Preparation method and application of polymer intercalation composite oil drag reducer

Abstract

The application provides a preparation method and application of a polymer intercalation composite oil product drag reducer. The preparation method adopts polymer solution intercalation: under the action of an interfacial compatibilizer, layered silicate particles are soaked in a polymer solution and heated and stirred, the polymer is directly inserted into the interlayer from the solution to form a nanocomposite. The application obtains an intercalation type nanocomposite oil product drag reducer based on the intercalation composite process of the polymer intercalation type, the product has high strength and high toughness, and has good shear resistance; the drag reduction and transportation increase effect is good.

Description

Technical Field

[0001] This invention belongs to the field of oil additive technology, specifically relating to an oil drag reducer with shear resistance that can be used in oil transportation pipelines. Background Technology

[0002] With the development of the petroleum industry, transportation has become an extremely important link. Pipeline transportation has many advantages, such as low investment, small footprint, minimal impact from geography and climate, and environmental friendliness, and is widely used in industrial oil transportation. Oil pipeline transportation faces problems such as long distances, large pipe diameters, and high energy consumption. While pressurization is often used to maintain the original oil flow rate, this can lead to safety hazards. Currently, the international standard is to use oil drag-reducing agents to address the drag reduction and increased transport capacity issues. Oil drag-reducing agents are a type of pipeline chemical additive. By injecting a very small amount (approximately a few parts per million) of polymer drag-reducing agent into the oil, the elastic deformation of the polymer chains reduces the frictional resistance of the oil during flow, achieving the effect of drag reduction and increased transport capacity.

[0003] Currently, drag-reducing agents used in industry are mainly linear polymers, such as α-olefin polymers and polyisobutylene. They have a wide range of applications and good performance, possessing advantages such as high molecular weight, good oil solubility, and high drag reduction rate. Generally, the drag reduction rate of drag-reducing agents increases with increasing molecular weight; these agents are characterized by very high molecular weights, sometimes exceeding several million. However, linear polymer drag-reducing agents are prone to shear degradation during application: that is, after passing through the high-turbulence region of a pipeline, their polymeric covalent bonds break down into low-molecular-weight polymers with little or no drag reduction effect, leading to a decrease in drag reduction rate. To maintain the drag reduction effect, timely replenishment is necessary after passing through high-shear regions, which significantly increases the amount of drag-reducing agent used and affects economic efficiency. Therefore, research on shear-resistant drag-reducing agents is a development trend.

[0004] With the increasing demand for oil, pipeline transportation has become increasingly demanding. The application of drag-reducing agents can increase pipeline capacity, reduce energy consumption, and improve the economic efficiency of pipeline transportation. The application of drag-reducing agents in oil pipelines is an inevitable trend. Strengthening research and exploration into the production process and drag-reducing mechanism of drag-reducing agents, reducing production costs, and improving drag reduction and transportation efficiency are essential choices for the development of the oil pipeline industry. Therefore, the development of drag-reducing agents for oil products with shear resistance, aiming to minimize the number of station-to-station pressure transfers to ensure the stability of oil pipelines and reduce transportation costs, is of great research significance. Due to the complexity of developing shear-resistant drag-reducing agents for oil products, it has become a challenging and hot research topic in this field. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a method for preparing a polymer intercalation composite oil drag reducer with thermal stability and shear resistance.

[0006] The technical solution adopted in this invention is: a method for preparing a polymer intercalation composite oil drag reducer, comprising the following steps:

[0007] 1) Preparation of polymer solution: Dissolve polyα-olefin in n-heptane and stir at a rate of 100-200 r / min for 5-7 days to obtain polymer solution.

[0008] 2) Preparation of interfacial compatibilizer: Poly-α-olefin is dispersed in an organic solvent to obtain a poly-α-olefin slurry; maleic anhydride is added to the poly-α-olefin slurry, and the resulting mixture is ultrasonically treated with an ultrasonic cell disruptor for 20-30 min, and then reacted at 80-90℃ for 3-4 h to obtain a poly-α-olefin solution grafted with maleic anhydride, which is the crude interfacial compatibilizer; the crude interfacial compatibilizer is poured into xylene, heated and refluxed to dissolve, and the solution is poured into acetone while hot. The grafted product is insoluble in acetone and forms a white flocculent precipitate. The precipitate is filtered, washed with acetone, filtered under vacuum, and dried. The resulting solid is the pure interfacial compatibilizer.

