Heavy oil hydrothermal cracking modification viscosity reducer and viscosity reduction method

Abstract

The invention relates to a heavy oil hydrothermal cracking modification viscosity reducer and a viscosity reduction method, and belongs to the technical field of heavy oil modification and viscosity reduction. The heavy oil hydrothermal cracking modification viscosity reducer comprises the following components in parts by weight: 0.2-0.4 part of a free radical initiator, 0.2-0.4 part of a catalyst and 9-12 parts of a hydrogen donor, wherein the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol which are mixed according to a mass ratio of 1: (2-3). The method comprises the following steps: mixing thickened oil with water, adding a catalyst, a hydrogen donor and a free radical initiator, carrying out a hydrothermal cracking reaction at 140-160 DEG C under an anaerobic condition, cooling to room temperature after the reaction is finished, and separating oil from water to obtain a modified oil sample. Through the synergistic effect of the free radical initiator, the catalyst and the specific hydrogen donor, the hydrothermal cracking reaction efficiency is improved under the low-temperature condition, and effective hydrothermal cracking modification and viscosity reduction of the thickened oil at the low temperature are achieved.

Description

Technical Field

[0001] This invention belongs to the field of heavy oil modification and viscosity reduction technology, and particularly relates to a heavy oil hydrothermal cracking modification and viscosity reduction agent and a viscosity reduction method. Background Technology

[0002] Heavy oil hydrothermal pyrolysis upgrading and viscosity reduction technology is a heavy oil thermal recovery method that has gradually emerged in the past forty years. Unlike traditional heavy oil thermal recovery technology, it adds a catalyst while injecting superheated steam into the oil well. The superheated steam provides energy and power, and under the action of the catalyst, the large molecules in the heavy oil are thermally pyrolyzed into smaller molecules, and the removal of heteroatoms is promoted, thereby improving the quality of heavy oil and reducing the pressure of subsequent processing.

[0003] Currently, hydrothermal cracking modification and viscosity reduction technologies can be mainly summarized as catalytic hydrothermal viscosity reduction and catalytic hydrogen-donating hydrothermal viscosity reduction processes. Among them, catalytic hydrogen-donating hydrothermal viscosity reduction technology mainly achieves a more efficient hydrothermal viscosity reduction and modification effect based on the cracking effect of the catalyst and the hydrogen-donating effect of the hydrogen donor. For example, patents CN102654047A and CN104533364A both disclose a method for hydrothermal viscosity reduction of heavy oil using hydrogen donors such as tetrahydronaphthalene and decahydronaphthalene and catalysts working together.

[0004] Due to the high activation energy of the initiation stage of the hydrothermal cracking reaction chain, conventional hydrothermal cracking requires a reaction temperature above 240℃ (see: Fan Zexia et al. Study on hydrothermal cracking for hydrogen donation to reduce viscosity of extra-heavy oil [J]. Journal of Fuel Chemistry, 2006, 1(03): 315-318; Al-Muntaser A, et al. Effect of decalin as hydrogen-donor for in-situ upgrading of heavy crude oil in presence of nickel-based catalyst. Fuel, 2021, 313(1): 122652; Chen Yanling et al. Study on chemical viscosity reduction mechanism of Kenxi heavy oil [J]. Earth Science, 1998, 1(06): 62-66; Zhao Fajun. Study on downhole viscosity reduction mechanism and application of heavy oil [D]. Daqing Petroleum Institute, 2008). However, reaching 240℃ in the reservoir requires a huge amount of energy, and the energy consumption increases by about 5%~10% for every 10℃ increase in temperature. Moreover, according to the characteristics of injected steam, the reservoir temperature decreases rapidly with the increase of the distance between the reservoir and the steam injection well. For example, the literature "Sun Lu et al. Temperature distribution during the steam injection stage of horizontal wells in low-permeability heavy oil reservoirs [J]. Fault-block Oil and Gas Field, 2016, 23(04): 509-513" reported that increasing the distance between the reservoir and the well axis by 10m can reduce the reservoir temperature from 250℃ to about 120℃, which seriously limits the effective range of hydrothermal pyrolysis. Therefore, improving energy efficiency and reducing reaction temperature have become the key to overcoming the technical bottleneck.

