wells. Over 100,000 oil wells have adopted the single-pipe unheated gathering method. The critical wall adhesion temperature has been widely accepted as a replacement for the pour point as the temperature boundary condition for gathering and transporting high water-cut, waxy crude oil. The gathering and transport temperature has decreased from 3-5°C above the traditional pour point to 5-10°C below, greatly reducing the energy consumption of the gathering and transport system. However, the large presence of oil clumps at low temperatures worsens the fluidity of the produced medium, and the increased adhesion of these clumps to gathering and transport pipelines and equipment components negatively impacts the dehydration process after the produced fluid enters the station. Preheating the produced fluid before it enters the station is not only complex but also consumes a large amount of energy for heating the aqueous phase. These problems hinder the comprehensive and in-depth promotion of low-temperature gathering and transport technology.

[0003] The heating and transportation processes in crude oil gathering, processing, and transportation all consume a large amount of energy, which is detrimental to the implementation of energy conservation and emission reduction goals. Therefore, it is of great significance to adopt relevant technical means to reduce energy consumption in these processes.

[0004] Among various technical methods, oleophobic functional coatings have become a prominent approach due to their advantages such as requiring no additional energy input, no complex equipment, and simple maintenance. Oleophobic coatings belong to the category of superwetting materials, and superwetting materials, including oleophobic coatings, often exhibit remarkable properties, making them highly promising for applications in medicine, energy, construction, and manufacturing. Therefore, many superwetting materials based on different materials have been prepared using various methods. These materials typically possess micron / nano-scale microstructures and specific surface compositions to amplify their intrinsic wetting properties and achieve customized superwetting characteristics. By applying functionalized oleophobic coatings to the substrates of production facilities, the adhesion of oil agglomerates to the facilities can be reduced, lowering the resistance to produced fluid gathering and transportation, potentially solving the aforementioned problems and ensuring the smooth operation of cryogenic gathering, transportation, and processing.

[0005] The anti-oil adhesion properties of oleophobic coatings have been preliminarily explored. The inventors found that superwetting surfaces intended for oleophobic use are mostly oleophobic surfaces in air environments. According to Young's model theory, the surface energy of a solid must be less than or equal to 1 / 4 of the surface tension of the liquid to achieve intrinsic hydrophobicity. However, most organic liquids have very low surface tensions (mostly ranging from 20 to 40 mN / m), making the available coating materials even scarcer.

[0006] Among various materials, fluorinated polymers have the lowest surface tension, as low as around 20 mN / m. Therefore, fluorides are often used as low surface energy coatings for modification in existing technologies. However, commercially available fluorinated polymers, such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and perfluoropropylene (PFNP), are expensive, which limits the widespread adoption of oleophobic coatings. Furthermore, fluorinated substances gradually decompose within the coating or are lost under external forces. For example, the shear friction generated during the pressurized shear flow of extracted media causes the surface fluorine to be lost, weakening the oleophobic effect. In addition, fluorinated substances exhibit biotoxicity and environmental pollution, further hindering their widespread application. Therefore, currently used oleophobic coatings for airborne environments suffer from insufficient adhesion to the substrate, poor wear resistance, low mechanical / chemical stability, and short service life.

[0007] Furthermore, the gathering and treatment of produced fluids from oil wells involves typical multiphase flow processes. If oleophobic coatings are used to coat the gathering pipelines and in-station treatment equipment, the complex and variable service environment of the coatings presents a significant challenge to the development of adaptable oleophobic coatings. The uncertainties in the physicochemical properties of the crude oil itself, such as viscosity, pour point, chemical composition, and pH value, also pose greater challenges to coating performance and lifespan. More seriously, oilfields have entered a high water-cut stage, and the flow and physical properties of the produced fluids have changed significantly. Existing fluorinated modified oleophobic coatings for air environments are no longer suitable for high water-cut conditions. Therefore, how to adapt to the oleophobic requirements of produced fluids under high water-cut conditions is an urgent technical problem to be solved. Summary of the Invention

[0008] In order to solve the above-mentioned technical problems, the present invention aims to provide a coating and a coating formed therefrom, and a low-temperature gathering and transportation oil and gas equipment including the coating. The coating formed by the coating has better oleophobic properties, higher mechanical properties, higher substrate adhesion, and can better adapt to high water content conditions.