[0009] 3) Preparation of organic layered silicates: The layered silicates were dispersed in deionized water and stirred at 20-50℃ for 30-40 min. The pH of the system was adjusted to 9-11 with NaCO3 aqueous solution. After stirring for 2-4 h, the mixture was allowed to stand overnight to obtain a layered silicate dispersion. The layered silicate dispersion was heated to 75-85℃ and CTAB aqueous solution was added in 3-5 portions over 30 min. Isopropanol, an intercalating agent, was added dropwise or not while adding CTAB aqueous solution. After the addition was completed, the mixture was kept at a constant temperature for 3-4 h to obtain a modified layered silicate intercalation nanoslurry. The slurry was centrifuged and washed repeatedly with 50-75% anhydrous ethanol until no precipitate was formed when the washing liquid was tested with 0.1 mol / L silver nitrate solution. The slurry was dried at 105℃ for 24 h and ground through a 200-mesh sieve to obtain organic layered silicate powder.

[0010] 4) Polymerization reaction: Take polymer solution, interfacial compatibilizer and organic layered silicate powder, mix them evenly, and react at 70-75℃ for 1-2 hours to obtain polymer intercalation composite oil drag reducer.

[0011] Preferably, the polyα-olefin has a relative molecular mass of 5 × 10⁻⁶. 6 ~8×10 6 .

[0012] Preferably, the preparation method of the poly-α-olefin includes the following steps: cooling the α-olefin monomer to -30°C and adding the Ziegler-Natta catalyst, mixing evenly, and reacting in a -30°C ultra-low temperature water bath for 2 days in the absence of air. After the reaction is completed, the resulting reactants are cooled to below -130°C with liquid nitrogen to obtain a blocky crude poly-α-olefin. The blocky crude poly-α-olefin is pulverized using a ball mill with a liquid nitrogen bath, and a dispersant is added while pulverizing. After mixing evenly, it is passed through a 100-mesh sieve, and the material passing through the sieve is taken as poly-α-olefin.

[0013] Preferably, the Ziegler-Natta catalyst is composed of a main catalyst TiCl3 and a co-catalyst AlCl3.

[0014] Preferably, the dispersant is calcium stearate or sodium stearate; the amount of dispersant added is 15% to 30% of the crude polyalphaolefin mass.

[0015] Preferably, in step 1), the mass ratio of poly-α-olefin to n-heptane is 1:(50-100).

[0016] Preferably, in step 2), the organic solvent is n-octanol or anhydrous ethanol; by mass ratio, poly-α-olefin: organic solvent = 4:6, maleic anhydride: poly-α-olefin slurry = 1:(50-100).

[0017] Preferably, in step 3), the layered silicate is sodium-based bentonite; by mass ratio, layered silicate:deionized water = 1:(10-20); the amount of CTAB added is 3-5% of the mass of the layered silicate dispersion; the amount of isopropanol added is 4-6% of the mass of CTAB.

[0018] Preferably, in step 4), the polymer solution: interface compatibilizer: organic layered silicate powder is in the mass ratio of (15-25):(2-6):1.

[0019] The application of the polymer intercalation composite oil drag reducer provided by this invention in oil additives.

[0020] The beneficial effects of this invention are:

[0021] 1. In this invention, a poly-α-olefin solution is used to directly embed into the channels of layered silicate sheets under the action of an interfacial compatibilizer to obtain an intercalated nanocomposite material. This allows the inorganic and organic materials to have a synergistic effect. The inorganic nanoparticles dispersed phase has a large surface energy and rigidity, which makes the composite material have good mechanical properties, enhances the toughness of the composite material molecular chains, and improves the shear resistance.

