An asphalt-based wax inhibitor, its preparation method and application

Abstract

The application discloses asphalt-based wax-proofing agent and its preparation method and application. The preparation method comprises the following steps: (1) heating and melting the vacuum residue and the deoiled asphalt, adding them into a reaction kettle, adding a raw material modifier, and performing modification treatment under a protective gas; (2) after the obtained material is cooled, extracting an asphaltene component, obtaining a deasphaltene raw material, and separating a gum component; (3) mixing an asphaltene precipitation agent and an asphaltene dispersant to obtain an asphaltene extraction agent, mixing the asphaltene extraction agent with the asphaltene, filtering, drying, and obtaining solid substance A1; (4) continuously adding the asphaltene precipitation agent into the filtrate to obtain solid substance A2; (5) mixing the solid substance A1 with the gum component to obtain an asphaltene mixed component, mixing the asphaltene mixed component with a reaction activator and dimethylbenzene, adding the solid substance A2, and obtaining the asphalt-based wax-proofing agent. The wax-proofing agent can significantly reduce the wax deposition amount, has excellent performance and low cost, and can prolong the hydrate generation time and inhibit the generation of hydrates.

Description

Technical Field

[0001] This invention relates to the field of oil and gas production technology, specifically to an asphalt-based anti-wax agent for high-pressure oil-water systems and its evaluation method. Background Technology

[0002] In subsea oil-gas-water multiphase pipelines, due to the presence of natural emulsifiers and frequent pump shearing, the aqueous phase is mainly dispersed in the crude oil as droplets. In actual pipeline transportation, issues such as wax deposition and hydrate formation arise, posing challenges to pipeline flow safety. When the crude oil temperature falls below the wax precipitation point, wax crystals precipitate and migrate under the influence of the concentration gradient, depositing on the inner wall of the pipeline to form deposits. Wax deposition reduces the pipeline's inner diameter and increases pressure drop; if not removed promptly, it can lead to pipeline shutdowns and other safety issues. Simultaneously, oil-gas-water multiphase pipelines operating in low-temperature environments are at risk of hydrate formation under high pressure and turbulent conditions. Hydrate formation introduces solid, ice-like particles into the fluid, which can, in severe cases, block the pipeline and cause safety accidents.

[0003] To prevent wax deposits in pipelines from adversely affecting oil transportation, wax deposit control methods are widely used in actual field operations, including mechanical dewaxing, adding wax inhibitors, installing pipeline linings, and heat tracing. Common wax deposit solutions in oilfield production primarily involve mechanical cleaning and the use of wax inhibitors. Wax inhibitors can directly act on the prevention or removal of wax deposits, making operation more convenient. Meanwhile, to inhibit hydrate formation, hydrate inhibitors such as methanol and ethylene glycol are widely used in multiphase mixed-phase pipelines. Hydrate inhibitors can prolong the time before hydrates appear, ensuring the safe transport of fluids within the pipeline to processing or storage facilities. Therefore, the use of wax inhibitors and hydrate inhibitors has received widespread attention in engineering fields. However, the current use of chemical additives affects crude oil quality, has limited effectiveness, requires large quantities, and is costly.

[0004] CN111690392B discloses an environmentally friendly microbial composite wax inhibitor for oil wells. The wax inhibitor is mainly composed of wax-loving mixed bacterial solution, bacterial nutrient solution, first surfactant, second surfactant and mutual solvent. It is prepared by combining chemical and microbial methods to produce an environmentally friendly inhibitor. However, it involves a large number of chemical reagents, which affects the quality of crude oil. Furthermore, the addition of this wax inhibitor poses a risk of bacterial corrosion to the oil pipeline.

[0005] CN116535568A discloses a wax inhibitor, its preparation method, and its application. The α-olefin-maleic acid alkyl ester copolymer prepared by the method is used as a wax inhibitor and can effectively suppress wax crystal precipitation in normal pressure environment. However, its effect in high pressure environment is still unclear.

[0006] Therefore, developing cost-effective, high-pressure-enhancing anti-wax agents is a widely concerned issue in the field of pipeline safety. Considering that ensuring the flow of high-pressure multiphase mixed crude oil pipelines involves multiple aspects such as wax deposition and hydrate formation, developing additives that simultaneously prevent wax deposition and inhibit hydrate formation is of great significance for the safe operation of pipelines. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides an asphalt-based wax inhibitor, its preparation method, and its application. This wax inhibitor significantly reduces wax deposition and has the advantages of excellent performance, low cost, and low dosage. Furthermore, during application, this wax inhibitor can prolong the hydrate formation time and inhibit hydrate formation.

