A hydrate conversion inhibitor, its preparation method and application

Abstract

This invention discloses a hydrate conversion inhibitor, its preparation method, and its application. The hydrate conversion inhibitor of this invention comprises, by weight, the following raw materials: pretreated residue oil: 5-35 parts, alkane compounding agent: 0.2-6 parts, and dissolving and dispersing agent: 100 parts; wherein, the pretreated residue oil is deoiled bitumen obtained from pretreated vacuum residue oil, and the pretreated vacuum residue oil comprises, by weight, the following raw materials: vacuum residue oil: 100 parts, residue oil modifier: 2-8 parts, reaction initiator: 0.1-0.8 parts, and activator: 0.3-9 parts. This inhibitor can significantly reduce hydrate formation and has the advantages of excellent performance, low cost, and small dosage.

Description

Technical Field

[0001] This invention relates to the field of oil and gas production technology, specifically to a hydrate conversion inhibitor, its preparation method, and its application. Background Technology

[0002] The production of oil and gas involves ensuring the safety of pipeline flow, with wax deposition, hydrate formation, and asphaltenes precipitation being the most critical concerns. Oil-gas-water multiphase pipelines, operating in low-temperature environments, are at risk of hydrate formation under high pressure and disturbance. In multiphase pipelines, ice-like hydrate particles formed from produced water and components such as methane in the oil and gas can aggregate and deposit, reducing the pipeline's inner diameter, increasing energy consumption, and in severe cases, causing blockages and safety accidents.

[0003] In oil-gas-water multiphase pipelines, due to the presence of natural emulsifiers and frequent pump shearing, the aqueous phase is mainly dispersed in the oil phase as droplets. After hydrate nucleation, it grows rapidly, with water droplets gradually transforming into hydrate particles. During this growth process, small gas molecules from the oil and gas phases diffuse from the oil phase towards the surface of the hydrate particles, then further penetrate the hydrate shell and enter the interior of the particles, causing the free water inside to gradually form a crystalline structure. During this process, the hydrate shell gradually thickens. Simultaneously, free water inside the hydrate particles moves from the interior to the surface under capillary forces, contacting the small gas molecules on the particle surface to form a crystalline structure. Under the combined effects of gas diffusion and water molecule movement, the hydrate grows rapidly.

[0004] During hydrate growth, gas molecules are bound within solid hydrate particles, causing a gradual decrease in gas concentration and system pressure in a constant-volume gas phase. Higher hydrate conversion efficiency in a system with the same water content indicates a greater amount of hydrate formed. The presence of numerous hydrate particles in a pipeline increases fluid viscosity, increases pipeline pressure drop, and can even cause blockages, leading to safety accidents. Higher hydrate growth rates and greater hydrate formation rates increase the risk of pipeline blockage. To ensure pipeline safety, current methods primarily involve adding inhibitors or risk control. Additives such as ethylene glycol can prolong the time before hydrate formation, but their effectiveness is uncertain, and they require large quantities and pollute the environment. Risk control involves adding additives to disperse the generated hydrate particles as a slurry flowing within the pipe, but the amount of hydrate formed should not be excessive. Hydrate conversion inhibitors can reduce the amount of hydrate formed, mitigating the risk of blockage. Simultaneously, conversion inhibitors can also slow down the hydrate growth rate, making hydrate formation more slow and extending the safe operation time of the hydrate-containing system.

[0005] CN1635006A discloses the application of a copolymer of vinylpyrrolidone and vinyl acetate as a hydrate growth inhibitor. This method uses the copolymer of vinylpyrrolidone and vinyl acetate as a hydrate growth inhibitor, and by compounding them in different proportions under the action of an initiator, it can inhibit the growth of hydrates in oil and gas pipelines. However, this method requires large amounts of vinylpyrrolidone and vinyl acetate, which is expensive and affects the quality of crude oil.

[0006] CN109135702A discloses a hydrate inhibitor and its application. This method primarily uses glucosinolates extracted from rapeseed meal as the main component to prepare the hydrate inhibitor. The hydroxyl groups in the glucosinolate compound form hydrogen bonds with water molecules to inhibit hydrate conversion, thus reducing the conversion rate during hydrate growth. However, this inhibitor is mainly applied to pure water systems; its effectiveness in oil-water systems has not been evaluated. Furthermore, the large amount added to actual pipeline oil-in-water emulsion systems increases the difficulty of subsequent oil-water separation.

[0007] In summary, hydrate transformation inhibitors play a crucial role in the prevention and control of hydrate formation. Currently used nucleation inhibitors, such as polyvinylpyrrolidone (PVP), have some inhibitory effect on the hydrate transformation process, but they are expensive, have poor efficacy, and negatively impact crude oil quality. Therefore, there is a need to develop highly effective and low-cost hydrate transformation inhibitors. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a novel hydrate conversion inhibitor, its preparation method, and its application. This inhibitor can significantly reduce hydrate formation and has the advantages of excellent performance, low cost, and small dosage.

