Paraffin-control pour point depressant as well as preparation method and application thereof
The graft copolymerization of walnut shell liquid with EVA enhances EVA's crystallization and nucleation abilities, addressing the limitations of existing EVA inhibitors, thereby improving the flow properties and safety of high-wax crude oils.
Patent Information
- Application Number
- CN202510458194.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-14
- Publication Date
- 2025-07-15
AI Technical Summary
The existing vinyl acetate copolymer (EVA) type decoagulation agents are not ideal in high wax-containing crude oils, especially after the polarity is enhanced, the solubility is deteriorated or nanohybrid modification is not conducive to crude oil processing, and it is difficult to simultaneously improve the eutectic and nucleation capabilities of wax crystals.
The anti-wax deflation agent was prepared by solution grafting method using cashew shell liquid and alcoholylated EVA. The long-chain alkanes in cashew acid were used to enhance the eutectic effect, and the molecular rigidity was improved through the benzene ring structure and nucleation ability was enhanced.
It significantly improves the coagulation effect and stability of the anti-wax deflation agent, reduces the crude oil coagulation point and viscosity, improves fluidity, and solves the problem of wax crystal deposition.
Smart Images
Figure CN120309779A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of paraffin inhibitors and pour point depressants, and specifically relates to a paraffin inhibitor and pour point depressant, a preparation method thereof, and an application thereof. Background Art
[0002] The largest primary energy source globally is petroleum. With the development of the petrochemical industry and science and technology, light crude oil has been gradually depleted, and industrial production, transportation, household electricity, etc. all rely on the supply of fossil energy. The crude oil produced in China is mainly paraffin-containing crude oil, which has the characteristics of high wax content, high pour point, and high viscosity. Its paraffin molecules begin to crystallize at relatively high temperatures. As the temperature further decreases, the spatial network structure formed by crystallization causes the wax crystal molecules to crosslink with each other, and over time, it will reduce the fluidity of the crude oil. When paraffin-containing crude oil is transported through pipelines, due to the temperature difference between the inside and outside of the pipeline, wax deposits are likely to form on the inner wall of the pipeline, greatly increasing the transportation difficulty. This not only increases the transportation cost of the crude oil but also poses certain safety hazards. Ethylene-vinyl acetate copolymer (EVA) is currently one of the most widely commercially used pour point depressants, but its pour point depressing effect on crude oil with high wax and asphaltene content is still not very ideal. Therefore, some researchers have chosen to further improve the improvement effect on the low-temperature fluidity of crude oil from two aspects: increasing the polarity of EVA through alcoholysis modification to enhance its dispersibility of wax crystals or enhancing the nucleation ability of EVA on wax crystals through nano-hybrid modification. However, the alcoholyzed EVA has poor solubility in some crude oils due to the enhanced polarity or the weakened eutectic effect with wax crystals, and the nano-hybrid modified EVA is not conducive to the subsequent crude oil processing process due to the high doping amount of nano-particles. Therefore, how to enhance the eutectic ability and nucleation ability of EVA with wax crystals while enhancing the polarity of EVA is the key factor to improve the applicable range of EVA-based pour point depressants in crude oil. Summary of the Invention
[0003] With the concept of environmental protection, the present invention extracts cashew shell liquid from cashew shells. The extracted cashew shell liquid is rich in cardanol acid. The cardanol acid molecule has a benzene ring structure, a long-chain alkane, and a carboxyl group at the same time. Therefore, the present invention uses the extracted cashew shell liquid to graft-modify alcoholyzed EVA (EVAL) to prepare a paraffin inhibitor and pour point depressant. Through the esterification grafting process of the carboxyl group in cardanol acid and the alcohol hydroxyl group of EVAL, the prepared paraffin inhibitor and pour point depressant, on the one hand, enhances the eutectic effect of EVAL through the long-chain alkane in cardanol acid, and on the other hand, improves the molecular rigidity of EVAL by introducing the benzene ring structure in cardanol acid, thereby enhancing its nucleation ability on wax crystals. Therefore, the paraffin inhibitor and pour point depressant prepared by the present invention significantly improves the effect on crude oil. So far, there has been no report on graft-modifying EVAL and cardanol acid as a crude oil pour point depressant.
