Oil-based hydrate nucleation inhibitor as well as preparation method and application thereof

Abstract

The invention discloses an oil-based hydrate nucleation inhibitor as well as a preparation method and application thereof. The preparation method of the inhibitor comprises the following steps: (1) heating furfural extract oil to a molten state, filling the furfural extract oil into a reaction kettle, introducing oxidizing gas, and carrying out oxidation heat treatment while stirring; (2) stopping the input of the oxidizing gas, replacing the oxidizing gas in the reaction kettle with shielding gas, and performing closed heat treatment on the material obtained in the step (1) under the shielding gas to obtain an oil-based inhibitor component; and (3) cooling the oil-based inhibitor component obtained in the step (2), placing the cooled oil-based inhibitor component in a solvent, and mixing the cooled oil-based inhibitor component with a light oil product to obtain the oil-based hydrate nucleation inhibitor. The oil-based hydrate nucleation inhibitor prepared by the method can obviously prolong the hydrate induction period and inhibit hydrate nucleation.

Description

Technical Field

[0001] The invention relates to the field of hydrate inhibitors, and in particular to an oil-based hydrate nucleation inhibitor and a preparation method and application thereof. Background Art

[0002] During the offshore oil production process, the wellhead produced fluid containing crude oil, natural gas and water needs to be transported to onshore processing equipment through submarine pipelines. The low temperature environment of the pipeline and the high pressure state inside the pipeline are very likely to cause the formation of gas hydrates. The formation of hydrates in the pipeline will increase the fluid viscosity and increase the pipeline pressure drop. In severe cases, it will block the pipeline and stop the pipeline, causing huge economic losses.

[0003] When the environment of a multiphase system meets the conditions for hydrate formation, hydrates will remain in a metastable state for a certain period of time and will not form until after a period of induction period. The induction period of hydrates is often defined as the difference between the time point when hydrates are formed and the time point when the system enters a three-phase equilibrium state. Once hydrates begin to appear, they will grow rapidly in a short period of time, which can easily lead to safety accidents. In order to prolong the hydrate formation time and increase the hydrate formation induction period, hydrate nucleation inhibitors have been widely used. In recent years, with the rapid development of the South China Sea oilfield and offshore oil and gas production, the demand for hydrate nucleation inhibitors has increased. Traditional thermodynamic inhibitors are mainly methanol and ethylene glycol, but they need to be added in large quantities when used, and the mass fraction is generally 30% to 50% of the liquid phase, which greatly affects the quality of crude oil and pollutes the environment.

[0004] CN116083065A discloses a low-dose natural gas hydrate inhibitor and a preparation method thereof, wherein a hydrate inhibitor is obtained by compounding organic solvents such as poly(N-vinyl caprolactam), dimethyl sulfoxide, formate and gemini quaternary ammonium salt, which can inhibit hydrate nucleation and prolong the time of hydrate appearance. However, this method requires the addition of multiple chemical reagents, which is complicated to operate and has high cost. At the same time, the addition of a large amount of poly(N-vinyl caprolactam) and quaternary ammonium salt in actual use will increase the viscosity of the liquid phase in the pipeline and the interfacial strength of the emulsion, thereby increasing the pipeline operation and crude oil processing pressure.

[0005] CN114276793A discloses an environmentally friendly natural gas hydrate inhibitor and its application, wherein the method mainly uses nisin as the main component of the hydrate inhibitor, and obtains the hydrate inhibitor by compounding with chitosan oligosaccharide and alcohol hydrate thermodynamic inhibitor. However, the hydrate inhibitor is mainly suitable for pure water system, and the amount of reagent added is large. When applied to crude oil pipelines, the addition of non-crude oil components such as nisin increases the difficulty of subsequent separation of crude oil.

[0006] In order to reduce the dosage of inhibitors, low-dose hydrate nucleation inhibitors are gaining more and more attention. Low-dose inhibitors can prolong the hydrate induction period and delay the hydrate formation time. In recent years, oil-based hydrate inhibitors have attracted extensive attention from researchers due to their low dosage, significant effect and little impact on crude oil quality. However, the current production efficiency of oil-based hydrate nucleation inhibitors is low, the proportion of effective ingredients in the raw materials is small, and the inhibitory effect on hydrate nucleation can be further enhanced. Summary of the invention

[0007] The purpose of the present invention is to provide an oil-based hydrate nucleation inhibitor and its preparation method and application. The oil-based hydrate inhibitor prepared by the present invention can significantly prolong the hydrate induction period and inhibit hydrate nucleation. The method of the present invention is simple, the raw materials are easily available, the price is low, the amount of chemical reagents used is small, the amount used when applied is low, and the effect is significant.