[0009] The first aspect of this invention provides a hydrate conversion inhibitor, which comprises, by weight, the following raw materials:

[0010] Pretreated residual oil: 5-35 parts, preferably 10-30 parts;

[0011] Alkane compounding agent: 0.2-6 parts, preferably 0.5-5 parts;

[0012] Dissolving and dispersing agent: 100 parts;

[0013] The pretreated residue oil is a deoiled bitumen obtained from pretreated vacuum residue oil, which, by weight, comprises the following raw materials:

[0014] Vacuum residue: 100 parts;

[0015] Residue oil modifier: 2-8 parts, preferably 2-6 parts;

[0016] Reaction initiator: 0.1–0.8 parts, preferably 0.2–0.6 parts;

[0017] Surfactant: 0.3 to 9 parts, preferably 1 to 5 parts.

[0018] Furthermore, the pretreated residue oil is de-oiled asphalt obtained by solvent deasphalting of pretreated vacuum residue oil.

[0019] Further, the properties of the vacuum residue include: a flash point of 260–268°C; by mass fraction, saturated fraction of 28.2%–38.6%, aromatic fraction of 25.2%–36.5%, gum fraction of 26.3%–36.6%, preferably gum fraction of 28.3%–33.0%, and asphaltenes fraction of 1.3%–5.1%; a softening point of 49.1–50.6°C; a dynamic viscosity of 468–493 Pa·s at 60°C; and a density of 0.96–0.99 g / cm³ at 25°C. 3 .

[0020] Furthermore, the vacuum residue can be CFMOTO vacuum residue or other vacuum residue that meets the above properties.

[0021] Furthermore, the residue oil modifier is one or more of maleic anhydride, polyoxohydrin, polyazelite anhydride, polyglutaric anhydride, tung oil anhydride, polyisobutylene succinic anhydride, or hydrolyzed polymaleic anhydride.

[0022] Furthermore, the reaction initiator is one or more of azobisisobutyronitrile, azobisisobutyronitrile, diisopropylbenzene peroxide, or cumene hydroperoxide.

[0023] Further, the activator is polyethyleneimine, with a molecular weight of 1000-10000, a decomposition temperature of 270℃-310℃, and a flash point of 250℃-260℃. By mass fraction, the amino groups of the polyethyleneimine contain 20%-35% primary amines, 20%-35% secondary amines, and 30%-60% tertiary amines.

[0024] Furthermore, the alkane compounding agent, by mass fraction, comprises: 3%–18% n-eicosane, 20%–40% n-tetracosane, 30%–50% n-octacosane, and 8%–20% n-dodecane.

[0025] Furthermore, the dissolving and dispersing agent is one or more of toluene, benzene, o-xylene, m-xylene, p-xylene, carbon disulfide, and carbon tetrachloride.

[0026] A second aspect of the present invention provides a method for preparing the above-mentioned hydrate conversion inhibitor, comprising the following steps:

[0027] (1) Add vacuum residue oil heated to a fluid state into the reactor, along with residue oil modifier and reaction initiator. Heat to the reaction temperature while stirring, and continue stirring under protective gas to carry out the reaction.

[0028] (2) Add the materials and activator obtained in step (1) to the solvent deasphalting device to carry out solvent deasphalting and obtain deasphalted oil and deoiled asphalt, i.e. pretreated residue oil.

[0029] (3) Heat the pretreated residue oil obtained in step (2) to a fluid state and transfer it into an oxidation reactor. Add alkane compounding agent, heat to the reaction temperature, and introduce oxidizing gas under stirring to carry out the oxidation reaction.

[0030] (4) The material obtained in step (3) is added to the dissolving and dispersing agent to obtain the hydrate conversion inhibitor.

[0031] In step (1), the temperature at which the vacuum residue is heated to a fluid state is generally 120-140℃.

[0032] In step (1), the reactor is a high-pressure reactor, and the initial temperature of the reactor is adjusted to 125-145℃.

[0033] In step (1), the reaction temperature is 145-185℃, preferably 150-160℃; the heating to the reaction temperature is preferably done by programmed heating at a rate of 1-3℃ / min; the reaction time is 2-8h, preferably 3-5h.

[0034] In step (1), it is preferable to add the residue oil modifier and the reaction initiator into the reaction vessel in sequence.

[0035] In step (1), the stirring speed is 300-500 r / min each independently.

[0036] In step (1), the protective gas is at least one of an inert gas or N2. The amount of the protective gas is such that the pressure inside the reactor is maintained at 0.2 to 0.8 MPa, preferably 0.4 to 0.8 MPa.

[0037] In step (2), a solvent needs to be added when performing solvent deasphalting. The solvent is one or more of propane and butane, and the volume ratio of the solvent to vacuum residue is 6 to 9:1.

[0038] In step (2), the yield of deasphalted oil in the solvent deasphalting process is 30–65 wt%. The softening point of the pretreated residue oil is 85–95 °C, and the carbon residue value is 0.5–25 wt%.

[0039] In step (3), the temperature at which the pretreated residue oil is heated to a fluid state is generally 120-150℃.

