Asphalt-based paraffin inhibitor as well as preparation method and application thereof

Abstract

The invention discloses an asphalt-based paraffin inhibitor as well as a preparation method and application thereof. The preparation method comprises the following steps: (1) heating and melting vacuum residue and deoiled asphalt, adding into a reaction kettle, adding a raw material modifier, and carrying out modification treatment under shielding gas; (2) cooling the obtained material, extracting an asphaltene component, obtaining an asphaltene-removed raw material, and separating out a colloid component; (3) mixing an asphaltene precipitation agent with an asphaltene dispersing agent to obtain an asphaltene extracting agent, mixing the asphaltene extracting agent with asphaltene, filtering, and drying to obtain a solid substance A1; (4) continuing to add an asphaltene precipitation agent into the filtrate to obtain a solid substance A2; and (5) mixing the solid substance A1 with a colloid component to obtain an asphaltene mixed component, mixing the asphaltene mixed component with a reaction active agent and xylene, and adding the solid substance A2 to obtain the asphalt-based paraffin inhibitor. The paraffin inhibitor can remarkably reduce the wax deposition amount, is excellent in performance and low in cost, and can prolong the hydrate generation time and inhibit hydrate generation.

Description

Technical Field

[0001] The invention relates to the technical field of oil and natural gas production, and in particular to an asphalt-based wax inhibitor for a high-pressure oil-water system and an evaluation method thereof. Background Art

[0002] In submarine oil-gas-water multiphase pipelines, due to the presence of natural emulsifiers and frequent pump shear, the water phase is mainly dispersed in the crude oil in the form of droplets. In actual pipeline transportation, there are problems such as wax deposition and hydrate formation in pipeline flow safety assurance. When the crude oil temperature is lower than the wax precipitation point, wax crystals will precipitate and migrate under the action of concentration gradient and deposit on the inner wall of the pipeline to form sediments. Wax deposition will reduce the inner diameter of the pipeline and increase the pipeline pressure drop. If it is not removed in time, it will cause safety problems such as pipeline shutdown. At the same time, oil-gas-water multiphase pipelines in a low-temperature environment are at risk of hydrate formation under high pressure and disturbance conditions. Hydrate formation will cause solid ice particles to appear in the fluid, which will block the pipeline in severe cases and cause safety accidents.

[0003] In order to prevent the wax deposits in the pipeline from having an adverse effect on the oil transportation process, wax deposit prevention methods have been widely used in the actual on-site operation process, including mechanical wax removal, adding wax inhibitors, adding pipeline linings and heating. The common wax deposition solutions in oilfield production are mainly mechanical pipe cleaning and the use of wax inhibitors. Wax inhibitors can directly act on the prevention or removal process of wax deposition, and the operation is more convenient. At the same time, in order to inhibit the formation of hydrates, hydrate inhibitors such as methanol and ethylene glycol are widely used in multiphase mixed pipelines. Hydrate inhibitors can prolong the time for hydrates to appear, so that the fluid in the pipeline can be safely transported to the processing or storage equipment. Therefore, the use of wax inhibitors and hydrate inhibitors has received widespread attention at the engineering site. However, the current use of chemical additives affects the quality of crude oil, has a single effect, is used in large quantities, and has a high cost.

[0004] CN111690392B discloses an environmentally friendly microbial composite wax remover and inhibitor for oil wells. The wax remover is mainly composed of a wax-loving mixed bacterial solution, a bacterial nutrient solution, a first surfactant, a second surfactant and a mutual solvent. The inhibitor with environmental benefits is prepared by combining chemical and microbiological methods. However, there are many chemical reagents, which affect the quality of crude oil, and there is a risk of bacterial corrosion in the oil pipeline after the wax remover is added.

[0005] CN116535568A discloses a wax inhibitor, a preparation method and application thereof. The prepared α-olefin-alkyl maleate copolymer is used as a wax inhibitor, which can effectively inhibit the precipitation of wax crystals in a normal pressure environment. However, the effect in a high-pressure environment on site is still unclear.