[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:
[0005] The object of the present invention is to provide a paraffin inhibitor and pour point depressant, which is obtained by a one-step reaction of cardanol (CNSL) and alcoholized EVA through solution grafting method.
[0006] Furthermore, it is defined that the mass ratio of cardanol (CNSL) to alcoholized EVA is (1-20):1.
[0007] Furthermore, it is defined that the cardanol (CNSL) is prepared by the following steps: after cleaning the cashew nut shells to remove impurities, drying at 60°C - 80°C for 2h - 4h, repeatedly extracting with acetone for 3h - 8h, filtering the extract and separating acetone to obtain cardanol (CNSL); the mass ratio of cashew nut shells to acetone is 1∶(2-5).
[0008] Furthermore, it is defined that the alcoholized EVA is prepared by the following steps: completely dissolving EVA (ethylene-vinyl acetate copolymer) in toluene, adding methanol, magnetically stirring at 30°C - 70°C for 0.5h - 8h, then dropping sodium hydroxide solution, cooling to 30°C - 60°C after dropping, reacting for 2h - 5h, filtering, washing with methanol and drying at 60°C to remove residual solvent, thus obtaining alcoholized EVA (EVAL).
[0009] Furthermore, it is defined that the mass ratio of EVA to the volume of toluene is 50g:(10-1000)mL.
[0010] Furthermore, it is defined that the mass ratio of EVA to the volume of methanol is 50g:(200-500)mL.
[0011] Furthermore, it is defined that the concentration of the sodium hydroxide solution is 5g / L - 30g / L.
[0012] Furthermore, it is defined that the mass ratio of EVA to the volume of the sodium hydroxide solution is 50g:20mL.
[0013] Another object of the present invention is to provide a preparation method of a paraffin inhibitor and pour point depressant, including the following steps: dissolving cardanol (CNSL) and alcoholized EVA in a toluene solvent, carrying out solution stirring reaction under heating, filtering, washing with methanol and drying in vacuum to obtain the paraffin inhibitor and pour point depressant.
[0014] Furthermore, it is defined that the solution stirring reaction is carried out at 70°C - 110°C for 1h - 24h.
[0015] Furthermore, it is defined that drying in vacuum is carried out at 60°C for 16h - 24h.
[0016] Another object of the present invention is to provide an application of a paraffin inhibitor and pour point depressant, and the paraffin inhibitor and pour point depressant is injection molded into a paraffin prevention block for paraffin prevention in an oil well borehole.
[0017] Another object of the present invention is to provide an application of a paraffin inhibitor and pour point depressant, which is dissolved in an organic solvent and used as an additive for a waxy crude oil transportation pipeline.
[0018] In the present invention, anacardic acid in cashew nutshells is extracted by a low-boiling-point solvent acetone, and hydroxyl groups are introduced by alcoholysis of the polymer EVA. Through the method of solution grafting, esterification grafting of anacardic acid and EVAL is achieved. On the one hand, the prepared paraffin inhibitor and pour point depressant enhances the eutectic effect of EVAL through the long-chain alkanes in anacardic acid, and on the other hand, improves the molecular rigidity of EVAL and thus enhances its nucleation ability for wax crystals by introducing the benzene ring structure in anacardic acid, thereby improving the pour point depressing effect and stability of the paraffin inhibitor and pour point depressant. At the same time, cashew nutshells are cheap and easily available, belonging to bio-renewable biomass raw materials, and also recycling agricultural waste.
[0019] In order to further understand the features and technical content of the present invention, please refer to the following detailed description of the present invention and the attached drawings. However, the attached drawings are only for reference and illustration purposes and are not used to limit the present invention. Description of the Drawings
[0020] Figure 1 is the wax crystal morphology diagram of crude oil without any treatment;
[0021] Figure 2 is the wax crystal morphology diagram of crude oil with the paraffin inhibitor and pour point depressant added;
[0022] Figure 3 is the viscosity-temperature curve of crude oil before and after adding the additive. Detailed Embodiments
[0023] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, and at the same time do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can still be made. These all belong to the protection scope of the present invention.