[0040] In step (3), the oxidizing gas is oxygen-enriched air (oxygen volume content of 25v% to 60v%), and the gas flow rate is 0.05 to 0.3 m³ / h. 3 / kg / h.

[0041] In step (3), the reaction temperature is 180–350°C, preferably 240–280°C. The oxidation reaction time is 3–6 hours, and the stirring speed during the oxidation process is 100–250 r / min.

[0042] In step (3), the alkane compounding agent is preferably heated and stirred evenly before being added. The heating temperature is 60-80℃, the heating time is 30-60min, and the stirring rate is 200-500r / min.

[0043] In step (4), the material obtained in step (3) is cooled and added to the dissolving and dispersing agent, and then subjected to ultrasonic vibration. The ultrasonic vibration time is 20 to 40 minutes, the ultrasonic frequency is 20 to 40 kHz, and the ultrasonic vibration temperature is 30 to 60°C.

[0044] A third aspect of the present invention provides an application of the above-mentioned hydrate conversion inhibitor in an oil-water system.

[0045] Furthermore, when the hydrate conversion inhibitor is used, the amount added is 0.1% to 3.5% of the total mass of the liquid phase in the oil-water system, preferably 0.8% to 3.0%, and the mass of the oil phase in the oil-water system is preferably not less than 40% of the total mass of the liquid phase.

[0046] The efficacy evaluation method for the hydrate conversion inhibitor of this invention is as follows:

[0047] The effect evaluation method is to characterize the effect of the hydrate inhibitor by calculating the hydrate conversion rate and average conversion rate during the growth process.

[0048] The hydrate conversion rate can be used to calculate the percentage of aqueous phase transformed into hydrate in a system, thus characterizing the amount of hydrate formed. A higher hydrate conversion rate in the same system indicates that more hydrate is formed. The specific calculation method is as follows:

[0049]

[0050] Among them, P1, Z1, T1 and n w1 The parameters are: pressure, compressibility factor, temperature, and molar amount of dissolved gas in the liquid phase of the system before hydrate formation; P2, Z2, T2, and n. w2Here, represents the pressure, compressibility factor, temperature, and molar amount of dissolved gas in the liquid phase of the system after hydrate formation; V is the gas phase volume of the constant-volume system during hydrate formation; R is the thermodynamic constant; H is the number of hydrates; M is the molar mass of water; ρ is the density of water; V w This represents the total volume of the aqueous phase in the system before hydrates are formed.

[0051] The average conversion rate of hydrates can be used to reflect the growth rate of hydrates; the smaller the average conversion rate, the slower the hydrate growth.

[0052]

[0053] Among them, P1, Z1, T1 and n w1 The parameters are: pressure, compressibility factor, temperature, and molar amount of dissolved gas in the liquid phase of the system before hydrate formation; P2, Z2, T2, and n. w2 The values ​​are: pressure, compressibility factor, temperature, and molar amount of dissolved gas in the liquid phase, respectively, after hydrate formation; V is the gas phase space volume of the constant-volume system during hydrate formation; R is the thermodynamic constant; H is the number of hydrates; M is the molar mass of water; and t is the total time from the start to the end of hydrate growth.

[0054] Compared with the prior art, the present invention has the following advantages:

[0055] (1) This invention uses vacuum residue as raw material, which is not suitable for producing high-grade road asphalt, such as CFMOTO vacuum residue with high gum content and poor overall performance. This invention uses a combination of vacuum residue, residue modifier, reaction inducer and activator to obtain pretreated residue through a series of reactions, which enhances its potential effect as a hydrate conversion inhibitor, expands the application scenarios of vacuum residue, and increases its added value.

[0056] (2) The activator introduced in this invention has highly adsorbent amine groups that can react with carboxyl groups in asphalt to form hydrogen bonds. When applied to solvent deasphalting process, it can make the de-oiled asphalt produced by solvent deasphalting operation have stronger interfacial activity.

[0057] (3) The addition of the alkane compounding agent of the present invention has a stepwise increasing carbon number relationship, which can synergistically adsorb the active components in the oil-water system with the active components in the residue oil, improve the coating of the conversion inhibitor on the surface of the water droplet, and at the same time, crystallization can occur in the low temperature environment, which can not only inhibit the conversion of hydrates, but also disperse hydrate particles and reduce the effect of particle growth through collision.

[0058] (4) The present invention selects specific raw materials and preparation and pretreatment methods. The resulting hydrate conversion inhibitor has significant inhibitory performance, which can reduce the amount of hydrate generated and the conversion rate. The resulting inhibitor has low dosage and good effect, does not require large-scale application of chemical reagents, reduces costs and has little impact on crude oil quality. Detailed Implementation

[0059] 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.

[0060] The effectiveness of the hydrate conversion inhibitor was evaluated using a reaction vessel experiment. After nucleation within the reaction vessel, hydrates begin to grow. The hydrate conversion rate and average conversion rate can be calculated using relevant parameters such as temperature, pressure, and solubility during the reaction process to characterize the effect of the hydrate inhibitor. The specific steps of the evaluation experiments in the embodiments and comparative examples of this invention are as follows:

[0061] (1) After cleaning the high-pressure reactor with petroleum ether, pour in 1000 mL of oil-water emulsion, with an aqueous phase volume of 200 mL. After adding an oil-based hydrate inhibitor, seal the reactor.