[0008] This invention provides a method for preparing an asphalt-based wax inhibitor, comprising the following steps:

[0009] (1) Heat and melt vacuum residue and deoiled asphalt, then add them to a reaction vessel, add raw material modifier, and carry out modification treatment under protective gas;

[0010] (2) After cooling the material obtained in step (1), extract the asphalt components and obtain deasphalted raw material, and then separate the resin components from the deasphalted raw material.

[0011] (3) Mix the asphaltene precipitant and the asphaltene dispersant to obtain the asphaltene extractant. Mix the asphaltene extractant with the asphaltene obtained in step (2), filter, and dry to obtain solid substance A1.

[0012] (4) Add asphaltene precipitant to the filtrate obtained after filtration in step (3), dry, and obtain solid substance A2;

[0013] (5) The solid substance A1 obtained in step (3) is mixed with the gum component obtained in step (2) to obtain the asphalt mixture component, which is then mixed with the reactive agent and xylene, and then the solid substance A2 obtained in step (4) is added to obtain the asphalt-based anti-wax agent.

[0014] Further, in step (1), the properties of the vacuum residue include: a softening point of 48.1–50.4°C, a dynamic viscosity of 470–495 Pa·s at 60°C, and by mass fraction, 30.2%–36.6% saturated matter, 28.7%–34.7% aromatic matter, 27.8%–40.1% gum, and 1.0%–4.0% asphaltenes, with the gum preferably being 28.3%–40.1%.

[0015] Further, in step (1), the properties of the deoiled bitumen include: a carbon content of 84.73–87.96 wt%, a softening point of 88.0–122.0 °C, and a density of 1.02–1.04 g / cm³ at 20 °C.3 The residual carbon content is 16.3 wt% to 34.1 wt%. By mass fraction, the saturated components account for 3.9% to 9.6%, the aromatic components account for 17.1% to 34.3%, the resin accounts for 45.2% to 62.6%, and the asphaltenes account for 8.3% to 27.8%. The resin is preferably 49.7% to 59.2%, and the asphaltenes are preferably 8.6% to 19.8%.

[0016] Further, in step (1), the mass ratio of the vacuum residue oil to the deoiled bitumen is 1:1 to 3.

[0017] Furthermore, in step (1), the heating and melting temperature is 120-160°C.

[0018] Further, in step (1), the raw material modifier is one or more of phthalic anhydride, butenediary anhydride, or hydrolyzed polymaleic anhydride. The mass ratio of the total mass of the vacuum residue and deoiled bitumen to the mass of the raw material modifier is 1:0.02 to 0.1.

[0019] Further, in step (1), the protective gas is at least one of nitrogen or an inert gas. The amount of protective gas added is such that the pressure is maintained at 0.2 to 0.8 MPa, preferably 0.4 to 0.8 MPa.

[0020] Further, in step (1), the conditions for the modification treatment are as follows: the temperature of the modification treatment is 130–180°C, preferably 150–160°C, and the time of the modification treatment is 1–4 hours, preferably 2–3 hours. Heating to the required temperature for the modification treatment is preferably performed using a programmed temperature increase, with a heating rate of 1–3°C / min. The modification treatment is carried out under stirring, with a stirring speed of 200–400 r / min.

[0021] Furthermore, in step (2), the material obtained in step (1) is generally cooled to room temperature.

[0022] Furthermore, in step (2), the extraction and separation process of asphaltene and resin components adopts the four-component analysis method. The specific operation procedure can be referred to the standard NB / SH / T 0509-2010 "Determination of Four Components of Petroleum Asphalt".

[0023] Further, in step (3), the asphaltene precipitant is one or more of petroleum ether, isopentane, n-pentane, cyclohexane, or n-hexane. The asphaltene dispersant is one or more of strongly polar reagents such as chloroform, benzene, p-xylene, dichloroethane, dichloromethane, or tetrahydrofuran.

[0024] Further, in step (3), the volume ratio of the asphaltene precipitant to the asphaltene dispersant is 7:2 to 4. The mass-volume ratio of the asphaltene to the asphaltene extractant is 1:15 to 25 (g / mL).

[0025] Further, in step (3), the asphalt extractant is mixed with the asphalt obtained in step (2) and then subjected to ultrasonic vibration treatment. The ultrasonic vibration time is 30-60 min, the ultrasonic vibration temperature is 13-18℃, and the ultrasonic frequency is 20-40 kHz.

