Aged oil demulsifier and preparation method thereof

Abstract

The invention belongs to the technical field of aged oil dehydration, and discloses an aged oil demulsifier. The aged oil demulsifier is prepared by using polyphenyl ether as an initiator to carry out propoxylation and ethoxylation reactions with propylene oxide and ethylene oxide, and then carrying out esterification reaction with maleic anhydride, and finally carrying out acylation with polyamine as a capping agent. The invention provides a demulsifier that can be used under low-temperature dehydration conditions, so as to solve the oil-water separation problem in the low-temperature dehydration of aged oil, realize rapid demulsification, oil purification and water purification under low-temperature conditions, save energy, and improve economic benefits and equipment treatment rate.

Description

Technical Field

[0001] The invention belongs to the technical field of aged oil dehydration, and particularly relates to an aged oil demulsifier and a preparation method thereof. Background Art

[0002] As oilfield development enters the middle and late stages, the amount of aged oil generated in the crude oil production process gradually increases. According to research, aged oil mainly comes from crude oil storage, three-phase separation of crude oil dehydration and oil transfer stations, electric dehydration, and oily sludge and sewage treatment, which are complex oil-in-water and water-in-oil emulsions containing a large amount of surfactants, sewage, and sediment. Analysis shows that the high degree of emulsification of aged oil is mainly due to its high content of colloid and asphaltene. On the one hand, colloid and asphaltene are easily adsorbed on the oil-water interface to form a strong interfacial film, thereby enhancing the emulsification degree of crude oil; on the other hand, aged oil contains more metal elements, which is more conducive to nucleation and enrichment of macromolecules such as colloid and asphaltene, thereby enhancing the stability of the aged oil itself. Due to the stable state of aged oil, its existence is not only easy to cause the dehydration temperature in the crude oil processing system to increase, the amount of reagents applied, and the production cost to increase. Summary of the invention

[0003] The purpose of the present invention is to provide an aged oil demulsifier and a preparation method thereof, and to provide a demulsifier that can be used under low-temperature dehydration conditions to solve the oil-water separation problem in the low-temperature dehydration of aged oil, to achieve rapid demulsification, oil purification and water purification under low-temperature conditions, to save energy, and to improve economic benefits and equipment processing rate.

[0004] The above technical objectives of the present invention are achieved through the following technical solutions: an aged oil demulsifier, wherein the aged oil demulsifier is prepared by using polyphenyl ether as an initiator to carry out propoxylation and ethoxylation reactions with propylene oxide and ethylene oxide, and then carrying out esterification reactions with maleic anhydride, and finally carrying out acylation with polyamine as a capping agent. The general structural formula of the aged oil demulsifier is:

[0005]

[0006] Where: m = 26

[0007] n=40~218

[0008] p=84~344

[0009] s=3.

[0010] The aged oil demulsifier is prepared from the following substances: polyphenylene ether, propylene oxide, ethylene oxide, xylene, an alkali metal catalyst and an organic acid.

[0011] By using polyphenylene ether (PPO) with strong molecular chain rigidity as the lipophilic head initiator and polyamine as the end-capping agent, the obtained demulsifier has higher surface activity than conventional structure demulsifiers and can effectively reduce the strength of the oil-water interface film. Under the dual effects of mechanical energy and thermal energy, the natural emulsifiers such as colloids adsorbed on the emulsion interface film are more easily replaced gradually due to their lower activity than the demulsifier. At the same time, the demulsifier molecules are given a faster diffusion speed and stronger adsorption capacity when entering the emulsion to the oil-water interface film under low temperature conditions, thereby achieving rapid demulsification under low temperature conditions.

[0012] The polyphenylene ether is a low molecular weight double-terminated hydroxyl polyphenylene ether.

[0013] The polyphenylene ether is a low molecular weight double-terminated hydroxyl polyphenylene ether (molecular weight of about 2500, model SA-90 or similar products, preparation method refers to US Pat. No. 6211327).

[0014] The mass ratio of the polyphenylene ether, propylene oxide and ethylene oxide is 1:3-10:3-12.

[0015] The amount of the alkali metal catalyst added is 0.05-0.6% of the total mass of propylene oxide and ethylene oxide.

[0016] The amount of the organic acid added is equivalent to the amount of the alkali metal catalyst added.

[0017] The alkali metal catalyst is one or both of sodium hydroxide and potassium hydroxide.

