A demulsifier for polymeric crude oil and a method for preparing the same

Abstract

The application belongs to the technical field of demulsifiers, and relates to a preparation method of a demulsifier for poly-containing crude oil. An alcohol ether with a high-activity double bond is used as a starter to carry out a polymerization reaction with a functional monomer containing not less than two vinyl groups, and a liquid aliphatic or alicyclic diisocyanate is used as a chain extender to prepare the demulsifier for the poly-containing crude oil. The demulsifier has stronger demulsification capacity and can not only make water droplets flocculate but also has a good flocculation effect on machine sundries.

Description

Technical Field

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

[0002] With the continuous development of oil fields and the extensive use of new polymers and surfactants in various acidizing, water-blocking, and enhanced oil recovery technologies, polymers inevitably appear in some crude oil produced fluids. These produced fluids are usually referred to as polymer-containing crude oil. The presence of residual polymers in polymer-containing crude oil leads to increased stability of oil-water emulsions, making oil-water separation difficult. It also causes many problems such as increased emulsified oil and high impurity content in purified oil, which cause significant damage and burden to the formation and gathering and transportation system. Consequently, subsequent crude oil demulsification and resource recovery face new challenges, and conventional demulsifiers are difficult to handle such produced fluids. Summary of the Invention

[0003] The purpose of this invention is to provide a demulsifier for crude oil containing polymers and its preparation method, to provide a demulsifier that can solve the problem of difficult oil-water separation of crude oil containing polymers, and to provide a demulsifier that solves the problem of incomplete dehydration of crude oil caused by excessive organic impurities in crude oil emulsions, thereby achieving rapid demulsification, clear oil and water, saving energy, and improving economic efficiency and equipment processing rate.

[0004] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a method for preparing a demulsifier for crude oil containing polypropylene, which is prepared by: using an alcohol ether with a highly active double bond as an initiator and a functional monomer containing no less than two vinyl groups to carry out a polymerization reaction, and using a liquid aliphatic or alicyclic diisocyanate as a chain extender to prepare a demulsifier for crude oil containing polypropylene.

[0005] A method for preparing a demulsifier for polymer-containing crude oil, comprising the following steps:

[0006] S1: 4-hydroxybutyl vinyl ether is propoxylated and ethoxylated with propylene oxide and ethylene oxide under an alkali metal catalyst to obtain intermediate A;

[0007] The reaction process is as follows:

[0008]

[0009] In the formula, m = 5 - 40, n = 5 - 60;

[0010] The alkali metal catalyst is potassium hydroxide;

[0011] The amount of alkali metal catalyst added is 0.05-0.6% of the total mass of propylene oxide and ethylene oxide;

[0012] The mass ratio of the 4-hydroxybutyl vinyl ether to propylene oxide and ethylene oxide is 1:3-16:3-18;

[0013] The reaction conditions of the 4-hydroxybutyl vinyl ether with propylene oxide and ethylene oxide are 110-140℃ and 0.1-0.4MPa.

[0014] S2: The intermediate A obtained in step S1 is polymerized with a functional monomer containing no less than two vinyl groups in xylene solvent in the presence of an initiator to obtain intermediate B.

[0015] The reaction process is as follows (taking glycerol-A,A'-diallyl ether as an example):

[0016]

[0017] In the formula, m = 5 - 40, n = 5 - 60, and p = 100 - 300;

[0018] The organic solvent is xylene;

[0019] The amount of xylene is 50-150% of the total amount of intermediate A;

[0020] The functional monomer is one or two of the following: glycerol-A,A'-diallyl ether, trimethylolpropane-diallyl ether, pentaerythritol triacrylate, and pentaerythritol trienyl ether.

[0021] The amount of the functional monomer is 1-25% of the total amount of intermediate A;

[0022] The initiator is one or two of azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate, and the amount of the initiator added is 0.01-1% of the total amount of intermediate A;

[0023] The polymerization reaction temperature is 50-100℃;

[0024] The polymerization time is 3-8 hours.

[0025] S3: The intermediate B obtained in step S2 is further reacted with an aliphatic or alicyclic diisocyanate chain extender to obtain a demulsifier for crude oil containing polyisocyanates.

