Demulsifier as well as preparation method and application thereof

Abstract

The invention discloses a preparation method of a demulsifier. The preparation method comprises the following steps: (1) carrying out alkylation reaction on polyisobutene, solvent oil D40 and phenol to obtain polyisobutene phenol; (2) carrying out Mannich amination reaction on the polyisobutene phenol obtained in the step (1), formaldehyde and organic amine to obtain polyisobutene Mannich amine; and (3) carrying out an alkoxylation reaction on the polyisobutene mannich amine after the reaction in the step (2) and an epoxy compound to generate a polyether compound, namely the demulsifier. The invention also discloses the demulsifier prepared by the preparation method of the demulsifier and application of the demulsifier in a crude oil pretreatment agent. The demulsifier prepared by the invention has better low-temperature demulsification performance, can be used as a main agent of a crude oil pretreatment agent, is less in addition amount, and is applied to atmospheric and vacuum distillation and desalination, dehydration and impurity removal of crude oil.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical industry, and in particular to a demulsifier and a preparation method and application thereof. Background Art

[0002] With the development of oil fields year by year, the water content of crude oil continues to rise, the oil production decreases, the gas consumption per ton of oil increases, and the treatment cost of crude oil production fluid also increases year by year. At present, the most direct and effective measure to reduce the energy consumption of oil collection and dehydration is to reduce the oil collection and dehydration temperature. However, the demulsification problem under low temperature conditions is one of the technical difficulties faced.

[0003] The main reason why crude oil is difficult to demulsify at low temperature is the influence of temperature. Compared with high temperature dehydration, the viscosity of crude oil increases significantly at low temperature, the diffusion and adsorption process of demulsifier in crude oil is hindered, and the migration speed of demulsifier becomes lower.

[0004] Conventional demulsifiers not only have low low-temperature demulsification efficiency and fail to reduce viscosity and drag, which aggravates the overload operation of oil transportation equipment, causes increased energy consumption, and increases the difficulty of crude oil gathering and transportation, but also have poor low-temperature demulsification effect, resulting in high water content and high oil content in the removed crude oil, which increases the difficulty of sewage treatment.

[0005] CN111423903A discloses a method for preparing a multi-branched cationic polyether reverse demulsifier, but the dosage is large and the demulsification temperature is high. At the same time, the introduction of halogenated hydrocarbons into the system will further pollute the water body. CN106700059A discloses a method for preparing a phenolamine-aldehyde block polyether low-temperature demulsifier, but the dosage of the product in the demulsification experiment is relatively high, reaching 80ppm, which is about 8 times the dosage of the present application. The demulsification temperature is above 40°C, and the water phase is turbid after demulsification (especially at 40°C), and the dehydration rate is not high.

[0006] Therefore, there is an urgent need for an environmentally friendly demulsifier with good low-temperature demulsification performance to solve the problem of high water content in crude oil and high oil content in water after electrical desalting. Summary of the invention

[0007] In order to solve the technical problem that conventional demulsifiers in the prior art have poor low-temperature demulsification effect, the present invention provides a demulsifier and a preparation method and application thereof.

[0008] The technical scheme adopted by the present invention is: a method for preparing a demulsifier, which specifically comprises the following steps: (1) after polyisobutylene, solvent oil D40 and phenol are uniformly stirred, a catalyst is added under an inert gas atmosphere to carry out an alkylation reaction to obtain polyisobutylene phenol, wherein the reaction temperature is 30°C, the stirring time is 24 hours, the catalyst is trifluoromethanesulfonic acid, and there is no specific requirement for the amount of solvent oil D40 added as a solvent; (2) the polyisobutylene phenol obtained in step (1) is subjected to a Mannich amination reaction with formaldehyde and an organic amine to obtain polyisobutylene Mannich amine, wherein the temperature is 100°C and the reaction time is 3 hours, and the reaction is carried out under pressure at a pressure of 0.1 MPa; (3) the polyisobutylene Mannich amine obtained in step (2) is subjected to an alkoxylation reaction with an epoxy compound to generate a polyether compound, i.e., a demulsifier, wherein the temperature is maintained at 140°C during the reaction process, and when the pressure in the kettle does not change, the material is cooled and discharged to obtain the demulsifier.

