Hydrate conversion inhibitor as well as preparation method and application thereof

Abstract

The invention discloses a hydrate conversion inhibitor as well as a preparation method and application thereof. The hydrate conversion inhibitor is prepared from the following raw materials in parts by weight: 5 to 35 parts of pretreated residual oil, 0.2 to 6 parts of alkane compounding agent and 100 parts of dissolving dispersant, wherein the pretreated residual oil is deoiled asphalt obtained by taking pretreated vacuum residual oil as a raw material, and the pretreated vacuum residual oil is prepared from the following raw materials in parts by weight: 100 parts of vacuum residual oil, 2-8 parts of a residual oil modifier, 0.1-0.8 part of a reaction inducer and 0.3-9 parts of an active agent. The inhibitor can significantly reduce the generation amount of hydrates, and has the advantages of excellent performance, low cost and small dosage.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and natural gas production, and in particular to a hydrate conversion inhibitor and a preparation method and application thereof. Background Art

[0002] During the production of oil and gas, pipeline flow safety issues are faced. Among them, the most concerned issues for pipeline transportation safety are wax deposition, hydrate formation, and asphaltene precipitation. Oil-gas-water multiphase pipelines in low-temperature environments are at risk of hydrate formation under high pressure and disturbance conditions. In multiphase pipelines, ice-like hydrate particles formed by components such as oil well produced water and methane in oil and gas will aggregate and deposit, thereby reducing the inner diameter of the pipeline and increasing the energy consumption of pipeline operation. In severe cases, the pipeline will be blocked, causing safety accidents.

[0003] In the oil-gas-water multiphase pipeline, due to the presence of natural emulsifiers and frequent over-pump shear, the water phase is mainly dispersed in the oil phase in the form of droplets. After nucleation, the hydrate will grow rapidly, and the water droplets will gradually transform into hydrate particles. During the growth process, the small molecular gas in the oil and gas will gradually diffuse from the oil phase to the surface of the hydrate particles, and then further pass through the hydrate shell into the interior of the hydrate particles, so that the free water inside the hydrate particles gradually forms a crystal structure. In this process, the hydrate shell gradually thickens. At the same time, the free water inside the hydrate particles will move from the inside of the hydrate particles to the surface of the hydrate particles under the action of capillary force, and contact the small molecular gas on the surface of the particles to form a crystal structure. Under the dual action of gas diffusion and water molecule movement, hydrates will grow rapidly.

[0004] During the growth of hydrates, gas molecules will be bound in solid hydrate particles, so that the gas concentration in the constant volume gas phase space gradually decreases, and the pressure of the system gradually decreases. The higher the hydrate conversion efficiency in the system with the same water content, the more hydrates are generated. When a large number of hydrate particles appear in the pipeline, the fluid viscosity will increase, the pipeline pressure drop will increase, and even the pipeline will be blocked, causing safety accidents. The higher the hydrate growth rate and the more hydrates are generated, the greater the risk of pipeline blockage. In order to ensure pipeline safety, the main methods currently used are to add inhibitors or risk control. The use of additives such as ethylene glycol can prolong the time of hydrate appearance, but the effect is uncertain, the dosage is large and pollutes the environment. Risk control can be achieved by adding additives to disperse the generated hydrate particles in the form of slurry and flow in the pipe, but the amount of hydrate generated should not be too much. Hydrate conversion inhibitors can reduce the amount of hydrates generated and reduce the risk of hydrate blocking. At the same time, conversion inhibitors can also reduce the growth rate of hydrates, making hydrates generate more slowly and prolonging the safe operation time of hydrate-containing systems.

[0005] CN1635006A discloses the use of a copolymer of vinyl pyrrolidone and vinyl acetate as a hydrate growth inhibitor. The method uses the copolymer of vinyl pyrrolidone and vinyl acetate as a hydrate growth inhibitor, and can inhibit the growth of hydrates in oil and natural gas pipelines by compounding in different proportions under the action of an initiator. However, the method requires a large amount of vinyl pyrrolidone and vinyl acetate, which is expensive and affects the quality of crude oil.

