A demulsifier, its preparation method and application

Abstract

The application discloses a preparation method of a demulsifier, which comprises the following steps: (1) performing an alkylation reaction on polyisobutylene, solvent oil D40 and phenol to obtain polyisobutylene phenol; (2) performing a Mannich amination reaction on the polyisobutylene phenol obtained in the step (1) with formaldehyde and an organic amine to obtain polyisobutylene Mannich amine; and (3) performing an alkoxylation reaction on the polyisobutylene Mannich amine after the reaction in the step (2) with an epoxide compound to generate a polyether compound, namely the demulsifier. The application further discloses the demulsifier prepared by using the preparation method of the demulsifier and application of the demulsifier to a crude oil pretreatment agent. The demulsifier prepared by the application has good low-temperature demulsification performance, can be used as a main agent of the crude oil pretreatment agent, has a small addition amount, and is applied to atmospheric and vacuum distillation to remove salt, water and impurities from crude oil.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of petroleum chemical industry, and particularly relates to a demulsifier, a preparation method and application thereof. BACKGROUND

[0002] With the development of oil fields year by year, the water content in crude oil is increasing, the oil production is decreasing, the gas consumption per ton of oil is increasing, and the processing cost of crude oil production liquid is also increasing year by year. At present, the most direct and effective measure to reduce the energy consumption of oil gathering and dehydration is to reduce the oil gathering and dehydration temperature. However, the demulsification problem under low temperature condition is one of the technical problems.

[0003] The main reason for the difficulty of low-temperature demulsification of crude oil is the influence of temperature. Compared with high-temperature dehydration, the viscosity of crude oil under low temperature is significantly increased, the diffusion and adsorption process of demulsifier in crude oil is hindered, and the migration speed of demulsifier is low.

[0004] The conventional demulsifier not only has low demulsification efficiency under low temperature, but also cannot reduce the viscosity and resistance, which aggravates the overload operation of oil transportation equipment, increases the energy consumption, and increases the difficulty of crude oil gathering and transportation. In addition, the conventional demulsifier has poor low-temperature demulsification effect, the water content in demulsified crude oil is high, the oil content in water is high, and the difficulty of sewage treatment is increased.

[0005] CN111423903A discloses a preparation method of a multi-branched cationic polyether reverse demulsifier, but the dosage is large, the demulsification temperature is high, and halogenated hydrocarbon is introduced into the system, which further pollutes the water body. CN106700059A discloses a preparation method of a phenolic amine aldehyde block polyether low-temperature demulsifier, but the dosage of the product in the demulsification experiment is high, reaching 80 ppm, which is about 8 times of the dosage of the present application, the demulsification temperature is above 40 DEG C, and the water phase is turbid after demulsification (especially at 40 DEG C), and the dehydration rate is not high.

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

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

[0008] The technical solution adopted in this invention is: a method for preparing a demulsifier, specifically including the following steps: (1) after stirring polyisobutylene, solvent oil D40 and phenol evenly, 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℃, the stirring time is 24h, the catalyst is trifluoromethanesulfonic acid, and the amount of solvent oil D40 added as a solvent is not specifically required; (2) the polyisobutylene phenol obtained in step (1) is subjected to a Mannich amination reaction with formaldehyde and organic amine to obtain polyisobutylene Mannich amine, wherein the temperature is 100℃, the reaction time is 3h, the reaction is carried out under pressure, and the pressure is 0.1Mpa; (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℃ during the reaction process, and when the pressure in the reactor does not change, the material is cooled and discharged to obtain the demulsifier.

[0009] This invention introduces highly reactive polyisobutylene onto phenol via an alkylation reaction. This not only extends the carbon chain of the benzene ring and increases the molecular weight of the substance, but also, because polyisobutylene has active C=C double bonds at both ends, it can react with epoxy compounds to obtain highly reactive epoxy groups, forming long-chain epoxy compounds, which thus become the main component of the demulsifier. At the same time, the block polyether generated after 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 to polyisobutylene and 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 or propylene oxide.

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

[0014] Preferably, the alkaline catalyst KOH accounts for 0.5% of the mass of 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 above method, wherein the number average molecular weight of the demulsifier is in the range of 3000-5000.

[0017] The above-mentioned number-average molecular weight range is used to achieve more efficient and rapid demulsification of emulsified crude oil, while balancing product quality and reaction costs.