[0026] Furthermore, in step (3), the drying temperature is 100-120°C and the drying time is 40-80 min.

[0027] Further, in step (4), the volume ratio of the amount of asphaltene precipitant added to the amount of asphaltene precipitant added in step (3) is 1:1.2 to 1.8, preferably 1:1.3 to 1.5.

[0028] Further, in step (4), after adding the asphaltene precipitant, the mixture is centrifuged to obtain solid substance A2. The centrifugal rotation speed is 6000-8000 rpm, and the centrifugal rotation time is 40-60 min.

[0029] Furthermore, in step (4), the drying temperature is 105-120°C and the drying time is 90-150 min.

[0030] Furthermore, in step (5), the mass ratio of the solid substance A1 obtained in step (3) to the colloidal component obtained in step (2) is 2 to 5:1.

[0031] Further, in step (5), the reactive agent is one or more of polyvinyl alcohol (molecular weight 16,000–130,000), polyacrylic acid (molecular weight 5,000–200,000), sodium polyacrylate (molecular weight 1,000–30,000), or polyethylene glycol (molecular weight 1,000–8,000). The mass ratio of the asphaltene mixture to the reactive agent is 10–30:1.

[0032] Further, in step (5), the mass ratio of the asphalt mixture to xylene is 1:10 to 50.

[0033] Further, in step (5), the asphalt mixture is mixed with the reactive agent and xylene and then subjected to ultrasonic vibration treatment. The ultrasonic vibration time is 20 to 40 minutes, the ultrasonic vibration temperature is 30 to 60°C, and the ultrasonic frequency is 20 to 40 kHz.

[0034] Furthermore, in step (5), the mass ratio of the amount of solid substance A2 to the amount of solid substance A1 added is 1:1.5 to 3.0.

[0035] Further, in step (5), after adding the solid substance A2 obtained in step (4), ultrasonic vibration is performed again. The time for ultrasonic vibration is 60 to 90 minutes, the temperature for ultrasonic vibration is 30 to 60°C, and the ultrasonic frequency is 20 to 40 kHz.

[0036] The present invention also provides an asphalt-based anti-wax agent prepared by the above method.

[0037] The present invention also provides an application of the asphalt-based anti-wax agent prepared by the above method in an oil-water system.

[0038] When the asphalt-based anti-wax agent is used, its addition amount is 0.1% to 4.0% of the total mass of the oil-water emulsion, preferably 0.5% to 3.0%, and the mass of the oil phase in the oil-water emulsion is preferably not less than 50% of the total mass of the liquid phase.

[0039] Compared with the prior art, the asphalt-based anti-wax agent of the present invention has the following advantages:

[0040] (1) This invention uses low-value-added vacuum residue and deoiled bitumen as raw materials to produce wax inhibitors, thereby improving their social and economic value. This invention uses vacuum residue, deoiled bitumen, raw material modifiers and reactive agents to carry out a series of reactions, thereby improving the inhibitory effect of the mixed raw materials of vacuum residue and deoiled bitumen on wax crystal precipitation and deposition, and formulating a bitumen-based wax inhibitor suitable for high-pressure systems.

[0041] (2) The present invention divides asphalt into two components with different functions by using different ratios of asphalt extractant and asphalt dispersant. The asphalt is then combined with the resin and the preferentially extracted solid substance A1 to improve its dispersion degree and effect. Then, it works together with the subsequently extracted solid substance A2 to improve the effect of the anti-wax agent.

[0042] (3) The introduction of reactive agents in this invention improves the activity of asphaltenes and gums in asphalt-based wax inhibitors, enhances the effect of wax inhibitors, and strengthens the effect of hydrophilic groups in asphalt-based wax inhibitors. This allows the wax inhibitors to not only reduce the quality of wax deposition, but also inhibit the formation of hydrates, thus having the dual effect of wax inhibitors and hydrate inhibitors.