[0005] Existing studies have proposed using free radical initiators to improve the thermal reaction efficiency of petroleum. For example, the literature includes: “Shi Bin et al. Study on the effect of free radical initiators on heavy oil hydrocracking [J]. Journal of Fuel Chemistry, 2010, 38(4):422-427”, “Zhang Xurui. Study on the free radical reaction regulation of the thermal conversion process of heavy organic resources [D]. Beijing University of Chemical Technology, 2022”, “Shi Bin et al. Study on the use of free radical initiators for residue oil viscosity reduction cracking [J]. Journal of Fuel Chemistry, 2010, 38 (06):696-700”, “Zhu C, et al. Initiated pyrolysis of heavy oil in the presence of near-critical water. Fuel Processing Technology 2003, 111(2):111-117”, “Shubhangi T, et al. Metal-free efficient cross coupling of aromatic aldehydes with aryldiazonium tetrafluoroborates using DTBP as a radical initiator. Tetrahedron Letters”. References include "2015, 56:4211-4214". Free radical initiators, as highly reactive substances, can spontaneously decompose during reaction heating to generate free radicals. These free radicals can abstract hydrogen from heavy oil molecules, thereby initiating the entire cracking reaction and replacing the chain initiation process of traditional hydrothermal cracking. Theoretically, the activation energy of this process can be reduced to about one-tenth of that of the traditional reaction, thus improving the initiation efficiency in petroleum thermal reaction processes. However, in the aforementioned literature, the application temperatures of free radical initiators in petroleum thermal reaction systems (such as thermal cracking, viscosity-reducing cracking, etc.) are generally higher than 380℃, making them unsuitable for hydrothermal cracking systems. Currently, the lowest applicable temperature for the free radical initiator to effectively enhance hydrothermal cracking is still 250℃, as disclosed in the literature "Zhang Y, et al. The effect of free radical initiator in promoting aquathermolysis of heavy oil under mild conditions. Fuel 2024,375:132576". In the temperature range of 150℃ to 210℃ below this, the free radical initiator not only has no enhancing effect, but also makes the oil sample relatively viscous after the reaction, which cannot meet the requirements of low-temperature energy-saving development.The literature “Liu Yigang et al. Enhanced viscosity reduction behavior of heavy oil catalytic hydrothermal cracking by free radical initiators [J]. Science in China: Chemistry, 2018, 48(04): 451-458” also reported the application of free radical initiators in hydrothermal cracking. The optimal reaction temperature disclosed was 220℃ and the viscosity reduction rate reached 72.7%. At the same time, it was disclosed that the addition of free radical initiators at 150℃ could achieve a viscosity reduction rate of 69.7%, the asphaltene content decreased from the initial 5.6wt% to 4.8wt%, and the cracking rate was 14.29%. However, it is worth noting that under the same conditions at 150℃, the viscosity reduction rate without the addition of free radical initiators could also reach 61.4%, and the asphaltene content decreased from the initial 5.6wt% to 5.0wt%, with a cracking rate of 10.71%. This also means that the addition of free radical initiators at 150℃ does not significantly improve the reaction efficiency.

[0006] Therefore, how to achieve effective hydrothermal cracking and viscosity reduction of heavy oil under low-temperature conditions is a technical problem that urgently needs to be solved. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a heavy oil hydrothermal cracking modification and viscosity reduction agent and a viscosity reduction method. This heavy oil hydrothermal cracking modification and viscosity reduction agent improves the hydrothermal cracking reaction efficiency under low temperature conditions through the synergistic effect of free radical initiators, catalysts and specific hydrogen donors, thereby achieving effective heavy oil hydrothermal cracking modification and viscosity reduction at low temperatures.