[0026] The reaction process is as follows (taking methylcyclohexane diisocyanate as an example):

[0027]

[0028] In the formula, m = 5-40, n = 5-60, p = 100-300. The basic unit structure of the crude oil demulsifier containing polypropylene is as follows:

[0029] In the formula, m = 5-40, n = 5-60, p = 100-300. The structure of M in the formula is:

[0030]

[0031] In the formula, the wavy line represents the carbon-oxygen bond;

[0032] In the formula, m = 5 - 40, n = 5 - 60, and p = 100 - 300;

[0033] The chain extension reaction temperature is 30-70℃;

[0034] The chain expansion time is 3-8 hours;

[0035] The aliphatic or alicyclic diisocyanate is one or two of isophorone diisocyanate, methylcyclohexane diisocyanate, and trimethylhexamethylene diisocyanate;

[0036] The amount of the diisocyanate chain extender added is 0.1-1% of the dry weight of intermediate B.

[0037] The beneficial effects of this invention are:

[0038] 1. The demulsifier prepared by this invention provides a demulsifier that can solve the problem of oil-water separation difficulties in crude oil containing polymers. This invention also provides a demulsifier that solves the problem of incomplete crude oil dehydration caused by excessively high organic impurity content in crude oil emulsions, achieving rapid demulsification, clear oil and water, saving energy, and improving economic efficiency and equipment processing rate.

[0039] 2. This invention uses alcohol ethers with highly active double bonds as initiators, which makes it easier to obtain ultra-high molecular weight demulsifiers. As is well known, ultra-high molecular weight demulsifiers have a stronger demulsification ability than conventional demulsifiers due to their strong flocculation-agglomeration effect. They can not only flocculate water droplets, but also have a good flocculation effect on impurities.

[0040] 3. This invention uses functional monomers containing two or more vinyl groups and initiators for polymerization reactions. Compared with monovinyl monomers such as maleic anhydride, fumaric acid, and acrylic acid, functional monomers containing two or more vinyl groups are more likely to prepare ultra-high molecular weight polymers.

[0041] 4. This invention uses liquid aliphatic or alicyclic diisocyanate as a chain extender. Compared with commonly used toluene diisocyanate (TDI), it avoids many problems such as poor solubility of solid toluene diisocyanate, which can easily lead to excessively high local material concentration, violent reaction, and the formation of lumps that affect product quality during the addition process. Detailed Implementation

[0042] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0043] Example 1

[0044] 1. Synthesis of intermediate A: 116 kg of 4-hydroxybutylvinyl ether was added to a high-pressure reactor, along with 5 kg of potassium hydroxide. The mixture was dehydrated at 100-110°C for half an hour. The temperature was then raised to 130-150°C, and 580 kg of propylene oxide was introduced. The reaction was allowed to proceed until complete. Then, 440 kg of ethylene oxide was introduced until the reaction was complete, yielding intermediate A. The mixture was cooled to below 80°C and discharged for later use.

[0045] 2. Synthesis of Intermediate B: 568 kg of intermediate A and 500 kg of xylene were added to a polymerization reactor under nitrogen purging protection. The temperature was raised to 60-70℃, and 43 kg of glycerol-A,A'-diallyl ether and 0.8 kg of azobisisoheptanenitrile were added. The reaction was carried out at 60-70℃ for 2-6 hours to obtain intermediate B. The temperature was then lowered to 35-45℃ for later use.

[0046] 3. Synthesis of poly-containing crude oil demulsifier: At 35-45℃, 3Kg of methylcyclohexane diisocyanate (diluted with 115Kg xylene) is pumped into the polymerization reactor of intermediate B within 1-4 hours, and reacted at 35-45℃ for 2-6 hours to obtain the poly-containing crude oil demulsifier.

[0047] Example 2

[0048] 1. Synthesis of intermediate A: 116 kg of 4-hydroxybutylvinyl ether was added to a high-pressure reactor, along with 5 kg of potassium hydroxide. The mixture was dehydrated at 100-110°C for half an hour. The temperature was then raised to 130-150°C, and 800 kg of propylene oxide was introduced. The reaction was allowed to proceed until complete. Then, 600 kg of ethylene oxide was introduced until the reaction was complete, yielding intermediate A. The mixture was cooled to below 80°C and discharged for later use.