[0006] CN109135702A discloses a hydrate inhibitor and its application. The method mainly uses glucosinolate extracted from rapeseed meal as the main component to prepare the hydrate inhibitor, and the hydroxyl groups in the glucosinolate compound form hydrogen bonds with water molecules to inhibit hydrate conversion and reduce the conversion rate during hydrate growth. However, the inhibitor is mainly used in pure water systems, and its effect in oil-water systems has not been evaluated. In addition, a large amount of the inhibitor is added to the oil-in-water emulsion system of the actual pipeline, which increases the difficulty of subsequent oil-water separation.

[0007] In summary, hydrate conversion inhibitors play an important role in the prevention and treatment of hydrates. Currently used nucleation inhibitors such as polyvinyl pyrrolidone have a certain inhibitory effect on the transformation process of hydrates, but they are expensive, have poor effects and affect the quality of crude oil. Therefore, it is necessary to develop hydrate conversion inhibitors with significant effects and low costs. Summary of the invention

[0008] In view of the shortcomings of the prior art, the present invention provides a novel hydrate conversion inhibitor and its preparation method and application. The inhibitor can significantly reduce the amount of hydrate formation and has the advantages of excellent performance, low cost and small dosage.

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

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

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

[0012] Dissolving dispersant: 100 parts;

[0013] The pretreated residual oil is deoiled asphalt obtained by taking pretreated vacuum residual oil as raw material, and the pretreated vacuum residual oil comprises the following raw materials by weight:

[0014] Vacuum residue: 100 parts;

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

[0016] Reaction inducing agent: 0.1 to 0.8 parts, preferably 0.2 to 0.6 parts;

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

[0018] Furthermore, the pretreated residual oil is deoiled asphalt obtained by solvent deasphalting using pretreated vacuum residual oil as raw material.

[0019] Furthermore, the properties of the vacuum residue oil include: a flash point of 260-268°C, by mass fraction, saturated components account for 28.2%-38.6%, aromatic components account for 25.2%-36.5%, and gum accounts for 26.3%-36.6%, preferably gum accounts for 28.3%-33.0%, and asphaltene accounts for 1.3%-5.1%; softening point is 49.1-50.6°C, 60°C dynamic viscosity is 468-493 Pa·s, 25°C density is 0.96-0.99 g / cm 3 .

[0020] Furthermore, the vacuum residue oil may be spring-wind vacuum residue oil or other vacuum residue oil satisfying the above properties.

[0021] Furthermore, the residual oil modifier is one or more of maleic anhydride, polyoxalic anhydride, polyazelaic anhydride, polyglutaric anhydride, tung oil anhydride, polyisobutylene succinic anhydride or hydrolyzed polymaleic anhydride.

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

[0023] Furthermore, the active agent is polyethyleneimine, with a molecular weight of 1000-10000, a decomposition temperature of 270°C-310°C, a flash point of 250°C-260°C, and, by mass fraction, primary amines account for 20%-35% of the amine groups of the polyethyleneimine, secondary amines account for 20%-35%, and tertiary amines account for 30%-60%.

[0024] Furthermore, the alkane compounding agent includes, by mass fraction, 3% to 18% of n-eicosane, 20% to 40% of n-tetracosane, 30% to 50% of n-octacosane, and 8% to 20% of n-dotriacontane.

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

[0027] (1) adding vacuum residue oil heated to a fluid state into a reactor, adding a residue oil modifier and a reaction inducer, heating to a reaction temperature under stirring, and continuously stirring under the action of a protective gas to react;

[0028] (2) adding the material obtained in step (1) and the active agent to a solvent deasphalting device to perform solvent deasphalting to obtain deasphalted oil and deoiled asphalt, i.e., pretreated residual oil;

[0029] (3) heating the pretreated residual oil obtained in step (2) to a fluid state and transferring it into an oxidation reactor, adding an alkane compounding agent, heating it to a reaction temperature, and introducing an oxidizing gas under stirring to carry out an oxidation reaction;

[0030] (4) The material obtained in step (3) is added to a dissolving dispersant to obtain a hydrate conversion inhibitor.

