Pour-point-depressing paraffin inhibitor and preparation method and application thereof

Abstract

The invention relates to the technical field of pour point depressing and paraffin inhibition agents, in particular to a pour point depressing and paraffin inhibition agent and a preparation method and application thereof. The conventional polymer type pour point depressing paraffin inhibitor can increase the viscosity of crude oil while exerting the pour point depressing paraffin inhibition effect, obviously increases the conveying resistance of a crude oil pipeline, and improves the energy consumption. In order to solve the technical problems, the invention provides the pour point depressing paraffin inhibitor, the pour point depressing paraffin inhibitor is obtained by grafting alkyl acrylamide on the surface of a sulfydryl nanosphere, and the sulfydryl nanosphere is obtained by hydrolyzing and polycondensing a sulfydryl silane coupling agent under an alkaline condition. The obtained nanosphere pour point depressant is simple and feasible in preparation method and excellent in pour point depressing and paraffin inhibition effect, and compared with a conventional polymer type pour point depressing and paraffin inhibition agent, the nanosphere pour point depressant has no tackifying effect and has a good application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of a wax inhibitor and a setting point depressant, and in particular to a wax inhibitor and a preparation method and application thereof. Background Art

[0002] Wax deposition is a major engineering problem faced by waxy crude oil production and gathering and transportation. Many unfavorable working conditions of high-waxy crude oil gathering and transportation or long-distance pipelines highlight the importance of studying wax deposition.

[0003] Chemical wax inhibitors can reduce the pour point of petroleum, improve its low-temperature fluidity, and inhibit or slow down wax deposition from the source. They are a technical means with both theoretical research value and practical application potential. Compared with mechanical wax removal and hot oil wax melting methods, chemical wax inhibitors can not only extend the wax removal cycle and increase crude oil production, but also reduce the labor intensity of workers, save investment, and reduce wax removal costs. At the same time, the proper selection of chemical wax inhibitors can also achieve multiple effects such as wax prevention and viscosity reduction, further improving economic benefits.

[0004] Polymer-based paraffin inhibitors are the most commonly used pour point depressants in the production and transportation of waxy crude oil. They have significant pour point depressants and paraffin inhibitors, but they also have some limitations. Polymer-based paraffin inhibitors can effectively prevent the formation and aggregation of wax crystals through their special molecular structure. These polymers usually have a structure similar to paraffin wax and can form a network structure at low concentrations, so that paraffin crystals are dispersed and not easily deposited on the wall of the oil well pipe. In addition, polymer-based paraffin inhibitors can also change the charge balance in the oil well, further reducing wax deposition. However, polymer-based paraffin inhibitors also have some disadvantages, such as relatively high cost, poor timeliness, and limited resistance to over-pump shear. At the same time, the use of polymer-based paraffin inhibitors often increases the viscosity of crude oil, and it is necessary to consider its compatibility with crude oil and possible environmental impact.

[0005] Therefore, the research and development of new high-efficiency wax inhibitors with better performance and strong adaptability to pipeline process conditions is of great significance for the safe flow of high-viscosity oil. Summary of the invention

[0006] The problem in the prior art is that while conventional polymer-based wax inhibitors exert their wax inhibitor effects, they also increase crude oil viscosity, significantly increase crude oil transportation resistance in pipelines, and increase energy consumption. In response to the above technical problems, the present invention provides a wax inhibitor that is obtained by grafting alkyl acrylamide onto the surface of a mercapto nanosphere. The mercapto nanosphere is a mercapto nanosphere obtained by hydrolyzing and polycondensing a mercaptosilane coupling agent under alkaline conditions. During the grafting process, the mercapto groups on the surface of the mercapto nanospheres react with the double bonds of the alkyl acrylamide to form a nucleophilic addition reaction. The structural schematic diagram of the wax inhibitor is shown in the attached specification. Figure 2 As shown, n in the structural formula is determined by the type of alkyl acrylamide.

[0007] Preferably, the mercaptosilane coupling agent includes one or both of γ-mercaptopropyltriethoxysilane and γ-mercaptopropyltrimethoxysilane.

[0008] Preferably, the alkyl acrylamide includes one or more of N-dodecyl acrylamide, N-tetradecyl acrylamide, N-hexadecyl acrylamide and N-octadecyl acrylamide.

[0009] Preferably, the preparation method of the aforementioned wax inhibitor comprises the following steps: (1) dissolving a mercaptosilane coupling agent in hydrochloric acid and hydrolyzing it under acidic conditions, and then adjusting the pH of the solution to be alkaline after the hydrolysis is completed, stirring the solution at room temperature, and after the reaction is completed, filtering, washing with water, and drying in sequence to obtain mercapto nanospheres; (2) Adding mercapto nanospheres and alkyl acrylamide into toluene, and then adding an alkaline catalyst, stirring and reacting at room temperature. After the reaction is completed, filtering, washing with water, and drying to obtain a wax reducing and anti-wax agent.

[0010] Preferably, the mass ratio of the mercapto nanospheres to the alkyl acrylamide is 0.5:0.5-2.

