A compound demulsifier composition and demulsification method

Abstract

This invention belongs to the field of thin oil demulsification technology, specifically relating to a compound demulsifier composition and demulsification method. The demulsifier composition includes demulsifier components, specifically FW-type demulsifier, M-41T-type demulsifier, APE-type demulsifier, HC-1-type demulsifier, and tetramethylolphosphine sulfate. This invention achieves a demulsification rate greater than 70% for highly emulsified crude oil; moreover, the process of this invention has a high degree of integration, enabling on-site treatment of highly emulsified crude oil without the need for tank cleaning and transportation, reducing enterprise operating costs; after treatment, the oil contains less than 20% water, less than 1000 mg / L of oil in the water, less than 1000 mg / L of suspended solids, and less than 0.4% of mechanical impurities.

Description

Technical Field

[0001] This invention belongs to the field of thin oil demulsification technology, specifically relating to a compound demulsifier composition and a demulsification method. Background Technology

[0002] Crude oil contains components such as gums, asphaltenes, and paraffin wax, which act as natural high-performance emulsifiers. The emulsion form of crude oil presents challenges in transportation, processing, and sales. Simultaneously, water and salt in crude oil can react chemically, generating deposits and scale that clog pipes and equipment. Salts can also form catalysts with other impurities, severely impacting the stability of the crude oil emulsion, disrupting its original structure, and generating new impurities. The presence of salt and water in crude oil also poses significant risks to the stable operation of atmospheric and vacuum distillation units and downstream equipment, as well as causing equipment corrosion. Therefore, demulsification, desalting, and dehydration of crude oil are essential steps in the production process, requiring demulsification treatment, typically using demulsifiers.

[0003] Currently, the demulsifiers used in domestic oilfields are mainly polyether-based. However, these demulsifiers are not ideal when used alone, have poor broad-spectrum adaptability to different crude oil products, and fail to meet the required demulsification effect. Moreover, as oilfields enter the medium-to-high water-cut stage, a large amount of external fluids such as fracturing flowback fluid and acidizing operation waste fluid continuously enter the crude oil processing system, causing the emulsion in the settling tank of the light oil centralized processing station to gradually thicken into a stable emulsion. In addition, since there is no separate treatment process for the emulsion in the settling tank after settling and dehydration, the original treatment process can no longer meet the current demulsification requirements. In order to maintain production, the only treatment methods are simple tank cleaning, significantly increasing the temperature, and increasing the concentration of demulsifier, which leads to a significant increase in treatment costs.

[0004] Chinese invention patent application CN101121898A discloses a rapid demulsification method, including microwave radiation and the addition of a demulsifier according to the mass fraction of water content in the emulsified crude oil, wherein the mass fraction ratio of water to demulsifier is 1:0.5×10. -4 -5×10 -4 Microwave demulsification is performed. The demulsifier is one or a mixture of two or more of the following: polyamine-based polyoxypropylene polyoxyethylene ether, resin-based polyoxypropylene polyoxyethylene ether, higher alcohol-based initiator demulsifier, or propylene glycol-based demulsifier. The microwave radiation frequency is 2450MHz or 915MHz. Utilizing the synergistic effect of the demulsifier and microwave radiation, water-in-oil emulsions can be demulsified in a shorter time, achieving a higher dehydration rate and improving demulsification efficiency. However, this method is difficult to control due to the different physicochemical properties of different crude oils, requiring different reaction conditions; many applications have only been conducted in the laboratory and have not been widely applied to industrial production.

[0005] Chinese invention patent application CN104560127A discloses a method for treating crude oil wastewater. This method uses a filter, a high-pressure pump, and a reverse osmosis membrane tube to separate oil and water. When the wastewater passes through the membrane surface, the hydrophilicity, oleophilicity, and balance of various particles are disrupted. The wastewater undergoes demulsification of the emulsion particles in the membrane tube, and then aggregates and coarse-grained, thereby achieving separation. However, the efficiency of this method needs to be improved, and it is not suitable for large-scale industrial production.