[0062] (2) Turn on the stirring paddle and set the speed to 300 rpm. Collect the temperature and pressure parameters inside the vessel in real time through the data acquisition system. Open the gas cylinder and the air inlet valve to introduce carbon dioxide gas into the high-pressure stirring vessel to replace the residual air inside the vessel.

[0063] (3) After the gas is replaced, the reaction gas is continuously introduced into the stirred tank to increase the pressure inside the tank to 2.4 MPa, in order to create a high-pressure environment to generate carbon dioxide hydrate.

[0064] (4) By adjusting the temperature-controlled water bath, the fluid temperature in the stirred tank is gradually reduced from 10℃ to 2.5℃ and maintained at this temperature until hydrate is formed. When hydrate begins to form, the temperature rises rapidly and the pressure drops significantly. As the hydrate transforms, the pressure continues to decrease and the temperature will begin to drop after reaching its peak.

[0065] (5) When the system temperature and pressure do not change within 10 minutes, the hydrate formation experiment is terminated and the high-pressure stirred tank is cleaned with petroleum ether.

[0066] (6) After the hydrate experiment is completed, the time from the start of hydrate formation to the end of formation is calculated, and the hydrate conversion rate and average conversion rate are calculated by measuring parameters such as temperature and pressure.

[0067] Example 1

[0068] (1) 100 parts of spring breeze slag heated to a fluid state at 130℃ (properties shown in Table 2) were added to a reactor at 125℃. 2 parts of maleic anhydride and 0.3 parts of dicumyl peroxide were added in sequence. The mixture was heated to 145℃ at a rate of 1℃ / min under stirring at 300r / min. The reaction was carried out under N2 atmosphere. The pressure in the reactor was maintained at 0.5MPa and the reaction time was 3h.

[0069] (2) The material obtained in step (1) and 1 part of polyethyleneimine (molecular weight of 6000, decomposition temperature of 280℃, flash point of 255℃, wherein the content of primary amine is 20%, secondary amine is 25%, and tertiary amine is 55%) are mixed and added to a solvent deasphalting device. Solvent deasphalting is carried out at 3.2 MPa using propane as solvent. The volume ratio of solvent to slag is 7:1. After solvent deasphalting, deasphalted oil and pretreated slag oil are obtained. The yield of deasphalted oil is 40.2 wt%, the softening point of pretreated slag oil is 87.1℃, and the carbon residue value is 1.43 wt%.

[0070] (3) Heat 5 parts by weight of the pretreated residue oil obtained in step (2) to 130°C until it reaches a molten state and transfer it into an oxidation reactor. Add 0.5 parts by weight of an alkane compounding agent (by mass fraction, n-eicosane accounts for 15%, n-tetracosane for 30%, n-octacosane for 40%, and n-triane for 15%, and the alkane compounding agent is stirred and heated at 70°C for 40 minutes before being added, with a stirring rate of 300 r / min). Adjust the temperature inside the reactor to 250°C, and introduce oxygen-enriched air (oxygen volume content of 25v%) under stirring at 100 r / min to carry out the oxidation reaction. The gas flow rate during the oxidation process is 0.1 m³ / min. 3 / kg / h, oxidation time is 3h.

[0071] (4) Take the cooled material obtained in step (3) and add it to 100 parts by weight of toluene. Use an ultrasonic oscillator with a frequency of 20KHz to ultrasonically oscillate for 20min at a temperature of 30℃, so that the material is evenly dispersed in the dissolving and dispersing agent to obtain hydrate conversion inhibitor A1.

[0072] 8.72 g (1.0% of the total mass of the liquid phase) of hydrate conversion inhibitor A1 was added to the oil-water system (the oil phase in the oil-water system accounted for 77% of the total mass of the liquid phase) to conduct an evaluation experiment on the effect of the hydrate inhibitor. The hydrate conversion rate and average conversion rate during the growth process were calculated. The results are shown in Table 3.

[0073] Example 2

[0074] (1) 100 parts of spring breeze slag (properties shown in Table 2) heated to a fluid state at 130℃ were added to a reactor at 125℃. 4 parts of polyethylene anhydride and 0.3 parts of dicumyl peroxide were added in sequence. The reactor was heated to 145℃ at a rate of 1℃ / min under stirring at 300r / min. The reaction was carried out under N2 atmosphere. The pressure in the reactor was maintained at 0.5MPa and the reaction time was 4h.

[0075] (2) The material obtained in step (1) and 1 part of polyethyleneimine (molecular weight of 6000, decomposition temperature of 280℃, flash point of 255℃, wherein the content of primary amine is 20%, secondary amine is 25%, and tertiary amine is 55%) are mixed and added to a solvent deasphalting device. Solvent deasphalting is carried out at 3.2 MPa using propane as solvent. The volume ratio of solvent to slag is 7:1. After solvent deasphalting, deasphalted oil and pretreated slag oil are obtained. The yield of deasphalted oil is 40.2 wt%, the softening point of pretreated slag oil is 87.1℃, and the carbon residue value is 1.43 wt%.