[0043] (4) The high-pressure oil-water system asphalt-based anti-wax agent of the present invention can significantly reduce the amount of wax deposition. It is suitable for crude oil system and oil-water system, and has the advantages of excellent performance, low cost and low usage. At the same time, the dual function of the anti-wax agent of the present invention can also reduce the amount of other hydrate inhibitors added, reduce the amount of chemical reagents used, and reduce the difficulty of crude oil processing. Detailed Implementation

[0044] The present invention will be further described in detail below through specific embodiments. The described embodiments are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0045] The anti-wax agent of the present invention is evaluated using a high-pressure wax deposition reactor. The main steps are as follows: (1) The anti-wax agent and oil-water emulsion are added to the cleaned high-pressure wax deposition reactor and a wax deposition experiment is carried out at a pressure of 1 MPa for 12 hours. Then, the cold finger is taken out, the deposit is scraped, the weight is weighed, and the wax content is determined to evaluate the anti-wax effect of the anti-wax agent; (2) The cold finger is cleaned and put back into the reactor and a hydrate formation experiment is carried out at a pressure of 3 MPa. The hydrate induction period is calculated to evaluate the effect on hydrate formation.

[0046] Example 1

[0047] (1) Heat 1000g of vacuum residue (properties shown in Table 1) and 1000g of deoiled bitumen (properties shown in Table 2) to 140℃ to make them melt and add them to a high-pressure stirred reactor. Add 60g of phthalic anhydride to it, heat it to 130℃ at 1℃ / min in a 0.5MPa nitrogen atmosphere, and stir the reaction at 300r / min for 2h.

[0048] (2) Take out the material obtained in step (1) and cool it to room temperature. Extract the asphalt components with n-heptane according to the standard NB / SH / T 0509-2010 "Determination of Four Components of Petroleum Asphalt". The mass-volume ratio of asphalt to n-heptane during asphalt extraction is 1:100 g / mL. The heating and reflux time is 1 h to obtain deasphalted raw material. Then, separate the resin components from the deasphalted raw material.

[0049] (3) Mix n-pentane and chloroform in a volume ratio of 7:3 to obtain 2000 mL of asphalt extractant. Take 100 g of the asphalt obtained in step (2) and add it to the asphalt extractant. Use ultrasonic vibration at 20 kHz in a 15°C environment for 30 min to dissolve the soluble components. Then filter to obtain solid substance A1. Dry it at 105°C for 50 min for later use.

[0050] (4) Add 2000 mL of n-pentane to the filtrate obtained in step (3), centrifuge at 8000 rpm for 50 min to obtain solid substance A2, and dry it at 105℃ for 50 min for later use.

[0051] (5) Mix 10g of solid substance A1 obtained in step (3) and 5g of gum obtained in step (2) to obtain asphalt mixture. Add the asphalt mixture and 0.8g of polyvinyl alcohol (molecular weight 20000) to 200g of xylene. Use ultrasonic vibration at 20KHz in a 30℃ environment for 30min. Then add 5g of solid substance A2 and ultrasonically vibrate again at 20KHz in a 30℃ environment for 80min to obtain asphalt-based anti-wax agent B1 for high-pressure oil-water system.

[0052] 17.48g of wax inhibitor B1 was added to 2000mL of an oil-water emulsion with a water content of 10% (mass of 1748g, properties are shown in Table 4) to conduct an evaluation experiment on the wax inhibitor effect. The results are shown in Table 3.

[0053] Example 2

[0054] (1) Heat 1000g of vacuum residue (properties shown in Table 1) and 1000g of deoiled bitumen (properties shown in Table 2) to 140℃ to make them melt and add them to a high-pressure stirred reactor. Add 60g of phthalic anhydride to it, heat it to 130℃ at 1℃ / min in a 0.6MPa nitrogen atmosphere, and stir the reaction at 300r / min for 3h.

[0055] (2) Take out the material obtained in step (1) and cool it to room temperature. Extract the asphalt components with n-heptane according to the standard NB / SH / T 0509-2010 "Determination of Four Components of Petroleum Asphalt". The mass-volume ratio of asphalt to n-heptane during asphalt extraction is 1:100 g / mL. The heating and reflux time is 1 h to obtain deasphalted raw material. Then, separate the resin components from the deasphalted raw material.

[0056] (3) Mix n-pentane and dichloromethane in a volume ratio of 7:3 to obtain 2000 mL of asphalt extractant. Take 100 g of the asphalt obtained in step (2) and add it to the asphalt extractant. Use ultrasonic vibration at 40 kHz in a 15°C environment for 30 min to dissolve the soluble components. Then filter to obtain solid substance A1. Dry it at 105°C for 50 min for later use.

[0057] (4) Add 2000 mL of n-pentane to the filtrate obtained in step (3), centrifuge at 8000 rpm for 50 min to obtain solid substance A2, and dry it at 105℃ for 50 min for later use.