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

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

[0033] In step (1), the reaction temperature is 145-185°C, preferably 150-160°C; the heating to the reaction temperature is preferably carried out by programmed heating to the reaction temperature, and the heating rate is 1-3°C / min; the reaction time is 2-8h, preferably 3-5h.

[0034] In step (1), the residual oil modifier and the reaction initiator are preferably added into the reactor in sequence.

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

[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 in 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 during solvent deasphalting, wherein the solvent is one or more of propane and butane, and the volume ratio of the solvent to the vacuum residue is 6 to 9:1.

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

[0039] In step (3), the pretreated residual oil is heated to a fluid temperature of generally 120 to 150°C.

[0040] In step (3), the oxidizing gas is oxygen-enriched air (oxygen volume content is 25v% to 60v%), and the gas flow rate is 0.05 to 0.3m 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 to mix evenly before being added, the heating temperature is 60-80° C., the heating time is 30-60 min, and the stirring rate is 200-500 r / min.

[0043] In step (4), the material obtained in step (3) is cooled and added to a dissolving dispersant, and ultrasonically shaken. The ultrasonic shaking time is 20 to 40 minutes, the ultrasonic frequency is 20 to 40 kHz, and the ultrasonic shaking temperature is 30 to 60°C.

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

[0045] Furthermore, when the hydrate conversion inhibitor is used, its addition amount is 0.1% to 3.5%, preferably 0.8% to 3.0% of the total mass of the liquid phase in the oil-water system, 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 effect evaluation method of the hydrate conversion inhibitor of the present 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 the average conversion rate during the growth process.

[0048] The hydrate conversion rate can be used to calculate the percentage of water phase in the system converted to hydrate, thereby characterizing the amount of hydrate generated. The higher the hydrate conversion rate in the same system, the more hydrate is generated. The specific calculation method is:

[0049]

[0050] Among them, P1, Z1, T1 and n w1 are the pressure, compressibility factor, temperature and molar amount of gas dissolved in the liquid phase of the system before hydrate formation; P2, Z2, T2 and n w2are the pressure, compressibility factor, temperature and molar amount of gas dissolved in the liquid phase of the system after the hydrate formation is completed; V is the gas phase space volume of the constant volume system when the hydrate is formed; R is the thermodynamic constant; H is the hydrate number; M is the molar mass of water; ρ is the density of water; V w It is the total volume of the aqueous phase when no hydrate is formed in the system.

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

[0052]

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

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

[0055] (1) The present invention uses vacuum residue as raw material, which is not suitable for producing high-grade road asphalt, such as spring-wind residue with high colloid content and poor comprehensive performance. The present invention adopts vacuum residue, residue modifier, reaction inducer and activator to obtain pretreated residue through a series of reactions, which enhances its potential effect of application in hydrate conversion inhibitor, expands the application scene of vacuum residue and improves its added value.

[0056] (2) The active agent introduced in the present invention has a highly absorbent amine group that can react with the carboxyl group in asphalt to form a hydrogen bond. When applied to the solvent deasphalting process, the deoiled asphalt produced by the solvent deasphalting operation can have stronger interfacial activity.

[0057] (3) The addition of the alkane compounding agent of the present invention has a step-by-step increase in carbon number, which can produce a synergistic adsorption effect with the active components in the residual oil in the oil-water system, thereby improving the coating of the conversion inhibitor on the surface of the water droplet. At the same time, a crystallization process can occur in a low-temperature environment, which can not only inhibit the hydrate conversion, but also disperse the 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 and can reduce the amount of hydrate formation and conversion rate. The resulting inhibitor has a low dosage and good effect. It does not require the use of a large amount of chemical reagents, which reduces costs and has little impact on crude oil quality. DETAILED DESCRIPTION

[0059] 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.

