A method for preparing a coating resistant to cage hydrates

Abstract

The present disclosure relates to a method for preparing a coating layer against cage-shaped hydrate, and relates to the technical field of paint preparation, which comprises the following steps: dispersing three-dimensional dendritic SiO2 nanoparticles in ethanol with an alcohol concentration of 95% to obtain a first dispersion liquid, and adding a surface modifier to the first dispersion liquid to modify and obtain a modified dispersion liquid; ultrasonic dispersing powder A into a mixed solvent to obtain a second dispersion liquid; adding N-vinyl caprolactam monomer and azobisisobutyronitrile initiator into the second dispersion liquid to perform a polymerization reaction, and obtaining a polymerization reaction result after the polymerization reaction is completed; centrifugally washing and drying the polymerization reaction result to obtain powder B, and uniformly mixing powder B, polyhydroxy polyether resin and an organic solvent to obtain a paint against cage-shaped hydrate, so as to obtain a coating layer against cage-shaped hydrate according to the paint against cage-shaped hydrate. The coating layer prepared by the present disclosure has the effects of significantly inhibiting hydrate nucleation and reducing hydrate adhesion.

Description

Technical Field

[0001] This disclosure relates to the field of coating preparation technology, and more specifically, to a method for preparing a coating that resists cage-like hydrates. Background Technology

[0002] Pipeline transportation is the primary mode of natural gas transport. In practical applications, free water molecules within natural gas pipelines associate into cage-like structures through hydrogen bonding under specific temperature and pressure conditions. These cage-like structures then encapsulate small molecules such as methane, forming hydrate nuclei. In this scenario, hydrates grow and accumulate on the pipeline walls, reducing transport capacity and potentially causing blockages, leading to significant safety accidents and economic losses.

[0003] To address the aforementioned issues, superhydrophobic coatings, due to their excellent hydrophobicity and low adhesion, have become ideal materials for preventing hydrate adhesion in some related technical solutions. In practical applications, the low adhesion between hydrate particles and the hydrophobic solid surface (i.e., the inner wall of natural gas pipelines) makes the hydrate particles easily carried away by the shearing action of the pipeline fluid, thus preventing their accumulation on the pipe wall and achieving the goal of avoiding hydrate blockage. However, the surface of superhydrophobic coatings easily accumulates gas and induces the orderly arrangement of water molecules. This characteristic, in turn, promotes the formation of hydrate cage structures and accelerates the hydrate nucleation process. Therefore, while superhydrophobic coatings possess the advantage of low adhesion, they also present a contradiction by promoting hydrate nucleation. This limitation restricts their practical application in gas pipelines.

[0004] It should be noted that the information in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this disclosure is to provide a method for preparing a coating that resists cage-like hydrates, thereby overcoming, to at least some extent, the problem that it is impossible to obtain a coating that has both low adhesion and can inhibit the formation of cage-like structures of hydrates due to the limitations and defects of related technologies.

[0006] According to one aspect of this disclosure, a method for preparing an anti-cage hydrate coating is provided, comprising: Step 1, dispersing three-dimensional dendritic SiO2 nanoparticles in 95% ethanol to obtain a first dispersion, and adding a surface modifier to the first dispersion to modify it to obtain a modified dispersion; Step 2, centrifuging, washing and drying the modified dispersion to obtain powder A, and ultrasonically dispersing powder A in a mixed solvent to obtain a second dispersion; Step 3, adding N-vinylcaprolactam monomer and azobisisobutyronitrile initiator to the second dispersion to carry out a polymerization reaction, and obtaining the polymerization reaction result after the polymerization reaction is completed; Step 4, centrifuging, washing and drying the polymerization reaction result to obtain powder B, and mixing powder B, polyhydroxy polyether resin and organic solvent evenly to obtain the anti-cage hydrate coating, thereby obtaining an anti-cage hydrate coating.

[0007] In one exemplary embodiment of this disclosure, the particle size of the three-dimensional dendritic SiO2 nanoparticles is 200-350 nm, and the specific surface area of ​​the three-dimensional dendritic SiO2 nanoparticles is 920-1200 m². 2 / g.

[0008] In an exemplary embodiment of this disclosure, the surface modifier includes a first surface modifier and a second surface modifier; the first surface modifier is one or more of perfluorooctyltriethoxysilane, perfluorodecyltriethoxysilane, and perfluorododecyltriethoxysilane; the second surface modifier is a silane coupling agent.

[0009] In one exemplary embodiment of this disclosure, the molar ratio of the first surface modifier to the second surface modifier is 2.5:1 to 5:1; the total amount of the first surface modifier and the second surface modifier added is 3% to 8% of the mass of the three-dimensional dendritic SiO2 nanoparticles.

