A demulsifier for crude oil containing impurities and its preparation method

Abstract

This invention provides a demulsifier for crude oil containing impurities and its preparation method, belonging to the technical field of oilfield demulsifiers. The method includes the following steps: S1, reacting a polyol and epichlorohydrin under Lewis acid catalysis to obtain a hydroxyl-terminated chloropolyether; then partially amination of the hydroxyl-terminated chloropolyether with an alkanolamine in an organic solvent to obtain an aminochloropolyether; S2, etherifying the aminochloropolyether with sodium alkoxide to obtain an aminoalkoxypolyether; then further reacting the aminoalkoxypolyether with an aliphatic or alicyclic diisocyanate to obtain a crosslinked polyether; S3, compounding the crosslinked polyether with a phenolic amine resin polyether to obtain the demulsifier for crude oil containing impurities. The technical solution provided by this invention achieves good demulsification effect on crude oil containing impurities.

Description

Technical Field

[0001] This invention relates to the field of oilfield demulsifier technology, specifically to a crude oil demulsifier containing impurities and its preparation method. Background Technology

[0002] As oilfields continue to be developed, they are gradually aging. To improve crude oil recovery, various methods have been proposed, among which chemical flooding technology, as one of the most promising methods, is widely used in oilfield recovery. Chemical flooding includes polymer flooding, alkaline water flooding, and surfactant flooding, which improve recovery by changing fluid properties or increasing the contact area between the fluid and the rock and crude oil. However, due to the extensive use of new polymers and surfactants, polymers inevitably appear in some crude oil produced fluids. The presence of residual polymers in crude oil leads to increased stability of oil-water emulsions, making oil-water separation difficult, and causing many problems such as increased emulsified oil and high impurity content in purified oil. This causes significant damage and burden to the formation and gathering and transportation system, thus posing new challenges to subsequent crude oil demulsification and resource recovery. Conventional demulsifiers are difficult to use to handle such produced fluids.

[0003] Patent CN114736337B, entitled "A Demulsifier, Its Preparation Method and Its Application," discloses a demulsifier that is a copolymer containing vinyl aromatics, long-chain α-olefins, and allyl alcohol polyethers. Using the copolymer as the main agent in heavy oil pretreatment, it exhibits good compatibility with heavy oil asphaltenes and resins, demonstrating excellent demulsification effects on stubborn emulsions formed by asphaltenes and sludge in heavy oil. Anionic surfactants such as dodecylbenzenesulfonic acid can disperse sludge emulsions, facilitating the better functioning of the copolymer demulsifier. However, the above technical solution has limited effectiveness in demulsifying crude oil containing polymers.

[0004] Therefore, there is a need to provide a crude oil demulsifier containing impurities and its preparation method to solve the problems existing in the prior art. Summary of the Invention

[0005] In view of this, the present invention provides a demulsifier for crude oil containing impurities and its preparation method, thereby achieving a good demulsification effect on crude oil containing impurities.

[0006] To achieve the above objectives, the present invention provides a method for preparing a crude oil demulsifier containing impurities, comprising the following steps: S1, polyol and epichlorohydrin are reacted under Lewis acid catalysis to obtain hydroxyl-terminated chlorinated polyether, and the hydroxyl-terminated chlorinated polyether is partially amination reaction with an alcohol amine in an organic solvent to obtain an amino-chlorinated polyether. S2. The aminochloropolyether is subjected to an etherification reaction with sodium alkoxide to obtain an aminoalkoxypolyether. The aminoalkoxypolyether is further reacted with an aliphatic or alicyclic diisocyanate to obtain a crosslinked polyether. S3. The cross-linked polyether and phenolic amine resin polyether are compounded to obtain a crude oil demulsifier containing impurities.

[0007] In the technical solution provided by this invention, the product obtained by ring-opening of polyol and epichlorohydrin is gradually subjected to amination and etherification reactions with alkanolamine and sodium alkoxide to obtain aminoalkoxy polyether. After crosslinking, it is compounded with phenolic amine resin polyether. The resulting demulsifier has a rich polar amine structure. Combined with each raw material, it can achieve flocculation-agglomeration effect, flocculate impurities in crude oil, not only with good demulsification effect and flocculation of water droplets, but also facilitates subsequent impurity removal from crude oil.

[0008] Optionally, the conditions for synthesizing the hydroxyl-terminated chlorinated polyether are a temperature of 50-60°C and a time of 2-8 hours; the conditions for synthesizing the amino-chlorinated polyether are a temperature of 50-100°C and a time of 2-8 hours.

[0009] Optionally, the molar ratio of the polyol to epichlorohydrin is 1:9~30; the mass of the Lewis acid is 0.1~0.8% of the mass of the epichlorohydrin; and the mass ratio of the alkanolamine:terminated hydroxyl chloropolyether:organic solvent is 0.1~0.6:1:1~3.

