A wax crystal dispersion inhibitor, its preparation method and application
By preparing a wax crystal dispersion inhibitor using copolymers and modified flake graphite, the problem of poor low-temperature performance of existing polymeric wax inhibitors was solved, achieving good wax crystal suppression and improved crude oil fluidity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YANGTZE UNIVERSITY
- Filing Date
- 2025-01-10
- Publication Date
- 2026-06-12
AI Technical Summary
Existing polymeric wax inhibitors have poor wax-preventing effects at low temperatures and are difficult to effectively inhibit the deposition of paraffin crystals in oil wells and pipelines.
A wax crystal dispersion inhibitor was prepared by using copolymers and modified flake graphite. The copolymers formed eutectic with paraffin and were adsorbed, while the modified flake graphite improved the lubricity and dispersibility of crude oil, thereby enhancing the wax crystal inhibition effect.
It significantly improves crude oil fluidity under low temperature conditions, reduces wax deposition on pipeline walls, and enhances the anti-wax effect.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention relates to the field of wax inhibitor preparation technology, specifically to a wax crystal dispersion inhibitor, its preparation method, and its application. Background Technology
[0002] Most of the crude oil produced in my country is paraffin-based, characterized by high wax content and a high wax precipitation point. For example, the wax content of crude oil from oilfields such as Daqing, Changqing, North China, and Zhongyuan is greater than 10%, with some blocks in Daqing and Changqing having a wax content of over 30% and a wax precipitation point as high as 29°C. As a result, during crude oil production and gathering and transportation, when the temperature of the wellbore and pipeline is lower than the wax precipitation point, the wax in the crude oil begins to crystallize and precipitate, depositing on the casing, pipes, and gathering and transportation pipelines, which has a serious negative impact on the production and operation of the oilfield.
[0003] Currently, commonly used wax removal and prevention technologies in oilfields include mechanical wax removal, thermal wax removal, surface energy wax prevention, magnetic wax prevention, microbial wax removal, and chemical wax removal. Chemical wax prevention is widely used in many oilfields due to its advantages such as rapid effectiveness, simple operation, and low cost. Polymer-based wax inhibitors are mostly oil-soluble comb-like polymers with side chains. After being injected into the well and mixed with crude oil, their paraffin-like structure forms a eutectic with the wax molecules. The polar groups in their molecules cause the formed crystal nuclei to distort and deform, preventing further wax crystal growth. In addition, the long molecular chains of the polymer can form a network structure throughout the crude oil, dispersing small crystal nuclei and preventing their aggregation and deposition, allowing them to easily flow away with the oil flow. However, current polymer-based wax inhibitors have drawbacks such as poor wax prevention effect, especially at low temperatures. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the present invention aims to provide a wax crystal dispersion inhibitor, its preparation method, and its application. The prepared wax crystal dispersion inhibitor has good anti-wax properties, especially low-temperature anti-wax properties.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] A method for preparing a wax crystal dispersion inhibitor includes the following steps:
[0007] S1. Preparation of copolymer: Glycidyl ether containing double bonds and maleic anhydride are added to solvent I, mixed evenly, and then an initiator is added. The mixture is heated to 100-150℃ and reacted for 2-10 hours. Then, an aliphatic primary amine or fatty alcohol is added to the mixture, and after mixing evenly, the mixture is reacted at 100-150℃ for 4-12 hours. After the reaction is completed, solvent I is removed to obtain the copolymer.
[0008] S2. Preparation of modified flake graphite: Flake graphite powder is added to concentrated H2SO4 solution and stirred and impregnated at 40-60℃ for 1-2 hours. After impregnation, it is filtered, washed, and dried, and then calcined at 800-1000℃ for 30-60 minutes to obtain a solid product. Subsequently, the solid product is immersed in hexadecyltrimethylammonium chloride solution and ultrasonically treated for 4-8 hours. After drying, modified flake graphite is obtained.
[0009] S3. Mix the copolymer, modified flake graphite and organic solvent evenly to obtain the wax crystal dispersion inhibitor.