[0058] (5) Mix 10g of solid substance A1 obtained in step (3) and 5g of gum obtained in step (2) to obtain asphalt mixture. Add the asphalt mixture and 0.8g of polyvinyl alcohol (molecular weight 20000) to 150g of xylene. Use ultrasonic vibration at 40KHz for 30min in a 30℃ environment. Then add 5g of solid substance A2 and ultrasonically vibrate again at 20KHz for 80min in a 30℃ environment to obtain asphalt-based anti-wax agent B2 for high-pressure oil-water system.

[0059] Add 52.44 wax inhibitor B2 to 2000 mL of an oil-water emulsion with a water content of 10% (mass 1748 g) to conduct an evaluation experiment on the wax inhibitor effect. The results are shown in Table 3.

[0060] Example 3

[0061] (1) Heat 1000g of vacuum residue (properties shown in Table 1) and 1000g of deoiled bitumen (properties shown in Table 2) to 140℃ to make them melt and add them to a high-pressure stirred reactor. Add 60g of phthalic anhydride to it, heat it to 130℃ at 1℃ / min in a 0.5MPa nitrogen atmosphere, and stir the reaction at 300r / min for 2h.

[0062] (2) Take out the material obtained in step (1) and cool it to room temperature. Extract the asphalt components with n-heptane according to the standard NB / SH / T 0509-2010 "Determination of Four Components of Petroleum Asphalt". The mass-volume ratio of asphalt to n-heptane during asphalt extraction is 1:100 g / mL. The heating and reflux time is 1 h to obtain deasphalted raw material. Then, separate the resin components from the deasphalted raw material.

[0063] (3) Mix n-pentane with a mixture of chloroform and dichloromethane (chloroform and dichloromethane volume ratio of 1:1) at a volume ratio of 7:3 to obtain 2000 mL of asphaltene extractant. Take 100 g of the asphaltene obtained in step (2) and add it to the asphaltene extractant. Use ultrasonic vibration at 20 kHz in an environment of 15 °C for 30 min to dissolve the soluble components. Then filter to obtain solid substance A1, and dry it at 105 °C for 50 min for later use.

[0064] (4) Add 2000 mL of n-pentane to the filtrate obtained in step (3), centrifuge at 8000 rpm for 50 min to obtain solid substance A2, and dry it at 105℃ for 50 min for later use.

[0065] (5) Mix 10g of solid substance A1 obtained in step (3) and 5g of gum obtained in step (2) to obtain asphalt mixture. Add the asphalt mixture and 1.0g of polyacrylic acid (molecular weight of 10000) to 200g of xylene. Use ultrasonic vibration at 20KHz in a 30℃ environment for 30min. Then add 5g of solid substance A2 and ultrasonically vibrate again at 20KHz in a 30℃ environment for 80min to obtain asphalt-based anti-wax agent B3 for high-pressure oil-water system.

[0066] 26.22g of wax inhibitor B3 was added to 2000mL of an oil-water emulsion with a water content of 10% (mass 1748g) to conduct an evaluation experiment on the wax inhibitor effect. The results are shown in Table 3.

[0067] Example 4

[0068] (1) Heat 800g of vacuum residue (properties shown in Table 1) and 1200g of deoiled bitumen (properties shown in Table 2) to 140℃ to make them melt and add them to a high-pressure stirred reactor. Add 100g of phthalic anhydride to it, heat it to 130℃ at 1℃ / min in a 0.5MPa nitrogen atmosphere, and stir the reaction at 300r / min for 3h.

[0069] (2) Take out the material obtained in step (1) and cool it to room temperature. Extract the asphalt components with n-heptane according to the standard NB / SH / T 0509-2010 "Determination of Four Components of Petroleum Asphalt". The mass-volume ratio of asphalt to n-heptane during asphalt extraction is 1:100 g / mL. The heating and reflux time is 1 h to obtain deasphalted raw material. Then, separate the resin components from the deasphalted raw material.

[0070] (3) Mix n-pentane with a mixture of chloroform and dichloromethane (chloroform and dichloromethane volume ratio of 1:1) at a volume ratio of 7:4 to obtain 2000 mL of asphaltene extractant. Take 100 g of the asphaltene obtained in step (2) and add it to the asphaltene extractant. Use ultrasonic vibration at 40 kHz for 60 min in an environment of 15 ℃ to dissolve the soluble components. Then filter to obtain solid substance A1, and dry it at 105 ℃ for 50 min for later use.