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

[0009] (1) heating the furfural extracted oil to a molten state, loading it into a reaction kettle, introducing an oxidizing gas and performing an oxidative heat treatment under stirring;

[0010] (2) stopping the input of the oxidizing gas, replacing the oxidizing gas in the reactor with a protective gas, and subjecting the material obtained in step (1) to a closed heat treatment under the protective gas to obtain an oil-based inhibitor component;

[0011] (3) After cooling, the oil-based inhibitor component obtained in step (2) is placed in a solvent and mixed with a light oil product to obtain an oil-based hydrate nucleation inhibitor.

[0012] Furthermore, in step (1), the properties of the furfural extracted oil include: a density of 0.92 to 1.04 g / cm at 20°C; 3 , residual carbon is 0.3wt%~8.6wt%, total aromatics mass content is 40.1wt%~65.0wt%, sulfur content is 0.1wt%~0.6wt%, kinematic viscosity at 100℃ is 8.3~30.8mm 2 / s, the total mass content of gum and asphalt is 5.8wt% ~ 30.5wt%, and the flash point is 210 ~ 258℃.

[0013] Furthermore, in step (1), the temperature for heating to a molten state is 130 to 180° C., preferably 130 to 150° C., and the heating time is preferably 1 to 3 hours.

[0014] Furthermore, in step (1), the furfural extracted oil heated to a molten state is preferably first distilled to remove light components.

[0015] Furthermore, the distillation may be atmospheric distillation and / or reduced pressure distillation, and the distillation temperature is 150 to 480°C, preferably 200 to 450°C.

[0016] Furthermore, the content of the distilled light components is 10 wt% to 60 wt% of the mass of the initial raw material, preferably 10 wt% to 30 wt% of the mass of the initial raw material.

[0017] Furthermore, in step (1), the reactor is a high-pressure reactor.

[0018] Furthermore, in step (1), the temperature of the oxidation heat treatment is 300-400°C, preferably 350-380°C, the heating is programmed, the heating rate is 0.5-2.5°C / min, the oxidation heat treatment time is 0.2-2h, preferably 0.5-1.5h. The stirring speed is 100-400rpm, preferably 100-300rpm.

[0019] Furthermore, in step (1), the oxidizing gas is oxygen-enriched air (oxygen volume content is 25v% to 60v%), and the gas flow rate is 0.05 to 0.5m 3 / kg / h.

[0020] Furthermore, in step (1), the oxidizing gas maintains the pressure in the reactor at 0.2-0.7 MPa.

[0021] Furthermore, in step (2), the protective gas is at least one of nitrogen and an inert gas; the gas flow rate of the protective gas is 0.05 to 0.5 m / s. 3 / kg / h.

[0022] Furthermore, in step (2), the temperature of the closed heat treatment is 360-450° C., preferably 380-420° C., the pressure of the closed heat treatment is 0.5-4.5 MPa, preferably 2-4 MPa, and the time of the closed heat treatment is 2-8 hours, preferably 3-6 hours. Stirring is continued during the closed heat treatment, and the stirring speed is 100-300 rpm.

[0023] Furthermore, in step (3), the cooling is cooling to room temperature. The solvent is one or more of toluene, xylene and quinoline. The light oil product is one or more of diesel, mineral oil and condensate oil. The mass ratio of the solvent to the light oil product is 1:0.5-2, and the mass ratio of the oil-based inhibitor component to the solvent is 2-5:95-98.

[0024] Furthermore, in step (3), the oil-based inhibitor obtained in step (2) is cooled, placed in a solvent, and subjected to ultrasonic vibration to fully disperse it. The ultrasonic frequency of the ultrasonic vibration process is 20KHz to 60KHz, the ultrasonic vibration time is 20 to 40 minutes, and the temperature of the ultrasonic vibration is preferably 20 to 60°C.

[0025] Furthermore, in step (3), the mixing with the light oil product is preferably carried out under ultrasonic oscillation, with an ultrasonic frequency of 20KHz to 60KHz, an ultrasonic oscillation time of 20 to 40 minutes, and an ultrasonic oscillation temperature of 20 to 60°C.