[0006] Therefore, the development of low-cost, effective, and suitable paraffin inhibitors for high-pressure environments is a widely-concerned issue in the field of pipeline safety. Considering that the flow assurance of high-pressure multiphase mixed crude oil pipelines involves multiple aspects such as wax deposition and hydrates, the development of additives that have both the effects of paraffin inhibition and hydrate formation inhibition is of great significance to the safe operation of pipelines. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention provides an asphalt-based wax inhibitor and a preparation method and application thereof. The wax inhibitor can significantly reduce the amount of wax deposition and has the advantages of excellent performance, low cost and small usage. At the same time, the wax inhibitor can also prolong the hydrate formation time and inhibit the formation of hydrates when used.

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

[0009] (1) heating and melting vacuum residue oil and deoiled asphalt, then adding them into a reactor, adding a raw material modifier thereto, and performing modification treatment under protective gas;

[0010] (2) cooling the material obtained in step (1), extracting the asphaltene component, and obtaining a deasphalted raw material, and then separating the colloid component from the deasphalted raw material;

[0011] (3) mixing an asphaltene precipitating agent and an asphaltene dispersing agent to obtain an asphaltene extracting agent, mixing the asphaltene extracting agent with the asphaltene obtained in step (2), filtering, and drying to obtain a solid substance A1;

[0012] (4) adding an asphaltene precipitation agent to the filtrate obtained after filtration in step (3), and drying to obtain a solid substance A2;

[0013] (5) The solid substance A1 obtained in step (3) is mixed with the colloid component obtained in step (2) to obtain an asphaltene mixed component, which is then mixed with a reactive agent and xylene, and then the solid substance A2 obtained in step (4) is added to obtain an asphalt-based paraffin inhibitor.

[0014] Furthermore, in step (1), the properties of the vacuum residue oil 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, saturated components account for 30.2%-36.6%, aromatic components account for 28.7%-34.7%, gum accounts for 27.8%-40.1%, and asphaltenes account for 1.0%-4.0%, with gum preferably accounting for 28.3%-40.1%.

[0015] Furthermore, in step (1), the properties of the deoiled asphalt 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 / cm at 20°C.3 The residual carbon is 16.3wt%~34.1wt%. By mass fraction, 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%. The gum is preferably 49.7%~59.2%, and the asphaltene is preferably 8.6%~19.8%.

[0016] Furthermore, in step (1), the mass ratio of the vacuum residue to the deoiled asphalt is 1:1-3.

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

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

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

[0020] Furthermore, in step (1), the modification treatment conditions are as follows: the modification treatment temperature is 130-180°C, preferably 150-160°C, and the modification treatment time is 1-4h, preferably 2-3h. The heating to the required temperature for the modification treatment is preferably performed by programmed heating, and the heating rate is 1-3°C / min. The modification treatment is performed under stirring, and the stirring speed is 200-400r / min.

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

[0022] Furthermore, in step (2), the asphaltene and resin component extraction and separation process adopts a four-component analysis method, and the specific operation process can refer to the standard NB / SH / T 0509-2010 "Four-component Determination Method for Petroleum Asphalt".

[0023] Furthermore, in step (3), the asphaltene precipitation agent is one or more of petroleum ether, isopentane, n-pentane, cyclohexane or n-hexane. The asphaltene dispersant is one or more of highly polar reagents such as chloroform, benzene, p-xylene, dichloroethane, methylene chloride or tetrahydrofuran.

[0024] Furthermore, in step (3), the volume ratio of the asphaltene precipitation agent 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] Furthermore, in step (3), after the asphaltene extractant is mixed with the asphaltene obtained in step (2), an ultrasonic oscillation treatment is performed. The ultrasonic oscillation time is 30 to 60 minutes, the ultrasonic oscillation temperature is 13 to 18° C., and the ultrasonic frequency is 20 to 40 KHz.

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

[0027] Furthermore, 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, preferably 1:1.3-1.5.

[0028] Furthermore, in step (4), after adding the asphaltene precipitation agent, the solid material A2 is obtained by centrifugal rotation. The speed of the centrifugal rotation is 6000-8000 rpm, and the time of the centrifugal rotation is 40-60 min.

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

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

[0031] Furthermore, in step (5), the reactive agent is one or more of polyvinyl alcohol (molecular weight of 16000-130000), polyacrylic acid (molecular weight of 5000-200000), sodium polyacrylate (molecular weight of 1000-30000) or polyethylene glycol (molecular weight of 1000-8000). The mass ratio of the asphaltene mixed component to the reactive agent is 10-30:1.

[0032] Furthermore, in step (5), the mass ratio of the asphaltene mixed component to xylene is 1:10 to 50.