[0010] In one exemplary embodiment of this disclosure, the mixed solvent includes anhydrous ethanol and isopropanol; the volume ratio of anhydrous ethanol to isopropanol in the mixed solvent is 4:6.

[0011] In one exemplary embodiment of this disclosure, during the process of ultrasonically dispersing powder A into a mixed solvent to obtain a second dispersion, nitrogen protection is used while stirring is maintained, the reaction temperature is 65~85 °C, and the reaction time is 8~12 h.

[0012] In an exemplary embodiment of this disclosure, the mass ratio of powder A to the added N-vinylcaprolactam monomer is 1:5 to 2:3; the mass ratio of N-vinylcaprolactam monomer to azobisisobutyronitrile initiator is 1:(0.01 to 0.1); and the mass-volume ratio of N-vinylcaprolactam monomer to the mixed solvent is 1 g:20 mL to 1 g:50 mL.

[0013] In one exemplary embodiment of this disclosure, the molecular weight of the polyhydroxy polyether resin is 80,000 to 100,000; the organic solvent includes multiple components such as xylene, ethylene glycol monobutyl ether, and cyclohexanone.

[0014] In an exemplary embodiment of this disclosure, the xylene in the organic solvent is 50-60 parts by weight; the ethylene glycol monobutyl ether is 20-30 parts by weight; and the cyclohexanone is 15-25 parts by weight.

[0015] In an exemplary embodiment of this disclosure, the prepared anti-cage hydrate coating includes multiple components from the following: powder B, polyhydroxy polyether resin, and organic solvent; the powder B has a weight ratio of 20-30 parts, the polyhydroxy polyether resin has a weight ratio of 10-15 parts, and the organic solvent has a weight ratio of 60-65 parts.

[0016] This disclosure provides a method for preparing an anti-cage hydrate coating. Firstly, three-dimensional dendritic SiO2 nanoparticles are dispersed in 95% ethanol to obtain a first dispersion. A surface modifier is added to the first dispersion to modify it, resulting in a modified dispersion. The modified dispersion is then centrifuged, washed, and dried to obtain powder A. Powder A is then ultrasonically dispersed in a mixed solvent to obtain a second dispersion. Next, N-vinylcaprolactam monomer and azobisisobutyronitrile initiator are added to the second dispersion to initiate a polymerization reaction. After the polymerization reaction, the polymerization result is obtained. Finally, the polymerization result is centrifuged, washed, and dried to obtain powder B. Powder B, polyhydroxy polyether resin, and an organic solvent are then mixed uniformly to obtain an anti-cage hydrate coating. This method provides an anti-cage hydrate coating. Because it utilizes a three-dimensional structure with a large specific surface area and high pore volume... Dendritic silica serves as the reaction center, and a surface modifier (i.e., hydrophobic silane) and lactam groups (i.e., the polymerization result obtained by polymerization based on a second dispersion, N-vinylcaprolactam monomer, and azobisisobutyronitrile initiator) are introduced into the surface of three-dimensional dendritic silica nanoparticles through a chemical grafting reaction. By controlling the geometric distribution of polyvinylcaprolactam on the surface, the nucleation inhibition performance of hydrates can be improved without sacrificing the low surface adhesion of hydrates. This solves the problem in related technical solutions of not being able to obtain a coating that has both low adhesion and can inhibit the formation of hydrate cage structures. On the other hand, by using high molecular weight polyhydroxy polyether resin as a binder, not only can the bonding strength between the anti-cage hydrate coating and the substrate be enhanced, but the hydroxyl groups in the polyhydroxy polyether resin can also form thermodynamic inhibition protection on the surface, further improving the nucleation inhibition performance of the anti-cage hydrate coating.

[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0019] Figure 1 The diagram schematically illustrates a flow chart of a method for preparing a coating against cage-like hydrates according to an exemplary embodiment of the present disclosure.

[0020] Figure 2The diagram schematically illustrates an example structure of an N-vinylcaprolactam monomer according to an exemplary embodiment of the present disclosure.

[0021] Figure 3 The diagram schematically illustrates an example of controlled grafting of polyvinylcaprolactam onto the surface of powder A according to an exemplary embodiment of the present disclosure.

[0022] Figure 4 The illustration schematically shows a transmission electron microscope image of a three-dimensional dendritic SiO2 nanoparticle according to an exemplary embodiment of the present disclosure.

[0023] Figure 5 The image schematically shows a scanning electron microscope (SEM) image of an anti-cage hydrate coating formed from a coating based on an example embodiment of the present disclosure.

[0024] Figure 6 This diagram schematically illustrates an example of the surface water contact angle of an anti-cage hydrate coating generated from an anti-cage hydrate coating obtained according to an exemplary embodiment of this disclosure, based on Example 1.