[0009] To achieve the above objectives, the present invention provides a coating comprising component A and component B. Component A comprises an aqueous solution of a binder matrix and fillers dispersed therein. The fillers comprise an iron oxide core and a silicon oxide layer covering its outer surface, and the surface of the silicon oxide layer has hydroxyl groups. Component B comprises a curing agent.

[0010] First, the silica layer in the filler coats the outer surface of the iron oxide core, encapsulating the iron oxide within the silica. This improves the mechanical strength of the coating and, more importantly, the hydroxyl groups on its surface enhance its binding with water, increasing the coating's hydrophilicity and making it better suited for high-water-content conditions. Furthermore, the filler, dispersed in the binder matrix aqueous solution, not only contributes to constructing suitable micro / nano structures but also modulates the surface energy of the subsequent coating through its chemical composition, resulting in improved oleophobic properties.

[0011] Secondly, the binder matrix can not only improve the bonding force between fillers through adhesion, but also effectively improve the bonding force between the subsequent coating and the substrate material, resulting in a longer coating service life.

[0012] Furthermore, during the subsequent coating formation process, the curing agent can undergo a cross-linking reaction with components in the coating (such as the base resin) to form a stronger and more durable network structure, thereby enhancing the coating's hardness, abrasion resistance, and chemical stability. By using a curing agent, the coating's weather resistance, chemical resistance, heat resistance, and mechanical properties can be significantly improved, making it more suitable for use in harsh environments. Simultaneously, the use of a curing agent can further enhance the adhesion between the coating and the substrate material, preventing the coating from easily peeling or detaching during long-term use and extending its service life.

[0013] In addition, the coating of the present invention is easy to formulate and control. It only requires controlling the type of raw materials, the amount of raw materials, the stirring rate and the reaction time. The reaction process is short, the cost is low, the resistance to disturbance is strong, it can be adapted to a variety of base materials, and it is more suitable for the high water content environment of oil well produced fluids. It is suitable for large-scale production and industrialization in low temperature gathering and transportation processes.

[0014] In a preferred embodiment, the weight ratio of filler to binder matrix in component A is 1–4:8. The ratio of filler to binder matrix affects not only the mechanical strength of the coating but also its apparent chemical composition and morphological structure. When the filler content is too low, the cross-linking between the coating matrices is tighter, resulting in higher mechanical stability, but it is less likely to form a layered, rough structure. Furthermore, the filler is more easily embedded in the matrix, reducing the content of hydrophilic groups on the outermost layer of the coating. Conversely, when the filler content is too high, a layered structure is more likely to form, and hydrophilic groups are more easily exposed. However, the microstructure is more fragile, and the stability of the coating decreases.

[0015] In a preferred embodiment, component A is prepared by the following steps: mixing and reacting a dispersion containing nano-iron oxide particles, a solution containing tetraethyl silicate, and ammonia to obtain a filler; dispersing the filler in an aqueous binder matrix using a low-speed shear dispersion method, wherein the filler is dispersed in the aqueous binder matrix in a colloidal state of multiple aggregates to form component A; the stirring speed during the low-speed shear dispersion process is 500-700 r / min.

[0016] Optionally, the weight ratio of the iron oxide core to the silicon oxide layer in the filler is 1:2 to 8. This filler not only plays a role in constructing suitable micro / nano structures but also regulates the surface energy of the entire coating through its chemical composition and dosage. Further, the iron oxide core comprises nano-iron oxide particles, and the silicon oxide layer comprises nano-silicon oxide particles. Even further, the particle size of the nano-iron oxide particles is 30–40 nm; the particle size of the nano-silicon oxide particles is 60–80 nm. Still further, the hydroxyl concentration on the surface of the silicon oxide layer is 2–5 μmol / m². 2 .