[0033] Furthermore, in step (5), the asphaltene mixed component is mixed with the reactive agent and xylene and then subjected to ultrasonic oscillation treatment, wherein the ultrasonic oscillation time is 20 to 40 minutes, the ultrasonic oscillation 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 added amount of solid material A2 to the added amount of solid material A1 is 1:1.5-3.0.

[0035] Furthermore, in step (5), after adding the solid material A2 obtained in step (4), ultrasonic oscillation is performed again, and the time of the ultrasonic oscillation is 60 to 90 minutes, the temperature of the ultrasonic oscillation is 30 to 60° C., and the ultrasonic frequency is 20 to 40 kHz.

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

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

[0038] When the asphalt-based paraffin inhibitor 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 paraffin inhibitor of the present invention has the following advantages:

[0040] (1) The present invention uses low-value-added vacuum residue and deoiled asphalt as raw materials to produce a wax inhibitor, thereby improving its social and economic value. The present invention uses vacuum residue, deoiled asphalt, a raw material modifier and a reaction activator through a series of reactions to improve the inhibitory effect of the vacuum residue and deoiled asphalt mixed raw material on wax crystal precipitation and deposition, and prepares an asphalt-based wax inhibitor suitable for a high-pressure system.

[0041] (2) The present invention divides asphaltene into two components with different functions by using different ratios of asphaltene precipitating agent and asphaltene dispersant, and improves its dispersion degree and effect through the synergistic effect of colloid and solid matter A1 component that precipitates first, and then works together with solid matter A2 that precipitates later to improve the effect of the paraffin inhibitor.

[0042] (3) The introduction of the reactive agent of the present invention increases the activity of asphaltene and colloid in the asphalt-based wax inhibitor, enhances the effect of the wax inhibitor, and also strengthens the action strength of the hydrophilic groups in the asphalt-based wax inhibitor, so that the wax inhibitor can not only reduce the mass of wax deposition, but also reflect the function of inhibiting the formation of hydrates, thus having the dual effects of wax inhibitor and hydrate inhibitor.

[0043] (4) The asphalt-based paraffin inhibitor for high-pressure oil-water systems of the present invention can significantly reduce the amount of wax deposition, is suitable for crude oil systems and oil-water systems, and has the advantages of excellent performance, low cost and small usage. At the same time, the dual efficacy of the paraffin inhibitor 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 DESCRIPTION

[0044] The present invention is further described in detail below through specific examples. The described examples are only used to explain the present invention but not to limit the scope of the present invention.

[0045] The wax inhibitor of the present invention is evaluated using a high-pressure wax deposition reactor, and the main steps are: (1) adding the wax inhibitor and the oil-water emulsion into a cleaned high-pressure wax deposition reactor, and conducting a wax deposition experiment for 12 hours at a pressure of 1 MPa, then taking out the cold finger to scrape the sediment, weighing the weight and determining the wax content, which is used to evaluate the wax inhibitor effect of the wax inhibitor; (2) cleaning the cold finger and re-installing it into the reactor, and conducting a hydrate formation experiment at a pressure of 3 MPa, calculating the hydrate induction period, which is used to evaluate the effect on hydrate formation.

[0046] Example 1

[0047] (1) 1000 g of vacuum residue oil (properties see Table 1) and 1000 g of deoiled asphalt (properties see Table 2) were heated to 140°C to melt and added to a high-pressure stirred reactor. 60 g of phthalic anhydride was added thereto. The temperature was raised to 130°C at 1°C / min in a 0.5 MPa nitrogen environment and the reaction was stirred at 300 r / min for 2 h.

[0048] (2) The material obtained in step (1) is taken out and cooled to room temperature, and the asphaltene component is extracted with n-heptane according to the standard NB / SH / T 0509-2010 "Determination of Four Components of Petroleum Asphalt", the mass volume ratio of asphaltene to n-heptane during asphaltene extraction is 1:100 g / mL, and the heating reflux time is 1 h to obtain a deasphalted raw material, and then the colloid component is separated from the deasphalted raw material.

[0049] (3) n-pentane and chloroform were mixed in a volume ratio of 7:3 to obtain 2000 mL of an asphaltene extractant. 100 g of the asphaltene obtained in step (2) was added to the asphaltene extractant. Ultrasonic vibration was used at 20 kHz for 30 min in an environment of 15° C. to dissolve the soluble components. The solid substance A1 was then filtered to obtain the solid substance A1, which was dried at 105° C. for 50 min and then used for later use.