[0060] The effect of the hydrate conversion inhibitor is evaluated by a reactor experiment. After the hydrate nucleates in the reactor, it begins to grow. The hydrate conversion rate and average conversion rate can be calculated by the temperature, pressure and solubility of the reaction process to characterize the effect of the hydrate inhibitor. The specific steps of the evaluation experiment in the embodiment of the present invention and the comparative example are as follows:

[0061] (1) After cleaning the autoclave with petroleum ether, pour 1000 mL of oil-water emulsion into it, with the volume of the water phase being 200 mL. After adding an oil-based hydrate inhibitor, seal the autoclave.

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

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

[0064] (4) The temperature of the fluid in the stirred tank is gradually reduced from 10°C to 2.5°C by adjusting the temperature-controlled water bath, and this temperature is maintained until hydrates are formed. When hydrates begin to form, the temperature rises rapidly and the pressure decreases significantly. As the hydrates are converted, the pressure continues to decrease, and the temperature begins to decrease after reaching a peak value.

[0065] (5) When the system temperature and pressure do not change within 10 min, 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 hydrate formation is calculated, and the hydrate conversion rate and average conversion rate are calculated based on the measured parameters such as temperature and pressure.

[0067] Example 1

[0068] (1) 100 parts of Chunfengjian residue (properties shown in Table 2) heated to a fluid state at 130°C were added to a reactor at a temperature of 125°C, and 2 parts of maleic anhydride and 0.3 parts of diisopropylbenzene peroxide were added in sequence. The mixture was heated to 145°C at a rate of 1°C / min under stirring at 300 r / min, and then reacted in a N2 atmosphere. The pressure in the reactor was maintained at 0.5 MPa, and the reaction time was 3 h.

[0069] (2) The material obtained in step (1) and 1 part of polyethyleneimine (molecular weight of 6000, decomposition temperature of 280° C., flash point of 255° C., and amine groups having a primary amine content of 20%, a secondary amine content of 25%, and a tertiary amine content of 55%) were mixed and added to a solvent deasphalting device, and solvent deasphalting was performed at 3.2 MPa using propane as solvent, and the volume ratio of the solvent to the spring wind residue was 7:1. After the solvent deasphalting operation, deasphalted oil and pretreated residual oil were obtained, wherein the yield of the deasphalted oil was 40.2wt%, the softening point of the pretreated residual oil was 87.1° C., and the residual carbon value was 1.43wt%.

[0070] (3) 5 parts by weight of the pretreated residual oil obtained in step (2) are heated to 130° C. to reach a molten state and transferred into an oxidation reactor, 0.5 parts by weight of an alkane compounding agent is added (in terms of mass fraction, n-eicosane accounts for 15%, n-tetracosane accounts for 30%, n-octacosane accounts for 40%, and n-triacontane accounts for 15%. The alkane compounding agent is stirred and heated at 70° C. for 40 min before being added, and the stirring rate is 300 r / min). The temperature in the reactor is adjusted to 250° C., and oxygen-enriched air (oxygen volume content is 25v%) is introduced under stirring at 100 r / min to carry out oxidation reaction. The gas flow rate during the oxidation process is 0.1 m 3 / kg / h, oxidation time is 3h.

[0071] (4) The cooled material obtained in step (3) was added to 100 parts by weight of toluene, and ultrasonically oscillated in an ultrasonic oscillator at a frequency of 20 kHz for 20 min at a temperature of 30° C. to uniformly disperse the material in the dissolving dispersant 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 mass of the oil phase in the oil-water system was 77% of the total mass of the liquid phase), and an experiment to evaluate the effect of the hydrate inhibitor was carried out. 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 condensate residue (properties shown in Table 2) heated to a fluid state at 130°C were added to a reactor at a temperature of 125°C, and 4 parts of polyoxalic anhydride and 0.3 parts of diisopropylbenzene peroxide were added in sequence. The mixture was heated to 145°C at a rate of 1°C / min under stirring at 300 r / min, and then reacted in a N2 atmosphere. The pressure in the reactor was maintained at 0.5 MPa, and the reaction time was 4 h.