[0010] Specifically, in step S1, the molar ratio of the glycidyl ether containing double bonds, maleic anhydride, initiator, aliphatic primary amine or fatty alcohol is 1:1-1.5:0.0001-0.0005:1-3.
[0011] Specifically, in step S1, the glycidyl ether containing a double bond is selected from one or more of allyl alcohol glycidyl ether, glycidyl methacrylate, glycidyl acrylate, and 4-hydroxybutyl acrylate glycidyl ether.
[0012] Specifically, in step S1, the initiator is selected from one or more of azobisisobutyronitrile, benzoyl peroxide, cumene hydroperoxide, tert-butyl peroxide, and diisopropyl peroxide.
[0013] Specifically, in step S1, the aliphatic primary amine is selected from one or more of octylamine, dodecylamine, octadecylamine, and tetradecylamine.
[0014] Specifically, in step S1, the fatty alcohol is selected from one or more of n-octanol, dodecanol, hexadecyl alcohol, and hexacosanol.
[0015] Specifically, in step S1, solvent I is selected from one or more of toluene, xylene, trimethylbenzene, and naphtha.
[0016] Specifically, in step S3, the mass ratio of the copolymer, modified flake graphite, and organic solvent is 10-25:5-10:100.
[0017] Specifically, in step S3, the organic solvent is selected from one or more of toluene, xylene, trimethylbenzene, and naphtha.
[0018] The present invention provides a wax crystal dispersion inhibitor prepared by the above preparation method.
[0019] The present invention also provides the application of the above-mentioned wax crystal dispersion inhibitor in the removal and prevention of wax in petroleum and natural gas.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] (1) The present invention obtains copolymers through copolymerization and side group modification. The side chains of the copolymers prepared have long alkyl chains similar to paraffin molecules. The long alkyl chains can form eutectics with paraffin molecules or adsorb paraffin crystals, so that microcrystalline paraffin is dispersed in crude oil, inhibiting crystal aggregation and growth. In addition, the hydrophilic groups connected on the main chain can be exposed on the surface of paraffin crystals, further inhibiting the crystallization of paraffin crystals and playing a good anti-waxing effect.
[0022] (2) In this invention, flake graphite powder is first treated with concentrated H2SO4 to introduce oxygen-containing functional groups into the graphite flakes. Then, the graphite is expanded by calcination, which increases the specific surface area and diffusivity of the flake graphite. Subsequently, it is immersed in a hexadecyltrimethylammonium chloride solution to load hexadecyltrimethylammonium chloride on the surface and between the flake graphite layers, thus obtaining modified flake graphite. Due to the introduction of modified flake graphite, the lubricity of crude oil is improved, the fluidity of crude oil is increased, and the pour point of crude oil is reduced, thereby reducing the deposition of wax on the pipe wall. The treatment of flake graphite with hexadecyltrimethylammonium chloride enhances the dispersibility and permeability of flake graphite in crude oil, increases the interfacial tension between paraffin and oil phase, and makes it difficult for wax to crystallize and precipitate by raising the nucleation barrier of wax, thus reducing the deposition of wax on the pipe wall.
[0023] (3) In the wax crystal dispersion inhibitor provided by the present invention, the copolymer improves the flow properties of crude oil by eutectic and / or adsorption with the wax in crude oil; the modified flake graphite can improve the lubricity of crude oil, thereby improving the flowability of crude oil. The composite wax inhibitor provided by the present invention has the characteristics of both wax crystal modifier and surfactant-type wax inhibitor. The copolymer and modified flake graphite work together to reduce the pour point of crude oil and reduce the deposition of wax on the pipe wall. Detailed Implementation
[0024] The present invention will be further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.
[0025] It should be noted that, unless otherwise specified, all chemical reagents involved in this invention were purchased through commercial channels.
[0026] The flake graphite powder used in this invention was purchased from Wuhan Jiyesheng Chemical Co., Ltd., CAS No.: 7782-42-5.