[0017] In a preferred embodiment, the filler can be prepared by the following steps: Step 1, dissolving solid ferric nitrate in water to prepare a 3-20 mmol / L ferric nitrate solution with a volume of 20-300 mL. Step 2, dissolving solid sodium hydroxide in water to prepare a 5-9 mmol / L sodium hydroxide solution with a volume of 7-110 mL. Step 3, mixing and reacting the prepared ferric nitrate solution and sodium hydroxide solution to generate ferric hydroxide precipitate, which is then filtered to obtain ferric hydroxide. Step 4, calcining the ferric hydroxide obtained in step 3 in a tube furnace at 250-350 °C to obtain iron oxide powder with a particle size of approximately 30-40 nm. Step 5, dispersing the iron oxide powder obtained in step 4 in 250-350 mL of ethanol and stirring until uniformly dispersed (preferably with a stirring speed controlled at 200-400 r / min and a stirring time of 10-20 min) to obtain a dispersion containing nano-iron oxide powder. Step six: Dissolve 5-20g of tetraethyl silicate in 100-200mL of ethanol to obtain a solution containing tetraethyl silicate. Step seven: Add the above solution containing tetraethyl silicate and 50-80mL of ammonia to the above dispersion containing nano-iron oxide to allow for reaction. The reaction of tetraethyl silicate and ammonia generates nano-silica particles with a particle size of 60-80nm. The nano-silica particles coat the outer surface of the nano-iron oxide particles. After drying and filtration, the above-mentioned filler is obtained.

[0018] In a preferred embodiment, the binder matrix in the binder matrix aqueous solution is selected from water-soluble epoxy resin and / or water-soluble polyvinyl alcohol resin. The binder matrix, through adhesion, can not only improve the bonding force between fillers but also enhance the overall bonding force between the coating and the substrate. Furthermore, as the main framework of the coating, the matrix is ​​preferably a resin with good mechanical strength, hardness, and toughness, and also with better hydrophilicity.

[0019] Optionally, the volume fraction of the adhesive matrix in the aqueous adhesive matrix solution is 5-40%. In some optional embodiments, 20-30 mL of water-soluble epoxy resin is dissolved in 15-90 mL of water to form a water-soluble epoxy resin solution; 30-40 mL of water-soluble polyvinyl alcohol resin is dissolved in 20-90 mL of water to form a water-soluble polyvinyl alcohol resin solution; the water-soluble epoxy resin solution and the water-soluble polyvinyl alcohol resin solution are mixed and stirred thoroughly (preferably at a stirring speed of 200-500 r / min) to obtain the aqueous adhesive matrix solution.

[0020] In a preferred embodiment, the mass ratio of component A to component B is 10:3 to 8. When applied as a coating, the curing agent accelerates the transformation of the coating from a liquid to a solid state, improving application efficiency and shortening drying time, thus enabling the coating to reach its application performance more quickly. The amount of curing agent is adjusted based on achieving better crosslinking performance and avoiding under-cured or under-crosslinked states.

[0021] Furthermore, the curing agent is selected from one or more combinations of polyimide, polyetheramine, fatty amine and dimethylaniline.

[0022] The present invention also provides a coating obtained by coating the aforementioned paint. Preferred coating method is spraying; in some alternative embodiments, a low-pressure, high-flow-rate spray gun may be used.