[0025] Figure 7 The diagram schematically illustrates an example of the surface water contact angle of an anti-cage hydrate coating generated from an anti-cage hydrate coating obtained according to an exemplary embodiment of the present disclosure, based on Comparative Example 2.

[0026] Figure 8 The illustration schematically shows a surface image of a continuous sliding water droplet on an anti-cage hydrate coating generated according to an example embodiment of the present disclosure, based on an anti-cage hydrate coating obtained in Example 2.

[0027] Figure 9 The diagram schematically illustrates an example of adhesion displacement between an anti-cage hydrate coating generated from an anti-cage hydrate coating obtained in Example 3 according to an exemplary embodiment of the present disclosure and a cyclopentane hydrate.

[0028] Figure 10 The diagram schematically illustrates an example of adhesion displacement between an anti-cage hydrate coating generated from an anti-cage hydrate coating obtained according to Comparative Example 2, based on an example embodiment of the present disclosure, and a cyclopentane hydrate.

[0029] Figure 11 The diagram schematically illustrates the adhesion test of a coating formed from an anti-cage hydrate coating obtained in Example 1 according to an exemplary embodiment of the present disclosure.

[0030] Figure 12 The diagram schematically illustrates the adhesion test of an anti-cage hydrate coating formed from an anti-cage hydrate coating obtained in Comparative Example 3 according to an exemplary embodiment of the present disclosure. Detailed Implementation

[0031] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this disclosure more comprehensive and complete, and to fully convey the concept of the example embodiments to those skilled in the art. The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced with one or more of the specific details omitted, or other methods, components, apparatus, steps, etc., can be employed. In other instances, well-known technical solutions are not shown or described in detail to avoid obscuring various aspects of this disclosure.

[0032] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0033] This disclosure first provides a method for preparing a coating to resist cage-like hydrates. Specifically, refer to... Figure 1 As shown, the method for preparing the anti-cage hydrate coating may include the following steps:

[0034] Step S110. Disperse three-dimensional dendritic SiO2 nanoparticles in 95% ethanol to obtain a first dispersion, and add a surface modifier (to the first dispersion) to modify it to obtain a modified dispersion.

[0035] Step S120. After centrifugation, washing and drying of the modified dispersion, powder A is obtained, and powder A is ultrasonically dispersed in a mixed solvent to obtain a second dispersion;

[0036] Step S130. Add N-vinylcaprolactam monomer and azobisisobutyronitrile initiator to the second dispersion to carry out the polymerization reaction, and obtain the polymerization result after the polymerization reaction is completed;

[0037] Step S140. After centrifugation, washing and drying of the polymerization reaction result, powder B is obtained. Powder B, polyhydroxy polyether resin and organic solvent are mixed evenly to obtain the anti-cage hydrate coating, so as to obtain an anti-cage hydrate coating based on the anti-cage hydrate coating.

[0038] In the above-described method for preparing an anti-cage hydrate coating, on one hand, a first dispersion is obtained by dispersing three-dimensional dendritic SiO2 nanoparticles in 95% ethanol, and a surface modifier is added to the first dispersion to modify it, resulting in a modified dispersion. Then, the modified dispersion is centrifuged, washed, and dried to obtain powder A, which is then ultrasonically dispersed in a mixed solvent to obtain a second dispersion. Next, N-vinylcaprolactam monomer and azobisisobutyronitrile initiator are added to the second dispersion to carry out a polymerization reaction, and the polymerization result is obtained after the polymerization reaction is completed. Finally, the polymerization result is centrifuged, washed, and dried to obtain powder B, which is then uniformly mixed with polyhydroxy polyether resin and an organic solvent to obtain an anti-cage hydrate coating. This anti-cage hydrate coating is obtained based on the anti-cage hydrate coating. Since three-dimensional dendritic nanoparticles with a large specific surface area and high pore volume can be used... Using silica as the reaction center, a surface modifier (i.e., hydrophobic silane) and lactam groups (i.e., the polymerization result obtained by polymerization based on a second dispersion, N-vinylcaprolactam monomer, and azobisisobutyronitrile initiator) are introduced into the surface of three-dimensional dendritic silica nanoparticles through a chemical grafting reaction. By controlling the geometric distribution of polyvinylcaprolactam on the surface, the nucleation inhibition performance of hydrates can be improved without sacrificing the low surface adhesion of hydrates. This solves the problem in related technical solutions that it is impossible to obtain a coating that has both low adhesion and can inhibit the formation of hydrate cage structures. On the other hand, by using high molecular weight polyhydroxy polyether resin as a binder, not only can the bonding strength between the anti-cage hydrate coating and the substrate be enhanced, but the hydroxyl groups in the polyhydroxy polyether resin can also form thermodynamic inhibition protection on the surface, further improving the nucleation inhibition performance of the anti-cage hydrate coating.