[0027] Example 1
[0028] A method for preparing a wax crystal dispersion inhibitor includes the following steps:
[0029] S1. Preparation of copolymer: 1 mol of allyl alcohol glycidyl ether and 1.1 mol of maleic anhydride were added to xylene and mixed evenly. Then 0.0001 mol of tert-butyl peroxide was added and the mixture was heated to 135℃ and reacted for 4 h. Then 2 mol of tetratetramine was added and mixed evenly. The mixture was then reacted at 135℃ for another 8 h. After the reaction was completed, the solvent was removed to obtain the copolymer.
[0030] S2. Preparation of modified flake graphite: 10g of flake graphite powder was added to concentrated H2SO4 solution and stirred and impregnated at 60℃ for 1h. After impregnation, the powder was filtered, washed and dried, and then calcined at 900℃ for 45min to obtain a solid product. The solid product was then impregnated in 4wt% hexadecyltrimethylammonium chloride solution and ultrasonically treated for 6h. After drying, modified flake graphite was obtained.
[0031] S3. Mix 15g of copolymer, 8g of modified flake graphite and 100g of organic solvent evenly, wherein the organic solvent is composed of 20% xylene, 40% trimethylbenzene and 40% naphtha, to obtain the wax crystal dispersion inhibitor.
[0032] Example 2
[0033] A method for preparing a wax crystal dispersion inhibitor includes the following steps:
[0034] S1. Preparation of copolymer: 1 mol glycidyl methacrylate and 1.2 mol maleic anhydride were added to xylene and mixed evenly. Then 0.0002 mol azobisisobutyronitrile was added and the mixture was heated to 135℃ and reacted for 4 h. Then 3 mol hexadecyl alcohol was added and mixed evenly. The mixture was then reacted at 135℃ for another 8 h. After the reaction was completed, the solvent was removed to obtain the copolymer.
[0035] S2. Preparation of modified flake graphite: 10g of flake graphite powder was added to concentrated H2SO4 solution and stirred and impregnated at 60℃ for 1h. After impregnation, the powder was filtered, washed and dried, and then calcined at 900℃ for 30min to obtain a solid product. The solid product was then impregnated in 3wt% hexadecyltrimethylammonium chloride solution and ultrasonically treated for 4h. After drying, modified flake graphite was obtained.
[0036] S3. Mix 12g of copolymer, 6g of modified flake graphite and 100g of organic solvent evenly, wherein the organic solvent is composed of 20% xylene, 40% trimethylbenzene and 40% naphtha, to obtain the wax crystal dispersion inhibitor.
[0037] Example 3
[0038] A method for preparing a wax crystal dispersion inhibitor includes the following steps:
[0039] S1. Preparation of copolymer: 1 mol glycidyl acrylate and 1.3 mol maleic anhydride were added to xylene and mixed evenly. Then 0.0002 mol azobisisobutyronitrile was added and the mixture was heated to 135℃ and reacted for 4 h. Then 2 mol cetyl alcohol was added and mixed evenly. The mixture was then reacted at 135℃ for another 8 h. After the reaction was completed, the solvent was removed to obtain the copolymer.
[0040] S2. Preparation of modified flake graphite: 10g of flake graphite powder was added to concentrated H2SO4 solution and stirred and impregnated at 60℃ for 1h. After impregnation, the powder was filtered, washed and dried, and then calcined at 900℃ for 45min to obtain a solid product. The solid product was then impregnated in 4wt% hexadecyltrimethylammonium chloride solution and ultrasonically treated for 6h. After drying, modified flake graphite was obtained.
[0041] S3. Mix 10g of copolymer, 10g of modified flake graphite and 100g of organic solvent evenly, wherein the organic solvent is composed of 20% toluene, 20% xylene, 30% trimethylbenzene and 30% naphtha, to obtain the wax crystal dispersion inhibitor.