[0075] (2) The material obtained in step (1) and 1 part of polyethyleneimine (molecular weight of 6000, decomposition temperature of 280° C., flash point of 255° C., and amine groups having a primary amine content of 20%, a secondary amine content of 25%, and a tertiary amine content of 55%) were mixed and added to a solvent deasphalting device, and solvent deasphalting was performed at 3.2 MPa using propane as solvent, and the volume ratio of the solvent to the spring wind residue was 7:1. After the solvent deasphalting operation, deasphalted oil and pretreated residual oil were obtained, wherein the yield of the deasphalted oil was 40.2wt%, the softening point of the pretreated residual oil was 87.1° C., and the residual carbon value was 1.43wt%.

[0076] (3) 10 parts by weight of the pretreated residual oil obtained in step (2) are heated to 130° C. to reach a molten state and transferred into an oxidation reactor, 2 parts by weight of an alkane compounding agent (in terms of mass fraction, n-eicosane accounts for 15%, n-tetracosane accounts for 30%, n-octacosane accounts for 40%, and n-triacontane accounts for 15%. The alkane compounding agent is stirred and heated at 70° C. for 40 min before being added, and the stirring rate is 300 r / min). The temperature in the reactor is adjusted to 250° C., and oxygen-enriched air (oxygen volume content is 25v%) is introduced under stirring at 100 r / min to carry out oxidation reaction. The gas flow rate during the oxidation process is 0.1 m 3 / kg / h, oxidation time is 3h.

[0077] (4) The cooled material obtained in step (3) was added to 100 parts by weight of toluene, and ultrasonically oscillated in an ultrasonic oscillator at a frequency of 20 kHz for 20 min at a temperature of 30° C. to uniformly disperse the material in the dissolving dispersant to obtain a 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 mass of the oil phase in the oil-water system was 77% of the total mass of the liquid phase), and an experiment to evaluate the effect of the hydrate inhibitor was carried out. 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 Chunfengjian residue (properties shown in Table 2) heated to a fluid state at 130°C were added to a reactor at a temperature of 125°C, and 6 parts of maleic anhydride and 0.6 parts of diisopropylbenzene peroxide were added in sequence. The mixture was heated to 145°C at a rate of 1°C / min under stirring at 300 r / min, and then reacted in a N2 atmosphere. The pressure in the reactor was maintained at 0.5 MPa, and the reaction time was 6 h.

[0081] (2) The material obtained in step (1) and 1 part of polyethyleneimine (molecular weight of 6000, decomposition temperature of 280° C., flash point of 255° C., and amine groups having a primary amine content of 20%, a secondary amine content of 25%, and a tertiary amine content of 55%) were mixed and added to a solvent deasphalting device, and solvent deasphalting was performed at 3.5 MPa using propane as solvent, and the volume ratio of the solvent to the spring wind residue was 7:1. After the solvent deasphalting operation, deasphalted oil and pretreated residual oil were obtained, wherein the yield of the deasphalted oil was 43.8%, the softening point of the pretreated residual oil was 88.5° C., and the residual carbon value was 1.32 wt%.

[0082] (3) 30 parts by weight of the pretreated residual oil obtained in step (2) are heated to 130° C. to reach a molten state and transferred into an oxidation reactor, 4 parts by weight of an alkane compounding agent (in terms of mass fraction, n-eicosane accounts for 15%, n-tetracosane accounts for 30%, n-octacosane accounts for 40%, and n-triacontane accounts for 15%. The alkane compounding agent is stirred and heated at 70° C. for 40 min before being added, and the stirring rate is 300 r / min). The temperature in the reactor is adjusted to 250° C., and oxygen-enriched air (oxygen volume content is 25%) is introduced under stirring at 100 r / min for oxidation reaction. The gas flow rate during the oxidation process is 0.1 m 3 / kg / h, oxidation time is 4h.