[0022] 2. In this invention, ultrasound is used in the preparation of the interfacial compatibilizer. When the ultrasonic waves treat the solution containing nanoparticles, cavitation occurs, generating cavities or bubbles in the mixture. These bubbles vibrate under the influence of the sound field. When the sound pressure reaches a certain value, the cavities or bubbles rapidly increase in size and then suddenly collapse, generating extremely high pressure in a localized area of ​​the liquid, causing violent movement of the liquid molecules. When the cavitation bubbles collapse, they form extremely high-velocity microjets that impact the aggregates with tremendous force. Under such strong force, the aggregated nanoparticles redisperse, and cavitation also improves the mass transfer process between the liquid medium and the solid surface. This pressure or violent movement of liquid molecules causes nanoparticle aggregates that could not be separated by stirring to disperse into smaller aggregates or individual particles, reducing nanoparticle aggregation and improving its uniformity of distribution in the liquid.

[0023] 3. In this invention, intercalation composite technology is used, which utilizes the layered structure of layered compound materials to insert monomers or polymer solutions between layered silicate layers, thereby destroying the layered structure of silicate, causing it to peel off into layered basic units, and uniformly dispersed in the polymer matrix, realizing the composite of polymer and layered silicate at the nanoscale, so that the composite material has high thermal stability, high strength and high toughness.

[0024] 4. In this invention, the preparation method of the polymer intercalation composite oil drag reducer is simple, the conditions are mild, the drag reduction and transportation increase effect is good, and the shear resistance is excellent. Detailed Implementation

[0025] Example 1: A method for preparing a polymer intercalation composite oil drag reducer (I) is as follows:

[0026] 1. Purification of α-olefins:

[0027] Multiple adsorption columns connected in series were fabricated using porous aluminate molecular sieves with a pore size of 1 nm. α-olefin monomers from the coarse feed tank were passed through the series of adsorption columns at a flow rate of 1 ml / min to remove water and impurities. The purity of the treated α-olefin monomers was determined by gas chromatography; impurity content <1 g / t was acceptable.

[0028] 2. Preparation of polyα-olefins:

[0029] The purified α-olefin monomer (52.5 g) was cooled to -30°C and then added to a reaction vessel along with the main catalyst TiCl3 (0.28 g) and the liquid co-catalyst AlCl3 (0.09 g). The vessel was shaken to mix thoroughly, and the mixture was placed in a -30°C ultra-low temperature water bath for 2 days in the absence of air. After the reaction, a highly viscous blocky reactant was obtained. The highly viscous blocky reactant was cooled to below its glass transition temperature of -130°C using liquid nitrogen to obtain a hard and brittle blocky crude poly-α-olefin. The blocky crude poly-α-olefin was then pulverized using a ball mill in a liquid nitrogen bath. While pulverizing, 20% (by weight) of the dispersant calcium stearate was added as dispersant. After mixing thoroughly, the mixture was passed through a 100-mesh sieve, and the material passing through the sieve was taken as the poly-α-olefin. The molecular weight of the poly-α-olefin was 5 × 10⁻⁶. 6 .

[0030] 3. Preparation of polymer solution:

[0031] The poly-α-olefin was dissolved in n-heptane at a mass ratio of 1:80, and the mixture was stirred at 100 r / min for 6 days to obtain a polymer solution.

[0032] 4. Preparation of interfacial compatibilizers:

[0033] By mass ratio of poly-α-olefin to n-octanol = 4:6, the poly-α-olefin is dispersed in n-octanol to obtain a poly-α-olefin slurry.

[0034] Dry maleic anhydride (0.3 g) was added to poly-α-olefin slurry (30 g). The resulting mixture was ultrasonically treated with an ultrasonic cell disruptor for 20–30 min, and then reacted at 80 °C for 3 h to obtain a poly-α-olefin solution grafted with maleic anhydride, which was the crude interfacial compatibilizer. The crude interfacial compatibilizer was poured into xylene and heated under reflux to dissolve the graft. While still hot, the solution was poured into acetone. The grafted product was insoluble in acetone, forming a white flocculent precipitate. The precipitate was filtered, washed with acetone, filtered again under vacuum, and dried. The resulting solid was the pure interfacial compatibilizer.

[0035] 5. Preparation of organosodium bentonite:

[0036] Sodium-based bentonite:deionized water = 1:20 by mass ratio; sodium-based bentonite is dispersed in deionized water, stirred at room temperature for 30 min, and then the pH of the system is adjusted to 9-11 with 0.1 mol / L NaCO3 aqueous solution. After stirring for 4 h, it is allowed to stand overnight to obtain sodium-based bentonite dispersion.