[0023] This invention also provides a cryogenic gathering and transportation equipment for oil and gas processing in high-water-content environments, where the water volume fraction is above 80%. The aforementioned coating is applied to the substrate material of the oil and gas equipment. The oil and gas equipment can be, for example, gathering pipelines and in-station processing equipment used in cryogenic gathering and transportation processes, such as oil gathering networks, three-phase separators, free water removers, and electrostatic dehydrators. The substrate material of the oil and gas equipment can be, for example, steel (carbon steel, alloy steel, cryogenic steel, fiberglass) and / or steel-plastic composite materials. Attached Figure Description

[0024] Figure 1 The diagram shows the contact angle test of the coated steel plate with oil droplets in the experimental group of Embodiment 1 of the present invention;

[0025] Figure 2 The image shows a test diagram of the contact angle of an uncoated steel plate with oil droplets in the comparative group of Embodiment 2 of the present invention;

[0026] Figure 3 The diagram shows the contact angle test of the coated steel plate with oil droplets in the experimental group of Embodiment 3 of the present invention;

[0027] Figure 4 The following is a test diagram of the contact angle of the substrate steel plate without the above coating in Comparative Example 1 of the present invention against oil droplets.

[0028] Figure 5 A schematic diagram of the mixing tank used for testing in Embodiment 3 and Comparative Example 1 of the present invention is shown. Detailed Implementation

[0029] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0030] Example 1

[0031] (I) Experimental Group: A method for preparing a coating is provided, which includes the following steps:

[0032] Filler preparation: Prepare 80 mL of ferric nitrate solution (ferric nitrate molar concentration of 7 mmol / L, solvent: water) and 20 mL of sodium hydroxide solution (sodium hydroxide molar concentration of 6 mmol / L, solvent: water). Mix the ferric nitrate solution and sodium hydroxide solution to react and generate ferric hydroxide precipitate. Collect the ferric hydroxide precipitate and calcine it in a tube furnace at 280℃ to obtain iron oxide powder. The average particle size of the iron oxide powder was measured to be approximately 32 nm.

[0033] The obtained iron oxide powder was dispersed in 250 mL of ethanol and stirred at 240 r / min for 10 min to form an iron oxide dispersion system. 5 g of liquid tetraethyl silicate was dissolved in 120 mL of ethanol to obtain a tetraethyl silicate solution. The prepared iron oxide dispersion system was injected into the tetraethyl silicate solution, followed by the addition of 60 mL of ammonia. The reaction of tetraethyl silicate and ammonia produced nano-silica particles with an average particle size of approximately 68 nm. These nano-silica particles coated the outer surface of the iron oxide powder. After drying and filtration, a filler was obtained (the weight ratio of the iron oxide core to the silica layer was 1:3). Fourier transform infrared spectroscopy (FTIR) was performed on the filler. The surface chemical structure was analyzed by measuring the absorption spectrum in the infrared region. An absorption peak was observed in the wavenumber region of 3300 cm⁻¹, indicating the presence of hydroxyl groups on the surface of the silica layer. The hydroxyl concentration was then determined to be 3.2 μmol / m² by characterizing the integral area of ​​the absorption peak. 2 This indicates that there is a high concentration of hydroxyl groups on the surface of the filler.

[0034] Preparation of adhesive matrix aqueous solution: Dissolve 20 mL of water-soluble epoxy resin in 85 mL of water to obtain a water-soluble epoxy resin solution; dissolve 30 mL of water-soluble polyvinyl alcohol resin in 75 mL of water to obtain a water-soluble polyvinyl alcohol resin solution; mix the water-soluble epoxy resin solution and the water-soluble polyvinyl alcohol resin solution, and stir at a stirring speed of 260 r / min to obtain an adhesive matrix aqueous solution (wherein, the volume fraction of water-soluble epoxy resin is 9.5% and the volume fraction of water-soluble polyvinyl alcohol resin is 14.3%).

[0035] Component A: The filler and binder matrix are mixed at a weight ratio of 2:8. The filler is dispersed in the binder matrix aqueous solution in a gel-like state as an agglomerate at a stirring speed of 500 r / min to form Component A.

[0036] Component B: Polyimide.

[0037] The two components, A and B, are mixed in a weight ratio of 10:4 to obtain a coating, which is then sprayed onto the outer surface of the steel plate to form a coating layer.

[0038] (II) Comparison group: steel plate.