[0039] In one possible example embodiment, the specific implementation process for regulating the geometric distribution of surface polyvinylcaprolactam described above is as follows: Since the surface modifier is divided into fluorinated silanes (i.e., perfluorooctyltriethoxysilane, perfluorodecyltriethoxysilane, and perfluorododecyltriethoxysilane) and silane coupling agent KH570, and KH570 contains carbon-carbon double bonds (C=C), it can react with N-vinylcaprolactam monomers (wherein, an example diagram of N-vinylcaprolactam monomers can be referred to...). Figure 2As shown, a free radical polymerization reaction is carried out on powder A to obtain polyvinylcaprolactam; further, a specific scenario example diagram of the controllable grafting of polyvinylcaprolactam onto the surface of powder A to obtain powder B can be found in the diagram. Figure 3 As shown; under this premise, the initiator will homolytically decompose under heating conditions to generate free radicals. These free radicals can initiate the polymerization reaction of the double bonds in KH570 and N-vinylcaprolactam monomers, thereby achieving the grafting of polyvinylcaprolactam; furthermore, by controlling the ratio of fluorinated silane and KH570 surface modifier, the distribution of KH570 on the surface can be controlled, thereby regulating the distribution ratio of polyvinylcaprolactam.

[0040] In one possible example embodiment, the lactam group effectively delays the nucleation of cage hydrates through the combined effects of two-site adsorption and steric hindrance. Compared to groups such as hydroxyl groups, it has a higher efficiency and requires only a trace amount to take effect. Therefore, this group can simultaneously achieve a significant nucleation inhibition effect on the anti-cage hydrate coating while completely maintaining the superhydrophobic properties of the obtained anti-cage hydrate coating.

[0041] The following will provide a detailed explanation and description of the coating preparation method for anti-cage hydrates described in the exemplary embodiments of this disclosure, in conjunction with the accompanying drawings.

[0042] In one example embodiment, the particle size of the three-dimensional dendritic SiO2 nanoparticles described above is 200~350 nm, and the specific surface area of ​​the three-dimensional dendritic SiO2 nanoparticles is 920~1200 m². 2 / g; among which, the particle size of 200~350 nm and the specific surface area of ​​920~1200 m² were selected. 2 The / g three-dimensional dendritic SiO2 nanoparticles are designed to take advantage of their large specific surface area and high pore volume to introduce surface modifiers (i.e., hydrophobic silanes) and lactam groups (i.e., the polymerization reaction results obtained by polymerization based on the second dispersion, N-vinylcaprolactam monomer and azobisisobutyronitrile initiator) onto the surface of the three-dimensional dendritic silica nanoparticles. This allows for a significant increase in the distribution density of lactam groups on the surface without compromising the hydrophobicity of the coating.

[0043] In one exemplary embodiment, the surface modifier described above includes a first surface modifier and a second surface modifier; and the first surface modifier is perfluorooctyltriethoxysilane, perfluorodecyltriethoxysilane, or perfluorododecyltriethoxysilane; the second surface modifier is a C=C hydrophobic agent, such as silane coupling agent KH570; wherein the first and second surface modifiers described herein function as hydrophobic agents; furthermore, the molar ratio of the first and second surface modifiers described herein is 2.5:1 to 5:1; the total amount of the first and second surface modifiers added is 3% to 8% of the mass of the three-dimensional dendritic SiO2 nanoparticles.

[0044] In one possible example embodiment, the first surface modifier described herein is a hydrophobic agent containing fluorine functional groups and having a certain carbon chain length, to balance the hydrophobicity and steric hindrance of the hydrate coating; the reason for using this first surface modifier is to balance the hydrophobicity and steric hindrance of the hydrate coating based on the carbon chain length; in practical applications, a carbon chain that is too short will result in insufficient hydrophobicity, while a chain that is too long will generate excessive steric hindrance, which is detrimental to subsequent polymerization reactions; in one possible example embodiment, the first surface modifier can be ( O Si-(C )2-(C )nC The value of n can be 5, 7, or 9. The advantages of the first surface modifier are: on the one hand, the interaction energy between fluorine-containing molecules and water molecules is significantly lower than that of hydrophobic carbon chains, thus the anti-adhesion effect of fluorine-containing molecules is superior; on the other hand, the CF bond is a strongly polar functional group with extremely weak chemical affinity for nonpolar molecules such as methane molecules, thus effectively preventing the nucleation and growth of hydrates inside the microstructure of the coating.