[0083] (4) The cooled material obtained in step (3) was added to 100 parts by weight of toluene, and ultrasonically oscillated in an ultrasonic oscillator at a frequency of 20 kHz for 20 min at a temperature of 30° C. to uniformly disperse the material in the dissolving dispersant to obtain a 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 mass of the oil phase in the oil-water system was 77% of the total mass of the liquid phase), and an experiment to evaluate the effect of the hydrate inhibitor was carried out. 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 Chunfengjian residue (properties shown in Table 2) heated to a fluid state at 130°C were added to a reactor at a temperature of 125°C, and 4 parts of polyethylene glycol anhydride, 0.2 parts of diisopropylbenzene peroxide and 0.1 parts of propylbenzene azobisisobutyronitrile were added in sequence. The mixture was heated to 145°C at a rate of 1°C / min under stirring at 300 r / min, and then reacted in a N2 atmosphere. The pressure in the reactor was maintained at 0.8 MPa and the reaction time was 6 h.

[0087] (2) The material obtained in step (1) and 1 part of polyethyleneimine (molecular weight of 6000, decomposition temperature of 280° C., flash point of 255° C., and amine groups having a primary amine content of 20%, a secondary amine content of 25%, and a tertiary amine content of 55%) were mixed and added to a solvent deasphalting device, and solvent deasphalting was performed at 3.2 MPa using propane as solvent, and the volume ratio of the solvent to the spring wind reduction residue was 7:1. After the solvent deasphalting operation, deasphalted oil and pretreated residual oil were obtained, wherein the yield of the deasphalted oil was 40.2%, the softening point of the pretreated residual oil was 87.1° C., and the residual carbon value was 1.43wt%.

[0088] (3) 20 parts by weight of the pretreated residual oil obtained in step (2) are heated to 130° C. to reach a molten state and transferred into an oxidation reactor, 5 parts by weight of an alkane compounding agent (by mass fraction, n-eicosane accounts for 15%, n-tetracosane accounts for 30%, n-octacosane accounts for 40%, and n-triacontane accounts for 15%. The alkane compounding agent is stirred and heated at 80° C. for 40 min before being added, and the stirring rate is 300 r / min), the temperature in the reactor is adjusted to 250° C., and oxygen-enriched air (oxygen volume content is 25%) is introduced under stirring at 100 r / min for oxidation reaction. The gas flow rate during the oxidation process is 0.1 m 3 / kg / h, oxidation time is 5h.

[0089] (4) The cooled material obtained in step (3) was added to 100 parts by weight of toluene, and ultrasonically oscillated in an ultrasonic oscillator at a frequency of 20 kHz for 20 min at a temperature of 30° C. to uniformly disperse the material in the dissolving dispersant to obtain a 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 mass of the oil phase in the oil-water system was 77% of the total mass of the liquid phase), and an experiment to evaluate the effect of the hydrate inhibitor was carried out. 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 Chunfengjian residue (properties shown in Table 2) heated to a fluid state at 130°C were added to a reactor at a temperature of 125°C, and 6 parts of polyoxalic anhydride, 0.2 parts of diisopropyl peroxide and 0.1 parts of propylbenzene azobisisobutyronitrile were added in sequence. The mixture was heated to 145°C at a rate of 1°C / min under stirring at 300 r / min, and then reacted in a N2 atmosphere. The pressure in the reactor was maintained at 0.8 MPa and the reaction time was 6 h.

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

[0094] (3) 20 parts by weight of the pretreated residual oil obtained in step (2) are heated to 130° C. to reach a molten state and transferred into an oxidation reactor, 5 parts by weight of an alkane compounding agent (by mass fraction, n-eicosane accounts for 10%, n-tetracosane accounts for 30%, n-octacosane accounts for 40%, and n-triacontane accounts for 20%. The alkane compounding agent is stirred and heated at 80° C. for 40 min before being added, and the stirring rate is 300 r / min), the temperature in the reactor is adjusted to 250° C., and oxygen-enriched air (oxygen volume content is 25%) is introduced under stirring at 100 r / min for oxidation reaction. The gas flow rate during the oxidation process is 0.1 m 3 / kg / h, oxidation time is 5h.

