Preparation method of high-drag-reduction type oil-soluble turbulence drag reducer

Abstract

The invention relates to the technical field of turbulent flow drag reduction, in particular to a preparation method of a high-drag-reduction type oil-soluble turbulent flow drag reducer, which comprises the following steps: (1) cleaning glassware required by reaction with absolute ethyl alcohol, drying, and putting into a glove box; the glove box is subjected to oxygen and water suction treatment, and nitrogen is continuously introduced till the oxygen content and the water content in the glove box are both smaller than 100 ppm; (2) adding quantitative heptane solution and triethyl aluminum into the flask in a glove box; adding a certain amount of an external electron donor solution (cyclohexylmethyldimethoxysilane) and a Ziegler-Natta catalyst after the mixture is stable, and adding a certain amount of an alpha-octylene monomer after the mixture is uniformly mixed; (3) sealing the flask, and stirring for 24 hours under the conditions that the constant temperature is 20-60 DEG C and the stirring rotating speed is 300r / min; and (4) freezing and dehydrating the solution for 24 hours. The raw materials for preparing the drag reducer are easy to obtain, the preparation process is simple, the drag reduction rate can reach 20% and the molecular weight reaches 2.15 * 10 < 6 > g / mol when the drag reducer is tested in a turbulent flow flat plate rheological device, the pipeline transportation energy consumption can be effectively reduced, and the economic benefit is improved.

Description

Technical Field

[0001] The invention relates to the technical field of turbulent drag reduction, in particular to a method for preparing a high-drag-reducing oil-soluble turbulent drag reducer. Background Art

[0002] As the domestic demand for oil and natural gas continues to grow, the pipeline transportation volume of oil and gas products has also increased, making the transportation cost an issue that cannot be ignored. In the long-distance pipeline transportation of oil products, the flow state in the pipeline has a significant impact on the transportation efficiency and energy consumption. Especially in long-distance pipelines, turbulence will cause a significant increase in flow resistance, which in turn will cause a large amount of energy loss and significantly increase transportation costs. In order to improve the efficiency of oil pipeline transportation, the preparation of high-performance turbulent drag reducers plays a vital role in improving pipeline transportation capacity, reducing pipeline friction resistance, and increasing pipeline economic benefits.

[0003] Olefin drag reducer is a chemical additive widely used in oil pipelines. It is an oil-soluble drag reducer. Only a very small amount (1 / 10 6 The drag reduction efficiency of drag reducers needs to be further improved. The molecular weight directly affects the drag reduction efficiency of drag reducers. The molecular weight determines the length of the polymer molecular chain. Longer molecular chains can stretch better in the fluid and have excellent viscoelasticity, thereby effectively absorbing turbulent energy, inhibiting the development of turbulent vortices, and reducing the friction resistance of fluid flow.

[0004] In summary, given the limitations of existing poly-α-olefin drag reducers in terms of molecular weight, drag reduction efficiency, stability and cost, it is particularly urgent to develop a new type of high drag reduction oil-soluble turbulent drag reducer. The drag reducer should have a higher molecular weight and better viscoelasticity to effectively absorb turbulent energy and inhibit the development of turbulent vortices, thereby significantly reducing the turbulent friction resistance of oil-based fluids. In addition, its preparation process should be cost-effective to meet the needs of large-scale industrial applications. By optimizing the molecular structure and preparation method of the drag reducer, it is expected to achieve efficient energy saving and emission reduction in the fluid transportation system of the oil industry without changing the structure of the existing fluid transportation system, providing strong support for efficient energy utilization and environmental protection. Summary of the invention

[0005] The present invention aims to solve the problems of low drag reduction performance, low molecular weight and high synthesis difficulty of oil-soluble turbulent drag reducers, and proposes a method for preparing a high drag reduction oil-soluble turbulent drag reducer. The high drag reduction oil-soluble turbulent drag reducer prepared by the present invention has the advantages of simple preparation, good drag reduction performance and ultra-high molecular weight.

[0006] The present invention is achieved through the following technical solutions:

[0007] All polymerization reactions must be carried out under anhydrous and oxygen-free conditions. The flasks, syringes and other glassware used for weighing and transferring catalysts, co-catalysts, solutions, etc. involved in all reactions must be treated to be anhydrous and oxygen-free.