[0071] (4) Add 1780 mL of n-pentane to the filtrate obtained in step (3), centrifuge at 8000 rpm for 60 min to obtain solid substance A2, and dry it at 105℃ for 50 min for later use.

[0072] (5) Mix 10g of solid substance A1 obtained in step (3) and 5g of gum obtained in step (2) to obtain asphalt mixture. Add the asphalt mixture and 1.2g of polyacrylic acid (molecular weight of 10000) to 150g of xylene. Use ultrasonic vibration at 40KHz in a 30℃ environment for 30min. Then add 5g of solid substance A2 and ultrasonic vibration at 20KHz in a 30℃ environment for 80min to obtain asphalt-based anti-wax agent B4 for high-pressure oil-water system.

[0073] 26.22g of wax inhibitor B4 was added to 2000mL of an oil-water emulsion with a water content of 10% (mass 1748g) to conduct an evaluation experiment on the effect of the wax inhibitor. The results are shown in Table 3.

[0074] Example 5

[0075] (1) Heat 1000g of vacuum residue (properties shown in Table 1) and 2000g of deoiled bitumen (properties shown in Table 2) to 140℃ to make them melt and add them to a high-pressure stirred reactor. Add 60g of phthalic anhydride to it, heat it to 130℃ at 1℃ / min in a 0.5MPa nitrogen atmosphere, and stir the reaction at 300r / min for 2h.

[0076] (2) Take out the material obtained in step (1) and cool it to room temperature. Extract the asphalt components with n-heptane according to the standard NB / SH / T 0509-2010 "Determination of Four Components of Petroleum Asphalt". The mass-volume ratio of asphalt to n-heptane during asphalt extraction is 1:100 g / mL. The heating and reflux time is 1 h to obtain deasphalted raw material. Then, separate the resin components from the deasphalted raw material.

[0077] (3) Mix n-pentane with a mixture of chloroform and dichloromethane (chloroform and dichloromethane volume ratio of 1:1) at a volume ratio of 7:3 to obtain 2000 mL of asphaltene extractant. Take 100 g of the asphaltene obtained in step (2) and add it to the asphaltene extractant. Use ultrasonic vibration at 20 kHz in an environment of 15 °C for 30 min to dissolve the soluble components. Then filter to obtain solid substance A1, and dry it at 105 °C for 50 min for later use.

[0078] (4) Add 2100 mL of n-pentane to the filtrate obtained in step (3), centrifuge at 8000 rpm for 50 min to obtain solid substance A2, and dry it at 105℃ for 50 min for later use.

[0079] (5) Mix 10g of solid substance A1 obtained in step (3) and 5g of gum obtained in step (2) to obtain asphalt mixture. Add the asphalt mixture and 1.1g of polyacrylic acid (molecular weight of 20000) to 200g of xylene. Use ultrasonic vibration at 20KHz in a 30℃ environment for 30min. Then add 5g of solid substance A2 and ultrasonically vibrate again at 20KHz in a 30℃ environment for 80min to obtain asphalt-based anti-wax agent B5 for high-pressure oil-water system.

[0080] 26.22g of wax inhibitor B5 was added to 2000mL of an oil-water emulsion with a water content of 10% (mass 1748g) to conduct an evaluation experiment on the wax inhibitor effect. The results are shown in Table 3.

[0081] Comparative Example 1

[0082] The difference from Example 3 is that no raw material modifier is added during the preparation process, resulting in asphalt-based wax inhibitor D1 for use in high-pressure oil-water systems.

[0083] 26.22g of wax inhibitor D1 was added to 2000mL of an oil-water emulsion with a water content of 10% (mass 1748g) to conduct an evaluation experiment on the wax inhibitor effect. The results are shown in Table 3.

[0084] Comparative Example 2

[0085] The difference from Example 3 is that solid substance A2 is not prepared and added during the preparation process, resulting in asphalt-based anti-wax agent D2 for use in high-pressure oil-water systems.

[0086] 26.22g of wax inhibitor D2 was added to 2000mL of an oil-water emulsion with a water content of 10% (mass 1748g) to conduct an evaluation experiment on the wax inhibitor effect. The results are shown in Table 3.

[0087] Comparative Example 3

[0088] The difference from Example 3 is that the raw materials are not processed. Instead, 20g of vacuum residue and deoiled bitumen are added to 200g of xylene at a mass ratio of 1:1, and ultrasonic vibration is performed at 20KHz for 30min in a 30°C environment to obtain bitumen-based anti-wax agent D3 for high-pressure oil-water systems.