[0050] (4) Add 2000 mL of n-pentane to the filtrate obtained in step (3), and centrifuge at 8000 rpm for 50 min to obtain a solid substance A2, which is dried at 105° C. for 50 min and set aside.

[0051] (5) 10 g of the solid substance A1 obtained in step (3) and 5 g of the colloid obtained in step (2) are mixed to obtain an asphaltene mixed component. The asphaltene mixed component and 0.8 g of polyvinyl alcohol (molecular weight 20,000) are added to 200 g of xylene, and the mixture is ultrasonically vibrated at 20 kHz for 30 min at 30°C. Then 5 g of the solid substance A2 is added, and the mixture is ultrasonically vibrated again at 20 kHz for 80 min at 30°C to obtain an asphalt-based paraffin inhibitor B1 for high-pressure oil-water systems.

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

[0053] Example 2

[0054] (1) 1000 g of vacuum residue oil (properties see Table 1) and 1000 g of deoiled asphalt (properties see Table 2) were heated to 140°C to melt and added to a high-pressure stirred reactor. 60 g of phthalic anhydride was added thereto. The temperature was raised to 130°C at 1°C / min in a 0.6 MPa nitrogen environment and the reaction was stirred at 300 r / min for 3 h.

[0055] (2) The material obtained in step (1) is taken out and cooled to room temperature, and the asphaltene component is extracted with n-heptane according to the standard NB / SH / T 0509-2010 "Determination of Four Components of Petroleum Asphalt", the mass volume ratio of asphaltene to n-heptane during asphaltene extraction is 1:100 g / mL, and the heating reflux time is 1 h to obtain a deasphalted raw material, and then the colloid component is separated from the deasphalted raw material.

[0056] (3) n-pentane and dichloromethane were mixed in a volume ratio of 7:3 to obtain 2000 mL of an asphaltene extractant, 100 g of the asphaltene obtained in step (2) was added to the asphaltene extractant, and ultrasonic vibration was used at 40 kHz for 30 min in an environment of 15° C. to dissolve the soluble components, and then the solid substance A1 was obtained by filtration, and dried at 105° C. for 50 min for later use.

[0057] (4) Add 2000 mL of n-pentane to the filtrate obtained in step (3), and centrifuge at 8000 rpm for 50 min to obtain a solid substance A2, which is dried at 105° C. for 50 min and then used for later use.

[0058] (5) 10 g of the solid substance A1 obtained in step (3) and 5 g of the colloid obtained in step (2) are mixed to obtain an asphaltene mixed component. The asphaltene mixed component and 0.8 g of polyvinyl alcohol (molecular weight 20,000) are added to 150 g of xylene, and the mixture is ultrasonically vibrated at 40 kHz for 30 min at 30° C., and then 5 g of the solid substance A2 is added. The mixture is ultrasonically vibrated again at 20 kHz for 80 min at 30° C. to obtain an asphalt-based paraffin inhibitor B2 for high-pressure oil-water system.

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

[0060] Example 3

[0061] (1) 1000 g of vacuum residue oil (properties see Table 1) and 1000 g of deoiled asphalt (properties see Table 2) were heated to 140°C to melt and added to a high-pressure stirred reactor. 60 g of phthalic anhydride was added thereto. The temperature was raised to 130°C at 1°C / min in a 0.5 MPa nitrogen environment and the reaction was stirred at 300 r / min for 2 h.

[0062] (2) The material obtained in step (1) is taken out and cooled to room temperature, and the asphaltene component is extracted with n-heptane according to the standard NB / SH / T 0509-2010 "Determination of Four Components of Petroleum Asphalt", the mass volume ratio of asphaltene to n-heptane during asphaltene extraction is 1:100 g / mL, and the heating reflux time is 1 h to obtain a deasphalted raw material, and then the colloid component is separated from the deasphalted raw material.

[0063] (3) n-pentane and a mixture of chloroform and dichloromethane (the volume ratio of chloroform and dichloromethane is 1:1) are mixed in a volume ratio of 7:3 to obtain 2000 mL of an asphaltene extractant. 100 g of the asphaltene obtained in step (2) is added to the asphaltene extractant, and ultrasonic vibration is used at 20 kHz for 30 min in an environment of 15° C. to dissolve the soluble components. The solid substance A1 is then filtered to obtain the solid substance A1, which is dried at 105° C. for 50 min and then used for later use.