[0009] The invention introduces highly active polyisobutylene into phenol through an alkylation reaction, which can not only extend the carbon chain of the benzene ring and increase the molecular weight of the substance, but also active C=C double bonds exist at both ends of the polyisobutylene, which can react with epoxy compounds to obtain highly active epoxy groups and form long-chain epoxy compounds, thereby becoming the main component of the demulsifier. At the same time, the block polyether generated by the reaction of the Mannich amination product with the epoxy compound further improves the demulsification performance.

[0010] Preferably, in step (1), the molar ratio of polyisobutylene to phenol is 1:1-1:2; in step (2), the molar ratio of formaldehyde, organic amine and polyisobutylene phenol is 1-3::1-3:1; and in step (3), the mass ratio of polyisobutylene Mannich amine to epoxy compound is 1:0.6-1:2.7.

[0011] Preferably, the organic amine in step (2) is one or more of dimethylamine, diethylamine or dipropylamine.

[0012] Preferably, the epoxy compound in step (3) is one or both of ethylene oxide and propylene oxide.

[0013] Preferably, the detailed operation of step (3) is as follows: the product of the reaction in step (2), polyisobutylene Mannich amine, and the catalyst KOH are placed in a high-pressure reactor, the pipeline and the reactor are purged with an inert gas (preferably nitrogen), stirred and heated, and then the epoxy compound is added to continue the reaction until the pressure in the reactor no longer changes.

[0014] Preferably, the basic catalyst KOH accounts for 0.5% of the mass of the polyisobutylene Mannich amine.

[0015] Preferably, the temperature when the epoxy compound is introduced is 140° C. and the pressure is 0.3 MPa.

[0016] The present invention also provides a demulsifier prepared by the method, wherein the number average molecular weight of the demulsifier is in the range of 3000-5000.

[0017] The above number average molecular weight range is adopted in order to better demulsify the emulsified crude oil efficiently and quickly while balancing product quality and reaction cost.

[0018] The present invention also provides an application of the above demulsifier in a crude oil pretreatment agent, which comprises 20-40% of the above prepared polyether compound, 1-5% of dodecylbenzene sulfonic acid and 55-79% of aromatic solvent oil, based on the mass of the crude oil pretreatment agent. When used, the polyether compound, dodecylbenzene sulfonic acid and aromatic solvent oil are mixed.

[0019] Beneficial effects of the present invention: The demulsifier prepared by the invention has good low-temperature demulsification performance, can be used as the main agent of crude oil pretreatment agent, and has a small addition amount, and is applied to atmospheric and vacuum distillation to desalt, dehydrate and remove impurities from crude oil. DETAILED DESCRIPTION

[0020] The technical scheme of the present invention is further described in detail below through specific implementation methods. The compounds used in the examples are all commercially available, and the technical means not specified in the examples are all based on existing technologies. Example 1 To prepare the demulsifier, the steps are as follows:

[0021] (1) Add 120 g of melted phenol, 500 g of solvent oil D40 and 1000 g of polyisobutylene (weight average molecular weight 1000) into a reactor and stir evenly. Replace the air in the reactor with nitrogen three times (the molar ratio of phenol to polyisobutylene is 1.27:1). Then, add 5 g of trifluoromethanesulfonic acid as a catalyst dropwise into the reactor. Set the reaction temperature in the reactor to 30°C and stir for 24 hours to obtain polyisobutylene phenol.

[0022] (2) 1100 g of the polyisobutylene phenol obtained in step (1) was added with 164 g of a 33% aqueous dimethylamine solution and 97 g of a 37% formaldehyde solution (wherein the molar ratio of dimethylamine, formaldehyde to polyisobutylene phenol was 1.2:1), and the temperature was raised to 100° C. to carry out a Mannich amination reaction for 3 h. The reaction was carried out under pressure at a pressure of 0.1 MPa to obtain polyisobutylene Mannich amine.