[0018] The organic acid is one or two of formic acid, acetic acid and lactic acid.

[0019] A method for preparing an aged oil demulsifier comprises the following preparation steps:

[0020] S1: polyphenylene ether and an alkali metal catalyst are mixed in a xylene solvent, and after reflux and water separation, propylene oxide and ethylene oxide are successively pumped in for ring-opening polymerization, and then the obtained polymerization product is neutralized with an organic acid to obtain an intermediate A;

[0021] The reaction process is as follows:

[0022]

[0023] Where:

[0024] m=25-27

[0025] n=40-218

[0026] p=84-344

[0027] S2: reacting the intermediate A obtained in step S1 with maleic anhydride to obtain an intermediate B; wherein the esterification reaction temperature is 50-100° C., the esterification time is 3-8 hours; and the mass ratio of the intermediate A to maleic anhydride is 100:1-10;

[0028] The reaction process is as follows:

[0029]

[0030] In the formula

[0031] m=25-27

[0032] n=40-218

[0033] p=84-344

[0034] S3: Acylation reaction is performed on the intermediate B obtained in step S2 with polyamine to obtain an aged oil demulsifier, wherein the amount of the polyamine is the same as the molar amount of maleic anhydride. The polyamine is tetraethylenepentamine.

[0035] The reaction process is as follows:

[0036]

[0037] In the formula

[0038] m=25-27

[0039] n=40-218

[0040] p=84-344

[0041] s=3

[0042] Beneficial effects of the present invention:

[0043] 1. The present invention adopts polyphenylene ether (PPO) with strong molecular chain rigidity as the lipophilic head initiator and polyamine as the end-capping agent. The obtained demulsifier has higher surface activity than conventional structure demulsifiers and can effectively reduce the strength of the oil-water interface film. Under the dual effects of mechanical energy and thermal energy, the natural emulsifiers such as colloids adsorbed on the emulsion interface film are more easily replaced gradually because their activity is lower than that of the demulsifier. At the same time, the demulsifier molecules are given a faster diffusion speed and stronger adsorption capacity when entering the emulsion to the oil-water interface film under low temperature conditions, thereby achieving rapid demulsification under low temperature conditions.

[0044] 2. The present invention adopts polyamine as the end-capping agent. Polyamine has the positive charge of cations and the characteristics of non-ions, can effectively neutralize the negative charge at the oil-water interface, flocculate metal and other impurities in the aged oil, and has good compatibility with anions, thus avoiding the disadvantage that cationic demulsifiers and anions coagulate and affect the demulsification effect. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Specific embodiment:

[0047] Example 1

[0048] 1. Synthesis of intermediate A: 100 kg polyphenylene ether and 600 kg xylene were put into a reactor, heated to 60-70 ° C, stirred until completely dissolved, 4 kg potassium hydroxide was added, heated to 120 ° C, refluxed and separated for 2 hours, and then heated to 130-150 ° C, 580 kg propylene oxide was introduced, and the pressure was controlled at 0.1-0.4 MPa. After the reaction was complete, 440 kg ethylene oxide was introduced, and the reaction was complete. The temperature was lowered to below 60 ° C, and 4 kg glacial acetic acid was used for neutralization. The obtained liquid material was recorded as intermediate A solution for standby use;

[0049] 2. Synthesis of intermediate B: The reactor of intermediate A solution was deoxygenated by nitrogen replacement, and the temperature was raised to 70-80°C. 39 kg of maleic anhydride was added in batches over 1 hour. The reaction was continued at 70-80°C for 3-4 hours to obtain intermediate B.

[0050] 3. Continue to add 76 kg of tetraethylene pentamine to the intermediate B, raise the temperature to 130-150°C, and reflux for 6-8 hours to obtain an aged oil demulsifier.

[0051] Example 2

[0052] 1. Synthesis of intermediate A: 100 kg polyphenylene ether and 580 kg xylene were put into a reactor, heated to 60-70 ° C, stirred until completely dissolved, 3 kg potassium hydroxide was added, heated to 120 ° C, refluxed and separated for 2 hours, and then heated to 130-150 ° C, 400 kg propylene oxide was introduced, and the pressure was controlled at 0.1-0.4 MPa. After the reaction was complete, 620 kg ethylene oxide was introduced, and the reaction was complete. The temperature was lowered to below 60 ° C, and neutralized with 3 kg glacial acetic acid. The resulting liquid material was recorded as intermediate A for standby use;

[0053] 2. Synthesis of intermediate B: In the reactor of intermediate A, nitrogen was replaced to deoxygenate, the temperature was raised to 70-80°C, 20 kg of maleic anhydride was added in batches over 1 hour, and the reaction was continued at 70-80°C for 3-4 hours to obtain intermediate B;

[0054] 3. Continue to add 38 kg of tetraethylene pentamine to the intermediate B, raise the temperature to 130-150°C, and reflux for 6-8 hours to obtain an aged oil demulsifier.