[0018] This invention also provides an application of the above-mentioned demulsifier in crude oil pretreatment agents, wherein, based on the mass of the crude oil pretreatment agent, it comprises 20-40% of the polyether compound prepared above, 1-5% of dodecylbenzenesulfonic acid, and 55-79% of aromatic solvent oil. In use, the polyether compound, dodecylbenzenesulfonic acid, and aromatic solvent oil are simply mixed.

[0019] The beneficial effects of this invention are:

[0020] The demulsifier prepared by this invention has good low-temperature demulsification performance. It can be used as the main agent of crude oil pretreatment agent, and the amount added is small. It can be applied to atmospheric and vacuum distillation to desalt, dehydrate and remove impurities from crude oil. Detailed Implementation

[0021] The technical solution of the present invention will be further described in detail below through specific embodiments. All compounds used in the embodiments are commercially available, and any technical means not explicitly stated in the embodiments are existing technologies.

[0022] Example 1

[0023] The steps for preparing a demulsifier are as follows:

[0024] (1) Add 120g of melted phenol, 500g of solvent oil D40 and 1000g of polyisobutylene (weight average molecular weight 1000) to the reactor and stir until homogeneous. Then replace the air in the reactor with nitrogen three times (the molar ratio of phenol to polyisobutylene is 1.27:1). Then add 5g of trifluoromethanesulfonic acid catalyst to the reactor. Set the reaction temperature in the reactor to 30℃ and stir for 24h to obtain polyisobutylene phenol.

[0025] (2) Take 1100g of polyisobutylene phenol obtained in step (1), add 164g of a 33% dimethylamine aqueous solution and 97g of a 37% formaldehyde solution (the molar ratio of dimethylamine, formaldehyde and polyisobutylene phenol is 1.2:1), and heat to 100℃ for Mannich amination reaction for 3h. The reaction is carried out under pressure of 0.1MPa to obtain polyisobutylene Mannich amine.

[0026] (3) Take 1200g of polyisobutylene Mannich amine obtained in step (2) and add 6g of catalyst KOH (accounting for 0.5% of the amount of polyisobutylene Mannich amine) to a high-pressure reactor. Purge the pipeline and reactor with nitrogen three times, stir and raise the temperature. Under the conditions of reaction temperature of 140℃ and pressure of 0.3MPa, add 1760g of ethylene oxide and 580g of propylene oxide respectively. After the addition is complete, keep the temperature at 140℃ and continue the reaction until the pressure in the reactor no longer changes. Cool and discharge to obtain the demulsifier.

[0027] The number-average molecular weight of the block polyether was determined to be 3020 by GPC (gel permeation chromatography).

[0028] The steps for preparing the crude oil pretreatment agent are as follows:

[0029] 20 parts of demulsifier, 1 part of dodecylbenzenesulfonic acid and 79 parts of aromatic solvent oil 1500# were mixed and stirred for 20 minutes to obtain crude oil pretreatment agent.

[0030] Example 2

[0031] The steps for preparing a demulsifier are as follows:

[0032] (1) Add 102g of melted phenol, 500g of solvent oil D40, and 1000g of highly active polyisobutylene (weight average molecular weight 1000) to the reactor and stir until homogeneous. Then replace the air in the reactor with nitrogen three times (the molar ratio of phenol to polyisobutylene is 1.1:1). Then add 7g of trifluoromethanesulfonic acid catalyst to the reactor. Set the reaction temperature in the reactor to 30℃ and stir for 24h to obtain polyisobutylene phenol product.

[0033] (2) Take 1094g of polyisobutylene phenol obtained in step (1), add 110g of water, 110g of diethylamine, and 122g of 37% formaldehyde solution (where the molar ratio of diethylamine, formaldehyde, and polyisobutylene phenol is 1.5:1), and heat to 100℃ for Mannich amination reaction for 3h. The reaction is carried out under pressure of 0.1MPa to obtain polyisobutylene Mannich amine.

[0034] (3) Take 1250g of polyisobutylene Mannich amine obtained in step (2), add 6.25g of catalyst KOH (0.5% of the amount of polyisobutylene Mannich amine) to a high-pressure reactor, purge the pipeline and reactor with nitrogen three times, stir and heat. Under the conditions of reaction temperature of 140℃ and pressure of 0.3MPa, add 1320g of ethylene oxide and 1160g of propylene oxide respectively. After the addition is complete, maintain the temperature at 140℃ and continue the reaction until the pressure in the reactor no longer changes. Cool and discharge to obtain the demulsifier.