[0076] (3) Heat 10 parts by weight of the pretreated residue oil obtained in step (2) to 130°C until it reaches a molten state and transfer it into an oxidation reactor. Add 2 parts by weight of an alkane compound (by mass fraction, n-eicosane accounts for 15%, n-tetracosane for 30%, n-octacosane for 40%, and n-triane for 15%, and the alkane compound is stirred and heated at 70°C for 40 minutes before being added, with a stirring rate of 300 r / min). Adjust the temperature inside the reactor to 250°C, and introduce oxygen-enriched air (oxygen volume content of 25v%) while stirring at 100 r / min to carry out the oxidation reaction. The gas flow rate during the oxidation process is 0.1 m³ / min. 3 / kg / h, oxidation time is 3h.

[0077] (4) Take the cooled material obtained in step (3) and add it to 100 parts by weight of toluene. Use an ultrasonic oscillator with a frequency of 20KHz to oscillate for 20min at a temperature of 30℃, so that the material is evenly dispersed in the dissolving and dispersing agent to obtain hydrate conversion inhibitor A2.

[0078] 13.08 g (1.5% of the total mass of the liquid phase) of hydrate conversion inhibitor A2 was added to the oil-water system (the oil phase in the oil-water system accounted for 77% of the total mass of the liquid phase) to conduct an evaluation experiment on the effect of the hydrate inhibitor. The hydrate conversion rate and average conversion rate during the growth process were calculated. The results are shown in Table 3.

[0079] Example 3

[0080] (1) 100 parts of spring breeze slag heated to a fluid state at 130℃ (properties shown in Table 2) were added to a reactor at 125℃. 6 parts of maleic anhydride and 0.6 parts of dicumyl peroxide were added in sequence. The reactor was heated to 145℃ at a rate of 1℃ / min under stirring at 300r / min. The reaction was carried out under N2 atmosphere. The pressure in the reactor was maintained at 0.5MPa and the reaction time was 6h.

[0081] (2) The material obtained in step (1) and 1 part of polyethyleneimine (molecular weight of 6000, decomposition temperature of 280℃, flash point of 255℃, wherein the content of primary amine is 20%, secondary amine is 25%, and tertiary amine is 55%) are mixed and added to the solvent deasphalting device. Solvent deasphalting is carried out at 3.5 MPa using propane as solvent. The volume ratio of solvent to slag is 7:1. After solvent deasphalting, deasphalted oil and pretreated slag oil are obtained. The yield of deasphalted oil is 43.8%, the softening point of pretreated slag oil is 88.5℃, and the carbon residue value is 1.32 wt%.

[0082] (3) Heat 30 parts by weight of the pretreated residue oil obtained in step (2) to 130°C until it reaches a molten state and transfer it into an oxidation reactor. Add 4 parts by weight of an alkane compound (by mass fraction, n-eicosane accounts for 15%, n-tetracosane for 30%, n-octacosane for 40%, and n-triane for 15%, and the alkane compound is stirred and heated at 70°C for 40 minutes before being added, with a stirring rate of 300 r / min). Adjust the temperature inside the reactor to 250°C, and introduce oxygen-enriched air (oxygen volume content of 25%) under stirring at 100 r / min to carry out the oxidation reaction. The gas flow rate during the oxidation process is 0.1 m³ / min. 3 / kg / h, oxidation time is 4h.

[0083] (4) Take the cooled material obtained in step (3) and add it to 100 parts by weight of toluene. Use an ultrasonic oscillator with a frequency of 20KHz to ultrasonically oscillate for 20min at a temperature of 30℃, so that the material is evenly dispersed in the dissolving and dispersing agent to obtain hydrate conversion inhibitor A3.

[0084] 26.16 g (3.0% of the total mass of the liquid phase) of hydrate conversion inhibitor A3 was added to the oil-water system (the oil phase in the oil-water system accounted for 77% of the total mass of the liquid phase) to conduct an evaluation experiment on the effect of the hydrate inhibitor. The hydrate conversion rate and average conversion rate during the growth process were calculated. The results are shown in Table 3.

[0085] Example 4

[0086] (1) 100 parts of the spring breeze slag (properties shown in Table 2) heated to a fluid state at 130℃ were added to a reactor at 125℃. 4 parts of polyethylene anhydride, 0.2 parts of dicumyl peroxide and 0.1 parts of propylbenzene azobisisobutyronitrile were added in sequence. The mixture was heated to 145℃ at a rate of 1℃ / min under stirring at 300r / min. The reaction was carried out under N2 atmosphere, with the pressure in the reactor maintained at 0.8MPa and the reaction time being 6h.