[0055] Example 3

[0056] 1. Synthesis of intermediate A: 100 kg polyphenylene ether and 695 kg xylene were put into a reactor, heated to 60-70 ° C, stirred until completely dissolved, 5 kg potassium hydroxide was added, heated to 120 ° C, refluxed and separated for 2 hours, and then heated to 130-150 ° C, 700 kg propylene oxide was introduced, and the pressure was controlled at 0.1-0.4 MPa. After the reaction was complete, 500 kg ethylene oxide was introduced, and the reaction was complete. The temperature was lowered to below 60 ° C, and 5 kg glacial acetic acid was used for neutralization. The obtained liquid material was recorded as intermediate A for standby use;

[0057] 2. Synthesis of intermediate B: In the reactor of intermediate A, nitrogen was replaced to deoxygenate, the temperature was raised to 70-80°C, 39 kg of maleic anhydride was added in batches over 1 hour, and the reaction was continued at 70-80°C for 3-4 hours to obtain intermediate B;

[0058] 3. Continue to add 76 kg of tetraethylene pentamine to the intermediate B, raise the temperature to 130-150°C, and reflux for 6-8 hours to obtain an aged oil demulsifier.

[0059] Example 4

[0060] 1. Synthesis of intermediate A: 100 kg polyphenylene ether and 620 kg xylene were put into a reactor, heated to 60-70 ° C, stirred until completely dissolved, 4 kg potassium hydroxide was added, heated to 120 ° C, refluxed and separated for 2 hours, and then heated to 130-150 ° C, and 630 kg propylene oxide was introduced, and the pressure was controlled at 0.1-0.4 MPa. After the reaction was complete, 450 kg ethylene oxide was introduced, and the reaction was complete. The temperature was lowered to below 60 ° C, and 4 kg glacial acetic acid was used for neutralization. The obtained liquid material was recorded as intermediate A for standby use;

[0061] 2. Synthesis of intermediate B: In the reactor of intermediate A, replace with nitrogen to deoxygenate, heat to 70-80°C, add 25 kg of maleic anhydride in batches over 1 hour, and continue to react at 70-80°C for 3-4 hours to obtain intermediate B;

[0062] 3. Continue to add 48 kg of tetraethylenepentamine to the intermediate B, raise the temperature to 130-150°C, and reflux for 6-8 hours to obtain an aged oil demulsifier.

[0063] Reference sample 1: main component: maleic anhydride-modified phenolic amine polyoxypropylene polyoxyethylene resin, model HZ-37 (industrial product), from Jingzhou Dongze Chemical Technology Co., Ltd.;

[0064] Reference sample 2: Main ingredient: TDI (toluene diisocyanate) modified phenolic amine polyoxypropylene polyoxyethylene resin, model A-38 (industrial product), from Jingzhou Dongze Chemical Technology Co., Ltd.

[0065] The demulsifier samples obtained from Examples 1-4 and Reference Sample 1 and Reference Sample 2 were tested for relative solubility (RSN) and interfacial tension.

[0066] The RSN value (relative solubility) test method is: weigh 1g of demulsifier sample (accurate to 0.001g) and dissolve it in 40g of dioxane, and test its relative solubility with deionized water at 25°C.

[0067] The interfacial tension test method is as follows: weigh 0.1 g of demulsifier sample (accurate to 0.0001 g), dilute it with 1 g of ethanol, and then dilute it with deionized water to 100 mg / L, and test its interfacial tension by the drop volume method at 25°C.