[0064] (4) Add 2000 mL of n-pentane to the filtrate obtained in step (3), and centrifuge at 8000 rpm for 50 min to obtain a solid substance A2, which is dried at 105° C. for 50 min and set aside.

[0065] (5) 10 g of the solid substance A1 obtained in step (3) and 5 g of the colloid obtained in step (2) were mixed to obtain an asphaltene mixed component. The asphaltene mixed component and 1.0 g of polyacrylic acid (molecular weight 10,000) were added to 200 g of xylene, and ultrasonically vibrated at 20 kHz for 30 min at 30° C., and then 5 g of the solid substance A2 was added. The mixture was ultrasonically vibrated again at 20 kHz for 80 min at 30° C. to obtain an asphalt-based paraffin inhibitor B3 for high-pressure oil-water system.

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

[0067] Example 4

[0068] (1) 800 g of vacuum residue oil (properties see Table 1) and 1200 g of deoiled asphalt (properties see Table 2) were heated to 140°C to melt and added to a high-pressure stirred reactor. 100 g of phthalic anhydride was added thereto. The temperature was raised to 130°C at a rate of 1°C / min in a 0.5 MPa nitrogen environment and the reaction was stirred at a rate of 300 r / min for 3 h.

[0069] (2) The material obtained in step (1) is taken out and cooled to room temperature, and the asphaltene component is extracted with n-heptane according to the standard NB / SH / T 0509-2010 "Determination of Four Components of Petroleum Asphalt", the mass volume ratio of asphaltene to n-heptane during asphaltene extraction is 1:100 g / mL, and the heating reflux time is 1 h to obtain a deasphalted raw material, and then the colloid component is separated from the deasphalted raw material.

[0070] (3) n-pentane and a mixture of chloroform and dichloromethane (the volume ratio of chloroform and dichloromethane is 1:1) are mixed in a volume ratio of 7:4 to obtain 2000 mL of an asphaltene extractant. 100 g of the asphaltene obtained in step (2) is added to the asphaltene extractant, and ultrasonic vibration is used at 40 kHz for 60 min in an environment of 15° C. to dissolve the soluble components, and then the solid substance A1 is obtained by filtration, and dried at 105° C. for 50 min for later use.

[0071] (4) Add 1780 mL of n-pentane to the filtrate obtained in step (3), and centrifuge at 8000 rpm for 60 min to obtain a solid substance A2, which is dried at 105° C. for 50 min and set aside.

[0072] (5) 10 g of the solid substance A1 obtained in step (3) and 5 g of the colloid obtained in step (2) were mixed to obtain an asphaltene mixed component. The asphaltene mixed component and 1.2 g of polyacrylic acid (molecular weight 10,000) were added to 150 g of xylene, and the mixture was ultrasonically vibrated at 40 kHz for 30 min at 30° C., and then 5 g of the solid substance A2 was added. The mixture was ultrasonically vibrated again at 20 kHz for 80 min at 30° C. to obtain an asphalt-based paraffin inhibitor B4 for high-pressure oil-water system.

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

[0074] Example 5

[0075] (1) 1000 g of vacuum residue oil (properties see Table 1) and 2000 g of deoiled asphalt (properties see Table 2) were heated to 140°C to melt and added to a high-pressure stirred reactor. 60 g of phthalic anhydride was added thereto. The temperature was raised to 130°C at 1°C / min in a 0.5 MPa nitrogen environment and the reaction was stirred at 300 r / min for 2 h.

[0076] (2) The material obtained in step (1) is taken out and cooled to room temperature, and the asphaltene component is extracted with n-heptane according to the standard NB / SH / T 0509-2010 "Determination of Four Components of Petroleum Asphalt", the mass volume ratio of asphaltene to n-heptane during asphaltene extraction is 1:100 g / mL, and the heating reflux time is 1 h to obtain a deasphalted raw material, and then the colloid component is separated from the deasphalted raw material.

[0077] (3) n-pentane and a mixture of chloroform and dichloromethane (the volume ratio of chloroform and dichloromethane is 1:1) are mixed in a volume ratio of 7:3 to obtain 2000 mL of an asphaltene extractant. 100 g of the asphaltene obtained in step (2) is added to the asphaltene extractant, and ultrasonic vibration is used at 20 kHz for 30 min in an environment of 15° C. to dissolve the soluble components, and then the solid substance A1 is obtained by filtration, and dried at 105° C. for 50 min for later use.