[0008] This invention provides a heavy oil hydrothermal cracking modifier and viscosity reducer, comprising the following components in parts by weight: 0.2-0.4 parts of free radical initiator, 0.2-0.4 parts of catalyst, and 9-12 parts of hydrogen donor; wherein the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:(2-3).

[0009] In some embodiments, the free radical initiator is selected from any one or more of nickel dodecylbenzenesulfonate, iron dodecylbenzenesulfonate, and cobalt dodecylbenzenesulfonate.

[0010] In some of these embodiments, the catalyst is selected from one or more of di-tert-butyl peroxide, azobisisobutyronitrile, and potassium persulfate.

[0011] In some embodiments, the heavy oil hydrothermal cracking modifier and viscosity reducer comprises the following components in parts by weight: 0.4 parts di-tert-butyl peroxide, 0.4 parts nickel dodecylbenzenesulfonate, and 12 parts hydrogen donor; wherein the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3.

[0012] In some embodiments, the viscosity reduction rate of the heavy oil hydrothermal pyrolysis modifier is greater than 80% and the asphaltene pyrolysis rate is greater than 30% at 140℃~160℃.

[0013] This invention also provides a method for modifying and reducing viscosity of heavy oil through hydrothermal cracking, comprising the following steps: Thick oil is mixed with water to obtain oil-water mixture A; Add a catalyst and a hydrogen donor to oil-water mixture A and mix thoroughly to obtain oil-water mixture B; wherein the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:(2~3); Add a free radical initiator to oil-water mixture B and mix thoroughly to obtain oil-water mixture C; The oil-water mixture C was subjected to hydrothermal pyrolysis at 140℃~160℃ under anaerobic conditions. After the reaction was completed, the mixture was cooled to room temperature, and the oil and water were separated to obtain a modified oil sample.

[0014] In some embodiments, the amount of catalyst added is 0.2% to 0.4% of the heavy oil mass, the amount of hydrogen donor added is 9% to 12% of the heavy oil mass, and the amount of free radical initiator added is 0.2% to 0.4% of the heavy oil mass.

[0015] In some embodiments, the catalyst is selected from one or more of di-tert-butyl peroxide, azobisisobutyronitrile, and potassium persulfate, and the free radical initiator is selected from one or more of nickel dodecylbenzenesulfonate, ferric dodecylbenzenesulfonate, and cobalt dodecylbenzenesulfonate.

[0016] In some embodiments, the mass ratio of heavy oil to water in oil-water mixture A is (1~2):1.

[0017] In some embodiments, the reaction time for the hydrothermal pyrolysis reaction is 24h to 48h.

[0018] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1. The heavy oil hydrothermal cracking modifier and viscosity reducer provided by this invention constructs a ternary synergistic system of "free radical initiator-catalyst-hydrogen donor". It uses tetrahydronaphthalene and ethanol mixed in a specific ratio as hydrogen donors, which are combined with free radical initiators and catalysts in a specific ratio. Ethanol can improve the compatibility of hydrogen donors with heavy oil while providing hydrogen, and tetrahydronaphthalene has a high hydrogen donation capacity. The combination of the two can capture free radicals generated by cracking in time and inhibit the secondary polymerization of heavy components, thereby effectively improving the cracking efficiency of hydrothermal cracking reaction at low temperature and realizing the high-efficiency cracking and upgrading of heavy oil at low temperature. 2. The viscosity reducer for heavy oil hydrothermal cracking modification provided by this invention has a viscosity reduction rate of more than 80% at 140℃~160℃, which is equivalent to the viscosity reduction effect of traditional catalytic hydrogen-donating hydrothermal cracking viscosity reduction process at 240℃, but its energy consumption can be reduced by 50%~60%; 3. The heavy oil hydrothermal cracking modifier and viscosity reducer provided by the present invention has a bituminous cracking rate of more than 30% at 140℃~160℃, which is more than 50% higher than the traditional catalytic hydrogen-donating hydrothermal cracking viscosity reducer technology, and significantly reduces the difficulty of subsequent processing. 4. The heavy oil hydrothermal cracking modification and viscosity reduction method provided by the present invention achieves heavy oil hydrothermal cracking and viscosity reduction at 140℃~160℃ through the ternary synergy of free radical initiator, catalyst and hydrogen donor, with a viscosity reduction rate of more than 80% and a bituminous cracking rate of more than 30%. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention provides a heavy oil hydrothermal cracking modifier and viscosity reducer, comprising the following components in parts by weight: 0.2-0.4 parts of free radical initiator, 0.2-0.4 parts of catalyst, and 9-12 parts of hydrogen donor; wherein the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:(2-3).