[0068] The following test data table is obtained:

[0069] Table 1 Demulsifier test data table

[0070] project Active ingredient content (%) RSN value (ml) Interfacial tension (mN / m) Example 1 67±0.5 11.92 16.4 Example 2 67±0.5 14.11 15.2 Example 3 67±0.5 11.36 17.5 Example 4 67±0.5 11.14 18.0 Reference Sample 1 67±0.5 11.42 35.6 Reference Sample 2 67±0.5 10.95 38.1

[0071] The demulsifier of the present invention was used to conduct demulsification experiments on aged Changqing crude oil at a temperature of 35-45°C:

[0072] The determination method and reagents of the bottle test method refer to the petroleum and natural gas industry standard SY / T 5281-2000 of the People's Republic of China "Test Method for Performance of Crude Oil Demulsifier (Bottle Test Method)";

[0073] The physical properties of Changqing crude oil aging oil are as follows:

[0074] Oil sample density (density bottle method): 0.9287g / ml (20℃)

[0075] Water content of oil sample (distillation method): 38.5%

[0076] Organic impurities content: 5.3%

[0077] Table 2 Test data of demulsification experiment of various demulsifiers on aged oil at 40℃

[0078]

[0079] Table 3 Demulsification test data of various demulsifiers on aged oil at 35°C

[0080]

[0081] As can be seen from Table 1 and Table 2, the present invention uses polyphenylene ether (PPO) with strong molecular chain rigidity as the lipophilic head initiator and polyamine as the end-capping agent, and the obtained demulsifier (Examples 1-4) has higher surface activity than the conventional structure demulsifier (reference sample 1 or 2), and can effectively reduce the strength of the oil-water interface film. The demulsifiers in Examples 1-4 have a higher dehydration rate and no emulsified interface layer. At the same time, the demulsifier molecules enter the emulsion under low temperature conditions and have a faster diffusion speed and stronger adsorption capacity on the oil-water interface film, thereby achieving rapid demulsification under low temperature conditions.

Claims

1. An aged oil demulsifier, characterized in that: The aged oil demulsifier is prepared by using polyphenyl ether as an initiator to carry out propoxylation and ethoxylation reaction with propylene oxide and ethylene oxide, and then carrying out esterification reaction with maleic anhydride, and finally carrying out acylation with polyamine as a capping agent. The general structural formula of the aged oil demulsifier is: ； Where: m = 25-27; n=40~218； p=84~344； s=3。 2. The aged oil demulsifier according to claim 1, characterized in that: The solvent for the propoxylation and ethoxylation reaction of the polyphenylene ether with propylene oxide and ethylene oxide is xylene, the catalyst is an alkali metal catalyst, and the polymer product obtained by the reaction is neutralized with an organic acid.

3. The aged oil demulsifier according to claim 1, characterized in that: The polyphenylene ether is a double-terminated hydroxyl polyphenylene ether.

4. The aged oil demulsifier according to claim 1, characterized in that: The mass ratio of the polyphenylene ether, propylene oxide and ethylene oxide is 1:3-10:3-12.

5. The aged oil demulsifier according to claim 2, characterized in that: The amount of the alkali metal catalyst added is 0.05-0.6% of the total mass of propylene oxide and ethylene oxide.

6. The aged oil demulsifier according to claim 2, characterized in that: The amount of the organic acid added is equal to the amount of the alkali metal catalyst added.

7. The aged oil demulsifier according to claim 2, characterized in that: The alkali metal catalyst is one or both of sodium hydroxide and potassium hydroxide.

8. The aged oil demulsifier according to claim 2, characterized in that: The organic acid is one or two of formic acid, acetic acid and lactic acid.

9. The method for preparing an aged oil demulsifier according to any one of claims 1 to 8, characterized in that: The method comprises the following preparation steps: S1: polyphenylene ether and an alkali metal catalyst are mixed in a xylene solvent, and after reflux and water separation, propylene oxide and ethylene oxide are successively pumped in for ring-opening polymerization, and then the obtained polymerization product is neutralized with an organic acid to obtain an intermediate A; S2: subjecting the intermediate A obtained in step S1 to an esterification reaction with maleic anhydride to obtain an intermediate B; wherein the esterification reaction temperature is 50-100° C., the esterification time is 3-8 hours, and the mass ratio of the intermediate A to maleic anhydride is 100:1-10; S3: The intermediate B obtained in step S2 is subjected to an acylation reaction with polyamine to obtain an aged oil demulsifier, wherein the added molar amount of the polyamine is the same as the molar amount of maleic anhydride.

10. The method for preparing an aged oil demulsifier according to claim 9, characterized in that: The polyamine is tetraethylenepentamine.

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