[0026] The present invention provides an oil-based hydrate nucleation inhibitor prepared by the above method.

[0027] The present invention provides an application of the oil-based hydrate nucleation inhibitor prepared by the above method in the field of multiphase pipeline transportation.

[0028] When the oil-based hydrate nucleation inhibitor is in use, the volume of the water phase is less than 60% of the total volume of the oil and water phases, preferably 10% to 50%. The added mass of the oil-based hydrate nucleation inhibitor accounts for 1% to 5% of the mass of the oil phase. The operating temperature range is -10 to 50°C, and the operating pressure range is 0.1 to 30 MPa.

[0029] Compared with the prior art, the oil-based hydrate nucleation inhibitor of the present invention has the following advantages:

[0030] (1) The present invention uses furfural extracted oil as raw material, which is itself a low-value by-product in the petroleum refining process. Its application as a raw material for oil-based hydrate nucleation inhibitor broadens its application, increases its added value, and has economic benefits.

[0031] (2) The oil-based hydrate nucleation inhibitor of the present invention has the advantages of simple preparation method, readily available raw materials, low price, small amount of chemical reagents, small impact on crude oil quality, and small amount used during application. The oil-based hydrate nucleation inhibitor prepared by the present invention has significant effect and can significantly prolong the hydrate formation time, which is of great significance to pipeline safety.

[0032] (3) In the preparation method of the present invention, the oxidation heat treatment and the closed heat treatment can cause the raw materials to undergo condensation polymerization, oxidation and other reactions in a high temperature and high pressure environment, thereby increasing the content of the effective components of the hydrate inhibitor in the raw materials and enhancing the effect of the inhibitor. DETAILED DESCRIPTION

[0033] 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.

[0034] In a specific embodiment, the effect of hydrate inhibition of nucleation is evaluated by a high-pressure stirred tank experiment. When hydrates are generated, the system temperature rises rapidly due to the heat release of hydrate formation, and the pressure decreases significantly due to gas consumption. The evaluation experimental steps are as follows:

[0035] (1) After cleaning the autoclave with petroleum ether, pour 2 L of oil-water emulsion into it, with the volume of the water phase being 400 mL. After adding an oil-based hydrate inhibitor, seal the autoclave.

[0036] (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.

[0037] (3) After replacing the gas, the reaction gas is continuously introduced into the stirred tank to increase the pressure in the tank to 2.3 MPa, so as to create a high-pressure environment to generate carbon dioxide hydrate.

[0038] (4) The temperature of the fluid in the stirred tank was gradually reduced from 15°C to 2.6°C by adjusting the temperature-controlled water bath, and this temperature was maintained until hydrates were formed. The time point of hydrate formation was identified by the mutation point of the temperature and pressure curves, and the hydrate nucleation induction period was calculated based on the time point of hydrate formation and the time point of three-phase equilibrium.

[0039] (5) When the system temperature does not change within 30 min, the hydrate formation experiment is terminated and the high-pressure stirred tank is cleaned with petroleum ether.

[0040] During the cooling process of the system, the temperature of the fluid in the stirred tank will gradually drop to the equilibrium temperature, and then continue to drop to 2.6°C and maintain constant. When the system temperature is lower than the equilibrium temperature, there is a possibility of hydrate formation, so hydrates may appear in both the cooling process and the constant temperature process in the experiment.

[0041] Example 1

[0042] (1) 200 g of furfural extracted oil (properties shown in Table 2) was heated in an oven at 140°C for 2 h to reach a molten state;

[0043] (2) heating the molten furfural extracted oil in step (1) to 397° C. by using an atmospheric distillation apparatus to perform atmospheric distillation, distilling 10 wt % of the initial raw material mass, and removing low-boiling light components in the furfural extracted oil;

[0044] (3) The material distilled in step (2) was loaded into a high-pressure reactor, and oxygen-enriched air (oxygen volume content of 45%) was introduced into the material under stirring at 100 r / min to perform oxidative heat treatment. The gas flow rate during the heat treatment was 0.1 m 3 / kg / h, the pressure in the reactor was maintained at 0.6MPa, the oxidation temperature was 370℃, the heating rate was 2.0℃ / min, and the oxidation time was 0.5h.