[0024] Example 1. The preparation method of the paraffin inhibitor and pour point depressant in this example is achieved through the following steps:
[0025] Extraction of cashew nut shell liquid CNSL rich in anacardic acid: 100 g of raw cashew nut shells were cleaned to remove mechanical impurities and then placed in a forced-air drying oven, heated and dried at 70 °C for 2 h. Then, the dried cashew nut shells were put into a Soxhlet extractor, and 500 g of low-boiling-point solvent acetone was added for repeated extraction for 6 h. The extract was then filtered through a fast quantitative filter paper to remove the floccules and mechanical impurities of cashew nut shell particles in the solution. Then, according to the relative volatility, acetone was separated and recovered in a rotary evaporator under vacuum. Finally, the extract in the distillation flask was collected to obtain cashew nut shell liquid CNSL.
[0026] Preparation of alcoholysis EVA: 50 g of EVA (ethylene-vinyl acetate copolymer) was dissolved in 625 mL of solvent toluene. After the EVA was completely dissolved, 500 mL of methanol was added, and magnetic stirring was carried out at a temperature of 70 °C for 0.5 h. Then, 20 ml of sodium hydroxide solution (concentration 5 g / L) prepared was added dropwise to the flask at a rate of 2 drops per second, and then the temperature was lowered to 50 °C, and the reaction was carried out for 2 h. After the reaction ended, the product was filtered, washed with methanol, and then placed in a vacuum drying oven at 60 °C for drying for 24 h to remove the small amount of residual solvent therein. The product was EVAL (alcoholysis EVA).
[0027] The cashew nut shell liquid CNSL and EVAL were reacted at a mass ratio of 1:1 by stirring in solution at 100 °C for 4 h. After the reaction ended, the product was filtered, washed with methanol until the color no longer changed, and then placed in a vacuum drying oven at 60 °C for drying for 24 h to obtain the paraffin inhibitor and pour point depressant.
[0028] According to the mass of the crude oil, 400 ppm by weight of the paraffin inhibitor and pour point depressant was added, and then added to the waxy crude oil. The temperature was controlled at about 70 °C. After fully stirring for ten minutes, tests and characterizations of the pour point, viscosity-temperature curve, paraffin inhibition rate, and wax crystal morphology were carried out. The parameter data of the crude oil without any treatment and the crude oil added with the paraffin inhibitor and pour point depressant are as follows:
[0029] A: Changes in wax crystal structure
[0030] As Figure 1 shown, the wax crystals in the crude oil without the pour point depressant presented a dense three-dimensional network structure, and the oil phase was completely wrapped. As Figure 2 shown, after adding the paraffin inhibitor and pour point depressant, the wax crystal morphology in the crude oil showed a butterfly-like structure and was evenly dispersed, without forming a closed structure, and the oil phase was fully released.
[0031] B: Changes in pour point
[0032] Table 1 Pour point
[0033] Crude oil without any treatment Crude oil with paraffin inhibitor and pour point depressant 34℃ 11℃
[0034] As shown in Table 1, the pour point of the crude oil with the paraffin inhibitor and pour point depressant added decreased from the initial 34°C to 11°C.
[0035] C: The paraffin inhibition rate of the crude oil with the paraffin inhibitor and pour point depressant added reached 92.5%.
[0036] D: Viscosity-temperature curve
[0037] The viscosity-temperature curves of the crude oil before and after adding the agent are as Figure 3 shown. It can be seen that the viscosity of the crude oil with the paraffin inhibitor and pour point depressant added decreased by more than 30% respectively compared with the viscosity of the crude oil with the same dosage of EVA and EVAL pour point depressants added, and decreased by more than 70% compared with the viscosity of the crude oil without the agent added.
[0038] Example 2. The preparation method of the paraffin inhibitor and pour point depressant in this example is achieved through the following steps:
[0039] Extract cashew nut shell liquid CNSL rich in anacardic acid: Wash 100 g of raw cashew nut shells to remove mechanical impurities, then place them in a forced-air drying oven and heat-dry at 60°C for 4 h. Then put the dried cashew nut shells into a Soxhlet extractor, add 100 g of low-boiling-point solvent acetone and repeatedly extract for 8 h. Then filter the extract with a fast quantitative filter paper to remove the flocculants and mechanical impurities of cashew nut shell particles in the solution. Then separate and recover acetone in a rotary evaporator under reduced pressure according to the relative volatility. Finally, collect the extract in the distillation flask to obtain cashew nut shell liquid CNSL.