[0037] After heating the sodium-based bentonite dispersion to 75℃, 3% (by weight) of an aqueous solution of CTAB was added in five portions over 30 minutes. Simultaneously with the addition of the CTAB aqueous solution, 5% (by weight) of isopropanol (a CTAB intercalating agent) was added dropwise. After the addition was complete, the mixture was kept at a constant temperature for 3 hours to obtain a modified sodium-based bentonite intercalated nanoslurry. The modified sodium-based bentonite intercalated nanoslurry was centrifuged to remove the liquid, and repeatedly washed with 50% anhydrous ethanol until no precipitate formed when tested with 0.1 mol / L silver nitrate solution. The mixture was then dried at 105℃ for 24 hours, ground, and passed through a 200-mesh sieve to obtain organo-sodium-based bentonite powder.

[0038] 6. Polymerization reaction:

[0039] Take a polymer solution (30g), an interfacial compatibilizer (6g), and an organic sodium bentonite powder (1.5g), mix them evenly, and react them at 70℃ for 1.5h to obtain a polymer intercalation composite oil drag reducer.

[0040] (II) Application

[0041] Using the oil drag reducer loop test system, when the concentration of the polymer intercalated composite oil drag reducer was 50 ppm, the drag reduction rate was measured to be 54.7%. After one pump shearing, the drag reduction rate remained at 28.9%, which is 52.8% of the initial drag reduction rate.

[0042] Example 2: A method for preparing a polymer intercalation composite oil drag reducer (I) is as follows:

[0043] 1. Purification of α-olefins: Same as in Example 1.

[0044] 2. Preparation of poly-α-olefin: Same as in Example 1.

[0045] 3. Preparation of polymer solution: Same as in Example 1.

[0046] 4. Preparation of interfacial compatibilizer: Same as in Example 1.

[0047] 5. Preparation of organosodium bentonite:

[0048] Sodium-based bentonite:deionized water = 1:20 by mass ratio; sodium-based bentonite is dispersed in deionized water, stirred at room temperature for 30 min, and then the pH of the system is adjusted to 9-11 with 0.1 mol / L NaCO3 aqueous solution. After stirring for 4 h, it is allowed to stand overnight to obtain sodium-based bentonite dispersion.

[0049] After heating the sodium-based bentonite dispersion to 75℃, 3% (by weight) of an aqueous solution of CTAB was added dropwise in 5 portions over 30 minutes. After the addition was complete, the mixture was kept at a constant temperature for 3 hours to obtain a modified sodium-based bentonite intercalated nanoslurry. The modified sodium-based bentonite intercalated nanoslurry was centrifuged to remove the liquid, and repeatedly washed with 50% anhydrous ethanol until no precipitate formed when tested with 0.1 mol / L silver nitrate solution. It was then dried at 105℃ for 24 hours, ground, and passed through a 200-mesh sieve to obtain organo-sodium-based bentonite powder.

[0050] 6. Polymerization reaction:

[0051] Take a polymer solution (30g), an interfacial compatibilizer (6g), and an organic sodium bentonite powder (1.5g), mix them evenly, and react them at 70℃ for 1.5h to obtain a polymer intercalation composite oil drag reducer.

[0052] (II) Application

[0053] Using the oil drag reducer loop test system, when the concentration of the polymer intercalated composite oil drag reducer was 50 ppm, the drag reduction rate was measured to be 54.3%. After one pump shearing, the drag reduction rate remained at 28.1%, which is 51.7% of the initial drag reduction rate.

[0054] Example 3: A method for preparing a polymer intercalation composite oil drag reducer (I) is as follows:

[0055] 1. Purification of α-olefins: Same as in Example 1.

[0056] 2. Preparation of poly-α-olefin: Same as in Example 1.

[0057] 3. Preparation of polymer solution: Same as in Example 1.

[0058] 4. Preparation of interfacial compatibilizer: Same as in Example 1.