[0045] In an exemplary embodiment, the mixed solvent described above includes anhydrous ethanol and isopropanol; the volume ratio of ethanol to isopropanol in the mixed solvent is 4:6; in practical applications, anhydrous ethanol and isopropanol can be mixed based on the volume ratio described herein to serve as a mixed solvent; based on this, it can achieve the following effects: on the one hand, it has good solubility for monomers and initiators, and on the other hand, it is beneficial to the uniform dispersion of three-dimensional dendritic silica (powder A and powder B).

[0046] In one exemplary embodiment, during the process of ultrasonically dispersing powder A into a mixed solvent to obtain a second dispersion, nitrogen protection and stirring are maintained, the reaction temperature is 65-85 °C, and the reaction time is 8-12 h. Specifically, in practical applications, nitrogen protection and stirring are used because free radical reactions require nitrogen protection to eliminate interference from oxygen, as oxygen has a strong inhibitory or even destructive effect on most free radical reactions.

[0047] In one exemplary embodiment, the mass ratio of the powder A described above to the added N-vinylcaprolactam monomer is 1:5 to 2:3; the mass ratio of the N-vinylcaprolactam monomer to the azobisisobutyronitrile initiator is 1:(0.01 to 0.1); and the mass-volume ratio between the N-vinylcaprolactam monomer and the mixed solvent is 1 g:20 mL to 1 g:50 mL.

[0048] In one exemplary embodiment, the molecular weight of the polyhydroxyl polyether resin is 80,000 to 100,000. Using a high molecular weight polyhydroxyl polyether resin as a binder enhances the bonding strength with the substrate and allows the hydroxyl groups to form a thermodynamically inhibiting barrier on the surface, further improving the hydrate nucleation inhibition performance. Furthermore, the organic solvent described above includes multiple components from the following: xylene, ethylene glycol monobutyl ether, and cyclohexanone. Specifically, in this organic solvent, the weight percentages of xylene are 50 to 60 parts; the weight percentages of ethylene glycol monobutyl ether are 20 to 30 parts; and the weight percentages of cyclohexanone are 15 to 25 parts. The role of the organic solvent described here is to facilitate the uniform dispersion of powder B, the dissolution of the resin, and the film-forming properties of the subsequent coating, ensuring that evaporation is neither too fast nor too slow.

[0049] In one exemplary embodiment, the prepared anti-cage hydrate coating comprises multiple components selected from the following: powder B, polyhydroxy polyether resin, and organic solvent; the powder B is present in parts by weight of 20-30 parts, the polyhydroxy polyether resin in parts by weight of 10-15 parts, and the organic solvent in parts by weight of 60-65 parts. Furthermore, the coating prepared based on this anti-cage hydrate coating exhibits excellent anti-hydrate performance, reducing the adhesion between cyclopentane hydrate and pipe steel from 0.58 mN / m to a level undetectable by instruments; additionally, the coating can extend the methane hydrate nucleation induction time from 284 min to 4500 min; therefore, this anti-cage hydrate coating has promising application prospects in its relevant fields.

[0050] The following will further explain and illustrate the coating preparation method for anti-cage hydrate described in the exemplary embodiments of this disclosure, with reference to specific examples.

[0051] Example 1: A) Preparation of Powder B: First, 10 g of three-dimensional dendritic SiO2 nanoparticles were dispersed in 100 mL of 95% ethanol, and 0.25 g of perfluorooctyltriethoxysilane and 0.05 g of silane coupling agent KH570 surface modifier were added. The mixture was stirred at room temperature for 12 h, then washed with anhydrous ethanol by centrifugation, and dried under vacuum at 60 °C to obtain powder A. Second, 10 g of powder A and 15 g of N-vinylcaprolactam monomer were ultrasonically dispersed in a mixed solvent of 120 mL of anhydrous ethanol and 180 mL of isopropanol. Nitrogen gas was purged and stirring was started. Then, 1.5 g of azobisisobutyronitrile initiator was added and the temperature was raised to 75 °C for polymerization. The reaction was stopped after 10 h, and then washed with anhydrous ethanol by centrifugation at 60 °C. Powder B was obtained after vacuum drying at ℃; II) Preparation of anti-cage hydrate coating: 32.5 parts xylene, 19.5 parts ethylene glycol monobutyl ether, and 13 parts cyclohexanone were mixed evenly, and then 15 parts polyhydroxy polyether resin (average molecular weight 80,000) were added. After the polyhydroxy polyether resin was completely dissolved, 20 parts powder B were added, and the mixture was dispersed at 1500 rpm for 30 min to obtain an anti-cage hydrate coating. Finally, the anti-cage hydrate coating was applied to the surface of the inner wall of the natural gas transportation pipeline to obtain the corresponding coating. The transmission electron microscope image of the three-dimensional dendritic SiO2 nanoparticles described here can be found in [reference needed]. Figure 4 As shown.