[0006] Taking a certain oilfield as an example, its water wells are currently in a high water-cut phase, with a large amount of external fluids such as fracturing flowback fluid continuously entering the crude oil processing system. This causes the emulsion in the settling tank of the centralized processing station to gradually thicken into a stable emulsion. To maintain production, only passive treatment methods such as simple tank cleaning can be used, with annual treatment costs reaching as high as 3.2 million yuan. Analysis of the highly emulsified crude oil showed that the emulsion had a very high absolute value of Zeta potential, a density close to that of water, a high content of suspended solids, and a high content of asphaltenes and resins. It is a typical "Pickering" type emulsion. Even when the temperature is raised to 60℃ and the demulsifier concentration reaches 200 mg / L, it cannot be demulsified. It is necessary to further increase the processing temperature and the dosage of the demulsifier significantly.

[0007] Existing high-emulsification crude oil processing technologies suffer from problems such as large demulsifier usage and high heating temperatures, leading to a significant increase in processing costs and energy consumption. Therefore, providing an efficient demulsification method for high-emulsification crude oil in light oil to ensure the normal operation of light oil processing plants has become an urgent technical problem to be solved. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the technical problem actually solved by this invention is to provide a compound demulsifier composition and demulsification method that reduces the amount of demulsifier used and processing energy consumption while ensuring that the treated crude oil meets the processing index requirements.

[0009] To achieve the above-mentioned objectives of this invention, the specific technical solution adopted by this invention is as follows:

[0010] A compound demulsifier composition, the demulsifier composition comprising a demulsifier component, the demulsifier component comprising an FW type demulsifier, an M-41T type demulsifier, an APE type demulsifier, an HC-1 type demulsifier, and tetramethylphosphoric acid.

[0011] Preferably, the FW-type demulsifier has a weight percentage of 10-25% based on a solid content of 80%.

[0012] Preferably, the M-41T type demulsifier has a weight percentage of 25-40% based on a solid content of 80%.

[0013] Preferably, the APE-type demulsifier has a weight percentage of 10-35% based on a solid content of 80%.

[0014] Preferably, the HC-1 type demulsifier is 15-30% by weight based on a solid content of 80%.

[0015] Preferably, the tetramethylolphosphine sulfate comprises 10-25% by weight, based on a solid content of 75%.

[0016] Preferably, the FW-type demulsifier is FW-135 demulsifier, and the APE-type demulsifier is APE-8166 demulsifier.

[0017] Preferably, M-41T is a polyoxyethylene polyoxypropylene block polyether with imidazoline as the initiator, and APE-8166 is a polyoxyethylene polyoxypropylene polyether with polyethylene polyamine as the initiator.

[0018] Preferably, the APE-type demulsifier is prepared using polyethylene polyamine as an initiator, toluene-2,4-diisocyanate as a crosslinking agent, and methanol as a solvent.

[0019] Preferably, the composition further includes an alcohol solvent selected from one or more of methanol, ethanol, and glycerol; the weight ratio of the demulsifier component to the alcohol solvent is 10:5-10:1, preferably 2:1-4:1.

[0020] Preferably, the composition further includes water, and the demulsifier component is present in the composition at a weight percentage of 20-40%, preferably 25-30%.

[0021] The present invention also relates to a demulsification method, the demulsification method comprising: adding the above-mentioned demulsifier composition to the produced fluid, heating, centrifuging and filtering.

[0022] Preferably, the concentration of the demulsifier composition in the produced fluid is 150-250 mg / L.

[0023] Preferably, the heating temperature is 50-70℃ and the heating time is 35-50 minutes.

[0024] Preferably, the centrifugation speed is 1800-2200 rpm; the filtration is performed using a membrane filter device.

[0025] The purpose of the heat treatment is to accelerate the chemical demulsification reaction while achieving partial thermal demulsification.

[0026] The purpose of centrifugation is to separate oil and water, and solid and liquid, through centrifugation.

[0027] The purpose of filtration is to remove suspended solids from the produced water in a secondary manner, thereby improving the quality of the effluent and ensuring that it meets the standards for oilfield reinjection water.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention achieves a demulsification rate of 90% for highly emulsified crude oil;

[0030] (2) The process of this invention has a high degree of integration, realizing the on-site treatment of highly emulsified crude oil without the need for tank cleaning and transportation, thus reducing the operating costs of enterprises;

[0031] (3) After the present invention, the oil contains less than 20% water, the water contains less than 700 mg / L oil, the suspended solids content is less than 600 mg / L, and the mechanical impurity content is less than 0.4%, thereby realizing the recovery of crude oil and the re-mixing of water. Attached Figure Description

[0032] Figure 1 This is a process flow diagram of the present invention for the treatment of highly emulsified crude oil in light oil. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be further described in detail below. The described embodiments are only a part of the present invention and are used to explain the present invention, but are not intended to limit the present invention. Therefore, other embodiments obtained by other people skilled in the art without creative labor are all within the protection scope of the present invention.