[0042] Example 4
[0043] A method for preparing a wax crystal dispersion inhibitor includes the following steps:
[0044] S1. Preparation of copolymer: 1 mol of 4-hydroxybutyl acrylate glycidyl ether and 1.1 mol of maleic anhydride were added to xylene and mixed evenly. Then 0.0003 mol of benzoyl peroxide was added and the mixture was heated to 120℃ and reacted for 6 h. Then 2 mol of octadecylamine was added and mixed evenly. The mixture was then reacted at 120℃ for another 10 h. After the reaction was completed, the solvent was removed to obtain the copolymer.
[0045] S2. Preparation of modified flake graphite: 10g of flake graphite powder was added to concentrated H2SO4 solution and stirred and impregnated at 60℃ for 1h. After impregnation, the powder was filtered, washed, and dried. Then, it was calcined at 1000℃ for 30min to obtain a solid product. Subsequently, the solid product was immersed in 3wt% hexadecyltrimethylammonium chloride solution and ultrasonically treated for 8h. After drying, modified flake graphite was obtained.
[0046] S3. Mix 20g of copolymer, 5g of modified flake graphite and 100g of organic solvent evenly, wherein the organic solvent is composed of 20% xylene, 40% trimethylbenzene and 40% naphtha, to obtain the wax crystal dispersion inhibitor.
[0047] Comparative Example 1
[0048] A method for preparing a wax crystal dispersion inhibitor includes the following steps:
[0049] S1. Preparation of copolymer: 1 mol of allyl alcohol glycidyl ether and 1.1 mol of maleic anhydride were added to xylene and mixed evenly. Then 0.0001 mol of tert-butyl peroxide was added and the mixture was heated to 135℃ and reacted for 4 h. Then 2 mol of tetratetramine was added and mixed evenly. The mixture was then reacted at 135℃ for another 8 h. After the reaction was completed, the solvent was removed to obtain the copolymer.
[0050] S2. Mix 15g of copolymer and 100g of organic solvent evenly, wherein the organic solvent is composed of 20% xylene, 40% trimethylbenzene and 40% naphtha, to obtain the wax crystal dispersion inhibitor.
[0051] Comparative Example 2
[0052] A method for preparing a wax crystal dispersion inhibitor includes the following steps:
[0053] S1. Preparation of copolymer: 1 mol of allyl alcohol glycidyl ether and 1.1 mol of maleic anhydride were added to xylene and mixed evenly. Then 0.0001 mol of tert-butyl peroxide was added and the mixture was heated to 135℃ and reacted for 4 h. Then 2 mol of tetratetramine was added and mixed evenly. The mixture was then reacted at 135℃ for another 8 h. After the reaction was completed, the solvent was removed to obtain the copolymer.
[0054] S2. Mix 15g of copolymer, 8g of flake graphite and 100g of organic solvent evenly, wherein the organic solvent is composed of 20% xylene, 40% trimethylbenzene and 40% naphtha, to obtain the wax crystal dispersion inhibitor.
[0055] The anti-wax properties of the wax crystal dispersion inhibitors prepared in Examples 1-4 and Comparative Examples 1-2 in crude oil were evaluated:
[0056] The evaluation shall be conducted in accordance with the provisions of standard SYT6300-2009 "Technical Conditions for Cleaning and Wax Inhibitors in Oil Production", and the specific steps are as follows:
[0057] Anhydrous crude oil samples were stirred and cooled in a stainless steel cup. During the cooling process, a temperature gradient existed between the oil sample and the inner wall of the stainless steel cup, resulting in paraffin deposition. The effectiveness of the paraffin inhibitor was evaluated by measuring the difference in the amount of paraffin deposited on the inner wall of the stainless steel cup under conditions of adding and not adding the inhibitor. The dosages of the paraffin crystal dispersion inhibitor were 1000 ppm, 1500 ppm, and 2000 ppm, respectively. The experimental results are shown in Table 1.