[0089] 26.22g of wax inhibitor D3 was added to 2000mL of an oil-water emulsion with a water content of 10% (mass 1748g) to conduct an evaluation experiment on the wax inhibitor effect. The results are shown in Table 3.

[0090] Comparative Example 4

[0091] Without adding the prepared anti-wax agent, 2000 mL of oil-water emulsion with a water content of 10% was used as the control group to evaluate the effect of the anti-wax agent. The results are shown in Table 3.

[0092] The wax-prevention effect of this invention was analyzed using wax deposition amount, wax content in sediments, and wax precipitation deposition rate. The hydrate inhibition effect was analyzed using the induction period. The parameters were obtained by referring to "Properties of Waxy Crude Oil Sediments in Pipeline Transportation" (Oil & Gas Storage and Transportation, 2016.35(9):946-951) and "Research Progress on Hydrate Formation Induction Period" (Chemical Industry and Engineering Progress, 2018.37(2):505-516), respectively. The calculation results are shown in Table 3.

[0093] Table 1. Properties of vacuum residue used in the examples and comparative examples.

[0094] Saturated fraction / wt% 34.30 Aromatic components / wt% 31.72 Gel / wt% 30.31 Asphalt / wt% 3.67 Softening point / °C 49.8 Flash point / °C 261 Dynamic viscosity (60℃) / Pa.s 486 25℃ penetration / 0.1mm 63

[0095] Table 2 Properties of the deoiled bitumen used in the examples and comparative examples

[0096]

[0097]

[0098] Table 3. Results of wax inhibitor application in the examples and comparative examples.

[0099]

[0100] Experimental results show that the asphalt-based wax inhibitor of this invention can significantly reduce the amount of wax deposition, the wax content of the deposits, and the wax precipitation rate in high-pressure oil-water emulsions, demonstrating a good wax-preventing effect. Simultaneously, the wax inhibitor of this invention can also increase the hydrate formation induction period, significantly prolonging the hydrate formation time. This wax inhibitor is highly efficient, requires a small dosage, and has minimal impact on crude oil quality; it can exert a significant effect when added at only 0.5% to 3%.

[0101] Table 4. Oil properties of the oil-water emulsions in the examples and comparative examples.

[0102] Wax precipitation point / ℃ 15.23 Wax content / wt% 4.89 Pour point / °C -15 Viscosity (5℃) / mPa·s 8.4

[0103] The scope of protection of this invention is not limited to the above embodiments, but is defined by the claims. Those skilled in the art can make appropriate modifications to these embodiments without departing from the technical concept and spirit of this invention, and these modified embodiments are also included within the scope of protection of this invention.

Claims

1. A process for the preparation of an asphalt-based wax inhibitor, characterized by: The method comprises the following steps: (1) heating and melting the vacuum residue and the deoiled asphalt, and then adding them into a reaction kettle, adding a raw material modifier into the reaction kettle, and performing a modification treatment under a protective gas; (2) cooling the material obtained in step (1), extracting an asphaltene component, and obtaining a deasphaltene raw material, and separating a gum component from the deasphaltene raw material; (3) mixing an asphaltene precipitation agent and an asphaltene dispersant to obtain an asphaltene extraction agent, mixing the asphaltene extraction agent with the asphaltene obtained in step (2), filtering, and drying to obtain a solid substance A1; (4) continuously adding the asphaltene precipitation agent into the filtrate obtained after the filtering in step (3), and drying to obtain a solid substance A2; (5) mixing the solid substance A1 obtained in step (3) with the gum component obtained in step (2) to obtain an asphaltene mixed component, mixing the asphaltene mixed component with a reaction active agent and dimethylbenzene, and then adding the solid substance A2 obtained in step (4) to obtain an asphaltene-based paraffin inhibitor; In step (1), the vacuum residue has the following properties: a softening point of 48.1-50.4 ℃, a dynamic viscosity at 60 ℃ of 470-495 Pa·s, and, in terms of mass fraction, a saturated fraction of 30.2%-36.6%, an aromatic fraction of 28.7%-34.7%, a gum of 27.8%-40.1%, and an asphaltene of 1.0%-4.0%. The deoiled asphalt has the following properties: carbon content of 84.73-87.96 wt%, softening point of 88.0-122.0℃, density of 1.02-1.04 g / cm 3 at 20℃, and carbon residue of 16.3 wt%-34.1 wt%, wherein the saturated fraction accounts for 3.9%-9.6%, the aromatic fraction accounts for 17.1%-34.3%, the gum accounts for 45.2%-62.6%, and the asphaltene accounts for 8.3%-27.8% by mass fraction. In step (1), the raw material modifier is one or more of phthalic anhydride, butene anhydride, or hydrolyzed polymaleic anhydride. In step (1), the protective gas is at least one of nitrogen or an inert gas. In step (1), the modification treatment is performed at a temperature of 130-180 ℃ for 1-4 h, and the temperature is raised at a rate of 1-3 ℃ / min. In step (3), the asphaltene precipitation agent is one or more of petroleum ether, isopentane, n-pentane, cyclohexane, or n-hexane; and the asphaltene dispersant is one or more of trichloromethane, benzene, p-xylene, dichloroethane, dichloromethane, or tetrahydrofuran. In step (5), the reaction active agent is one or more of polyvinyl alcohol with a molecular weight of 16,000-130,000, polyacrylic acid with a molecular weight of 5,000-200,000, sodium polyacrylate with a molecular weight of 1,000-30,000, or polyethylene glycol with a molecular weight of 1,000-8,000.