[0010] Optionally, the polyol is glycerol or trimethylolpropane; the Lewis acid is one of triisobutylaluminum, aluminum trichloride, boron trifluoride ether, and phosphoric acid; the alkanolamine is monoethanolamine or isopropanolamine; and the organic solvent is xylene or S-1500 solvent oil.

[0011] Optionally, the synthesis conditions for the aminoalkoxy polyether are a temperature of 50~100℃ and a time of 2~8h; the synthesis conditions for the crosslinked polyether are 40~60℃ and a time of 2~8h; and the synthesis conditions for the compounding are a temperature of 40~50℃ and a time of 3~4h.

[0012] Optionally, the mass of the aliphatic or alicyclic diisocyanate is 0.5-5% of the mass of the terminal hydroxyl chlorinated polyether, and the mass of the sodium alkoxide is 10-60% of the mass of the terminal hydroxyl chlorinated polyether.

[0013] Optionally, the aliphatic or alicyclic diisocyanate includes one or more combinations of isophorone diisocyanate, methylcyclohexane diisocyanate and trimethylhexamethylene diisocyanate, and the sodium alkoxide is sodium methoxide or sodium ethoxide.

[0014] Optionally, the mass ratio of crosslinked polyether to phenolic amine resin polyether in S3 is 1:1~3.

[0015] Optionally, the epichlorohydrin, the alkanolamine, the sodium alkoxide, and the aliphatic or alicyclic diisocyanate are added dropwise; the aliphatic or alicyclic diisocyanate is dissolved in xylene and added dropwise to the aminoalkoxy polyether.

[0016] To achieve the above objectives, the present invention also provides a crude oil demulsifier containing impurities prepared by the above preparation method.

[0017] The above-described technical solution of the present invention has at least the following beneficial effects: In the technical solution provided by this invention, the product obtained by ring-opening of polyol and epichlorohydrin is gradually subjected to amination and etherification reactions with alkanolamine and sodium alkoxide to obtain aminoalkoxy polyether. After crosslinking, it is compounded with phenolic amine resin polyether. The resulting demulsifier has a rich polar amine structure. Combined with each raw material, it can achieve flocculation-agglomeration effect, flocculate impurities in crude oil, not only with good demulsification effect and water droplet flocculation, but also facilitates subsequent impurity removal of crude oil, achieving rapid demulsification, clean oil and water, saving energy, improving economic efficiency and equipment processing rate. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0019] The phenolic amine resin polyether used in the embodiments of this invention is a conventional phenolic amine resin polyether, which can be purchased or synthesized. One synthesis method is provided below: Synthesis of phenolic amine resin polyether (DPA): 292.5 kg of polyethylene polyamine (n=2) and 114.2 kg of bisphenol A were added to a reactor. The temperature was raised to 40-50°C, and 164.6 kg of formaldehyde (36.5%) solution was added dropwise over 2 hours. The mixture was kept at this temperature for 3 hours, and then dehydrated at 100-110°C under a vacuum of 0.085-0.095 MPa for about 3 hours to obtain 535 kg of phenolic amine resin (DP). The mixture was then cooled to 80°C for later use. 430.7 kg of phenolic amine resin (DP) was added to a high-pressure reactor, along with 1.5 kg of potassium hydroxide. The mixture was dehydrated at 100-110°C for half an hour, then the temperature was raised to 130-150°C. 580 kg of propylene oxide was introduced, and the reaction was allowed to proceed until complete. Then, 330 kg of ethylene oxide was introduced, and the reaction was allowed to proceed until complete to obtain phenolic amine resin polyether (DPA). The mixture was cooled to below 80°C and discharged for later use.

[0020] Example 1 92 kg of glycerol and 5 kg of boron trifluoride ether were added to a reaction vessel, heated to 50°C, and 925 kg of epichlorohydrin was added dropwise over 3 hours. The reaction continued for 4 hours to obtain hydroxyl-terminated chloropolyether, intermediate A. The temperature was then lowered to below 80°C, and the product was discharged for later use. 500 kg of intermediate A and 500 kg of xylene were added to a reaction vessel, heated to 100°C, and 100 kg of monoethanolamine was added dropwise over 2 hours. The reaction continued for 3 hours to obtain amino-terminated chloropolyether, intermediate B. The temperature was then lowered to below 80°C, and the product was discharged. 1100 kg of intermediate B was added to a reaction vessel, heated to 100°C, and 80 kg of xylene was added dropwise. 1 kg of sodium methoxide was added dropwise over 2 hours, and the reaction continued for 5 hours to obtain aminoalkoxy polyether, i.e., intermediate C. The mixture was cooled to below 80°C and discharged. 1100 kg of intermediate C was added to the reactor, the temperature was raised to 40°C, and 5 kg of trimethylhexamethylene diisocyanate (dissolved in 20 kg of xylene) was added dropwise over 2 hours. The reaction continued for 3 hours to obtain crosslinked polyether, i.e., intermediate D. The mixture was cooled to below 50°C and discharged. 1100 kg of intermediate D was added to the reactor, the temperature was raised to 40°C, and 2000 kg of phenolic amine resin polyether (DPA) was pumped in over 2 hours. The mixture was stirred for 2 hours to obtain crude oil demulsifier containing impurities, which was then discharged.