[0034] FW-135 demulsifier and M-41T demulsifier were both purchased from AkzoNobel (Boxin);

[0035] APE-8166 demulsifier and HC-1 demulsifier were both purchased from CNOOC Tianjin Oilfield Chemical Company.

[0036] Tetramethylolphosphine sulfate (THPS), purchased from Jiangsu Kangxiang Industrial Co., Ltd.;

[0037] Unless otherwise specified, all reagents used in this invention are industrial products and are commercially available.

[0038] Example 1

[0039] Demulsifier composition: By weight percentage, 30% of the demulsifier component (of which the mass ratio of FW-135 demulsifier, M-41T demulsifier, APE-8166 demulsifier, HC-1 demulsifier and tetramethylolphosphine sulfate is 1:1:1:1:1), 10% of methanol and 60% of water are mixed evenly at 40°C to obtain the final product.

[0040] Methods to break down breasts:

[0041] like Figure 1The process flow diagram for demulsifying highly emulsified crude oil in light oil is shown. When the produced water treatment equipment is operating normally, the highly emulsified crude oil first enters the chemical dosing unit, allowing the chemicals and emulsified oil to mix thoroughly. The emulsified oil then enters the heating furnace, where the temperature rises to perform thermochemical demulsification, removing some of the emulsified oil and free water. The remaining emulsified oil is centrifuged, where centrifugation further decomposes the emulsified oil into oil, water, and mechanical impurities. The centrifuge effluent enters a membrane filter, where oil, suspended solids, and other impurities are removed. The filtered water is then stored in a purified water tank for later reinjection into the oilfield. The centrifuge effluent is directly re-blended, and a very small amount of mechanical impurities is treated as solid waste.

[0042] (1) Add the above-mentioned novel demulsifier (200 mg / L);

[0043] (2) Heating device: The liquid from the dosing unit enters the heating unit and is heated to 60°C to accelerate the thermochemical demulsification rate. The reaction time is 40 min.

[0044] (3) Centrifugation: The remaining emulsion is pumped to the centrifuge unit at a speed of 2000 rpm and the emulsion residence time is 20 min to separate oil, water and mechanical impurities;

[0045] (4) Filtration: The effluent is filtered through a membrane to remove suspended solids.

[0046] Example 2

[0047] Demulsifier composition: By weight percentage, 28% of demulsifier components (of which the mass ratio of FW-135 demulsifier, M-41T demulsifier, APE-8166 demulsifier, HC-1 demulsifier and tetramethylphosphoric acid sulfate is 2:3:1:2:2), 8% of ethanol and 64% of water are mixed evenly at 40°C to obtain the final product.

[0048] Methods to break down breasts:

[0049] (1) Add the above-mentioned novel demulsifier (150 mg / L);

[0050] (2) Heating device: The liquid from the dosing unit enters the heating unit and is heated to 70°C to accelerate the thermochemical demulsification rate. The reaction time is 35 min.

[0051] (3) Centrifugation: The remaining emulsion is pumped to the centrifuge unit at a speed of 1800 rpm and the emulsion residence time is 25 min to separate oil, water and mechanical impurities;

[0052] (4) Filtration: The effluent is filtered through a membrane to remove suspended solids.

[0053] Example 3

[0054] Demulsifier composition: By weight percentage, 25% of demulsifier components (of which the mass ratio of FW-135 demulsifier, M-41T demulsifier, APE-8166 demulsifier, HC-1 demulsifier and tetramethylolphosphine sulfate is 2:1:2:3:2), 14% of glycerol and 58% of water are mixed evenly at 40°C to obtain the final product.

[0055] Methods to break down breasts:

[0056] (1) Add the above-mentioned novel demulsifier (250 mg / L);

[0057] (2) Heating device: The liquid from the dosing unit enters the heating unit and is heated to 50°C to accelerate the thermochemical demulsification rate. The reaction time is 50 min.