[0049] 2. Synthesis of Intermediate B: 758 kg of intermediate A and 650 kg of xylene were added to a polymerization reactor under nitrogen purging protection. The temperature was raised to 60-70℃, and 75 kg of glycerol-A,A'-diallyl ether and 0.8 kg of azobisisoheptanenitrile were added. The reaction was carried out at 60-70℃ for 2-6 hours to obtain intermediate B. The temperature was then lowered to 35-45℃ for later use.

[0050] 3. Synthesis of poly-containing crude oil demulsifier: At 35-45℃, 10Kg of isophorone diisocyanate (diluted with 194Kg of xylene) is pumped into the polymerization reactor of intermediate B within 1-4 hours, and reacted at 35-45℃ for 2-6 hours to obtain the poly-containing crude oil demulsifier.

[0051] Example 3

[0052] 1. Synthesis of intermediate A: 116 kg of 4-hydroxybutylvinyl ether was added to a high-pressure reactor, along with 5 kg of potassium hydroxide. The mixture was dehydrated at 100-110°C for half an hour. The temperature was then raised to 130-150°C, and 580 kg of propylene oxide was introduced. The reaction was allowed to proceed until complete. Then, 440 kg of ethylene oxide was introduced until the reaction was complete, yielding intermediate A. The mixture was cooled to below 80°C and discharged for later use.

[0053] 2. Synthesis of intermediate B: 568 kg of intermediate A and 500 kg of xylene were added to a polymerization reactor under nitrogen purging protection. The temperature was raised to 60-70℃, and 45 kg of trimethylolpropane diallyl ether and 0.8 kg of azobisisobutyronitrile were added. The reaction was carried out at 60-70℃ for 2-6 hours to obtain intermediate B. The temperature was then lowered to 35-45℃ for later use.

[0054] 3. Synthesis of crude oil demulsifier containing polyphosphate: At 35-45℃, 8 kg of isophorone diisocyanate (diluted with 122 kg of xylene) is pumped into the polymerization reactor of intermediate B within 1-4 hours, and reacted at 35-45℃ for 2-6 hours to obtain the crude oil demulsifier containing polyphosphate.

[0055] Example 4

[0056] 1. Synthesis of intermediate A: 116 kg of 4-hydroxybutylvinyl ether was added to a high-pressure reactor, along with 5 kg of potassium hydroxide. The mixture was dehydrated at 100-110°C for half an hour. The temperature was then raised to 130-150°C, and 580 kg of propylene oxide was introduced. The reaction was allowed to proceed until complete. Then, 440 kg of ethylene oxide was introduced until the reaction was complete, yielding intermediate A. The mixture was cooled to below 80°C and discharged for later use.

[0057] 2. Synthesis of intermediate B: 568 kg of intermediate A and 500 kg of xylene were added to a polymerization reactor under nitrogen purging protection. The temperature was raised to 60-70℃, and 45 kg of trimethylolpropane diallyl ether and 0.8 kg of azobisisobutyronitrile were added. The reaction was carried out at 60-70℃ for 2-6 hours to obtain intermediate B. The temperature was then lowered to 35-45℃ for later use.

[0058] 3. Synthesis of poly-containing crude oil demulsifier: At 35-45℃, 3Kg of methylcyclohexane diisocyanate (diluted with 117Kg xylene) is pumped into the polymerization reactor of intermediate B within 1-4 hours, and reacted at 35-45℃ for 2-6 hours to obtain the poly-containing crude oil demulsifier.

[0059] Reference Sample 1: The main component is maleic anhydride modified phenolic amine polyoxypropylene polyoxyethylene resin, model HZ-37 (industrial product), from Jingzhou Dongze Chemical Technology Co., Ltd.

[0060] Reference Sample 2: Phenolic amine polyoxypropylene polyoxyethylene resin modified with TDI (toluene diisocyanate) as the main component, model A-38 (industrial grade), from Jingzhou Dongze Chemical Technology Co., Ltd.

[0061] The relative solubility (RSN) and apparent viscosity of the demulsifier samples obtained from Examples 1-4, Reference Sample 1, and Reference Sample 2 were tested.

[0062] The RSN (relative solubility) test method is as follows: Weigh 1g of demulsifier sample (accurate to 0.001g) and dissolve it in 40g of dioxane, then test it with deionized water at 25℃.