[0023] (3) 1200 g of the polyisobutylene Mannich amine obtained in step (2) was added to a high-pressure reactor with 6 g of catalyst KOH (accounting for 0.5% of the amount of polyisobutylene Mannich amine used), and the pipeline and the reactor were purged with nitrogen for 3 times, stirred and heated. Under the conditions of a reaction temperature of 140° C. and a pressure of 0.3 MPa, 1760 g of ethylene oxide and 580 g of propylene oxide were respectively introduced. After the addition, the temperature was maintained at 140° C. and the reaction was continued until the pressure in the reactor no longer changed. The product was cooled and discharged to obtain a demulsifier.

[0024] The number average molecular weight of the block polyether was measured by GPC (gel chromatography) and was 3020.

[0025] The steps for preparing crude oil pretreatment agent are as follows: 20 parts of demulsifier, 1 part of dodecyl sulfonic acid and 79 parts of 1500# aromatic solvent oil were mixed and stirred for 20 minutes to obtain a crude oil pretreatment agent. Example 2

[0026] To prepare the demulsifier, the steps are as follows:

[0027] (1) Add 102 g of melted phenol, 500 g of solvent oil D40, and 1000 g of high-activity polyisobutylene (weight-average molecular weight 1000) into a reactor, stir evenly, replace the air in the reactor with nitrogen three times (wherein the molar ratio of phenol to polyisobutylene is 1.1:1), then dropwise add 7 g of catalyst trifluoromethanesulfonic acid into the reactor, set the reaction temperature in the reactor to 30°C, and stir the reaction for 24 hours; obtain polyisobutylene phenol product.

[0028] (2) 1094 g of the polyisobutylene phenol obtained in step (1) was added with 110 g of water, 110 g of diethylamine, and 122 g of a 37% formaldehyde solution (wherein the molar ratio of diethylamine, formaldehyde to polyisobutylene phenol was 1.5:1), and the temperature was raised to 100° C. to carry out a Mannich amination reaction for 3 h. The reaction was carried out under pressure at a pressure of 0.1 MPa to obtain polyisobutylene Mannich amine.

[0029] (3) Take 1250g of the polyisobutylene Mannich amine obtained in step (2), add 6.25g of catalyst KOH (accounting for 0.5% of the amount of polyisobutylene Mannich amine used) into a high-pressure reactor, purge the pipeline and the reactor with nitrogen for 3 times, stir and heat. Under the conditions of reaction temperature of 140°C and pressure of 0.3MPa, add 1320g of ethylene oxide and 1160g of propylene oxide respectively, keep the temperature at 140°C after addition and continue the reaction until the pressure in the reactor no longer changes, cool and discharge the material to obtain a demulsifier.

[0030] The number average molecular weight of the block polyether was measured by GPC (gel chromatography) and was 3820.

[0031] The steps for preparing crude oil pretreatment agent are as follows: 25 parts of demulsifier, 3 parts of dodecyl sulfonic acid and 72 parts of 1500# aromatic solvent oil were mixed and stirred for 20 minutes to obtain a crude oil pretreatment agent. Example 3

[0032] To prepare the demulsifier, the steps are as follows:

[0033] (1) Add 94 g of melted phenol, 500 g of solvent oil D40, and 1000 g of high-activity polyisobutylene (weight-average molecular weight 1000) into a reactor, stir evenly, replace the air in the reactor with nitrogen three times (wherein the molar ratio of phenol to polyisobutylene is 1:1), then dropwise add 7 g of catalyst trifluoromethanesulfonic acid into the reactor, set the reaction temperature in the reactor to 30°C, and stir the reaction for 24 hours; obtain polyisobutylene phenol product.