[0087] (2) The material obtained in step (1) and 1 part of polyethyleneimine (molecular weight of 6000, decomposition temperature of 280℃, flash point of 255℃, wherein the content of primary amine is 20%, secondary amine is 25%, and tertiary amine is 55%) are mixed and added to a solvent deasphalting device. Solvent deasphalting is carried out at 3.2 MPa using propane as solvent. The volume ratio of solvent to slag is 7:1. After solvent deasphalting, deasphalted oil and pretreated slag oil are obtained. The yield of deasphalted oil is 40.2%, the softening point of pretreated slag oil is 87.1℃, and the carbon residue value is 1.43 wt%.

[0088] (3) Heat 20 parts by weight of the pretreated residue oil obtained in step (2) to 130°C until it reaches a molten state and transfer it into an oxidation reactor. Add 5 parts by weight of an alkane compound (by mass fraction, n-eicosane accounts for 15%, n-tetracosane for 30%, n-octacosane for 40%, and n-triane for 15%, and the alkane compound is stirred and heated at 80°C for 40 minutes before being added, with a stirring rate of 300 r / min). Adjust the temperature inside the reactor to 250°C, and introduce oxygen-enriched air (oxygen volume content of 25%) under stirring at 100 r / min to carry out the oxidation reaction. The gas flow rate during the oxidation process is 0.1 m³ / min. 3 / kg / h, oxidation time is 5h.

[0089] (4) Take the cooled material obtained in step (3) and add it to 100 parts by weight of toluene. Use an ultrasonic oscillator with a frequency of 20KHz to oscillate for 20min at a temperature of 30℃, so that the material is evenly dispersed in the dissolving and dispersing agent to obtain hydrate conversion inhibitor A4.

[0090] 13.08 g (1.5% of the total mass of the liquid phase) of hydrate conversion inhibitor A4 was added to the oil-water system (the oil phase in the oil-water system accounted for 77% of the total mass of the liquid phase) to conduct an evaluation experiment on the effect of the hydrate inhibitor. The hydrate conversion rate and average conversion rate during the growth process were calculated. The results are shown in Table 3.

[0091] Example 5

[0092] (1) 100 parts of Chunfeng slag (properties shown in Table 2) heated to a fluid state at 130℃ were added to a reactor at 125℃. 6 parts of polyethylene anhydride, 0.2 parts of diisocyanate peroxide and 0.1 parts of propylbenzene-azobisisobutyronitrile were added in sequence. The mixture was heated to 145℃ at a rate of 1℃ / min under stirring at 300r / min and then reacted under a N2 atmosphere. The pressure in the reactor was maintained at 0.8MPa and the reaction time was 6h.

[0093] (2) The material obtained in step (1) and 3 parts of polyethyleneimine (molecular weight of 8000, decomposition temperature of 275℃, flash point of 258℃, the content of primary amine of 30%, secondary amine of 30%, and tertiary amine of 40%) were mixed and added to the solvent deasphalting device. Solvent deasphalting was carried out at 3.2 MPa with propane as solvent. The volume ratio of solvent to slag was 7:1. After solvent deasphalting, deasphalted oil and pretreated slag oil were obtained. The yield of deasphalted oil was 40.2%, the softening point of pretreated slag oil was 87.1℃, and the carbon residue value was 1.43 wt%.

[0094] (3) Heat 20 parts by weight of the pretreated residue oil obtained in step (2) to 130°C until it reaches a molten state and transfer it into an oxidation reactor. Add 5 parts by weight of an alkane compound (by mass fraction, n-eicosane accounts for 10%, n-tetracosane for 30%, n-octacosane for 40%, and n-triane for 20%, and the alkane compound is stirred and heated at 80°C for 40 minutes before being added, with a stirring rate of 300 r / min). Adjust the temperature inside the reactor to 250°C, and introduce oxygen-enriched air (oxygen volume content of 25%) under stirring at 100 r / min to carry out the oxidation reaction. The gas flow rate during the oxidation process is 0.1 m³ / min. 3 / kg / h, oxidation time is 5h.

[0095] (4) Take the cooled material obtained in step (3) and add it to 100 parts by weight of toluene. Use an ultrasonic oscillator with a frequency of 20KHz to oscillate for 20min at a temperature of 30℃, so that the material is evenly dispersed in the dissolving and dispersing agent to obtain hydrate conversion inhibitor A5.

[0096] 13.08 g (1.5% of the total mass of the liquid phase) of hydrate conversion inhibitor A5 was added to the oil-water system (the oil phase in the oil-water system accounted for 77% of the total mass of the liquid phase) to conduct an evaluation experiment on the effect of the hydrate inhibitor. The hydrate conversion rate and average conversion rate during the growth process were calculated. The results are shown in Table 3.

[0097] Comparative Example 1

[0098] (1) 100 parts of Chunfeng slag (properties shown in Table 2) heated to a fluid state at 130℃ were added to a reactor at 125℃. 4 parts of polyethylene anhydride, 0.2 parts of dicumyl peroxide, and 0.1 parts of propylbenzene azobisisobutyronitrile were added in sequence. The mixture was heated to 145℃ at a rate of 1℃ / min under stirring at 300r / min. The reaction was carried out under N2 atmosphere, with the pressure in the reactor maintained at 0.8MPa and the reaction time being 6h.