[0045] (4) Stop adding oxygen-enriched air and increase the pressure to 0.1 m 3 Nitrogen is introduced into the reactor at a gas flow rate of / kg / h to replace the residual oxygen-rich air in the reactor. After the replacement is completed, the exhaust valve is closed and nitrogen is continuously introduced to increase the pressure to 2.0 MPa. The temperature is raised to 380°C and the stirring speed is maintained at 100 rpm / min. The material obtained in step (3) is sealed and heat treated for 3 h.

[0046] (5) After the closed heat treatment process is completed, the exhaust valve is opened to discharge the gas in the kettle, and the materials in the kettle are cooled to room temperature. 20 g of the material is taken into 40 g of o-xylene and oscillated at a temperature of 40° C. and a frequency of 40 kHz for 30 min. Then, 40 g of diesel is added thereto and ultrasonic oscillation is continued in this environment for 20 min to obtain an oil-based hydrate nucleation inhibitor.

[0047] 26.8 g (2% of the mass of the oil phase) of the hydrate inhibitor prepared in Example 1 was added to the oil-water emulsion (the volume of the water phase was 20% of the total volume of the oil-water phase), and a hydrate formation experiment was carried out using a high-pressure stirred tank (the final stable temperature was 2.6° C. and the operating pressure was 2.3 MPa). The hydrate formation results are shown in Table 3.

[0048] Example 2

[0049] (1) 200 g of furfural extracted oil (properties shown in Table 2) was heated in an oven at 140°C for 2 h to reach a molten state;

[0050] (2) heating the molten furfural extracted oil in step (1) to 397° C. by using an atmospheric distillation apparatus to perform atmospheric distillation, distilling 10 wt % of the initial raw material mass, and removing low-boiling light components in the furfural extracted oil;

[0051] (3) The material distilled in step (2) was loaded into a high-pressure reactor, and oxygen-enriched air (oxygen volume content of 45%) was introduced into the material under stirring at 200 r / min to perform oxidative heat treatment. The gas flow rate during the heat treatment was 0.1 m 3 / kg / h, the pressure in the reactor was maintained at 0.6MPa, the oxidation temperature was 380℃, the heating rate was 2.0℃ / min, and the oxidation time was 1h.

[0052] (4) Stop adding oxygen-enriched air and increase the pressure to 0.1 m 3Nitrogen is introduced into the reactor at a gas flow rate of / kg / h to replace the residual oxygen-rich air in the reactor. After the replacement is completed, the exhaust valve is closed and nitrogen is continuously introduced to increase the pressure to 4.0 MPa. The temperature is raised to 420°C and the stirring speed is maintained at 100 rpm / min. The material obtained in step (3) is sealed and heat treated for 5 h.

[0053] (5) After the closed heat treatment process is completed, the exhaust valve is opened to discharge the gas in the kettle, and the materials in the kettle are cooled to room temperature. 20 g of the material is taken into 40 g of o-xylene and oscillated at a temperature of 40° C. and a frequency of 40 kHz for 30 min. Then, 40 g of diesel is added thereto and ultrasonic oscillation is continued in this environment for 30 min to obtain an oil-based hydrate nucleation inhibitor.

[0054] 26.8 g (2% of the mass of the oil phase) of the hydrate inhibitor prepared in Example 2 was added to the oil-water emulsion (the volume of the water phase was 20% of the total volume of the oil-water phase), and a hydrate formation experiment was carried out using a high-pressure stirred tank (the final stable temperature was 2.6° C., and the operating pressure was 2.3 MPa). The hydrate formation results are shown in Table 3.

[0055] Example 3

[0056] (1) 200 g of furfural extracted oil (properties shown in Table 2) was heated in an oven at 140°C for 2 h to reach a molten state;

[0057] (2) heating the molten furfural extracted oil in step (1) to 434° C. by using an atmospheric distillation apparatus to perform atmospheric distillation, distilling 20 wt % of the initial raw material mass, and removing low-boiling light components in the furfural extracted oil;

[0058] (3) The material distilled in step (2) was loaded into a high-pressure reactor, and oxygen-enriched air (oxygen volume content of 45%) was introduced into the material under stirring at 100 r / min to perform oxidative heat treatment. The gas flow rate during the heat treatment was 0.1 m 3 / kg / h, the pressure in the reactor was maintained at 0.8MPa, the oxidation temperature was 370℃, the heating rate was 2.0℃ / min, and the oxidation time was 0.8h.