[0021] Example 2 92 kg of trimethylolpropane and 2.8 kg of triisobutylaluminum were added to a reactor, the temperature was raised to 60°C, and 2775 kg of epichlorohydrin was added dropwise over 3 hours. The reaction continued for 5 hours to obtain hydroxyl-terminated chloropolyether, i.e., intermediate A. The temperature was then lowered to below 80°C, and the product was discharged for later use. 600 kg of intermediate A and 1800 kg of S-1500 solvent oil were added to a reactor, the temperature was raised to 50°C, and 60 kg of isopropanolamine was added dropwise over 2 hours. The reaction continued for 5 hours to obtain aminochloropolyether, i.e., intermediate B. The temperature was then lowered to below 80°C, and the product was discharged. 1200 kg of intermediate B was added to a reactor and the temperature was raised to 50°C. Add 360 kg of sodium ethoxide dropwise over 2 hours, and continue the reaction for 3 hours to obtain aminoalkoxy polyether, i.e., intermediate C. Cool the mixture to below 80°C and discharge it. Add 1200 kg of intermediate C to the reactor, heat the mixture to 60°C, and add 30 kg of isophorone diisocyanate (dissolved in 20 kg of xylene) dropwise over 2 hours. Continue the reaction for 5 hours to obtain crosslinked polyether, i.e., intermediate D. Cool the mixture to below 50°C and discharge it. Add 1200 kg of intermediate D to the reactor, heat the mixture to 50°C, and add 1200 kg of phenolic amine resin polyether (DPA) over 2 hours. Continue stirring for 1 hour to obtain crude oil demulsifier containing impurities, and discharge it.

[0022] Example 3 92 kg of glycerol and 14.8 kg of aluminum trichloride were added to a reactor, the temperature was raised to 55°C, and 1850 kg of epichlorohydrin was added dropwise over 3 hours. The reaction continued for another 3 hours to obtain terminal hydroxyl chloropolyether, intermediate A. The temperature was then lowered to below 80°C, and the product was discharged for later use. 400 kg of intermediate A and 1200 kg of xylene were added to a reactor, the temperature was raised to 80°C, and 240 kg of isopropanolamine was added dropwise over 2 hours. The reaction continued for another 4 hours to obtain amino chloropolyether, intermediate B. The temperature was then lowered to below 80°C, and the product was discharged. 1000 kg of intermediate B was added to a reactor, the temperature was raised to 90°C, and 40 kg of isopropanolamine was added dropwise. 1000 kg of sodium ethoxide was added dropwise over 2 hours, and the reaction continued for 4 hours to obtain aminoalkoxy polyether, i.e., intermediate C. The mixture was cooled to below 80°C and discharged. 1000 kg of intermediate C was added to the reactor, the temperature was raised to 50°C, and 2 kg of methylcyclohexane diisocyanate (dissolved in 20 kg of xylene) was added dropwise over 2 hours. The reaction continued for 4 hours to obtain crosslinked polyether, i.e., intermediate D. The mixture was cooled to below 50°C and discharged. 1000 kg of intermediate D was added to the reactor, the temperature was raised to 45°C, and 3000 kg of phenolic amine resin polyether (DPA) was pumped in over 2 hours. The mixture was stirred for 1.5 hours to obtain crude oil demulsifier containing impurities, which was then discharged.

[0023] Example 4 Compared to Example 1, the only difference in Example 4 is that the aliphatic or alicyclic diisocyanate is 2.5 kg of isophorone diisocyanate and 2.5 kg of methylcyclohexane diisocyanate. All other raw materials and steps are the same as in Example 1.

[0024] Comparative Example 1 It is a commonly used modified phenolic amine polyoxypropylene polyoxyethylene resin demulsifier in the industry.

[0025] The demulsifiers of Examples 1-4 and Comparative Example 1 were tested for relevant performance. The demulsifier of the present invention was tested on crude oil containing impurities in an oilfield in Northwest China at a temperature of 45-55℃. The determination method and reagents of the bottle test method were in accordance with the People's Republic of China Petroleum and Natural Gas Industry Standard SY / T 5281-2000 "Test Method for Performance of Crude Oil Demulsifiers (Bottle Test Method)"; test conditions: 50℃, 50ml of oil, demulsifier dosage 100mg / l, manual mixing 100 times.