[0058] (3) Centrifugation: The remaining emulsion is pumped to the centrifuge unit at a speed of 2200 rpm and the emulsion residence time is 15 min to separate oil, water and mechanical impurities;

[0059] (4) Filtration: The effluent is filtered through a membrane to remove suspended solids.

[0060] Comparative Example 1

[0061] Demulsifier composition: By weight percentage, 30% of the demulsifier component (of which the mass ratio of FW-135 demulsifier, M-41T demulsifier, HC-1 demulsifier and tetramethylphosphoric acid sulfate is 1:2:1:1), 10% of methanol and 60% of water are mixed evenly at 40°C to obtain the final product.

[0062] The demulsification method is the same as in Example 1.

[0063] Comparative Example 2

[0064] Demulsifier composition: By weight percentage, 30% of the demulsifier component (of which the mass ratio of FW-135 demulsifier, APE-8166 demulsifier, HC-1 demulsifier and tetramethylphosphoric acid sulfate is 1:2:1:1), 10% of methanol and 60% of water are mixed evenly at 40°C to obtain the final product.

[0065] The demulsification method is the same as in Example 1.

[0066] Comparative Example 3

[0067] The commercially available demulsifier was purchased from Xinkeao Company, model: SQ-A01;

[0068] The demulsification method is the same as in Example 1.

[0069] Comparative Example 4

[0070] The demulsifier composition and preparation method are the same as in Example 1;

[0071] The only difference between the demulsification method and Example 1 is that step (3) centrifugation is not performed.

[0072] Comparative Example 5

[0073] The demulsifier composition and preparation method are the same as in Example 1;

[0074] The only difference between the demulsification method and Example 1 is that step (1) of adding drugs is not performed.

[0075] Effect test

[0076] The compound demulsifiers of each example and comparative example were evaluated according to SY / T5281-2000 to demulsify the produced fluid of highly emulsified crude oil at the Shixi Rare Oil Processing Station of Xinjiang Oilfield. The Shixi highly emulsified crude oil used in this experiment had a water content of 36%, a dehydration temperature of 60℃, and a demulsifier concentration of 200mg / L. The analysis results are shown in Table 1.

[0077] Table 1 Test Results

[0078] Water content in oil (%) Oil content in water (mg / L) Suspended solids content (mg / L) Mechanical impurity content (%) Demulsification rate (%) Example 1 5 500 300 0.1 90 Example 2 14 600 400 0.3 72 Example 3 16 620 550 0.3 71 Comparative Example 1 21 770 780 0.4 55 Comparative Example 2 25 740 1030 0.4 61 Comparative Example 3 33 1100 1540 0.6 3 Comparative Example 4 28 810 1150 0.5 32 Comparative Example 5 25 800 1100 0.5 40

[0079] The highly emulsified crude oil processed at the Shixi Rare Oil Processing Station of Xinjiang Oilfield meets the following requirements after treatment with this innovative method: water content in the oil is less than 20%, oil content in the water is less than 700 mg / L, suspended solids content is less than 600 mg / L, organic impurities content is less than 0.4%, and demulsification rate is greater than 70%. This achieves the goals of crude oil recovery and water re-blending, enabling on-site treatment of highly emulsified crude oil. The equipment used in this invention is mature and reliable, has strong impact resistance, occupies a small area, and has a high degree of automation.

[0080] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.

Claims

1. A method of breaking emulsions, characterized in that, It comprises the following steps: adding a demulsifier composition into the produced liquid, heating, centrifuging and filtering; the centrifuging speed is 1800-2200 rpm; The demulsifier composition is composed of 30% of a demulsifier component, 10% of methanol and 60% of water in percentage by mass, wherein the demulsifier component is composed of FW-135 demulsifier, M-41T demulsifier, APE-8166 demulsifier, HC-1 demulsifier and tetramethylammonium phosphate in a mass ratio of 1:1:1:1:

1.

2. The method of breaking emulsions according to claim 1, characterized in that, The concentration of the demulsifier composition in the produced liquid is 150-250 mg / L.

3. The method of claim 1, wherein, The heating temperature is 50-70 ℃, and the heating time is 35-50 min.

4. The method of claim 1, wherein, The filtering is performed by using a membrane filter device.

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