[0052] Example 2: I) Preparation of Powder B: First, 10 g of three-dimensional dendritic SiO2 nanoparticles were dispersed in 100 mL of 95% ethanol, and 0.36 g of perfluorodecyltriethoxysilane and 0.14 g of silane coupling agent KH570 surface modifier were added. The mixture was stirred at room temperature for 12 h, then washed with anhydrous ethanol by centrifugation, and vacuum dried at 60 °C to obtain powder A. Next, 10 g of powder A and 50 g of N-vinylcaprolactam monomer were ultrasonically dispersed in a mixed solvent of 700 mL ethanol and 1050 mL isopropanol. Nitrogen gas was purged and stirring was started. Then, 2.5 g of azobisisobutyronitrile initiator was added, and the temperature was raised to 85 °C for polymerization. The reaction was stopped after 8 h, and then washed with anhydrous ethanol by centrifugation at 60 °C. Powder B is obtained after vacuum drying at ℃; II) Preparation of anti-cage hydrate coating: 37.8 parts xylene, 15.75 parts ethylene glycol monobutyl ether, and 9.45 parts cyclohexanone are mixed evenly, and then 12 parts polyhydroxy polyether resin (average molecular weight 100,000) are added. After the resin is completely dissolved, 25 parts powder B are added, and the mixture is dispersed at 1500 rpm for 30 min to obtain anti-cage hydrate coating. Finally, the anti-cage hydrate coating is applied to the surface of the inner wall of the natural gas transportation pipeline to obtain the corresponding coating.

[0053] Example 3: I) Preparation of Powder B: First, 10 g of three-dimensional dendritic SiO2 nanoparticles were dispersed in 100 mL of 95% ethanol, and a surface modifier composed of 0.64 g of perfluorododecyltriethoxysilane and 0.16 g of silane coupling agent KH570 was added. The mixture was stirred at room temperature for 12 h, then washed with anhydrous ethanol by centrifugation, and vacuum dried at 60 °C to obtain powder A. Next, 10 g of powder A and 30 g of N-vinylcaprolactam monomer were ultrasonically dispersed in a mixed solvent composed of 600 mL of ethanol and 900 mL of isopropanol. Nitrogen gas was purged and stirring was started. Then, 0.3 g of azobisisobutyronitrile initiator was added, and the temperature was raised to 65 °C for polymerization. The reaction was stopped after 12 h, and then washed with anhydrous ethanol by centrifugation. Powder B is obtained after vacuum drying at ℃; II) Preparation of anti-cage hydrate coating: 33 parts xylene, 12 parts ethylene glycol monobutyl ether, and 15 parts cyclohexanone are mixed evenly, and then 10 parts polyhydroxy polyether resin (average molecular weight 89,000) are added. After the resin is completely dissolved, 30 parts powder B are added and dispersed at 1500 rpm for 30 min to obtain anti-cage hydrate coating. Finally, the anti-cage hydrate coating is applied to the surface of the inner wall of the natural gas transportation pipeline to obtain the corresponding coating.

[0054] Comparative Example 1: I) Preparation of Powder A: 10 g of three-dimensional dendritic SiO2 nanoparticles were dispersed in 100 mL of 95% ethanol, and 0.3 g of perfluorooctyltriethoxysilane surface modifier was added. The mixture was stirred at room temperature for 12 h, then washed with anhydrous ethanol by centrifugation, and dried under vacuum at 60 °C to obtain powder A; II) Preparation of anti-cage hydrate coating: 32.5 parts of xylene, 19.5 parts of ethylene glycol monobutyl ether, and 13 parts of cyclohexanone were mixed evenly, and then 15 parts of polyhydroxy polyether resin (average molecular weight 80,000) were added. After the resin was completely dissolved, 20 parts of powder A were added, and the mixture was dispersed at high speed of 1500 rpm for 30 min to obtain an anti-cage hydrate coating. Finally, the anti-cage hydrate coating was applied to the surface of the inner wall of the natural gas transportation pipeline to obtain the corresponding coating.