[0034] (2) Take 1000 g of the polyisobutylene phenol obtained in step (1), add 202 g of water, 202 g of dipropylamine, and 162 g of a 37% formaldehyde solution (wherein the molar ratio of dipropylamine, formaldehyde to polyisobutylene phenol is 2.2:1), raise the temperature to 100° C. and perform Mannich amination for 3 h. The reaction is carried out under pressure at a pressure of 0.1 MPa to obtain polyisobutylene Mannich amine.

[0035] (3) 1300 g of the polyisobutylene Mannich amine obtained in step (2) was added to a high-pressure reactor with 6.5 g of catalyst KOH (accounting for 0.5% of the amount of polyisobutylene Mannich amine used), and the pipeline and reactor were purged with nitrogen for 3 times, stirred and heated. Under the conditions of a reaction temperature of 140° C. and a pressure of 0.3 MPa, 2100 g of ethylene oxide and 700 g of propylene oxide were respectively introduced. After the addition, the temperature was maintained at 140° C. and the reaction was continued until the pressure in the reactor no longer changed. The product was cooled and discharged to obtain a demulsifier.

[0036] The number average molecular weight of the block polyether was measured by GPC (gel chromatography) and was 3916.

[0037] The steps for preparing crude oil pretreatment agent are as follows: 30 parts of demulsifier, 1 part of dodecyl sulfonic acid and 69 parts of 1500# aromatic solvent oil were mixed and stirred for 20 minutes to obtain a crude oil pretreatment agent. Example 4 To prepare the demulsifier, the steps are as follows:

[0038] (1) Add 135 g of melted phenol, 500 g of solvent oil D40, and 1000 g of high-activity polyisobutylene (weight-average molecular weight 1000) into a reactor, stir evenly, replace the air in the reactor with nitrogen three times (the molar ratio of phenol to polyisobutylene is 1.4:1), then dropwise add 5 g of catalyst trifluoromethanesulfonic acid into the reactor, set the reaction temperature in the reactor to 30°C, and stir the reaction for 24 hours; obtain polyisobutylene phenol product.

[0039] (2) 1100 g of the polyisobutylene phenol obtained in step (1) was added with 242 g of a 33% aqueous dimethylamine solution and 146 g of a 37% formaldehyde solution (wherein the molar ratio of dimethylamine, formaldehyde and polyisobutylene phenol was 1.8:1), and the temperature was raised to 100° C. to carry out a Mannich amination reaction for 3 h. The reaction was carried out under pressure at a pressure of 0.1 MPa to obtain polyisobutylene Mannich amine.

[0040] (3) Take 1200g of the polyisobutylene Mannich amine obtained in step (2), add 6g of catalyst KOH (accounting for 0.5% of the amount of polyisobutylene Mannich amine used) into a high-pressure reactor, purge the pipeline and the reactor with nitrogen for 3 times, stir and heat. At a reaction temperature of 140°C and a pressure of 0.3MPa, add 1440g of ethylene oxide and 1000g of propylene oxide respectively. After the addition, keep the temperature at 140°C and continue the reaction until the pressure in the reactor no longer changes, cool and discharge the material to obtain a demulsifier.

[0041] The number average molecular weight of the block polyether was measured by GPC (gel chromatography) and was 4029.

[0042] The steps for preparing crude oil pretreatment agent are as follows: 25 parts of demulsifier, 3 parts of dodecyl sulfonic acid and 72 parts of 1500# aromatic solvent oil were mixed and stirred for 20 minutes to obtain a crude oil pretreatment agent. Example 5 To prepare the demulsifier, the steps are as follows:

[0043] (1) Add 150 g of melted phenol, 500 g of solvent oil D40, and 1000 g of high-activity polyisobutylene (weight-average molecular weight 1000) into a reactor, stir evenly, replace the air in the reactor with nitrogen three times (the molar ratio of phenol to polyisobutylene is 1.6:1), then dropwise add 6 g of catalyst trifluoromethanesulfonic acid into the reactor, set the reaction temperature in the reactor to 30°C, and stir the reaction for 24 hours; obtain polyisobutylene phenol product.