[0059] 5. Preparation of organosodium bentonite:

[0060] Sodium-based bentonite:deionized water = 1:20 by mass ratio; sodium-based bentonite is dispersed in deionized water, stirred at 50℃ for 20 min, and then the pH of the system is adjusted to 9-11 with 0.1 mol / L NaCO3 aqueous solution. After stirring for 2 h, it is allowed to stand overnight to obtain sodium-based bentonite dispersion.

[0061] After heating the sodium-based bentonite dispersion to 85℃, a 5% (by weight) aqueous solution of CTAB was added dropwise in three portions over 30 minutes. The mixture was kept at this temperature for 3 hours to obtain a modified sodium-based bentonite intercalated nanoslurry. The modified sodium-based bentonite intercalated nanoslurry was centrifuged to remove the liquid, and repeatedly washed with 75% anhydrous ethanol until no precipitate formed when tested with 0.1 mol / L silver nitrate solution. It was then dried at 105℃ for 24 hours and ground through a 200-mesh sieve to obtain organo-sodium-based bentonite powder.

[0062] 6. Polymerization reaction:

[0063] Take a polymer solution (30g), an interfacial compatibilizer (6g), and an organic sodium bentonite powder (1.5g), mix them evenly, and react them at 70℃ for 1.5h to obtain a polymer intercalation composite oil drag reducer.

[0064] (II) Application

[0065] Using the oil drag reducer loop test system, when the concentration of the polymer intercalated composite oil drag reducer was 50 ppm, the drag reduction rate was measured to be 53.6%. After one pump shearing, the drag reduction rate remained at 27.5%, which is 51.3% of the initial drag reduction rate.

[0066] Example 4: A method for preparing a polymer intercalation composite oil drag reducer (I) is as follows:

[0067] 1. Purification of α-olefins: Same as in Example 1.

[0068] 2. Preparation of poly-α-olefin: Same as in Example 1.

[0069] 3. Preparation of polymer solution: Same as in Example 1.

[0070] 4. Preparation of interfacial compatibilizer: Same as in Example 1.

[0071] 5. Preparation of organosodium bentonite:

[0072] Sodium-based bentonite:deionized water = 1:20 by mass ratio; sodium-based bentonite is dispersed in deionized water, stirred at 50℃ for 20 min, and then the pH of the system is adjusted to 9-11 with 0.1 mol / L NaCO3 aqueous solution. After stirring for 2 h, it is allowed to stand overnight to obtain sodium-based bentonite dispersion.

[0073] After heating the sodium-based bentonite dispersion to 85℃, 3% (by weight) of an aqueous solution of CTAB was added in five portions over 30 minutes. Simultaneously with the addition of the CTAB aqueous solution, 5% (by weight) of isopropanol (a CTAB intercalating agent) was added dropwise. After the addition was complete, the mixture was kept at a constant temperature for 3 hours to obtain a modified sodium-based bentonite intercalated nanoslurry. The modified sodium-based bentonite intercalated nanoslurry was centrifuged to remove the liquid, and repeatedly washed with 75% anhydrous ethanol until no precipitate formed when tested with 0.1 mol / L silver nitrate solution. It was then dried at 105℃ for 24 hours, ground, and passed through a 200-mesh sieve to obtain organo-sodium-based bentonite powder.

[0074] 6. Polymerization reaction:

[0075] Take a polymer solution (30g), an interfacial compatibilizer (6g), and an organic sodium bentonite powder (1.5g), mix them evenly, and react them at 70℃ for 1.5h to obtain a polymer intercalation composite oil drag reducer.

[0076] (II) Application

[0077] Using the oil drag reducer loop test system, when the concentration of the polymer intercalated composite oil drag reducer was 50 ppm, the drag reduction rate was measured to be 53.2%. After one pump shearing, the drag reduction rate remained at 27.1%, which is 50.9% of the initial drag reduction rate.

[0078] As can be seen from Examples 1-4, the polymer intercalation composite oil drag reducer obtained by the present invention has good drag reduction effect and excellent shear resistance.