2. The method of claim 1, wherein: In step (1), the vacuum residue has a gum of 28.3%-40.1% in terms of mass fraction. And / or, the deoiled asphalt has a gum of 49.7%-59.2% and an asphaltene of 8.6%-19.8% in terms of mass fraction.

3. The method according to claim 1 or 2, characterized in that: In step (1), the mass ratio of the vacuum residue to the deoiled asphalt is 1:1-3.

4. The method of claim 1, wherein: In step (1), the heating and melting temperature is 120-160 ℃.

5. The method of claim 1, wherein: In step (1), the mass ratio of the total mass of the vacuum residue and the deoiled asphalt to the mass of the raw material modifier is 1:0.02-0.

1.

6. The method of claim 1, wherein: In step (1), the protective gas is added in an amount such that the system pressure is maintained at 0.2-0.8 MPa.

7. The method of claim 6, wherein: The protective gas is added in an amount to maintain the system pressure at 0.4-0.8 MPa.

8. The method of claim 1, wherein: In step (1), the modification treatment is performed at a temperature of 150-160°C for 2-3 hours. The modification treatment is performed under stirring at a speed of 200-400 r / min.

9. The method of claim 1, wherein: In step (3), the volume ratio of the asphaltene precipitation agent to the asphaltene dispersant is 7:2-4, and the mass-volume ratio of the asphaltene to the asphaltene extraction agent is 1 g:15-25 mL.

10. The method of claim 1, wherein: In step (3), the asphaltene extraction agent is mixed with the asphaltene obtained in step (2) and then subjected to ultrasonic oscillation treatment, the ultrasonic oscillation being performed for 30-60 min at a temperature of 13-18°C and at a frequency of 20-40 KHz.

11. The method of claim 1, wherein: In step (4), the volume ratio of the amount of the asphaltene precipitation agent added to the amount of the asphaltene precipitation agent added in step (3) is 1:1.2-1.

8.

12. The method of claim 11, wherein: In step (4), the volume ratio of the amount of the asphaltene precipitation agent added to the amount of the asphaltene precipitation agent added in step (3) is 1:1.3-1.

5.

13. The method of claim 1, wherein: In step (4), after the addition of the asphaltene precipitation agent, solid substance A2 is obtained by centrifugal rotation at a speed of 6000-8000 rpm for 40-60 min.

14. The method of claim 1, wherein: In step (5), the mass ratio of the solid substance A1 obtained in step (3) to the colloid component obtained in step (2) is 2-5:

1.

15. The method of claim 1, wherein: In step (5), the mass ratio of the asphaltene mixed component to the reaction activator is 10-30:

1.

16. The method of claim 1, wherein: In step (5), the mass ratio of the asphaltene mixed component to dimethylbenzene is 1:10-50.

17. The method of claim 1, wherein: In step (5), after the mixing of the asphaltene mixed component, the reaction activator and dimethylbenzene, ultrasonic oscillation treatment is performed for 20-40 min at a temperature of 30-60°C and at a frequency of 20-40 KHz. In step (5), after the addition of the solid substance A2 obtained in step (4), ultrasonic oscillation is performed again for 60-90 min at a temperature of 30-60°C and at a frequency of 20-40 KHz.

18. An asphalt-based wax inhibitor prepared by the method according to any one of claims 1-17.

19. Use of the asphalt-based wax inhibitor prepared by the method according to any one of claims 1-17 in an oil-water system.

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