[0078] (4) Add 2100 mL of n-pentane to the filtrate obtained in step (3), and centrifuge at 8000 rpm for 50 min to obtain a solid substance A2, which is dried at 105° C. for 50 min and set aside.

[0079] (5) 10 g of the solid substance A1 obtained in step (3) and 5 g of the colloid obtained in step (2) were mixed to obtain an asphaltene mixed component. The asphaltene mixed component and 1.1 g of polyacrylic acid (molecular weight 20,000) were added to 200 g of xylene, and ultrasonically vibrated at 20 kHz for 30 min at 30° C., and then 5 g of the solid substance A2 was added. The mixture was ultrasonically vibrated again at 20 kHz for 80 min at 30° C. to obtain an asphalt-based paraffin inhibitor B5 for high-pressure oil-water system.

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

[0081] Comparative Example 1

[0082] The only difference compared with Example 3 is that no raw material modifier is added during the preparation process to obtain an asphalt-based anti-wax agent D1 for a high-pressure oil-water system.

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

[0084] Comparative Example 2

[0085] The only difference compared with Example 3 is that the solid substance A2 is not prepared and added during the preparation process, and the asphalt-based anti-wax agent D2 for high-pressure oil-water system is obtained.

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

[0087] Comparative Example 3

[0088] The only difference compared with Example 3 is that the raw materials are not processed. A total of 20 g of vacuum residue oil and deoiled asphalt are directly added to 200 g of xylene at a mass ratio of 1:1, and ultrasonic vibration is used at 20 kHz for 30 minutes at 30°C to obtain an asphalt-based paraffin inhibitor D3 for high-pressure oil-water system.

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

[0090] Comparative Example 4

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

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

[0093] Table 1 Properties of vacuum residue oil used in Examples and Comparative Examples

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

[0095] Table 2 Properties of deoiled asphalt used in Examples and Comparative Examples

[0096]

[0097]

[0098] Table 3 Wax inhibitor application results in examples and comparative examples

[0099]

[0100] The test results show that the asphalt-based wax inhibitor of the present invention can significantly reduce the wax deposition amount, wax content of the sediment and wax precipitation deposition rate in the oil-water emulsion of the high-pressure system, and play a good wax prevention effect. At the same time, the wax inhibitor of the present invention can also increase the hydrate formation induction period and significantly prolong the hydrate formation time. The wax inhibitor of the present invention has high efficiency, small usage and little effect on crude oil quality. It can play a significant role when the addition amount is 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 Condensation point / ℃ -15 Viscosity (5℃) / mPa·s 8.4

[0103] The protection scope of the present invention is not limited by the above embodiments, but by the claims. Those skilled in the art may make appropriate changes to these embodiments without departing from the technical concept and purpose of the present invention, and these changed embodiments are also included in the protection scope of the present invention.

Claims

1. A method for preparing an asphalt-based wax inhibitor, characterized in that: The following steps are involved: (1) heating and melting vacuum residue oil and deoiled asphalt, then adding them into a reactor, adding a raw material modifier thereto, and performing modification treatment under protective gas; (2) cooling the material obtained in step (1), extracting the asphaltene component, and obtaining a deasphalted raw material, and then separating the colloid component from the deasphalted raw material; (3) mixing an asphaltene precipitating agent and an asphaltene dispersing agent to obtain an asphaltene extracting agent, mixing the asphaltene extracting agent with the asphaltene obtained in step (2), filtering, and drying to obtain a solid substance A1; (4) adding an asphaltene precipitation agent to the filtrate obtained after filtration in step (3), and drying to obtain a solid substance A2; (5) The solid substance A1 obtained in step (3) is mixed with the colloid component obtained in step (2) to obtain an asphaltene mixed component, which is then mixed with a reactive agent and xylene, and then the solid substance A2 obtained in step (4) is added to obtain an asphalt-based paraffin inhibitor.