[0058] Table 1
[0059]
[0060] The anti-wax properties of the wax crystal dispersion inhibitors prepared in Examples 1-4 and Comparative Examples 1-2 in natural gas condensate were evaluated:
[0061] Natural gas condensate samples were cooled to -40°C in a stainless steel cup and maintained for 2 hours. The flow state of the condensate was observed. The dosages of wax crystal dispersion inhibitors added were 0 ppm, 1000 ppm, 2000 ppm, and 3000 ppm, respectively. The experimental results are shown in Table 2.
[0062] Table 2
[0063] 0ppm 1000ppm 2000ppm 3000ppm Example 1 solidification Good liquidity Good liquidity Good liquidity Example 2 solidification Good liquidity Good liquidity Good liquidity Example 3 solidification Good liquidity Good liquidity Good liquidity Example 4 solidification Good liquidity Good liquidity Good liquidity Comparative Example 1 solidification solidification Good liquidity Good liquidity Comparative Example 2 solidification Good liquidity Good liquidity Good liquidity
[0064] Finally, it should be noted that the above embodiments do not limit the present invention in any way. Those skilled in the art can make modifications and improvements based on the present invention. Therefore, any modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.
Claims
1. A method for preparing a wax crystal dispersion inhibitor, characterized in that, Includes the following steps: S1. Preparation of copolymer: Glycidyl ether containing double bonds and maleic anhydride are added to solvent I, mixed evenly, and then an initiator is added. The mixture is heated to 100-150℃ and reacted for 2-10 hours. Then, an aliphatic primary amine or fatty alcohol is added to the mixture, and after mixing evenly, the mixture is reacted at 100-150℃ for 4-12 hours. After the reaction is completed, solvent I is removed to obtain the copolymer. S2. Preparation of modified flake graphite: Flake graphite powder is added to concentrated H2SO4 solution and stirred and impregnated at 40-60℃ for 1-2 hours. After impregnation, it is filtered, washed, and dried, and then calcined at 800-1000℃ for 30-60 minutes to obtain a solid product. Subsequently, the solid product is immersed in hexadecyltrimethylammonium chloride solution and ultrasonically treated for 4-8 hours. After drying, modified flake graphite is obtained. S3. Mix the copolymer, modified flake graphite and organic solvent evenly to obtain the wax crystal dispersion inhibitor; In step S1, the molar ratio of the glycidyl ether containing a double bond, maleic anhydride, initiator, aliphatic primary amine or fatty alcohol is 1:1-1.5:0.0001-0.0005:1-3. In step S1, the glycidyl ether containing a double bond is selected from one or more of allyl alcohol glycidyl ether, glycidyl methacrylate, and 4-hydroxybutyl acrylate glycidyl ether.
2. The method for preparing the wax crystal dispersion inhibitor according to claim 1, characterized in that, In step S1, the initiator is selected from one or more of azobisisobutyronitrile, benzoyl peroxide, cumene hydroperoxide, tert-butyl peroxide, and diisopropyl peroxide.
3. The method for preparing the wax crystal dispersion inhibitor according to claim 1, characterized in that, In step S1, the aliphatic primary amine is selected from one or more of octylamine, dodecylamine, octadecylamine, and tetradecylamine; the fatty alcohol is selected from one or more of n-octanol, dodecyl alcohol, hexadecyl alcohol, and hexadecyl alcohol.
4. The method for preparing the wax crystal dispersion inhibitor according to claim 1, characterized in that, In step S1, solvent I is selected from one or more of toluene, xylene, trimethylbenzene, and naphtha.
5. The method for preparing the wax crystal dispersion inhibitor according to claim 1, characterized in that, In step S3, the mass ratio of copolymer, modified flake graphite and organic solvent is 10-25:5-10:
100.
6. The method for preparing the wax crystal dispersion inhibitor according to claim 1, characterized in that, In step S3, the organic solvent is selected from one or more of toluene, xylene, trimethylbenzene, and naphtha.
7. The wax crystal dispersion inhibitor prepared by the preparation method according to any one of claims 1-6.
8. The application of the wax crystal dispersion inhibitor as described in claim 7 in the removal and prevention of wax in petroleum and natural gas.