[0055] Comparative Example 2: Preparation of Powder B: First, 10 g of three-dimensional dendritic SiO2 nanoparticles were dispersed in 100 mL of 95% ethanol, and 0.3 g of silane coupling agent KH570 was added as a surface modifier. The mixture was stirred at room temperature for 12 h, then washed with anhydrous ethanol by centrifugation, and vacuum dried at 60 °C to obtain powder A. Second, 10 g of powder A and 15 g of N-vinylcaprolactam monomer were ultrasonically dispersed in a mixed solvent of 120 mL of ethanol and 180 mL of isopropanol. Nitrogen gas was purged and stirring was started. Then, 1.5 g of azobisisobutyronitrile initiator was added, and the temperature was raised to 75 °C for polymerization. The reaction was stopped after 10 h, and then washed with anhydrous ethanol by centrifugation at 60 °C. Powder B is obtained after vacuum drying at ℃; II) Preparation of anti-cage hydrate coating: 32.5 parts xylene, 19.5 parts ethylene glycol monobutyl ether, and 13 parts cyclohexanone are mixed evenly, and then 15 parts polyhydroxy polyether resin (average molecular weight 80,000) are added. After the resin is completely dissolved, 20 parts powder B are added. After high-speed dispersion at 1500 rpm for 30 min, the anti-cage hydrate coating is obtained. Finally, the anti-cage hydrate coating is applied to the surface of the inner wall of the natural gas transportation pipeline to obtain the corresponding coating.

[0056] Comparative Example 3: Preparation of Powder B: First, 10 g of three-dimensional dendritic SiO2 nanoparticles were dispersed in 100 mL of 95% ethanol. 0.25 g of perfluorooctyltriethoxysilane and 0.05 g of silane coupling agent KH570 were added as surface modifiers. The mixture was stirred at room temperature for 12 h, then washed by centrifugation with anhydrous ethanol and vacuum dried at 60 °C to obtain powder A. Next, 10 g of powder A and 15 g of N-vinylcaprolactam monomer were ultrasonically dispersed in a mixed solvent of 120 mL of ethanol and 180 mL of isopropanol. Nitrogen gas was purged and stirring was started. Then, 1.5 g of azobisisobutyronitrile initiator was added, and the temperature was raised to 75 °C for polymerization. The reaction was stopped after 10 h, and the mixture was then washed by centrifugation with anhydrous ethanol and vacuum dried at 60 °C. Powder B is obtained after vacuum drying at ℃; II) Preparation of anti-cage hydrate coating: 32.5 parts xylene, 19.5 parts ethylene glycol monobutyl ether and 13 parts cyclohexanone are mixed evenly, then 15 parts epoxy resin E44 are added. After the resin is completely dissolved, 20 parts powder B are added. After high-speed dispersion at 1500 rpm for 30 min, the anti-cage hydrate coating is obtained. Finally, the anti-cage hydrate coating is applied to the surface of the inner wall of the natural gas transportation pipeline to obtain the corresponding coating.

[0057] Next, the coatings prepared in Examples 1-3 and Comparative Examples 1-3 will be subjected to performance tests. The parameters used in coating preparation are as follows: spraying pressure: ≥0.3 MPa; spray gun nozzle diameter: 1 mm; spraying distance: 20-30 cm. Examples 1-3 and Comparative Examples 1-2 were cured using the same method: the wet film could be cured in an oven at 150 °C for 30 min, or a curing agent (such as Miclean DIC-1001, added at 5% of the polyhydroxy ether resin) could be added to the coating and cured at room temperature for 48 h. Comparative Example 3 added a curing agent (such as phenolic amine T-31, added at 30% of the epoxy resin) to the coating. Scanning electron microscope images of the anti-cage hydrate coatings generated based on the exemplary examples of this disclosure (i.e., Examples 1-3) can be found in [reference needed]. Figure 5 As shown; an example diagram of the surface water contact angle of the anti-cage hydrate coating generated based on the anti-cage hydrate coating obtained in Example 1 can be referred to. Figure 6 As shown; an example diagram of the surface water contact angle of the anti-cage hydrate coating generated based on the anti-cage hydrate coating obtained in Comparative Example 2 can be referred to. Figure 7 As shown.

[0058] Furthermore, the obtained coating underwent performance testing, which included: firstly, testing the adhesion between the coating and the substrate using a cross-cut adhesion tester (grade 0 represents the highest grade); secondly, testing the water contact angle of a 5 μL water droplet on the coating surface using a contact angle meter; and thirdly, testing the adhesion between cyclopentane hydrate and the substrate material using relevant adhesion measurement devices and testing methods. Furthermore, the coating was laid flat in a low-temperature, high-pressure reactor, with a pressure of 6 MPa, a temperature of 278.15 K, and a stirring speed of 50 rpm, and the nucleation induction time of methane hydrate in the presence of different coatings was recorded. The continuous sliding surface image of water droplets on the anti-cage hydrate coating obtained based on Example 2 can be referenced. Figure 8 As shown; an example diagram illustrating the adhesion displacement between the anti-cage hydrate coating and cyclopentane hydrate generated based on the anti-cage hydrate coating obtained in Example 3 can be referenced. Figure 9 As shown; an example diagram illustrating the adhesion displacement between the anti-cage hydrate coating and cyclopentane hydrate generated based on the anti-cage hydrate coating obtained in Comparative Example 2 can be referenced. Figure 10 As shown; furthermore, the adhesion test chart of the anti-cage hydrate coating formed based on the anti-cage hydrate coating obtained in Example 1 can be referred to Figure 11 As shown; the adhesion test chart of the anti-cage hydrate coating formed by the anti-cage hydrate coating obtained in Comparative Example 3 can be referred to. Figure 12As shown in the figure. Meanwhile, the test results obtained are shown in Table 1 below.