[0039] A comparison was made between steel plates with and without the aforementioned coating. The contact angle of the samples in an 85% water-volume environment was measured using a contact angle meter to determine the effect of the coating on oil droplets (Daqing crude oil, density 867.4 kg / m³). 3 The macroscopic oil contact angle (with a freezing point of 35℃, a wax precipitation point of 45.2℃, a wax content of 22.2wt%, a gum content of 8.1wt%, and an asphaltene content of 2.9wt%) is as follows: Figure 1 The diagram shows the contact angle test results of a coated steel plate with oil droplets in the experimental group of Embodiment 1 of the present invention. Figure 2 The diagram shows the contact angle test results of an uncoated steel plate with oil droplets in the comparative group of Embodiment 1 of the present invention; the roll-off angle was determined using an optical contact angle tester with an attached tilting platform; the adhesion force between the oil droplets and the steel plate surface was measured using a high-precision microelectromechanical balancing system; and the bonding strength between the coating and the steel plate was determined using the cross-cut adhesion test. The measured data are shown in Table 1.

[0040] Table 1

[0041] Steel plates without the above coating Steel plates with the above coating Contact angle (°) 23 170 Roll angle (°) 85 5 Adhesion force (mN) 97 12 Number of peeling cycles (times) — 491 (Level 1 Adhesion)

[0042] Table 1 shows that, in terms of adhesion performance testing, compared to uncoated steel plates, coated steel plates exhibited a significantly improved oleophobic contact angle for oil droplets, increasing from 23° to 170°, a decrease in roll-off angle from 85° to 5°, and a decrease in oil droplet adhesion force from 97 mN to 12 mN. This indicates a substantial improvement in oleophobic performance in high-moisture environments. Furthermore, the adhesion between the coating and the substrate was determined using the cross-cut adhesion test, achieving 491 peel cycles and demonstrating a Class I adhesion strength.

[0043] Example 2

[0044] (I) Experimental Group: A method for preparing a coating is provided, which includes the following steps:

[0045] Filler preparation: 150 mL of ferric nitrate solution (ferric nitrate molar concentration of 14 mmol / L, solvent: water) and 80 mL of sodium hydroxide solution (sodium hydroxide molar concentration of 8 mmol / L, solvent: water) were prepared. The ferric nitrate solution and sodium hydroxide solution were mixed and reacted to generate ferric hydroxide precipitate. The ferric hydroxide precipitate was collected and calcined in a tube furnace at 300 °C to obtain iron oxide powder. The average particle size of the iron oxide powder was measured to be approximately 34 nm.

[0046] The obtained iron oxide powder was dispersed in 300 mL of ethanol and stirred at 300 rpm for 15 min to form an iron oxide dispersion system. 12 g of liquid tetraethyl silicate was dissolved in 160 mL of ethanol to obtain a tetraethyl silicate solution. The prepared iron oxide dispersion system was then added to the tetraethyl silicate solution, followed by the addition of 70 mL of ammonia water to initiate the reaction. The reaction of tetraethyl silicate and ammonia water produced nano-silica particles with an average particle size of approximately 75 nm. These nano-silica particles coated the outer surface of the iron oxide powder. After drying and filtration, the filler was obtained (where the weight ratio of the iron oxide core to the silica layer was 1:5).

[0047] Preparation of adhesive matrix aqueous solution: Dissolve 25 mL of water-soluble epoxy resin in 40 mL of water to obtain a water-soluble epoxy resin solution; dissolve 35 mL of water-soluble polyvinyl alcohol resin in 50 mL of water to obtain a water-soluble polyvinyl alcohol resin solution; mix the water-soluble epoxy resin solution and the water-soluble polyvinyl alcohol resin solution, and stir at a stirring speed of 350 r / min to obtain an adhesive matrix aqueous solution (wherein, the volume fraction of water-soluble epoxy resin is 16.7% and the volume fraction of water-soluble polyvinyl alcohol resin is 23.3%).

[0048] Component A: The filler and binder matrix aqueous solution are mixed at a weight ratio of 3:8. The filler is dispersed in the binder matrix aqueous solution in a gel-like state as an aggregate by stirring at 600 r / min to form Component A.