[0021] The aforementioned heavy oil hydrothermal cracking modifier for improving viscosity constructs a ternary synergistic system of "free radical initiator-catalyst-hydrogen donor". It uses tetrahydronaphthalene and ethanol mixed in a specific ratio as hydrogen donors, which are combined with free radical initiators and catalysts in a specific ratio. Ethanol can improve the compatibility of hydrogen donors with heavy oil while providing hydrogen, and tetrahydronaphthalene has a high hydrogen donation capacity. The combination of the two can capture free radicals generated by cracking in time and inhibit the secondary polymerization of heavy components (such as asphaltene), thereby effectively improving the cracking efficiency of hydrothermal cracking reaction at low temperature and realizing the high-efficiency cracking and upgrading of heavy oil at low temperature. Meanwhile, the aforementioned viscosity reducer for heavy oil hydrothermal cracking has a viscosity reduction rate of over 80% at 140℃~160℃, which is equivalent to the viscosity reduction effect of the traditional catalytic hydrogen-donating hydrothermal cracking viscosity reduction process at 240℃ (see the literature "Wang J, et al. Quartz sand proppant loaded with Ni and Mo for in-situa quathermolysis of heavy oil. Fuel 2021,306:121653"), but its energy consumption can be reduced by 50%~60% (calculated based on an increase of 5% in energy consumption for every 10℃ increase in temperature). Furthermore, the aforementioned heavy oil hydrothermal cracking modifier exhibits a bituminous cracking rate greater than 30% at 140℃~160℃, which is more than 50% higher than the traditional catalytic hydrogen-donating hydrothermal cracking viscosity reduction technology (reported in the literature "Muneer A, et al. Using the oil-soluble copper-based catalysts with different organic ligands for in-situ catalytic upgrading of heavy oil. Fuel 2022;312:122914" at 240℃), significantly reducing the difficulty of subsequent processing.

[0022] In some preferred embodiments, the free radical initiator is selected from one or more of nickel dodecylbenzenesulfonate, iron dodecylbenzenesulfonate, and cobalt dodecylbenzenesulfonate. This preferred embodiment specifically defines the types of free radical initiators that can initiate hydrothermal cracking of heavy oil at low temperatures of 140°C to 160°C.

[0023] In some preferred embodiments, the catalyst is selected from one or more of di-tert-butyl peroxide, azobisisobutyronitrile, and potassium persulfate. This preferred embodiment specifically defines the types of catalysts that can be combined with free radical initiators and hydrogen donors to achieve efficient cracking and upgrading of heavy oil at low temperatures.

[0024] In a preferred embodiment, the heavy oil hydrothermal pyrolysis modifier for viscosity reduction comprises the following components in parts by weight: 0.4 parts di-tert-butyl peroxide, 0.4 parts nickel dodecylbenzenesulfonate, and 12 parts hydrogen donor; wherein the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3. This preferred embodiment specifically defines the optimal components and proportions of the heavy oil hydrothermal pyrolysis modifier for viscosity reduction, which achieves a viscosity reduction rate of up to 83.21% and an asphaltene cracking rate of up to 41.06% at 160°C.