[0035] The number-average molecular weight of the block polyether was determined to be 3820 by GPC (gel permeation chromatography).

[0036] The steps for preparing the crude oil pretreatment agent are as follows:

[0037] 25 parts of demulsifier, 3 parts of dodecylbenzenesulfonic acid and 72 parts of aromatic solvent oil 1500# were mixed and stirred for 20 minutes to obtain crude oil pretreatment agent.

[0038] Example 3

[0039] The steps for preparing a demulsifier are as follows:

[0040] (1) Add 94g of melted phenol, 500g of solvent oil D40, and 1000g of highly active polyisobutylene (weight average molecular weight 1000) to the reaction vessel and stir until homogeneous. Then replace the air in the reaction vessel with nitrogen three times (the molar ratio of phenol to polyisobutylene is 1:1). Then add 7g of trifluoromethanesulfonic acid catalyst to the reaction vessel, set the reaction temperature in the vessel to 30℃, and stir the reaction for 24h to obtain polyisobutylene phenol product.

[0041] (2) Take 1000g of polyisobutylene phenol obtained in step (1), add 202g of water, 202g of dipropylamine, and 162g of 37% formaldehyde solution (where the molar ratio of dipropylamine, formaldehyde, and polyisobutylene phenol is 2.2:1), and heat to 100℃ for Mannich amination reaction for 3h. The reaction is carried out under pressure of 0.1MPa to obtain polyisobutylene Mannich amine.

[0042] (3) Take 1300g of polyisobutylene Mannich amine obtained in step (2), add 6.5g of catalyst KOH (accounting for 0.5% of the amount of polyisobutylene Mannich amine) to a high-pressure reactor, purge the pipeline and reactor with nitrogen three times, stir and heat. Under the conditions of reaction temperature of 140℃ and pressure of 0.3MPa, add 2100g of ethylene oxide and 700g of propylene oxide respectively. After the addition is complete, maintain the temperature at 140℃ and continue the reaction until the pressure in the reactor no longer changes. Cool and discharge to obtain the demulsifier.

[0043] The number-average molecular weight of the block polyether was determined to be 3916 by GPC (gel permeation chromatography).

[0044] The steps for preparing the crude oil pretreatment agent are as follows:

[0045] The crude oil pretreatment agent is obtained by mixing 30 parts of demulsifier, 1 part of dodecylbenzenesulfonic acid and 69 parts of aromatic solvent oil 1500# for 20 minutes.

[0046] Example 4

[0047] The steps for preparing a demulsifier are as follows:

[0048] (1) Add 135g of melted phenol, 500g of solvent oil D40, and 1000g of highly active polyisobutylene (weight average molecular weight 1000) to the reactor and stir until homogeneous. Then replace the air in the reactor with nitrogen three times (the molar ratio of phenol to polyisobutylene is 1.4:1). Then add 5g of trifluoromethanesulfonic acid catalyst to the reactor. Set the reaction temperature in the reactor to 30℃ and stir for 24h to obtain polyisobutylene phenol product.

[0049] (2) Take 1100g of polyisobutylene phenol obtained in step (1), add 242g of a 33% dimethylamine aqueous solution and 146g of a 37% formaldehyde solution (the molar ratio of dimethylamine, formaldehyde and polyisobutylene phenol is 1.8:1), and heat to 100℃ for Mannich amination reaction for 3h. The reaction is carried out under pressure of 0.1MPa to obtain polyisobutylene Mannich amine.

[0050] (3) Take 1200g of polyisobutylene Mannich amine obtained in step (2), add 6g of catalyst KOH (accounting for 0.5% of the amount of polyisobutylene Mannich amine) to a high-pressure reactor, purge the pipeline and reactor with nitrogen three times, stir and heat. At a reaction temperature of 140℃ and a pressure of 0.3MPa, add 1440g of ethylene oxide and 1000g of propylene oxide respectively. After the addition is complete, maintain the temperature at 140℃ and continue the reaction until the pressure in the reactor no longer changes. Cool and discharge to obtain the demulsifier.

[0051] The number-average molecular weight of the block polyether was determined to be 4029 by GPC (gel permeation chromatography).