[0049] Component B: Polyimide.

[0050] The two components, A and B, are mixed in a weight ratio of 10:5 to obtain a coating, which is then sprayed onto the outer surface of the steel plate to form a coating layer.

[0051] (II) Comparison group: steel plate.

[0052] A comparison was made between steel plates with and without the aforementioned coating. The contact angle of the samples in an 85% water-volume environment was measured using a contact angle meter to determine the effect of the coating on oil droplets (Daqing crude oil, density 867.4 kg / m³). 3 The macroscopic oil contact angle (with a freezing point of 35℃, a wax precipitation point of 45.2℃, a wax content of 22.2wt%, a gum content of 8.1wt%, and an asphaltene content of 2.9wt%) was measured, and the roll-off angle was determined using an optical contact angle test with an attached tilting platform. The adhesion force between the oil droplets and the steel plate surface was measured using a high-precision microelectromechanical balancing system. The bonding strength between the coating and the steel plate was determined using the cross-cut adhesion test. The measured data are shown in Table 2.

[0053] Table 2

[0054] Steel plates without the above coating Steel plates with the above coating Contact angle (°) 22 172 Roll angle (°) 84 4 Adhesion force (mN) 98 10 Number of peeling cycles (times) — 493 (Level 1 Adhesion)

[0055] Table 2 shows that, in terms of adhesion performance testing, compared to uncoated steel plates, coated steel plates exhibited a significantly improved oleophobic contact angle for oil droplets, increasing from 22° to 172°, a decrease in roll-off angle from 84° to 4°, and a decrease in oil droplet adhesion force from 98 mN to 10 mN. This indicates a substantial improvement in oleophobic performance in high-moisture environments. Furthermore, the adhesion between the coating and the substrate was determined using the cross-cut adhesion test, achieving 493 peel cycles and demonstrating a Class I adhesion strength.

[0056] Example 3

[0057] (I) Experimental Group: A method for preparing a coating is provided, which includes the following steps:

[0058] Filler preparation: 290 mL of ferric nitrate solution (ferric nitrate molar concentration of 19 mmol / L, solvent: water) and 105 mL of sodium hydroxide solution (sodium hydroxide molar concentration of 9 mmol / L, solvent: water) were prepared. The ferric nitrate solution and sodium hydroxide solution were mixed and reacted to generate ferric hydroxide precipitate. The ferric hydroxide precipitate was collected and calcined in a tube furnace at 320 °C to obtain iron oxide powder. The average particle size of the iron oxide powder was measured to be approximately 38 nm.

[0059] The obtained iron oxide powder was dispersed in 330 mL of ethanol and stirred at 350 r / min for 20 min to form an iron oxide dispersion system. 18 g of liquid tetraethyl silicate was dissolved in 180 mL of ethanol to obtain a tetraethyl silicate solution. The prepared iron oxide dispersion system was then added to the tetraethyl silicate solution, followed by the addition of 78 mL of ammonia water to initiate the reaction. The reaction of tetraethyl silicate and ammonia water generated nano-silica particles with an average particle size of approximately 80 nm. These nano-silica particles coated the outer surface of the nano-iron oxide powder. After drying and filtration, the filler was obtained (where the weight ratio of the iron oxide core to the silica layer was 1:7).

[0060] Preparation of adhesive matrix aqueous solution: Dissolve 30 mL of water-soluble epoxy resin in 90 mL of water to obtain a water-soluble epoxy resin solution; dissolve 40 mL of water-soluble polyvinyl alcohol resin in 90 mL of water to obtain a water-soluble polyvinyl alcohol resin solution; mix the water-soluble epoxy resin solution and the water-soluble polyvinyl alcohol resin solution, and stir at a stirring speed of 400 r / min to obtain an adhesive matrix aqueous solution (wherein, the volume fraction of water-soluble epoxy resin is 12% and the volume fraction of water-soluble polyvinyl alcohol resin is 16%).