[0059] (4) Stop adding oxygen-enriched air and increase the pressure to 0.1 m 3 Nitrogen is introduced into the reactor at a gas flow rate of / kg / h to replace the residual oxygen-rich air in the reactor. After the replacement is completed, the exhaust valve is closed and nitrogen is continuously introduced to increase the pressure to 3.0 MPa. The temperature is raised to 380°C and the stirring speed is maintained at 100 rpm / min. The material obtained in step (3) is sealed and heat treated for 3 h.

[0060] (5) After the closed heat treatment process is completed, the exhaust valve is opened to discharge the gas in the kettle, and the materials in the kettle are cooled to room temperature. 20 g of the material is taken into 40 g of o-xylene and oscillated at a temperature of 40° C. and a frequency of 40 kHz for 30 min. Then, 40 g of diesel is added thereto and ultrasonic oscillation is continued in this environment for 20 min to obtain an oil-based hydrate nucleation inhibitor.

[0061] 26.8 g (2% of the mass of the oil phase) of the hydrate inhibitor prepared in Example 3 was added to the oil-water emulsion (the volume of the water phase was 20% of the total volume of the oil-water phase), and a hydrate formation experiment was carried out using a high-pressure stirred tank (the final stable temperature was 2.6° C., and the operating pressure was 2.3 MPa). The hydrate formation results are shown in Table 3.

[0062] Example 4

[0063] (1) 200 g of furfural extracted oil (properties shown in Table 2) was heated in an oven at 140°C for 2 h to reach a molten state;

[0064] (2) heating the molten furfural extracted oil in step (1) to 434° C. by using an atmospheric distillation apparatus to perform atmospheric distillation, distilling 20 wt % of the initial raw material mass, and removing low-boiling light components in the furfural extracted oil;

[0065] (3) The material distilled in step (2) was loaded into a high-pressure reactor, and oxygen-enriched air (oxygen volume content of 45%) was introduced into the material under stirring at 100 r / min to perform oxidative heat treatment. The gas flow rate during the heat treatment was 0.1 m 3 / kg / h, the pressure in the reactor was maintained at 0.6MPa, the oxidation temperature was 370℃, the heating rate was 2.0℃ / min, and the oxidation time was 1h.

[0066] (4) Stop adding oxygen-enriched air and increase the pressure to 0.1 m 3 Nitrogen is introduced into the reactor at a gas flow rate of / kg / h to replace the residual oxygen-rich air in the reactor. After the replacement is completed, the exhaust valve is closed and nitrogen is continuously introduced to increase the pressure to 2.0 MPa. The temperature is raised to 380°C and the stirring speed is maintained at 100 rpm / min. The material obtained in step (3) is sealed and heat treated for 4 h.

[0067] (5) After the closed heat treatment process is completed, the exhaust valve is opened to discharge the gas in the kettle, and the materials in the kettle are cooled to room temperature. 20 g of the material is taken into 40 g of o-xylene and oscillated at a temperature of 40° C. and a frequency of 40 kHz for 30 min. Then, 40 g of diesel is added thereto and ultrasonic oscillation is continued in this environment for 20 min to obtain an oil-based hydrate nucleation inhibitor.

[0068] 20.1 g (1.5% of the mass of the oil phase) of the hydrate inhibitor prepared in Example 4 was added to the oil-water emulsion (the volume of the water phase was 20% of the total volume of the oil-water phase), and a hydrate formation experiment was carried out using a high-pressure stirred tank (the final stable temperature was 2.6° C., and the operating pressure was 2.3 MPa). The hydrate formation results are shown in Table 3.

[0069] Example 5

[0070] (1) 200 g of furfural extracted oil (properties shown in Table 2) was heated in an oven at 140°C for 2 h to reach a molten state;

[0071] (2) The molten furfural extracted oil is directly loaded into a high-pressure reactor, and oxygen-enriched air (oxygen volume content of 45%) is introduced under stirring at 100 r / min to perform oxidative heat treatment on the material. The gas flow rate during the heat treatment process is 0.1 m 3 / kg / h, the pressure in the reactor was maintained at 0.6MPa, the oxidation temperature was 370℃, the heating rate was 2.0℃ / min, and the oxidation time was 0.8h.