[0008] (1) First, all glassware required for the reaction were cleaned with anhydrous ethanol, dried and placed in a glove box; secondly, oxygen and water were extracted from the glove box, and nitrogen was continuously filled until the oxygen and water contents in the glove box were less than 100 ppm;

[0009] (2) adding a quantitative heptane solution and triethylaluminum to a flask in a glove box; adding a quantitative external electron donor solution (cyclohexylmethyldimethoxysilane) and a Ziegler-Natta catalyst after the solution is stabilized, and adding a quantitative α-octene monomer after the solution is mixed evenly;

[0010] (3) After the operation is completed, the flask is sealed and stirred at a constant temperature of 20-60°C and a stirring speed of 300 r / min for 24 h;

[0011] (4) After stirring, the solution becomes gel-like and is freeze-dehydrated for 24 h.

[0012] Preferably according to the present invention, in step (2), the concentration of triethylaluminum is 1 mol / L.

[0013] Preferably, according to the present invention, in step (2), cyclohexylmethyldimethoxysilane needs to be dissolved in white oil to ensure that the concentration of the prepared external electron donor solution is 0.1 mol / L.

[0014] The present invention has been found in experiments that the monomer ratio, polymerization method and polymerization temperature of the present invention have a good effect on the drag reduction of finished oil. When the synthesis temperature of the oil-soluble turbulent drag reducer is 20°C, the molecular weight is 2.15×10 6 g / mol, with a concentration of 60ppm, the drag reduction effect in an indoor turbulent flat plate rheology device is the best, up to 20%.

[0015] The technical features and advantages of the present invention are as follows:

[0016] The invention discloses a method for preparing a high drag reduction type oil-soluble turbulent drag reducer. The raw materials are readily available, the preparation process is simple, the molecular weight is high, and the drag reduction effect is good. The invention uses α-octene as a polymerization monomer and uses a catalyst to perform a polymerization reaction to obtain an oil-soluble turbulent drag reducer with a high molecular weight and good drag reduction performance. The oil-soluble turbulent drag reducer can effectively reduce the turbulent intensity, thereby achieving the beneficial effects of improving the oil product transportation efficiency and reducing the transportation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Purpose of the drawings: In order to more clearly illustrate the embodiments and technical solutions of the present invention, the drawings required for use in the embodiments will be simply marked and introduced below.

[0018] Figure 1 This is a molecular weight test chart of Example 1 of the wide-angle dynamic / static laser scattering instrument.

[0019] Figure 2 This is a molecular weight test chart of Example 2 of the wide-angle dynamic / static laser scattering instrument.

[0020] Figure 3 This is a molecular weight test chart of Example 3 of the wide-angle dynamic / static laser scattering instrument.

[0021] Figure 4 It is a turbulent flat plate rheology device.

[0022] Figure 5 This is a test diagram of drag reduction efficiency of Example 1.

[0023] Figure 6 This is a test diagram of drag reduction efficiency of Example 2.

[0024] Figure 7 This is a test diagram of drag reduction efficiency of Example 3.

[0025] Figure 8 This is a diagram of the polymerization process of oil-soluble turbulent drag reducer.

[0026] Fig. 9 This is a schematic diagram of the finished product of the oil-soluble turbulent drag reducer.

[0027] Fig.10 A technology roadmap for the preparation of oil-soluble turbulent drag reducers. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below in conjunction with the drawings in one or more embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of the specification, not all of the embodiments. Based on one or more embodiments of the specification, other embodiments obtained by ordinary technicians in this field without making creative work should all fall within the scope of protection of the embodiment solutions of this specification.

[0029] Example 1: Polymerization at 60°C

[0030] (1) First, all glassware required for the reaction were cleaned with anhydrous ethanol, dried and placed in a glove box; secondly, oxygen and water were extracted from the glove box, and nitrogen was continuously filled until the oxygen and water contents in the glove box were less than 100 ppm;

[0031] (2) In a glove box, add 1.2 ml of heptane solution and 3.2 ml of triethylaluminum into a flask; after the flask is stabilized, add 1.2 ml of external electron donor solution and 6.4 mg of Ziegler-Natta catalyst, mix the solution evenly, and then add 40 ml of α-octene monomer;

[0032] (3) After the operation is completed, the flask is sealed and stirred at a constant temperature of 60°C and a stirring speed of 300 r / min for 24 h;

[0033] (4) After stirring, the solution becomes gel-like and is freeze-dehydrated for 24 h.