[0061] Component A: The filler and binder matrix aqueous solution are mixed at a weight ratio of 3.5:8. The filler is dispersed in the binder matrix aqueous solution in a gel-like form as aggregates at a stirring speed of 680 r / min to form Component A.

[0062] Component B: Polyimide.

[0063] The two components, A and B, are mixed in a weight ratio of 10:7 to obtain a coating, which is then sprayed onto the outer surface of the steel plate to form a coating layer.

[0064] (II) Comparison group: steel plate.

[0065] A comparison was made between steel plates with and without the aforementioned coating. The contact angle of the samples in an environment with 87% water volume fraction was measured using a contact angle meter to determine the effect of the coating on oil droplets (Daqing crude oil, density 867.4 kg / m³). 3 The macroscopic oil contact angle is as follows: solidification point is 35℃, wax precipitation point is 45.2℃, wax content is 22.2wt%, gum content is 8.1wt%, and asphaltene content is 2.9wt%. Figure 3 The diagram shows the contact angle test results of the coated steel plate with oil droplets in the experimental group of Embodiment 2 of the present invention. Figure 4 The diagram shows the contact angle test results of an uncoated steel plate against an oil droplet in the comparative group of Embodiment 2 of the present invention; the roll-off angle was determined using an optical contact angle measuring device with an inclined platform; and a stirring vessel (e.g.) was used. Figure 5The amount of oil droplets adhering under simulated shear conditions over 30 minutes was measured. The bonding strength between the coating and the steel plate was determined using the cross-cut adhesion test. Adhesion amount and bonding strength tests were first conducted at a standard produced fluid salinity (3500 ppm). Then, calcium, magnesium, sodium, chloride, potassium, sulfate, and carbonate ions were added to a self-made mixing tank to increase the salinity to 35000 ppm before conducting a high salinity test. The measured data are shown in Table 3.

[0066] Table 3

[0067]

[0068] Table 3 shows that, in terms of adhesion performance testing, compared to the uncoated steel plate, the coated steel plate exhibited a significantly improved oleophobic contact angle for oil droplets, increasing from 24° to 167°, a decrease in the roll-off angle from 87° to 9°, and a reduction in the amount of oil droplets adhered to from 14g to 0.25g. This demonstrates a substantial improvement in oleophobic performance in high-water-content environments. Even with increased mineralization, the amount of oil droplets adhered remained at 0.25g, with a peel cycle count reaching 486 cycles. The bonding strength with the substrate reached Grade 1 adhesion, proving that the oleophobic coating maintained excellent chemical resistance.

[0069] Comparative Example 1

[0070] Experimental group: Commercially available fluorinated polyvinylidene fluoride was sprayed onto the outer surface of a steel plate to form a coating.

[0071] Comparison group: steel plate.

[0072] A comparison was made between steel plates with and without the aforementioned coating. The contact angle of the samples in an environment with 87% water volume fraction was measured using a contact angle meter to determine the effect of the coating on oil droplets (Daqing crude oil, density 867.4 kg / m³). 3 The macroscopic oil contact angle is as follows: Solidification point 35℃, wax precipitation point 45.2℃, wax content 22.2wt%, gum content 8.1wt%, and asphaltene content 2.9wt%. A mixing tank (e.g., [missing information]) is used. Figure 5 The amount of oil droplets adhering to the coating (on a patch on the inner wall of the tank, with a stirring speed of 300 r / min) under simulated shear conditions over a period of 30 minutes was measured. The bonding strength between the coating and the substrate was determined by the cross-cut adhesion test. The above tests were conducted under normal produced fluid salinity (3500 ppm). Calcium, magnesium, sodium, chloride, potassium, sulfate, and carbonate ions were added to a self-made stirring tank to increase the salinity to 35000 ppm. The adhesion amount was tested again to detect the chemical resistance of the coating. The measured data are shown in Table 4.