[0044] (2) Take 1105 g of the polyisobutylene phenol obtained in step (1), add 225 g of water, 225 g of diethylamine, and 243 g of a 37% formaldehyde solution (wherein the molar ratio of diethylamine, formaldehyde to polyisobutylene phenol is 3:1), and heat to 100° C. to carry out Mannich amination reaction for 3 h. The reaction is carried out under pressure at a pressure of 0.1 MPa to obtain polyisobutylene Mannich amine.

[0045] (3) Take 1400g of the polyisobutylene Mannich amine obtained in step (2), add 7g of catalyst KOH (accounting for 0.5% of the amount of polyisobutylene Mannich amine used) into a high-pressure reactor, purge the pipeline and the reactor with nitrogen for 3 times, stir and heat. Under the conditions of reaction temperature of 140°C and pressure of 0.3MPa, add 1980g of ethylene oxide, maintain the temperature at 140°C, and continue the reaction until the pressure in the reactor no longer changes, cool and discharge the material to obtain a demulsifier.

[0046] The number average molecular weight of the block polyether was measured by GPC (gel chromatography) and was 3511.

[0047] The steps for preparing crude oil pretreatment agent are as follows: 35 parts of demulsifier, 5 parts of dodecyl sulfonic acid and 60 parts of 1500# aromatic solvent oil were mixed and stirred for 20 minutes to obtain a crude oil pretreatment agent. Example 6 To prepare the demulsifier, the steps are as follows:

[0048] (1) Add 188 g of melted phenol, 500 g of solvent oil D40, and 1000 g of high-activity polyisobutylene (weight-average molecular weight 1000) into a reactor, stir evenly, replace the air in the reactor with nitrogen three times (the molar ratio of phenol to polyisobutylene is 2:1), then dropwise add 5 g of catalyst trifluoromethanesulfonic acid into the reactor, set the reaction temperature in the reactor to 30°C, and stir the reaction for 24 hours; obtain polyisobutylene phenol product.

[0049] (2) Take 1100 g of the polyisobutylene phenol obtained in step (1), add 101 g of water, 101 g of dipropylamine, and 81 g of a 37% formaldehyde solution (wherein the molar ratio of dipropylamine, formaldehyde to polyisobutylene phenol is 1:1), and heat to 100° C. to carry out Mannich amination reaction for 3 h. The reaction is carried out under pressure at a pressure of 0.1 MPa to obtain polyisobutylene Mannich amine.

[0050] (3) 1200 g of the polyisobutylene Mannich amine obtained in step (2) was added to a high-pressure reactor with 6 g of catalyst KOH (accounting for 0.5% of the amount of polyisobutylene Mannich amine used), and the pipeline and the reactor were purged with nitrogen for 3 times, stirred and heated. Under the conditions of a reaction temperature of 140° C. and a pressure of 0.3 MPa, 750 g of propylene oxide was added, the temperature was maintained at 140° C., and the reaction was continued until the pressure in the reactor no longer changed, and the material was cooled and discharged to obtain a demulsifier.

[0051] The number average molecular weight of the block polyether was measured by GPC (gel chromatography) and was 4146.

[0052] The steps for preparing crude oil pretreatment agent are as follows: 20 parts of demulsifier, 2 parts of dodecyl sulfonic acid and 78 parts of 1500# aromatic solvent oil were mixed and stirred for 20 minutes to obtain a crude oil pretreatment agent.

[0053] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that in the step of preparing the demulsifier, no epoxy compound is added after the Mannich amination reaction is completed.

[0054] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that in the step of preparing the crude oil pretreatment agent, 3 parts of dodecylbenzenesulfonic acid in Example 2 are replaced by an equal mass of aromatic solvent oil 1500#.