[0059] Table 1: Test results of Examples 1-3 and Comparative Examples 1-3.

[0060]

[0061] Furthermore, although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0062] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention described herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not invented by this disclosure. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

Claims

1. A method for preparing a coating to resist cage-like hydrates, characterized in that, include: Step 1: Disperse three-dimensional dendritic SiO2 nanoparticles in 95% ethanol to obtain a first dispersion, and add a surface modifier to the first dispersion to modify it to obtain a modified dispersion; the surface modifier includes a first surface modifier and a second surface modifier; the first surface modifier is a fluorinated silane, and the second surface modifier is a silane coupling agent containing carbon-carbon double bonds; Step 2: After centrifugation, washing and drying, the modified dispersion is used to obtain powder A, which is then ultrasonically dispersed in a mixed solvent to obtain a second dispersion. Step 3: N-vinylcaprolactam monomer and azobisisobutyronitrile initiator are added to the second dispersion to carry out the polymerization reaction, and the polymerization result is obtained after the polymerization reaction is completed; Step 4: After centrifugation, washing and drying of the polymerization reaction result, powder B is obtained. Powder B, polyhydroxy polyether resin and organic solvent are mixed evenly to obtain a coating against cage-like hydrates, and a coating against cage-like hydrates is obtained based on the coating against cage-like hydrates.

2. The method for preparing an anti-cage hydrate coating according to claim 1, characterized in that, The three-dimensional dendritic SiO2 nanoparticles have a particle size of 200-350 nm and a specific surface area of ​​920-1200 m². 2 / g.

3. The method for preparing a coating to resist cage-like hydrates according to claim 1, characterized in that, The first surface modifier is one or more of perfluorooctyltriethoxysilane, perfluorodecyltriethoxysilane, and perfluorododecyltriethoxysilane.

4. The method for preparing an anti-cage hydrate coating according to claim 3, characterized in that, The molar ratio of the first surface modifier to the second surface modifier is 2.5:1 to 5:1; The total amount of the first surface modifier and the second surface modifier added is 3% to 8% of the mass of the three-dimensional dendritic SiO2 nanoparticles.

5. The method for preparing a coating to resist cage-like hydrates according to claim 1, characterized in that, The mixed solvent includes anhydrous ethanol and isopropanol; The volume ratio of ethanol to isopropanol in the mixed solvent is 4:

6.

6. The method for preparing a coating to resist cage-like hydrates according to claim 1, characterized in that, During the process of ultrasonically dispersing powder A into a mixed solvent to obtain a second dispersion, nitrogen protection was used while stirring was maintained, the reaction temperature was 65~85 °C, and the reaction time was 8~12 h.

7. The method for preparing a coating to resist cage-like hydrates according to claim 1, characterized in that, The mass ratio of powder A to the added N-vinylcaprolactam monomer is 1:5 to 2:3; The mass ratio of the N-vinylcaprolactam monomer to the azobisisobutyronitrile initiator is 1:(0.01~0.1); The mass-to-volume ratio of the N-vinylcaprolactam monomer to the mixed solvent is 1 g:20 mL to 1 g:50 mL.

8. The method for preparing a coating to resist cage-like hydrates according to claim 1, characterized in that, The molecular weight of the polyhydroxy polyether resin is 80,000 to 100,000; The organic solvent includes multiple components such as xylene, ethylene glycol monobutyl ether, and cyclohexanone.

9. The method for preparing a coating to resist cage-like hydrates according to claim 8, characterized in that, In the organic solvent, the xylene is present in parts by weight of 50 to 60 parts. The ethylene glycol monobutyl ether is present in parts by weight of 20-30 parts. The cyclohexanone is present in parts by weight of 15 to 25 parts.

10. The method for preparing a coating to resist cage-like hydrates according to claim 1, characterized in that, The prepared anti-cage hydrate coating includes multiple components from the following: powder B, polyhydroxy polyether resin, and organic solvent; the powder B has a weight ratio of 20-30 parts, the polyhydroxy polyether resin has a weight ratio of 10-15 parts, and the organic solvent has a weight ratio of 60-65 parts.

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