[0063] The apparent viscosity test method is as follows: Weigh 300g of demulsifier sample (accurate to 0.1g) and test it at 25℃ using a drop type B rotational viscometer (2# rotor). Apparent viscosity is an important indicator for measuring the molecular weight of polymers. It can also be considered that apparent viscosity is directly proportional to the molecular weight of polymers. Within a certain range, the higher the degree of branching of the demulsifier and the larger the molecular weight, the better the dehydration effect.

[0064] The following test data table was obtained:

[0065] I. Demulsifier Test Data Table

[0066] Table 1. Demulsifier Detection Data

[0067]

[0068]

[0069] The demulsifier of this invention was tested on the polymer-containing crude oil of Changqing at a temperature of 35-45℃.

[0070] The determination method and reagents for the bottle test method refer to 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)";

[0071] The physical properties of Changqing polymer-containing crude oil are as follows:

[0072] Oil sample density (density bottle method): 0.9115 g / ml (20℃)

[0073] Water content of oil sample (distillation method): 36%

[0074] Machine-related impurities: 4.58%

[0075] Table 2. Demulsification test data of various demulsifiers on aged oil at 40℃.

[0076]

[0077] Table 3. Test data of demulsification experiments on aged oil by various demulsifiers at 35℃.

[0078]

[0079] As can be seen from Tables 1, 2, and 3, the apparent viscosity of the demulsifiers in Examples 1-4 is significantly greater than that of Reference Sample 1 and Reference Sample 2. Apparent viscosity is an important indicator for measuring the molecular weight of a polymer, and it can also be considered that apparent viscosity is directly proportional to the molecular weight of the polymer. Within a certain range, the higher the degree of branching of the demulsifier and the larger the molecular weight, the better the dehydration effect. Therefore, it is proven that the demulsifier prepared by this invention is an ultra-high molecular weight demulsifier, which has a stronger demulsification ability than the conventional demulsifier (Reference Sample 1). It can not only flocculate water droplets, but also has a good flocculation effect on impurities.

Claims

1. A method for preparing a demulsifier for polymer-containing crude oil, characterized in that: The demulsifier for use in crude oil containing polyimide is prepared by the following method: using an alcohol ether with a highly active double bond as a starting agent and a functional monomer containing no less than two vinyl groups as a polymerization reaction, and using liquid aliphatic or alicyclic diisocyanate as a chain extender. The alcohol ether with highly active double bonds is prepared by propoxylation and ethoxylation of 4-hydroxybutylvinyl ether with propylene oxide and ethylene oxide under an alkali metal catalyst. The functional monomer is one or two of glycerol-A,A'-diallyl ether, trimethylolpropane-diallyl ether, and pentaerythritol triacrylate. The aliphatic or alicyclic diisocyanate is one or two of isophorone diisocyanate, methylcyclohexane diisocyanate, and trimethylhexamethylene diisocyanate.

2. The method for preparing a demulsifier for polymer-containing crude oil according to claim 1, characterized in that: The preparation is carried out through the following steps: S1: 4-hydroxybutyl vinyl ether is propoxylated and ethoxylated with propylene oxide and ethylene oxide under an alkali metal catalyst to obtain intermediate A; S2: The intermediate A obtained in step S1 is polymerized with a functional monomer containing no less than two vinyl groups in xylene solvent in the presence of an initiator to obtain intermediate B. S3: The intermediate B obtained in step S2 is further reacted with an aliphatic or alicyclic diisocyanate chain extender to obtain a demulsifier for use in polymer-containing crude oil.

3. The method for preparing a demulsifier for polymer-containing crude oil according to claim 2, characterized in that: In step S1, the mass ratio of 4-hydroxybutyl vinyl ether to propylene oxide and ethylene oxide is 1:3-16:3-18.

4. The method for preparing a demulsifier for polymer-containing crude oil according to claim 2, characterized in that: In step S1, the alkali metal catalyst is potassium hydroxide, and its addition amount is 0.05-0.6% of the total mass of propylene oxide and ethylene oxide.

5. A method for preparing a demulsifier for polymer-containing crude oil according to claim 2, characterized in that: The initiator in step S2 is one or two of azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate.

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