[0034] Example 2: Polymerization at 40°C

[0035] (1) First, all glassware required for the reaction were cleaned with anhydrous ethanol, dried and placed in a glove box; secondly, oxygen and water were extracted from the glove box, and nitrogen was continuously filled until the oxygen and water contents in the glove box were less than 100 ppm;

[0036] (2) In a glove box, add 1.2 ml of heptane solution and 3.2 ml of triethylaluminum into a flask; after the flask is stabilized, add 1.2 ml of external electron donor solution and 6.4 mg of Ziegler-Natta catalyst, mix the solution evenly, and then add 40 ml of α-octene monomer;

[0037] (3) After the operation is completed, the flask is sealed and stirred at a constant temperature of 40°C and a stirring speed of 300 r / min for 24 h;

[0038] (4) After stirring, the solution becomes gel-like and needs to be freeze-dehydrated for 24 hours.

[0039] Example 3: Polymerization at 20°C

[0040] (1) First, all glassware required for the reaction were cleaned with anhydrous ethanol, dried and placed in a glove box; secondly, oxygen and water were extracted from the glove box, and nitrogen was continuously filled until the oxygen and water contents in the glove box were less than 100 ppm;

[0041] (2) In a glove box, add 1.2 ml of heptane solution and 3.2 ml of triethylaluminum into a flask; after the flask is stabilized, add 1.2 ml of external electron donor solution and 6.4 mg of Ziegler-Natta catalyst, mix the solution evenly, and then add 40 ml of α-octene monomer;

[0042] (3) After the operation is completed, the flask is sealed and stirred at a constant temperature of 20°C and a stirring speed of 300 r / min for 24 h;

[0043] (4) After stirring, the solution becomes gel-like and needs to be freeze-dehydrated for 24 hours.

[0044] Performance Testing

[0045] For the above embodiments, a turbulent flat plate rheometer was used to evaluate the drag reduction effect. The experimental conditions were room temperature 15°C, speed n = 1000-3000s -1 , the speed change rate per step is dn=100r / min.

[0046] The drag reduction effect evaluation data of the oil-soluble turbulent drag reducer in each embodiment are as follows: Figures 5 to 7 shown.

[0047] (1) The molecular weight of Example 1 was measured experimentally to be 1.08×10 6 g / mol, when the concentration is 60ppm, the drag reduction effect is the best, which can reach 14%.

[0048] (2) The molecular weight of Example 2 was measured by experiment to be 1.51×10 6 g / mol, when the concentration is 60ppm, the drag reduction effect is the best, which can reach 16%.

[0049] (3) The molecular weight of Example 3 was measured by experiment to be 2.15×10 6 g / mol, when the concentration is 60ppm, the drag reduction effect is the best, which can reach 20%.

[0050] Product Characterization

[0051] 1. Solution molecular weight test

[0052] For each of the above embodiments, five concentration gradients of oil-soluble turbulent drag reducer kerosene solutions need to be prepared, and the concentration gradients are: 100ppm, 300ppm, 500ppm, 1000ppm and 2000ppm respectively; before testing, the impurities in the solution need to be filtered with a filter and the surface of the container needs to be free of fingerprints and dust. A wide-angle dynamic / static laser scattering instrument is used to conduct a laser scattering experiment on the prepared oil-soluble turbulent drag reducer solution in a constant temperature water bath at 25°C and a test angle of θ=45-135° to obtain the molecular weight of the oil-soluble turbulent drag reducer solution.

[0053] 2. Solution macro drag reduction test

[0054] For the above embodiments, a turbulent flat plate rheology device was used to conduct test experiments. Figure 4 As shown. At room temperature 15℃ and speed 1000-3000min -1Under the conditions, test experiments were carried out on diesel solutions with oil-soluble turbulent drag reducers at concentrations of 5ppm, 10ppm, 20ppm, 40ppm and 60ppm, and the corresponding drag reduction test graphs were obtained.

[0055] Technological advantages and innovation

[0056] The method for preparing a high drag reduction oil-soluble turbulent drag reducer provided by the present invention achieves significant performance improvement and industrial application value by optimizing monomer ratio, polymerization conditions and process parameters, as follows:

[0057] 1. Excellent drag reduction performance and molecular weight

[0058] By optimizing the polymerization temperature (20-60°C), a 2.15×10 6 g / mol oil-soluble turbulent drag reducer (Example 3). The high molecular weight gives the oil-soluble turbulent drag reducer a longer molecular chain and stronger viscoelasticity, which can effectively inhibit the development of turbulent vortices and absorb turbulent energy, thereby significantly reducing flow resistance. Experiments show that at a concentration of 60ppm, the drag reduction efficiency can reach up to 20% (Example 3), which is significantly improved compared to existing poly-α-olefin drag reducers (usually less than 15%).