[0072] (3) Stop adding oxygen-enriched air and increase the pressure to 0.1 m 3 Nitrogen is introduced into the reactor at a gas flow rate of / kg / h to replace the residual oxygen-rich air in the reactor. After the replacement is completed, the exhaust valve is closed and nitrogen is continuously introduced to increase the pressure to 3.0 MPa. The temperature is raised to 400°C and the stirring speed is maintained at 100 rpm / min. The material obtained in step (3) is sealed and heat treated for 4 hours.

[0073] (4) After the closed heat treatment process is completed, the exhaust valve is opened to discharge the gas in the kettle, and the materials in the kettle are cooled to room temperature. 20 g of the material is taken into 40 g of o-xylene and oscillated at a temperature of 40°C and a frequency of 40 kHz for 30 min. Then, 40 g of diesel is added thereto and ultrasonic oscillation is continued in this environment for 20 min to obtain an oil-based hydrate nucleation inhibitor.

[0074] 26.8 g (2% of the mass of the oil phase) of the hydrate inhibitor prepared in Example 5 was added to the oil-water emulsion (the volume of the water phase was 20% of the total volume of the oil-water phase), and a hydrate formation experiment was carried out using a high-pressure stirred tank (the final stable temperature was 2.6° C., and the operating pressure was 2.3 MPa). The hydrate formation results are shown in Table 3.

[0075] Comparative Example 1

[0076] (1) 200 g of furfural extracted oil (properties shown in Table 2) was heated in an oven at 140°C for 2 h to reach a molten state;

[0077] (2) heating the molten furfural extracted oil in step (1) to 397° C. by using an atmospheric distillation apparatus to perform atmospheric distillation, distilling 10 wt % of the initial raw material mass, and removing low-boiling light components in the furfural extracted oil;

[0078] (3) Without undergoing oxidative heat treatment and closed heat treatment, 20 g of the material distilled in step (2) was directly taken into 40 g of o-xylene, and oscillated at a temperature of 40° C. and a frequency of 40 kHz for 30 min. Then, 40 g of diesel was added thereto and ultrasonic oscillation was continued in this environment for 20 min to obtain an oil-based hydrate nucleation inhibitor.

[0079] 26.8 g (2% of the mass of the oil phase) of the hydrate inhibitor prepared in Comparative Example 1 was added to the oil-water emulsion (the volume of the water phase was 20% of the total volume of the oil-water phase), and a hydrate formation experiment was carried out using a high-pressure stirred tank. The hydrate formation results are shown in Table 3.

[0080] Comparative Example 2

[0081] Compared with Example 1, the difference is that the oil-based inhibitor component obtained in the component dissolution stage is not compounded with the reagent and the light oil product, but is directly used after cooling in a room temperature environment (i.e., there is no step (5)). The hydrate formation results are shown in Table 3.

[0082] Comparative Example 3

[0083] Compared with Example 1, the difference is that 20g of furfural extracted oil is directly taken into 40g of o-xylene, and oscillated at a temperature of 40°C and a frequency of 40KHz for 30min, and then 40g of diesel is added thereto and ultrasonic oscillation is continued for 20min in this environment to obtain an oil-based hydrate inhibitor. 26.8g (the mass is 2% of the mass of the oil phase) of hydrate inhibitor is added to the oil-water emulsion, and a hydrate formation experiment is carried out using a high-pressure stirred tank. The hydrate formation results are shown in Table 3.

[0084] Comparative Example 4

[0085] No oil-based hydrate nucleation inhibitor was added to the oil-water emulsion, and the hydrate formation experiment was carried out using a high-pressure stirred tank. The hydrate formation results are shown in Table 3.

[0086] Table 1 Oil properties of the oil-water emulsions used in the examples and comparative examples

[0087] <![CDATA[Density (20 °C) / g / cm 3 > 0.83 Condensation point / ℃ -5 Flash point / ℃ 76.5 Ash / wt% 0.003 PAHs / wt% 4.5 <![CDATA[Kinematic viscosity (20 °C) / mm 2 / s]]> 4.1 Sulfur content mg / kg 2.8 Carbon residue value / wt% 0.04

[0088] Table 2 Properties of furfural extracted oil used in Examples and Comparative Examples

[0089]

[0090]

[0091] Table 3 Hydrate formation experimental results in Examples and Comparative Examples

[0092] project Generation temperature / ℃ Generation time / min Induction period / min Example 1 2.6 117 62 Example 2 2.6 151 96 Example 3 2.6 140 85 Example 4 2.7 109 54 Example 5 3.0 101 46 Comparative Example 1 3.2 82 27 Comparative Example 2 3.9 86 31 Comparative Example 3 3.0 68 13 Comparative Example 4 4.3 62 7

[0093] From the results in Table 3, it can be seen that the preparation method of the oil-based hydrate nucleation inhibitor provided by the present invention can further prolong the hydrate formation time and increase the hydrate formation induction period after the furfural extracted oil is subjected to heating and melting, light component distillation, oxidative heat treatment, closed heat treatment and component dissolution, and significantly enhance the effect of the oil-based hydrate inhibitor, which is of great significance for the management of hydrates and the safety of multiphase pipelines.