[0040] Prepare alcoholyzed EVA: Dissolve 50 g of EVA (ethylene-vinyl acetate copolymer, ethylene-vinyl acetate copolymer) in 400 mL of solvent toluene. After the EVA is completely dissolved, add 200 mL of methanol and carry out magnetic stirring at a temperature of 50°C for 6 h. Then add 20 mL of sodium hydroxide solution (concentration 30 g / L) dropwise into the flask at a rate of 1 drop per second, then lower the temperature to 30°C and react for 5 h. After the reaction is completed, filter the product, wash it with methanol, and then put it into a vacuum drying oven at 60°C to dry for 16 h to remove the small amount of residual solvent. The product is EVAL (alcoholyzed EVA).
[0041] Mix cashew nut shell liquid CNSL and EVAL in a mass ratio of 2:1, stir and react the solution at 70°C for 6 h. After the reaction is completed, filter the product, wash it with methanol until the color no longer changes, and then put it into a vacuum drying oven at 60°C to dry for 16 h to obtain the paraffin inhibitor and pour point depressant.
[0042] The specific embodiments of the present invention have been described above. It should be noted that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which do not affect the essence of the present invention.
Claims
1. A paraffin inhibitor and pour point depressant, characterized in that, The paraffin inhibitor and pour point depressant is obtained by a one-step reaction through solution grafting of cashew nut shell liquid (CNSL) and alcoholysis EVA.
2. The paraffin inhibitor and pour point depressant according to claim 1, characterized in that, The mass ratio of cashew nut shell liquid (CNSL) to alcoholysis EVA is (1 - 20):
1.
3. The paraffin inhibitor and pour point depressant according to claim 1, wherein The cashew nut shell liquid (CNSL) is prepared according to the following steps: After cleaning the cashew nut shells to remove impurities, drying them at 60°C - 80°C for 2h - 4h, repeatedly extracting with acetone for 3h - 8h, filtering the extract and separating out acetone to obtain the cashew nut shell liquid (CNSL); the mass ratio of cashew nut shells to acetone is 1∶(2 - 5).
4. The paraffin inhibitor and pour point depressant according to claim 1, characterized in that, The alcoholysis EVA is prepared according to the following steps: Completely dissolve EVA in toluene, then add methanol, magnetically stir at 30°C - 70°C for 0.5h - 8h, then dropwise add sodium hydroxide solution, after dropping, cool down to 30°C - 60°C, react for 2h - 5h, filter, wash with methanol and then dry at 60°C to remove the residual solvent, thus obtaining the alcoholysis EVA.
5. The paraffin inhibitor and pour point depressant according to claim 4, characterized in that, The mass ratio of EVA to the volume of toluene is 50g:(10 - 1000)mL; the mass ratio of EVA to the volume of methanol is 50g:(200 - 500)mL; the concentration of the sodium hydroxide solution is 5g / L - 30g / L, and the mass ratio of EVA to the volume of the sodium hydroxide solution is 50g:20mL.
6. The preparation method of the paraffin prevention and pour point depression agent according to any one of claims 1-5, characterized in that, It includes the following steps: Dissolve the cashew nut shell liquid (CNSL) and alcoholysis EVA in a toluene solvent, carry out solution stirring reaction under heating, filter, wash with methanol and then dry in vacuum to obtain the paraffin inhibitor and pour point depressant.
7. The method according to claim 6, wherein Carry out solution stirring reaction at 70°C - 110°C for 1h - 24h.
8. The method according to claim 6, wherein Dry in vacuum at 60°C for 16h - 24h.
9. The application of the paraffin inhibition and pour point depression agent according to any one of claims 1 to 5 or the paraffin inhibition and pour point depression agent according to any one of claims 6 to 8, characterized in that The paraffin inhibitor and pour point depressant is injection-molded into paraffin inhibitor blocks for paraffin inhibition in oil well boreholes.
10. The application of the paraffin inhibitor and pour point depressant according to any one of claims 1-5 or the paraffin inhibitor and pour point depressant according to any one of claims 6-8, characterized in that, The paraffin inhibitor and pour point depressant is dissolved in an organic solvent and used as an additive for the transportation pipeline of waxy crude oil.