[0095] (4) The cooled material obtained in step (3) was added to 100 parts by weight of toluene, and ultrasonically oscillated in an ultrasonic oscillator at a frequency of 20 kHz for 20 min at a temperature of 30° C. to uniformly disperse the material in the dissolving dispersant to obtain a 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 mass of the oil phase in the oil-water system was 77% of the total mass of the liquid phase), and an experiment to evaluate the effect of the hydrate inhibitor was carried out. 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 Chunfengjian residue (properties shown in Table 2) heated to a fluid state at 130°C were added to a reactor at a temperature of 125°C, and 4 parts of polyoxalic anhydride, 0.2 parts of diisopropylbenzene peroxide and 0.1 parts of propylbenzene azobisisobutyronitrile were added in sequence. The mixture was heated to 145°C at a rate of 1°C / min under stirring at 300 r / min, and then reacted in a N2 atmosphere. The pressure in the reactor was maintained at 0.8 MPa and the reaction time was 6 h.

[0099] (2) The material obtained in step (1) is directly added to a solvent deasphalting device, and solvent deasphalting is performed at 3.2 MPa using propane as solvent, and the volume ratio of the solvent to the spring wind reduction residue is 7:1. After the solvent deasphalting operation, deasphalted oil and pretreated residue oil are obtained, wherein the yield of the deasphalted oil is 40.2%, the softening point of the pretreated residue oil is 87.1°C, and the residual carbon value is 1.43wt%.

[0100] (3) 20 parts by weight of the pretreated residual oil obtained in step (2) are heated to 130° C. to reach a molten state and transferred into an oxidation reactor, 5 parts by weight of an alkane compounding agent (by mass fraction, n-eicosane accounts for 15%, n-tetracosane accounts for 30%, n-octacosane accounts for 40%, and n-triacontane accounts for 15%. The alkane compounding agent is stirred and heated at 80° C. for 40 min before being added, and the stirring rate is 300 r / min). The temperature in the reactor is adjusted to 250° C., and oxygen-enriched air (oxygen volume content is 25%) is introduced under stirring at 100 r / min for oxidation reaction. The gas flow rate during the oxidation process is 0.1 m 3 / kg / h, oxidation time is 5h.

[0101] (4) The cooled material obtained in step (3) was added to 100 parts by weight of toluene, and ultrasonically oscillated in an ultrasonic oscillator at a frequency of 20 kHz for 20 min at a temperature of 30° C. to uniformly disperse the material in the dissolving dispersant to obtain a 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), and an experiment to evaluate the effect of the hydrate inhibitor was carried out. 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 residual oil modifier and reaction inducer are added during the preparation process, and finally the hydrate conversion inhibitor B2 is obtained and an evaluation experiment is carried out (the evaluation method and conditions are the same as those of 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 is obtained and an evaluation experiment is carried out (the evaluation method and conditions are the same as those in Example 4).

[0107] Comparative Example 4

[0108] Compared with Example 4, the difference is that no hydrate conversion inhibitor was added during the evaluation experiment (the evaluation method and conditions were the same as those of 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 Spring Breeze Residue Used in Examples and Comparative Examples

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

[0114] Table 3 Experimental results of examples and comparative examples

[0115]

[0116]

[0117] 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 hydrate conversion inhibitor, characterized in that: The hydrate conversion inhibitor comprises the following raw materials in parts by weight: Pretreated residual oil: 5 to 35 parts, preferably 10 to 30 parts; Alkane compounding agent: 0.2-6 parts, preferably 0.5-5 parts; Dissolving dispersant: 100 parts; The pretreated residual oil is deoiled asphalt obtained by taking pretreated vacuum residual oil as raw material, and the pretreated vacuum residual oil comprises the following raw materials by weight: Vacuum residue: 100 parts; Residue oil modifier: 2 to 8 parts, preferably 2 to 6 parts; Reaction inducing agent: 0.1 to 0.8 parts, preferably 0.2 to 0.6 parts; Surfactant: 0.3 to 9 parts, preferably 1 to 5 parts.

2. The hydrate conversion inhibitor according to claim 1, characterized in that: The properties of the vacuum residue oil include: a flash point of 260-268°C; by mass fraction, saturated components account for 28.2%-38.6%, aromatic components account for 25.2%-36.5%, and gum accounts for 26.3%-36.6%, preferably gum accounts for 28.3%-33.0%, and asphaltene accounts for 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 / cm at 25°C. 3 .