[0011] Preferably, the mass ratio of the mercapto nanospheres to the alkyl acrylamide is 0.5:1.

[0012] Preferably, the alkaline catalyst is sodium ethoxide.

[0013] Preferably, the pH in step (1) is 7-9.

[0014] Preferably, the pH in step (1) is 8.

[0015] Preferably, the stirring speed in step (1) is 500-1000 rpm.

[0016] The present invention has the following beneficial effects: (1) The nanosphere pour point depressant obtained by the present invention has a simple and easy preparation method, excellent pour point depressant and wax prevention effect, and has no viscosity increasing effect compared with conventional polymer pour point depressants and wax prevention agents, and has good application prospects; (2) The present invention finds that the synthesis process of thiol nanospheres and the amount of alkyl acrylamide grafted on the surface of thiol nanospheres will significantly affect the effect of the obtained wax inhibitor in crude oil. For example, when the mass ratio of thiol nanospheres and alkyl acrylamide during affinity addition reaction is 0.5:1, the effect of the obtained wax inhibitor is better. When the pH value during condensation of thiol nanospheres is 8, the effect of the obtained wax inhibitor is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 : Scanning electron microscope image of the wax inhibitor obtained in Example 7 of the present invention.

[0018] Figure 2 : The structural diagram of the wax inhibitor of the present invention. DETAILED DESCRIPTION

[0019] The present invention is described in detail below with reference to the examples. However, it should be understood that the following examples are only illustrative of the embodiments of the present invention, and are not intended to limit the scope of the present invention.

[0020] Embodiment 1, a kind of pour point reducing wax inhibitor, its preparation method is as follows: (1) Dissolve 1 g of γ-mercaptopropyltriethoxysilane in 100 mL of 0.2 mol / L hydrochloric acid to completely hydrolyze it under acidic conditions. After the hydrolysis is completed, adjust the solution pH to 8 with 25% ammonia water, stir at room temperature (stirring speed is 500 rpm) for 5 h. After the reaction is completed, filter, wash with water until neutral, and dry to obtain mercapto nanospheres. (2) 0.5 g of thiol nanospheres and 1 g of N-dodecyl acrylamide were added to 50 mL of toluene, and then 0.1 g of sodium ethoxide was added. The mixture was stirred at room temperature (stirring speed was 500 rpm) for 2 h. After the reaction was completed, the mixture was filtered, washed with water until neutral, and dried to obtain a nano-spherical anti-wax agent.

[0021] Example 2 is the same as Example 1, except that Example 2 uses an equal amount of N-tetradecyl acrylamide to replace the N-dodecyl acrylamide in Example 1.

[0022] Example 3 is the same as Example 1, except that Example 3 uses an equal amount of N-hexadecyl acrylamide to replace the N-dodecyl acrylamide in Example 1.

[0023] Example 4 is the same as Example 1, except that Example 4 uses an equal amount of N-octadecyl acrylamide to replace the N-dodecyl acrylamide in Example 1.

[0024] Embodiment 5, a kind of pour point reducing wax inhibitor, its preparation method is as follows: (1) Dissolve 1 g of γ-mercaptopropyltrimethoxysilane in 100 mL of 0.2 mol / L hydrochloric acid to completely hydrolyze it under acidic conditions. After the hydrolysis is completed, adjust the solution pH to 8 with 27% ammonia water, stir at room temperature (stirring speed is 800 rpm) for 5 h. After the reaction is completed, filter, wash with water until neutral, and dry to obtain mercapto nanospheres. (2) 0.5 g of thiol nanospheres and 1 g of N-dodecyl acrylamide were added to 50 mL of toluene, and then 0.1 g of sodium ethoxide was added. The mixture was stirred at room temperature (stirring speed was 800 rpm) for 2 h. After the reaction was completed, the mixture was filtered, washed with water until neutral, and dried to obtain a nano-spherical anti-wax agent.

[0025] Embodiment 6, a kind of pour point reducing wax inhibitor, its preparation method is as follows: (1) Dissolve 1 g of γ-mercaptopropyltrimethoxysilane in 100 mL of 0.2 mol / L hydrochloric acid to completely hydrolyze it under acidic conditions. After the hydrolysis is completed, adjust the solution pH to 8 with 26% ammonia water, stir at room temperature (stirring speed is 1000 rpm) for 5 h. After the reaction is completed, filter, wash with water until neutral, and dry to obtain mercapto nanospheres. (2) 0.5 g of thiol nanospheres and 1 g of N-octadecyl acrylamide were added to 50 mL of toluene, and then 0.1 g of sodium ethoxide was added. The mixture was stirred at room temperature (stirring speed was 800 rpm) for 2 h. After the reaction, the mixture was filtered, washed with water until neutral, and dried to obtain a nano-spherical anti-wax agent.