[0073] Table 4

[0074]

[0075] Table 4 shows that, in terms of adhesion performance testing, compared to the uncoated substrate, the oleophobic contact angle of the substrate coated with conventional PVC increased from 23° to 135°, but this is still significantly lower than the 167° contact angle of the hydrophilic-oleophobic coating developed in this scheme; the roll-off angle decreased from 86° to 36°, but this is still significantly higher than the 9° of the hydrophilic-oleophobic coating developed in this scheme; and the amount of oil droplets adhered decreased from 14g to 4.8g, but this is still significantly higher than the 0.25g of the hydrophilic-oleophobic coating developed in this scheme. This indicates that the oleophobic effect of the conventional PVC coating in aquatic environments is improved, but compared to the hydrophilic-oleophobic coating developed in this scheme, the oleophobic effect is significantly worse. Increasing the mineralization resulted in an oil droplet adhesion amount of 6.2g, indicating that the conventional PVC coating has poor chemical resistance. Furthermore, the adhesion strength between the coating and the substrate was determined using the cross-cut adhesion test, with a peeling cycle count of 89 times, indicating that the adhesion strength between the conventional PVC coating and the substrate is also poor.

Claims

1. A coating, wherein, Includes component A and component B; Component A comprises an aqueous binder matrix and fillers dispersed therein; the fillers comprise an iron oxide core and a silicon oxide layer covering the outer surface of the iron oxide core, and the surface of the silicon oxide layer has hydroxyl groups; Component B includes a curing agent.

2. The coating according to claim 1, wherein, The adhesive matrix in the aqueous solution is selected from water-soluble epoxy resin and / or water-soluble polyvinyl alcohol resin.

3. The coating according to claim 1, wherein, The weight ratio of the filler to the binder matrix in the aqueous solution is 1 to 4:

8.

4. The coating according to claim 1, wherein, The volume fraction of the adhesive matrix in the aqueous adhesive matrix solution is 5% to 40%.

5. The coating according to claim 1, wherein, In the filler, the weight ratio of the iron oxide core to the silicon oxide layer is 1:2 to 8.

6. The coating according to claim 1, wherein, The concentration of hydroxyl groups on the surface of the silicon oxide layer is 2 to 5 μmol / m 2 .

7. The coating according to claim 1, wherein, The iron oxide core comprises nano-iron oxide particles, and the silicon oxide layer comprises nano-silicon oxide particles.

8. The coating according to claim 7, wherein, The particle size of the nano-iron oxide particles is 30-40 nm; the particle size of the nano-silicon oxide particles is 60-80 nm.

9. The coating according to claim 1, wherein, Component A is prepared through the following steps: The filler is obtained by mixing a dispersion containing nano-iron oxide particles, a solution containing tetraethyl silicate, and ammonia water and reacting them. The filler is dispersed in the binder matrix aqueous solution in a colloidal state as multiple aggregates by a low-speed shear dispersion method to form component A; The rotational speed of the low-speed shearing is 500–700 r / min.

10. The coating according to claim 1, wherein, The mass ratio of component A to component B is 10:3 to 8.

11. The coating according to claim 1, wherein, The curing agent is selected from one or more of polyimide, polyetheramine, fatty amine and dimethylaniline.

12. A coating, wherein, The coating is obtained by coating according to any one of claims 1 to 11.

13. A cryogenic gathering and transportation equipment for oil and gas processing in a high-water-content environment, wherein the water volume fraction of the high-water-content environment is above 80%, wherein, The base material of the oil and gas equipment is provided with the coating as described in claim 12.

14. The oil and gas gathering and transportation equipment for low-temperature processing in high water-cut environments according to claim 13, wherein, The oil and gas equipment includes an oil collection pipeline network, a three-phase separator, a free water remover, or an electrostatic dehydrator.

15. The oil and gas gathering and transportation equipment for low-temperature processing in high water-cut environments according to claim 13, wherein, The base material of the oil and gas equipment is selected from one or more combinations of carbon steel, alloy steel, low-temperature steel, fiberglass and steel-plastic composite materials.

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