3. The hydrate conversion inhibitor according to claim 1, characterized in that: The residual oil modifier is one or more of maleic anhydride, polyoxalic anhydride, polyazelaic anhydride, polyglutaric anhydride, tung oil anhydride, polyisobutylene succinic anhydride or hydrolyzed polymaleic anhydride.

4. The hydrate conversion inhibitor according to claim 1, characterized in that: The reaction inducing agent is one or more of azobisisoheptanitrile, azobisisobutyronitrile, diisopropylbenzene peroxide or isopropylbenzene hydroperoxide.

5. The hydrate conversion inhibitor according to claim 1, characterized in that: The active agent is polyethyleneimine, with a molecular weight of 1000-10000, a decomposition temperature of 270-310°C, a flash point of 250-260°C, and, by mass fraction, primary amines account for 20%-35% of the amine groups of the polyethyleneimine, secondary amines account for 20%-35%, and tertiary amines account for 30%-60%.

6. The hydrate conversion inhibitor according to claim 1, characterized in that: The alkane compounding agent comprises, by mass fraction, 3% to 18% of n-eicosane, 20% to 40% of n-tetracosane, 30% to 50% of n-octacosane, and 8% to 20% of n-dotriacontane.

7. The hydrate conversion inhibitor according to claim 1, characterized in that: The dissolving and dispersing agent is one or more of toluene, benzene, o-xylene, m-xylene, p-xylene, carbon disulfide and carbon tetrachloride.

8. The method for preparing the hydrate conversion inhibitor according to any one of claims 1 to 7, comprising the following steps: (1) adding vacuum residue oil heated to a fluid state into a reactor, adding a residue oil modifier and a reaction inducer, heating to a reaction temperature under stirring, and continuously stirring under the action of a protective gas to react; (2) adding the material obtained in step (1) and the active agent to a solvent deasphalting device to perform solvent deasphalting to obtain deasphalted oil and deoiled asphalt, i.e., pretreated residual oil; (3) heating the pretreated residual oil obtained in step (2) to a fluid state and transferring it into an oxidation reactor, adding an alkane compounding agent, heating it to a reaction temperature, and introducing an oxidizing gas under stirring to carry out an oxidation reaction; (4) The material obtained in step (3) is added to a dissolving dispersant to obtain a hydrate conversion inhibitor.

9. The method according to claim 8, characterized in that: In step (1), the reaction temperature is 145-185°C, preferably 150-160°C; the heating to the reaction temperature is preferably carried out by programmed heating to the reaction temperature, and the heating rate is 1-3°C / min; the reaction time is 2-8h, preferably 3-5h.

10. The method according to claim 8, characterized in that: 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 in the reactor is maintained at 0.2 to 0.8 MPa, preferably 0.4 to 0.8 MPa.

11. The method according to claim 8, characterized in that: In step (2), a solvent needs to be added during solvent deasphalting, wherein the solvent is one or more of propane and butane, and the volume ratio of the solvent to the vacuum residue is 6 to 9:

1.

12. The method according to claim 8, characterized in that: In step (2), the yield of deasphalted oil in the solvent deasphalting is 30-65wt%; the softening point of the pretreated residual oil is 85-95°C, and the residual carbon value is 0.5-25wt%.

13. The method according to claim 8, characterized in that: 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.

14. The method according to claim 8, characterized in that: In step (3), the alkane compounding agent is heated and stirred to mix evenly before being added, the heating temperature is 60-80° C., the heating time is 30-60 min, and the stirring rate is 200-500 r / min.

15. The method according to claim 8, characterized in that: In step (4), the material obtained in step (3) is cooled and added to a dissolving dispersant, and ultrasonically shaken. The ultrasonic shaking time is 20 to 40 minutes, the ultrasonic frequency is 20 to 40 kHz, and the ultrasonic shaking temperature is 30 to 60°C.

16. Use of the hydrate conversion inhibitor according to any one of claims 1 to 7 or the hydrate conversion inhibitor prepared by the method according to any one of claims 8 to 15 in an oil-water system.

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