Claims

1. A method for preparing a polymer-intercalated composite oil drag-reducing agent, characterized in that, The preparation method includes the following steps: 1) Preparation of polymer solution: Dissolve polyα-olefin in n-heptane and stir at a rate of 100-200 r / min for 5-7 days to obtain polymer solution; 2) Preparation of interfacial compatibilizer: Poly-α-olefin is dispersed in an organic solvent to obtain a poly-α-olefin slurry; maleic anhydride is added to the poly-α-olefin slurry, and the resulting mixture is ultrasonically treated with an ultrasonic cell disruptor for 20-30 min, and then reacted at 80-90℃ for 3-4 h to obtain a poly-α-olefin solution grafted with maleic anhydride, which is the crude interfacial compatibilizer; the crude interfacial compatibilizer is poured into xylene, heated under reflux to dissolve, and the solution is poured into acetone while hot. The grafted product is insoluble in acetone and forms a white flocculent precipitate. The precipitate is filtered, washed with acetone, filtered under vacuum, and dried. The resulting solid is the pure interfacial compatibilizer. 3) Preparation of organic layered silicates: The layered silicates were dispersed in deionized water and stirred at 20-50℃ for 30-40 min. The pH of the system was adjusted to 9-11 with NaCO3 aqueous solution. After stirring for 2-4 h, the mixture was allowed to stand overnight to obtain a layered silicate dispersion. The layered silicate dispersion was heated to 75-85℃ and CTAB aqueous solution was added in 3-5 portions over 30 min. Isopropanol, an intercalating agent, was added dropwise or not while adding CTAB aqueous solution. After the addition was completed, the mixture was kept at a constant temperature for 3-4 h to obtain a modified layered silicate intercalation nanoslurry. The slurry was centrifuged and washed repeatedly with 50-75% anhydrous ethanol until no precipitate was formed when the washing liquid was tested with 0.1 mol / L silver nitrate solution. The slurry was dried at 105℃ for 24 h and ground through a 200-mesh sieve to obtain organic layered silicate powder. 4) Polymerization reaction: Take polymer solution, interfacial compatibilizer and organic layered silicate powder, mix them evenly, and react at 70-75℃ for 1-2 hours to obtain polymer intercalation composite oil drag reducer.

2. The preparation method according to claim 1, characterized in that, The relative molecular mass of the polyα-olefin is 5 × 10⁻⁶. 6 ~8×10 6 .

3. The preparation method according to claim 1, characterized in that, The preparation method of the poly-α-olefin includes the following steps: cooling the α-olefin monomer to -30°C and adding the Ziegler-Natta catalyst, mixing evenly, and reacting in a -30°C ultra-low temperature water bath for 2 days in the absence of air. After the reaction is completed, the resulting reactants are cooled to below -130°C with liquid nitrogen to obtain crude block poly-α-olefin. The crude block poly-α-olefin is pulverized using a ball mill with a liquid nitrogen bath, and a dispersant is added while pulverizing. After mixing evenly, it is passed through a 100-mesh sieve, and the material passing through the sieve is taken as poly-α-olefin.

4. The preparation method according to claim 3, characterized in that, The Ziegler-Natta catalyst consists of TiCl3 as the main catalyst and AlCl3 as the co-catalyst.

5. The preparation method according to claim 3, characterized in that, The dispersant is calcium stearate or sodium stearate; the amount of dispersant added is 15% to 30% of the crude polyalphaolefin mass.

6. The preparation method according to claim 1, characterized in that, In step 1), the mass ratio of poly-α-olefin to n-heptane is 1:(50-100).

7. The preparation method according to claim 1, characterized in that, In step 2), the organic solvent is n-octanol or anhydrous ethanol; by mass ratio, poly-α-olefin: organic solvent = 4:6, maleic anhydride: poly-α-olefin slurry = 1:(50-100).

8. The preparation method according to claim 1, characterized in that, In step 3), the layered silicate is sodium-based bentonite; by mass ratio, layered silicate:deionized water = 1:(10-20); the amount of CTAB added is 3-5% of the mass of the layered silicate dispersion; the amount of isopropanol added is 4-6% of the mass of CTAB.

9. The preparation method according to claim 1, characterized in that, In step 4), the polymer solution: interface compatibilizer: organic layered silicate powder are in the mass ratio of (15-25):(2-6):

1.

10. The application of the polymer intercalation composite oil drag reducer prepared according to any one of claims 1-9 in oil additives.