[0059] 2. The preparation process is simple and the cost is controllable

[0060] The Ziegler-Natta catalyst system, combined with the standardized operation process without water and oxygen, simplifies the polymerization reaction steps and avoids complicated post-processing. For example, high molecular weight products can be obtained by polymerization at low temperature (20°C), reducing energy consumption and production costs. At the same time, raw materials (such as α-octene, white oil and heptane) are easily available and inexpensive, making them suitable for large-scale industrial production.

[0061] 3. Outstanding stability and adaptability

[0062] The oil-soluble turbulent drag reducer exhibits good solubility and stability in oil-based fluids such as kerosene and diesel, and has a wide applicable concentration range (5 to 60 ppm). By adjusting the polymerization temperature, the preparation method of the present invention can synthesize oil-soluble turbulent drag reducers suitable for different working conditions. For example, Examples 1, 2, and 3 were prepared by polymerization at 60°C, 40°C, and 20°C, respectively, and the resulting oil-soluble turbulent drag reducers all exhibited good drag reduction effects and had a wide range of applications. Tested by a turbulent flat plate rheology device, it can still maintain a stable drag reduction effect at different shear rates (such as Figures 5 to 7 It is suitable for the actual needs of complex flow conditions in long-distance pipelines.

[0063] 4. Significant economic and environmental benefits

[0064] The oil-soluble turbulent drag reducer only needs to be added in trace amounts (ppm level) to significantly reduce the friction resistance of pipeline transportation, reduce pumping energy consumption, and increase the output. The raw materials and solvents used in the preparation process are all oil-soluble substances and will not pollute the environment. At the same time, no harmful by-products are generated during the reaction process, which meets environmental protection requirements. Taking Example 3 as an example, a drag reduction efficiency of 20% can reduce transportation costs by about 15 to 20%, while reducing carbon emissions, which is in line with the industry trend of efficient energy utilization and green development.

[0065] 5. Technical Scalability

[0066] The present invention can flexibly control the molecular weight of the product (1.08×10 6 ~2.15×10 6 g / mol), meeting the personalized needs of different oil products and working conditions. In addition, its process is compatible with the existing fluid delivery system and can be directly applied without modifying the pipeline, which has significant promotion value.

[0067] In summary, the present invention provides a method for preparing an efficient, economical and environmentally friendly oil-soluble turbulent drag reducer through molecular design, process optimization and performance verification, which provides important technical support for long-distance transportation in the oil and gas industry.

[0068] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a high drag reduction oil-soluble turbulent drag reducer, characterized in that: The specific steps of the preparation method are as follows: (1) extracting oxygen and water from the glove box to ensure that the synthesis conditions are anhydrous and oxygen-free, and then filling with nitrogen; first, all glassware required for the synthesis reaction are cleaned with anhydrous ethanol, dried and placed in the glove box; secondly, extracting oxygen and water from the glove box, and continuously filling with nitrogen until the oxygen content and water content in the glove box are both less than 100 ppm; (2) adding a quantitative heptane solution and triethylaluminum to a flask in a glove box; adding a quantitative external electron donor solution (cyclohexylmethyldimethoxysilane) and a Ziegler-Natta catalyst after the solution is stabilized, and adding a quantitative α-octene monomer after the solution is mixed evenly; (3) After the operation is completed, the flask is sealed and stirred at a constant temperature of 20-60°C and a stirring speed of 300 r / min for 24 h; (4) After stirring, the solution becomes gel-like and needs to be freeze-dehydrated for 24 hours.

2. The method for preparing a high drag reduction oil-soluble turbulent drag reducer according to claim 1, characterized in that: In step (2) of claim 1, the concentration of triethylaluminum is 1 mol / L.

3. The method for preparing a high drag reduction oil-soluble turbulent drag reducer according to claim 1, characterized in that: In claim 1, the molecular weight of the oil-soluble turbulent drag reducer prepared by polymerization at 20°C is the highest, which can reach 2.15×10 6 g / mol.

4. The method for preparing a high drag reduction oil-soluble turbulent drag reducer according to claim 1, characterized in that: In the aforementioned claim 1, the oil-soluble turbulent drag reducer diesel solution prepared by polymerization at 20° C. has the highest drag reduction efficiency of up to 20% when tested at a concentration of 60 ppm.

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