[0055] Crude oil pretreatment agent performance test experiment: Crude oil in a storage tank of a refinery in Shandong (there are a lot of colloids, asphalt, fatty acids, cyclohexane acids, sulfur and nitrogen, as well as natural emulsifiers such as paraffin, sand, and clay in crude oil) was selected, with a water content of ≤0.6wt% and a salt content of 30 mgNaCl / L. In order to speed up the evaluation efficiency, deionized water was added and mixed evenly to prepare a stable emulsion of crude oil and water with a water content of 5 wt%.

[0056] Take 9 100mL stoppered measuring cylinders numbered 1 to 9 and add 50mL of the emulsion respectively, add 10ppm of the crude oil pretreatment agent of Examples 1 to 6, Comparative Example 1 and Comparative Example 2 to the stoppered measuring cylinders No. 1 to 8, and mix them evenly; No pretreatment agent is added to the No. 9 conical flask as a blank. Then put the 9 stoppered measuring cylinders into a 40°C constant temperature water bath, observe the oil-water separation status in the 9 stoppered measuring cylinders every 0.5 hours, and observe whether the oil-water interface is neat, and the results are shown in Table 1.

[0057] Table 1: Experimental results of crude oil pretreatment agent performance test

[0058] According to the data in Table 1, the demulsifier prepared in the present application has excellent demulsification effect; wherein the data of Examples 1-6 and Comparative Example 1 in Table 1 show that the block polyether generated by the reaction of the Mannich amination product with the epoxy compound can further improve the demulsification performance, and the block polyether demulsifier synthesized in the present application is better than the comparative agent; the data of Examples 1-6 and Comparative Example 2 in Table 1 show that the added dodecylbenzenesulfonic acid is a kind of demulsifier, and the demulsification ability of the product can be improved after addition.

[0059] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications are also within the protection scope of the present invention.

Claims

1. A method for preparing a demulsifier, characterized in that: The method comprises the following steps: (1) subjecting polyisobutylene, solvent oil D40 and phenol to an alkylation reaction to obtain polyisobutylene phenol; (2) subjecting the polyisobutylene phenol obtained in step (1) to a Mannich amination reaction with formaldehyde and an organic amine to obtain polyisobutylene Mannich amine; and (3) subjecting the polyisobutylene Mannich amine obtained in step (2) to an alkoxylation reaction with an epoxy compound to generate a polyether compound, i.e., a demulsifier.

2. The preparation method according to claim 1, characterized in that: In step (1), the molar ratio of polyisobutylene to phenol is 1:1-1:2; in step (2), the molar ratio of formaldehyde, organic amine and polyisobutylene phenol prepared in step (1) is 1-3:1-3:1; and in step (3), the mass ratio of polyisobutylene Mannich amine to epoxy compound is 1:0.6-1:2.

7.

3. The preparation method according to claim 1, characterized in that: The organic amine in step (2) is one or more of dimethylamine, diethylamine or dipropylamine.

4. The preparation method according to claim 1, characterized in that: The epoxy compound in step (3) is one or both of ethylene oxide and propylene oxide.

5. The preparation method according to claim 1, characterized in that: The detailed operation of step (3) is as follows: the product of step (2), polyisobutylene Mannich amine, and the catalyst KOH are placed in a reaction kettle, purged with an inert gas, stirred and heated, and then the epoxy compound is added to continue the reaction until the pressure in the kettle no longer changes.

6. The preparation method according to claim 5, characterized in that: The catalyst accounts for 0.5% of the mass of the polyisobutylene Mannich amine.

7. The preparation method according to claim 5, characterized in that: The temperature when the epoxy compound is added is: 140°C, and the pressure is: 0.3MPa.

8. The demulsifier prepared by the preparation method according to claim 1-7, characterized in that: The number average molecular weight of the demulsifier is in the range of 3000-5000.

9. The use of the demulsifier according to claim 8 in a crude oil pretreatment agent, characterized in that: Based on the quality of the crude oil pretreatment agent, it includes 20-40% of demulsifier, 1-5% of dodecylbenzene sulfonic acid and 55-79% of aromatic solvent oil.

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