[0099] (2) The material obtained in step (1) is directly added to the solvent deasphalting device. Solvent deasphalting is carried out at 3.2 MPa using propane as solvent. The volume ratio of solvent to slag is 7:1. After solvent deasphalting, deasphalted oil and pretreated slag oil are obtained. The yield of deasphalted oil is 40.2%, the softening point of pretreated slag oil is 87.1℃, and the carbon residue value is 1.43wt%.

[0100] (3) Heat 20 parts by weight of the pretreated residue oil obtained in step (2) to 130°C until it reaches a molten state and transfer it into an oxidation reactor. Add 5 parts by weight of an alkane compound (by mass fraction, n-eicosane accounts for 15%, n-tetracosane for 30%, n-octacosane for 40%, and n-triane for 15%, and the alkane compound is stirred and heated at 80°C for 40 minutes before being added, with a stirring rate of 300 r / min). Adjust the temperature inside the reactor to 250°C, and introduce oxygen-enriched air (oxygen volume content of 25%) under stirring at 100 r / min to carry out the oxidation reaction. The gas flow rate during the oxidation process is 0.1 m³ / min. 3 / kg / h, oxidation time is 5h.

[0101] (4) Take the cooled material obtained in step (3) and add it to 100 parts by weight of toluene. Use an ultrasonic oscillator with a frequency of 20KHz to oscillate for 20min at a temperature of 30℃, so that the material is evenly dispersed in the dissolving and dispersing agent to obtain hydrate conversion inhibitor B1.

[0102] 13.08 g (1.5% of the total mass of the liquid phase) of hydrate conversion inhibitor B1 was added to the oil-water system (same as in Example 1) to conduct an evaluation experiment on the effect of the hydrate inhibitor. The hydrate conversion rate and average conversion rate during the growth process were calculated. The results are shown in Table 3.

[0103] Comparative Example 2

[0104] Compared with Example 4, the difference is that no residue oil modifier and reaction initiator are added during the preparation process, and the hydrate conversion inhibitor B2 is finally obtained and evaluated (evaluation methods and conditions are the same as in Example 4).

[0105] Comparative Example 3

[0106] Compared with Example 4, the difference is that step (4) is omitted in the preparation process. Finally, the hydrate conversion inhibitor B3 was obtained and evaluated (evaluation methods and conditions are the same as in Example 4).

[0107] Comparative Example 4

[0108] Compared with Example 4, the difference is that no hydrate conversion inhibitors were added during the evaluation experiment (the evaluation method and conditions are the same as in Example 4).

[0109] Table 1. Oil properties of the oil-water emulsions used in the examples and comparative examples.

[0110]

[0111]

[0112] Table 2 Properties of the slag-reducing agent used in the examples and comparative examples.

[0113] Saturated fraction / wt% 34.30 Aromatic components / wt% 31.72 Gel / wt% 30.31 Asphalt / wt% 3.67 25℃ penetration / 0.1mm 63 <![CDATA[Density at 25°C / g·cm -3 > 0.98 Penetration Index (PI) -1.02 Ductility at 25℃ / cm >150 Softening point / °C 49.7 Flash point / °C 262 Dynamic viscosity (60℃) / Pa.s 485

[0114] Table 3. Experimental Results of Examples and Comparative Examples

[0115]

[0116]

[0117] 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 hydrate conversion inhibitor characterized in that: The hydrate conversion inhibitor is prepared from the following raw materials by weight parts: Pretreated residual oil: 5-35 parts; Alkane complexing agent: 0.2-6 parts; Dissolution dispersant: 100 parts; The pretreated residual oil is deoiled pitch obtained from pretreated vacuum residual oil as raw material, and the pretreated vacuum residual oil is prepared from the following raw materials by weight parts: Vacuum residual oil: 100 parts; Residual oil modifier: 2-8 parts; Reaction initiator: 0.1-0.8 parts; Active agent: 0.3-9 parts; The vacuum residue properties include: flash point of 260-268℃, saturated fraction of 28.2%-38.6% by mass fraction, aromatic fraction of 25.2%-36.5% by mass fraction, gum of 26.3%-36.6% by mass fraction, and asphaltene of 1.3%-5.1% by mass fraction; softening point of 49.1-50.6℃, dynamic viscosity at 60℃ of 468-493Pa·s, and density at 25℃ of 0.96-0.99g / cm 3 ​ The residual oil modifier is one or more of maleic anhydride, polyethylene anhydride, polyazelaic anhydride, polyglutaric anhydride, tung oil anhydride, polyisobutylene succinic anhydride or hydrolyzed polymaleic anhydride; The active agent is polyethylene imine with a molecular weight of 1000-10000, a decomposition temperature of 270-310℃, a flash point of 250-260℃, and, in terms of mass fraction, a primary amine content of 20-35%, a secondary amine content of 20-35%, and a tertiary amine content of 30-60%; The alkane complexing agent includes, in terms of mass fraction, n-eicosane 3-18%, n-tetracosane 20-40%, n-octacosane 30-50%, and n-dodecane 8-20%. The hydrate conversion inhibitor is prepared by the following method, comprising: (1) adding heated vacuum residual oil to a reaction kettle, adding residual oil modifier and reaction initiator, heating to reaction temperature under stirring, and continuously stirring under the action of protective gas to carry out reaction; (2) adding the material obtained in step (1) and active agent to a solvent deasphalting device to carry out solvent deasphalting, obtaining deasphalted oil and deoiled pitch, i.e. pretreated residual oil; (3) heating the pretreated residual oil obtained in step (2) to a flow state and moving it into an oxidation reaction kettle, adding alkane complexing agent, heating to reaction temperature, and carrying out oxidation reaction under stirring by introducing oxidizing gas; (4) adding the material obtained in step (3) to a dissolution dispersant to obtain hydrate conversion inhibitor.