Claims

1. A method for preparing an oil-based hydrate nucleation inhibitor, characterized in that: The following steps are involved: (1) heating the furfural extracted oil to a molten state, loading it into a reaction kettle, introducing an oxidizing gas and performing an oxidative heat treatment under stirring; (2) stopping the input of the oxidizing gas, replacing the oxidizing gas in the reactor with a protective gas, and subjecting the material obtained in step (1) to a closed heat treatment under the protective gas to obtain an oil-based inhibitor component; (3) After cooling, the oil-based inhibitor component obtained in step (2) is placed in a solvent and mixed with a light oil product to obtain an oil-based hydrate nucleation inhibitor.

2. The preparation method according to claim 1, characterized in that: In step (1), the properties of the furfural extracted oil include: a density of 0.92 to 1.04 g / cm at 20°C; 3 , residual carbon is 0.3wt%~8.6wt%, total aromatics mass content is 40.1wt%~65.0wt%, sulfur content is 0.1wt%~0.6wt%, kinematic viscosity at 100℃ is 8.3~30.8mm 2 / s, the total mass content of gum and asphalt is 5.8wt% ~ 30.5wt%, and the flash point is 210 ~ 258℃.

3. The preparation method according to claim 1, characterized in that: In step (1), the furfural extracted oil heated to a molten state is first distilled to remove light components, and then loaded into a reactor for reaction.

4. The preparation method according to claim 3, characterized in that: The content of the distilled light components is 10 wt% to 60 wt% of the mass of the initial raw material, preferably 10 wt% to 30 wt% of the mass of the initial raw material.

5. The preparation method according to claim 1, characterized in that: In step (1), the temperature of the oxidation heat treatment is 300-400°C, preferably 350-380°C, the heating is programmed, the heating rate is 0.5-2.5°C / min, the oxidation heat treatment time is 0.2-2h, preferably 0.5-1.5h; the stirring speed is 100-400rpm, preferably 100-300rpm.

6. The preparation method according to claim 1, characterized in that: The oxidizing gas is oxygen-enriched air, the oxygen volume content is 25v% to 60v%, and the gas flow rate is 0.05 to 0.5m 3 / kg / h; the oxidizing gas maintains the pressure in the reactor at 0.2-0.7MPa.

7. The preparation method according to claim 1, characterized in that: In step (2), the protective gas is at least one of nitrogen and an inert gas; the gas flow rate of the protective gas is 0.05 to 0.5 m / s. 3 / kg / h.

8. The preparation method according to claim 1, characterized in that: In step (2), the temperature of the closed heat treatment is 360-450°C, preferably 380-420°C, the pressure of the closed heat treatment is 0.5-4.5MPa, preferably 2-4MPa, and the time of the closed heat treatment is 2-8h, preferably 3-6h; stirring is continued during the closed heat treatment, and the stirring speed is 100-300rpm.

9. The preparation method according to claim 1, characterized in that: In step (3), the solvent is one or more of toluene, xylene and quinoline; the light oil product is one or more of diesel, mineral oil and condensate oil; the mass ratio of the solvent to the light oil product is 1:0.5-2, and the mass ratio of the oil-based inhibitor component to the solvent is 2-5:95-98.

10. The preparation method according to claim 1, characterized in that: In step (3), the mixing with the light oil product is carried out under ultrasonic oscillation, the ultrasonic frequency is 20KHz to 60KHz, the ultrasonic oscillation time is 20 to 40 minutes, and the ultrasonic oscillation temperature is 20 to 60°C.

11. An oil-based hydrate nucleation inhibitor prepared according to the preparation method according to any one of claims 1 to 10.

12. Use of the oil-based hydrate nucleation inhibitor prepared by the preparation method according to any one of claims 1 to 10 in the field of multiphase pipeline transportation.

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