[0052] The steps for preparing the crude oil pretreatment agent are as follows:

[0053] 25 parts of demulsifier, 3 parts of dodecylbenzenesulfonic acid and 72 parts of aromatic solvent oil 1500# were mixed and stirred for 20 minutes to obtain crude oil pretreatment agent.

[0054] Example 5

[0055] The steps for preparing a demulsifier are as follows:

[0056] (1) Add 150g of melted phenol, 500g of solvent oil D40, and 1000g of highly active polyisobutylene (weight average molecular weight 1000) to the reactor and stir until homogeneous. Then replace the air in the reactor with nitrogen three times (the molar ratio of phenol to polyisobutylene is 1.6:1). Then add 6g of trifluoromethanesulfonic acid catalyst to the reactor. Set the reaction temperature in the reactor to 30℃ and stir for 24h to obtain polyisobutylene phenol product.

[0057] (2) Take 1105g of polyisobutylene phenol obtained in step (1), add 225g of water, 225g of diethylamine, and 243g of 37% formaldehyde solution (where the molar ratio of diethylamine, formaldehyde, and polyisobutylene phenol is 3:1), and heat to 100℃ for Mannich amination reaction for 3h. The reaction is carried out under pressure of 0.1MPa to obtain polyisobutylene Mannich amine.

[0058] (3) Take 1400g of polyisobutylene Mannich amine obtained in step (2), add 7g of catalyst KOH (0.5% of the amount of polyisobutylene Mannich amine) to a high-pressure reactor, purge the pipeline and reactor with nitrogen three times, stir and heat. Under the conditions of reaction temperature of 140℃ and pressure of 0.3MPa, add 1980g of ethylene oxide and maintain the temperature at 140℃ to continue the reaction until the pressure in the reactor no longer changes, cool and discharge to obtain the demulsifier.

[0059] The number-average molecular weight of the block polyether was determined to be 3511 by GPC (gel permeation chromatography).

[0060] The steps for preparing the crude oil pretreatment agent are as follows:

[0061] The crude oil pretreatment agent is obtained by mixing 35 parts of demulsifier, 5 parts of dodecylbenzenesulfonic acid and 60 parts of aromatic solvent oil 1500# for 20 minutes.

[0062] Example 6

[0063] The steps for preparing a demulsifier are as follows:

[0064] (1) Add 188g of melted phenol, 500g of solvent oil D40, and 1000g of highly active polyisobutylene (weight average molecular weight 1000) to the reactor and stir until homogeneous. Then replace the air in the reactor with nitrogen three times (the molar ratio of phenol to polyisobutylene is 2:1). Then add 5g of trifluoromethanesulfonic acid catalyst to the reactor. Set the reaction temperature in the reactor to 30℃ and stir for 24h to obtain polyisobutylene phenol product.

[0065] (2) Take 1100g of polyisobutylene phenol obtained in step (1), add 101g of water, 101g of dipropylamine, and 81g of 37% formaldehyde solution (where the molar ratio of dipropylamine, formaldehyde, and polyisobutylene phenol is 1:1), and heat to 100℃ for Mannich amination reaction for 3h. The reaction is carried out under pressure of 0.1MPa to obtain polyisobutylene Mannich amine.

[0066] (3) Take 1200g of polyisobutylene Mannich amine obtained in step (2) and add 6g of catalyst KOH (accounting for 0.5% of the amount of polyisobutylene Mannich amine) to a high-pressure reactor. Purge the pipeline and reactor with nitrogen three times, stir and raise the temperature. Under the conditions of reaction temperature of 140℃ and pressure of 0.3MPa, add 750g of propylene oxide and maintain the temperature at 140℃ and continue the reaction until the pressure in the reactor no longer changes. Cool and discharge to obtain the demulsifier.

[0067] The number-average molecular weight of the block polyether was determined to be 4146 by GPC (gel permeation chromatography).

[0068] The steps for preparing the crude oil pretreatment agent are as follows:

[0069] 20 parts of demulsifier, 2 parts of dodecylbenzenesulfonic acid and 78 parts of aromatic solvent oil 1500# were mixed and stirred for 20 minutes to obtain crude oil pretreatment agent.

[0070] Comparative Example 1

[0071] The difference between Comparative Example 1 and Example 1 is that no epoxide compound is added after the Mannich amination reaction is completed in the demulsifier preparation step.