2. The hydrate conversion inhibitor of claim 1, wherein: The hydrate conversion inhibitor is prepared from the following raw materials by weight parts: Pretreated residual oil: 10-30 parts; Alkane complexing agent: 0.5-5 parts; Dissolution dispersant: 100 parts.

3. The hydrate conversion inhibitor according to claim 1 or 2, characterized in that: The pretreated residual oil is prepared from the following raw materials by weight parts: Vacuum residual oil: 100 parts; Residual oil modifier: 2-6 parts; Reaction initiator: 0.2-0.6 parts; Active agent: 1-5 parts.

4. The hydrate conversion inhibitor of claim 1, wherein: The vacuum residual oil has a gum content of 28.3-33.0% in terms of mass fraction.

5. The hydrate conversion inhibitor of claim 1, wherein: The reaction initiator is one or more of azobisdiisopropyl cyanide, azobisdiisobutyl cyanide, dicumyl peroxide or cumene hydroperoxide.

6. The hydrate conversion inhibitor of claim 1, wherein: The dissolution dispersant is one or more of toluene, benzene, o-xylene, m-xylene, p-xylene, carbon disulfide and carbon tetrachloride.

7. The preparation method of the hydrate conversion inhibitor according to any one of claims 1-6, comprising the following steps: (1) the vacuum residue heated to a flowable state is added to a reactor, and a residue modifier and a reaction initiator are added, and heated to a reaction temperature under stirring, and the reaction is carried out under continuous stirring under the protection of a protective gas; (2) the material obtained in step (1) and an active agent are added to a solvent deasphalting device, and solvent deasphalting is carried out, and deasphalted oil and deoiled pitch, i.e. pretreated residue, are obtained; (3) the pretreated residue obtained in step (2) is heated to a flowable state and moved to an oxidation reactor, an alkane complexing agent is added, and heated to a reaction temperature, and an oxidative gas is introduced under stirring to carry out an oxidation reaction; (4) the material obtained in step (3) is added to a dissolving dispersing agent to obtain a hydrate conversion inhibitor.

8. The method of claim 7, wherein: In step (1), the reaction temperature is 145-185℃, and the reaction time is 2-8h.

9. The method of claim 8, wherein: In step (1), the reaction temperature is 150-160℃; the heating to the reaction temperature is carried out by programmed heating to the reaction temperature at a heating rate of 1-3℃ / min; and the reaction time is 3-5h.

10. The method of claim 7, wherein: In step (1), the protective gas is at least one of an inert gas or N2; and the amount of the protective gas is such that the pressure in the reactor is maintained at 0.2-0.8MPa.

11. The method of claim 10, wherein: The amount of the protective gas is such that the pressure in the reactor is maintained at 0.4-0.8MPa.

12. The method of claim 7, wherein: In step (2), a solvent is added when solvent deasphalting is carried out, and the solvent is one or more of propane and butane, and the volume ratio of the solvent to the vacuum residue is 6-9:

1.

13. The method of claim 7, wherein: In step (2), the yield of deasphalted oil in the solvent deasphalting is 30-65wt%; and the softening point of the pretreated residue is 85-95℃, and the carbon residue value is 0.5-25wt%.

14. The method of claim 7, wherein: In step (3), the reaction temperature is 180-350℃, and the oxidation reaction time is 3-6h, and the stirring speed during the oxidation is 100-250r / min.

15. The method of claim 14, wherein: In step (3), the reaction temperature is 240-280℃.

16. The method of claim 7, wherein: In step (3), the alkane complexing agent is heated and stirred to mix uniformly before being added, the heating temperature is 60-80℃, the heating time is 30-60min, and the stirring speed is 200-500r / min.

17. The method of claim 7, wherein: In step (4), the material obtained in step (3) is added to a dissolving dispersing agent after being cooled, and ultrasonic oscillation is carried out, the ultrasonic oscillation time is 20-40min, the ultrasonic frequency is 20-40KHz, and the ultrasonic oscillation temperature is 30-60℃.

18. Use of the hydrate conversion inhibitor of any one of claims 1-6 or prepared according to the method of any one of claims 7-17 in an oil-water system.

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