[0026] Embodiment 7, a kind of pour point reducing wax inhibitor, its preparation method is as follows: (1) Dissolve 1 g of γ-mercaptopropyltrimethoxysilane in 100 mL of 0.2 mol / L hydrochloric acid to completely hydrolyze it under acidic conditions. After the hydrolysis is completed, adjust the solution pH to 9 with 28% ammonia water, stir at room temperature (stirring speed is 1000 rpm) for 5 h. After the reaction is completed, filter, wash with water until neutral, and dry to obtain mercapto nanospheres. (2) Add 0.5 g of mercapto nanospheres and 1 g of N-hexadecyl acrylamide to 50 mL of toluene, then add 0.1 g of sodium ethoxide, and stir at room temperature (stirring speed is 800 rpm) for 2 h. After the reaction is completed, filter, wash with water until neutral, and dry to obtain a nano-spherical pour point depressant and paraffin inhibitor. The scanning electron microscope image is shown in the attached manual. Figure 1 shown.

[0027] Comparative Example 1 is the same as Example 7, except that in step (1) of Comparative Example 1, pH=7.

[0028] Comparative Example 2 is the same as Example 7, except that the amount of N-hexadecyl acrylamide used in step (2) of Comparative Example 2 is 0.5 g.

[0029] Comparative Example 3 is the same as Example 7, except that the amount of N-hexadecyl acrylamide used in step (2) of Comparative Example 3 is 4 g.

[0030] Performance Testing According to the industry standard "SY / T0541-2009 Crude Oil Pour Point Determination Method", the pour point reducing and paraffin inhibitor obtained in the embodiment of the present invention and the comparative example were tested for pour point reducing effects. The crude oil used in the experiment was a highly waxy crude oil from the Agadem oil field in Niger, with a pour point of 40°C and a viscosity of 41.99 mPa·s at room temperature of 50°C.

[0031] The specific method is as follows: Crude oil was divided into 30 portions, each of which was a group of three portions. The pour point depressant and paraffin inhibitor obtained in the embodiment and the comparative example were added to each group and stirred evenly. The concentrations of the pour point depressant and paraffin inhibitor in the three portions of crude oil in each group were 100 ppm, 500 ppm, and 1000 ppm, respectively. Then, each portion of crude oil was subjected to a pour point test and a viscosity test. The specific test results are shown in Table 1, Table 1, and Table 2, respectively.

[0032] Pour point test: in accordance with the industry standard "SY / T0541-2009 Determination of pour point of crude oil".

[0033] Viscosity test (50°C): Anton Paar RS-600 rheometer at a shear rate of 7.3s -1 Test when.

[0034] The change value of crude oil pour point ∆T = 40℃ - pour point of crude oil after pour point reduction.

[0035] The change in crude oil viscosity ∆η = initial crude oil viscosity - viscosity of crude oil after degassing.

[0036] Table 1 .

[0037] Table 2 .

[0038] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A wax inhibitor, characterized in that The thiol nanospheres are obtained by grafting alkyl acrylamide on the surface of the thiol nanospheres. The thiol nanospheres are obtained by hydrolyzing and polycondensing the thiol silane coupling agent under alkaline conditions. During the grafting process, the thiol groups on the surface of the thiol nanospheres react with the double bonds of the alkyl acrylamide to undergo nucleophilic addition reaction.

2. A wax inhibitor according to claim 1, characterized in that: The mercaptosilane coupling agent includes one or two of γ-mercaptopropyltriethoxysilane and γ-mercaptopropyltrimethoxysilane.

3. A wax inhibitor according to claim 1, characterized in that: The alkyl acrylamide includes one or more of N-dodecyl acrylamide, N-tetradecyl acrylamide, N-hexadecyl acrylamide and N-octadecyl acrylamide.

4. A method for preparing a wax inhibitor, characterized in that , including the following steps: (1) dissolving a mercaptosilane coupling agent in hydrochloric acid and hydrolyzing it under acidic conditions, and then adjusting the pH of the solution to be alkaline after the hydrolysis is completed, stirring the solution at room temperature, and after the reaction is completed, filtering, washing with water, and drying in sequence to obtain mercapto nanospheres; (2) Adding mercapto nanospheres and alkyl acrylamide to toluene, and then adding an alkaline catalyst, stirring and reacting at room temperature. After the reaction is completed, filtering, washing with water, and drying to obtain the wax inhibitor according to any one of claims 1 to 3.

5. The method for preparing a wax inhibitor according to claim 4, characterized in that: The mass ratio of the mercapto nanospheres to the alkyl acrylamide is 0.5:0.5-2.

6. The method for preparing a wax inhibitor according to claim 5, characterized in that: The mass ratio of thiol nanospheres to alkyl acrylamide is 0.5:

1.

7. The method for preparing a wax inhibitor according to claim 4, characterized in that: The alkaline catalyst is sodium ethoxide.

8. The method for preparing a wax inhibitor according to claim 4, characterized in that: The pH in step (1) is 7-9.

9. The method for preparing a wax inhibitor according to claim 8, characterized in that: The pH in step (1) is 8.

10. The method for preparing a wax inhibitor according to claim 4, characterized in that: The stirring speed in step (1) is 500-1000 rpm.

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