[0072] Comparative Example 2

[0073] The difference between Comparative Example 2 and Example 2 is that in the step of preparing the crude oil pretreatment agent, the 3 parts of dodecylbenzenesulfonic acid in Example 2 were replaced with an equal mass of aromatic solvent oil 1500#.

[0074] Crude oil pretreatment agent performance test:

[0075] Crude oil (containing abundant gum, asphalt, fatty acids, naphthenic acids, sulfur and nitrogen, as well as natural emulsifiers such as paraffin, sand, and clay) from a refinery in Shandong Province was selected. The water content was ≤0.6 wt%, and the salt content was 30 mg NaCl / L. To expedite the evaluation process, deionized water was added and mixed thoroughly to prepare a stable emulsion of crude oil and water with a water content of 5 wt%.

[0076] Nine 100mL stoppered graduated cylinders, numbered 1 to 9, were each given 50mL of emulsion. In cylinders 1 to 8, 10ppm of the crude oil pretreatment agent from Examples 1 to 6, Comparative Examples 1 and 2 were added and mixed thoroughly. The conical flask number 9 was used as a blank reagent without any pretreatment agent. The nine stoppered graduated cylinders were then placed in a 40°C constant temperature water bath. The oil-water separation was observed every 0.5 hours, along with the smoothness of the oil-water interface. The results are shown in Table 1.

[0077] Table 1: Experimental Results Data for Crude Oil Pretreatment Agent Performance Testing

[0078]

[0079] According to the data in Table 1, the demulsifier prepared in this application has excellent demulsification effect. Among them, comparing the data of Examples 1-6 and Comparative Example 1 in Table 1, it can be seen that the block polyether generated after the reaction of the Mannich amination product with the epoxy compound can further improve the demulsification performance. The block polyether demulsifier synthesized in this application is better than the comparative agent. Comparing the data of Examples 1-6 and Comparative Example 2 in Table 1, it can be seen that the added dodecylbenzenesulfonic acid, as a demulsifier, can improve the demulsification ability of the product after addition.

[0080] The above description is only a preferred embodiment 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 are also within the protection scope of the present invention.

Claims

1. A crude oil pretreatment agent, characterized in that, Based on the mass of the crude oil pretreatment agent, it includes 20-40% demulsifier, 1-5% dodecylbenzenesulfonic acid and 55-79% aromatic solvent oil; the preparation of the demulsifier includes the following steps: (1) alkylating high-activity polyisobutylene, solvent oil D40 and phenol to obtain polyisobutylene phenol; (2) reacting the polyisobutylene phenol obtained in step (1) with formaldehyde and organic amine with Mannich amination to obtain polyisobutylene Mannich amine; (3) reacting the polyisobutylene Mannich amine obtained in step (2) with epoxy compound with alkoxylation to generate polyether compound, i.e. demulsifier.

2. The crude oil pretreatment agent according to claim 1, characterized in that, In step (1), the molar ratio of highly active polyisobutylene to phenol is 1:1-1:2; in step (2), the molar ratio of formaldehyde, organic amine and polyisobutylene-phenol obtained in step (1) is 1-3:1-3:1; in step (3), the mass ratio of polyisobutylene-Mannich amine to epoxy compound is 1:0.6-1:2.

7.

3. The crude oil pretreatment agent according to claim 1, characterized in that, The organic amine in step (2) is one or more of dimethylamine, diethylamine or dipropylamine.

4. The crude oil pretreatment agent according to claim 1, characterized in that, The epoxy compound in step (3) is one or both of ethylene oxide or propylene oxide.

5. The crude oil pretreatment agent according to claim 1, characterized in that, Step (3) is detailed as follows: the product polyisobutylene Mannich amine after the reaction in step (2) and the catalyst KOH are placed into the reactor, purged with inert gas, stirred and heated, and then an epoxy compound is added to continue the reaction until the pressure inside the reactor no longer changes.

6. The crude oil pretreatment agent according to claim 5, characterized in that, The catalyst accounts for 0.5% of the mass of polyisobutylene Mannich amine.

7. The crude oil pretreatment agent according to claim 5, characterized in that, The temperature at which the epoxide compound is added is 140℃, and the pressure is 0.3MPa.

8. The crude oil pretreatment agent according to claim 1, characterized in that, The number-average molecular weight of the demulsifier is in the range of 3000-5000.

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