2. The method according to claim 1, characterized in that: In step (1), the properties of the vacuum residue oil 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, saturated fractions account for 30.2%-36.6%, aromatic fractions account for 28.7%-34.7%, colloids account for 27.8%-40.1%, and asphaltenes account for 1.0%-4.0%, with colloids preferably accounting for 28.3%-40.1%; And / or, the properties of the deoiled asphalt 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 / cm at 20°C. 3 The residual carbon is 16.3wt%~34.1wt%. By mass fraction, 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%. The gum is preferably 49.7%~59.2%, and the asphaltene is preferably 8.6%~19.8%.

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 according to claim 1, characterized in that: In step (1), the heating and melting temperature is 120 to 160°C.

5. The method according to claim 1, characterized in that: In step (1), the raw material modifier is one or more of phthalic anhydride, maleic anhydride or hydrolyzed polymaleic anhydride; and the mass ratio of the total mass of the vacuum residue and deoiled asphalt to the raw material modifier is 1:0.02-0.

1.

6. The method according to claim 1, characterized in that: In step (1), the protective gas is at least one of nitrogen or an inert gas; the amount of the protective gas added is such that the system pressure is maintained at 0.2 to 0.8 MPa, preferably 0.4 to 0.8 MPa.

7. The method according to claim 1, characterized in that: In step (1), the conditions of the modification treatment are as follows: the temperature of the modification treatment is 130-180°C, preferably 150-160°C, the time of the modification treatment is 1-4h, preferably 2-3h; the heating to the required temperature for the modification treatment is preferably performed by programmed heating, and the heating rate is 1-3°C / min; the modification treatment is carried out under stirring, and the stirring speed is 200-400r / min.

8. The method according to claim 1, characterized in that: In step (3), the asphaltene precipitation agent is one or more of petroleum ether, isopentane, n-pentane, cyclohexane or n-hexane; the asphaltene dispersant is one or more of chloroform, benzene, p-xylene, dichloroethane, methylene chloride or tetrahydrofuran.

9. The method according to claim 1 or 8, characterized in that: In step (3), the volume ratio of the asphaltene precipitation agent to the asphaltene dispersant is 7:2-4; the mass volume ratio of the asphaltene to the asphaltene extraction agent is 1:15-25 (g / mL).

10. The method according to claim 1, characterized in that: In step (3), the asphaltene extractant is mixed with the asphaltene obtained in step (2) and then subjected to ultrasonic oscillation treatment; the ultrasonic oscillation time is 30 to 60 minutes, the ultrasonic oscillation temperature is 13 to 18° C., and the ultrasonic frequency is 20 to 40 KHz.

11. The method according to claim 1, characterized in that: 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, preferably 1:1.3-1.

5.

12. The method according to claim 1, characterized in that: In step (4), after adding the asphaltene precipitation agent, the solid material A2 is obtained by centrifugal rotation; the rotation speed of the centrifugal rotation is 6000-8000 rpm, and the time of the centrifugal rotation is 40-60 min.

13. The method according to claim 1, characterized in that: In step (5), the mass ratio of the solid material A1 obtained in step (3) to the colloid component obtained in step (2) is 2 to 5:

1.

14. The method according to claim 1, characterized in that: In step (5), the reactive agent is one or more of polyvinyl alcohol with a molecular weight of 16,000 to 130,000, polyacrylic acid with a molecular weight of 5,000 to 200,000, sodium polyacrylate with a molecular weight of 1,000 to 30,000, or polyethylene glycol with a molecular weight of 1,000 to 8,000; the mass ratio of the asphaltene mixed component to the reactive agent is 10 to 30:

1.

15. The method according to claim 1, characterized in that: In step (5), the mass ratio of the asphaltene mixed component to xylene is 1:10 to 50.

16. The method according to claim 1, characterized in that: In step (5), the asphaltene mixed component is mixed with the reactive agent and xylene, and then subjected to ultrasonic oscillation treatment, wherein the ultrasonic oscillation time is 20 to 40 minutes, the ultrasonic oscillation temperature is 30 to 60° C., and the ultrasonic frequency is 20 to 40 KHz; And / or, in step (5), after adding the solid material A2 obtained in step (4), ultrasonic oscillation is performed again, and the time of the ultrasonic oscillation is 60 to 90 minutes, the temperature of the ultrasonic oscillation is 30 to 60° C., and the ultrasonic frequency is 20 to 40 kHz.

17. An asphalt-based wax inhibitor prepared according to the method according to any one of claims 1 to 16.

18. Use of the asphalt-based paraffin inhibitor prepared according to any one of claims 1 to 16 in an oil-water system.

Images