[0026] The physical properties of the oil containing impurities are as follows: oil sample density (density bottle method): 0.9254 g / ml (20℃); oil sample water content (distillation method): 54%; organic impurity content: 7.4%; the results are shown in Table 1.

[0027] Table 1 Performance test table of Examples 1-4 and Comparative Example 1

[0028] As shown in Table 1, the demulsifiers prepared in Examples 1-4 of the present invention perform better in terms of demulsification effect and dehydration rate compared with Comparative Example 1.

[0029] After using the demulsifier of Comparative Example 1, a slight emulsion layer appeared at the oil-water interface, while after using the demulsifiers prepared in Examples 1-4 of this invention, no emulsion layer appeared. It can be seen that the demulsifier provided by this invention is superior to Comparative Example 1 in terms of demulsification effect.

[0030] The inorganic content in the sediment after using the demulsifier of Comparative Example 1 was much lower than that after using the demulsifiers prepared in Examples 1-4, indicating that the demulsifier prepared in this invention performs better in demulsifying and removing impurities from inorganic polymers.

[0031] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process for the preparation of a demulsifier for hetero- crudes, characterized in that, Includes the following steps: S1, polyol and epichlorohydrin are reacted under Lewis acid or phosphoric acid catalysis to obtain hydroxyl-terminated chlorinated polyether, and the hydroxyl-terminated chlorinated polyether is partially amination reaction with an alcohol amine in an organic solvent to obtain an amino-chlorinated polyether. S2. The aminochloropolyether is subjected to an etherification reaction with sodium alkoxide to obtain an aminoalkoxypolyether. The aminoalkoxypolyether is further reacted with an aliphatic or alicyclic diisocyanate to obtain a crosslinked polyether. S3. The cross-linked polyether and phenolic amine resin polyether are compounded to obtain a crude oil demulsifier containing impurities.

2. The process for preparing a hetero-containing crude oil demulsifier according to claim 1, characterized in that, The conditions for synthesizing the terminal hydroxyl chlorinated polyether are a temperature of 50-60℃ and a time of 2-8h; the conditions for synthesizing the amino chlorinated polyether are a temperature of 50-100℃ and a time of 2-8h.

3. The method for preparing the crude oil demulsifier containing impurities according to claim 1, characterized in that, The molar ratio of the polyol to epichlorohydrin is 1:9~30; the mass of the Lewis acid is 0.1~0.8% of the mass of the epichlorohydrin; the mass ratio of the alkanolamine:terminated hydroxyl chloropolyether:organic solvent is 0.1~0.6:1:1~3.

4. The method for preparing the crude oil demulsifier containing impurities according to claim 3, characterized in that, The polyol is glycerol or trimethylolpropane; the Lewis acid is one of triisobutylaluminum, aluminum trichloride, or boron trifluoride ether; the alkanolamine is monoethanolamine or isopropanolamine; and the organic solvent is xylene or S-1500 solvent oil.

5. The method for preparing the crude oil demulsifier containing impurities according to claim 1, characterized in that, The synthesis conditions for the aminoalkoxy polyether are a temperature of 50-100℃ and a time of 2-8h; the synthesis conditions for the crosslinked polyether are a temperature of 40-60℃ and a time of 2-8h; and the synthesis conditions for the compound are a temperature of 40-50℃ and a time of 3-4h.

6. The method for preparing the crude oil demulsifier containing impurities according to claim 1, characterized in that, The mass of the aliphatic or alicyclic diisocyanate is 0.5-5% of the mass of the terminal hydroxyl chlorinated polyether, and the mass of the sodium alkoxide is 10-60% of the mass of the terminal hydroxyl chlorinated polyether.

7. The method for preparing the crude oil demulsifier containing impurities according to claim 6, characterized in that, The aliphatic or alicyclic diisocyanate includes one or more combinations of isophorone diisocyanate, methylcyclohexane diisocyanate and trimethylhexamethylene diisocyanate, and the sodium alkoxide is sodium methoxide or sodium ethoxide.

8. The method for preparing the crude oil demulsifier containing impurities according to claim 1, characterized in that, The mass ratio of cross-linked polyether to phenolic amine resin polyether in S3 is 1:1~3.

9. The method for preparing the crude oil demulsifier containing impurities according to claim 1, characterized in that, The epichlorohydrin, the alkanolamine, the sodium alkoxide, and the aliphatic or alicyclic diisocyanate are added dropwise; the aliphatic or alicyclic diisocyanate is dissolved in xylene and added dropwise to the aminoalkoxy polyether.

10. A crude oil demulsifier containing impurities prepared by the method of preparing the crude oil demulsifier containing impurities as described in any one of claims 1-9.

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