[0025] This invention also provides a method for modifying and reducing viscosity of heavy oil through hydrothermal cracking, comprising the following steps: S1. Mix the heavy oil with water to obtain an oil-water mixture A; S2. Add catalyst and hydrogen donor to oil-water mixture A, mix evenly to obtain oil-water mixture B; wherein, the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:(2~3); S3. Add a free radical initiator to the oil-water mixture B, mix well, and obtain the oil-water mixture C. S4 and oil-water mixture C undergo hydrothermal pyrolysis under anaerobic conditions at 140℃~160℃. After the reaction is completed, the mixture is cooled to room temperature, and the oil and water are separated to obtain a modified oil sample.

[0026] The above-mentioned method for hydrothermal cracking and viscosity reduction of heavy oil achieves hydrothermal cracking and viscosity reduction of heavy oil at 140℃~160℃ through the synergistic effect of free radical initiator, catalyst and hydrogen donor. The viscosity reduction rate can reach more than 80%, and the asphaltene cracking rate can reach more than 30%.

[0027] In some preferred embodiments, the amount of catalyst added is 0.2% to 0.4% of the heavy oil mass, the amount of hydrogen donor added is 9% to 12% of the heavy oil mass, and the amount of free radical initiator added is 0.2% to 0.4% of the heavy oil mass. This preferred embodiment specifically defines the amounts of catalyst, hydrogen donor, and free radical initiator. Within the above preferred ranges, the catalyst, hydrogen donor, and free radical initiator can effectively work together to achieve the purpose of initiating hydrothermal cracking of heavy oil at low temperature, thereby effectively reducing the viscosity of heavy oil.

[0028] In some preferred embodiments, the catalyst is selected from one or more of di-tert-butyl peroxide, azobisisobutyronitrile, and potassium persulfate. This preferred embodiment specifically defines the types of free radical initiators capable of initiating hydrothermal cracking of heavy oil at low temperatures of 140°C to 160°C.

[0029] In some preferred embodiments, the free radical initiator is selected from one or more of nickel dodecylbenzenesulfonate, iron dodecylbenzenesulfonate, and cobalt dodecylbenzenesulfonate. This preferred embodiment specifically defines the types of catalysts that can be combined with the free radical initiator and hydrogen donor to achieve efficient cracking and upgrading of heavy oil at low temperatures.

[0030] In some preferred embodiments, the mass ratio of heavy oil to water in oil-water mixture A is (1~2):1. This preferred embodiment specifically defines the preferred ratio range of heavy oil to water in oil-water mixture A. By using the above-mentioned preferred ratio range for heavy oil and water, a good heavy oil hydrothermal cracking effect can be achieved.

[0031] In some preferred embodiments, the hydrothermal pyrolysis reaction time is 24h to 48h. This preferred embodiment specifically defines an optimal reaction time range for the hydrothermal pyrolysis reaction, within which both energy consumption and viscosity reduction effects can be balanced.

[0032] To more clearly and in detail introduce the heavy oil hydrothermal cracking modification viscosity reducer and viscosity reduction method provided in the embodiments of the present invention, the following description will be based on specific embodiments. It should be noted that the heavy oil used in the following embodiments and comparative examples has a viscosity of 69.7 Pa·s at 50°C and an asphaltene content of 4.36%.

[0033] Example 1 A heavy oil hydrothermal cracking modifier and viscosity reducer comprises the following components in parts by weight: 0.2 parts free radical initiator, 0.2 parts catalyst, and 12 parts hydrogen donor; wherein the free radical initiator is di-tert-butyl peroxide, the catalyst is nickel dodecylbenzenesulfonate, and the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3.

[0034] The method for modifying and reducing the viscosity of heavy oil using the above-mentioned heavy oil hydrothermal cracking modifier includes the following steps: (1) Mix 100g of heavy oil with 50g of deionized water and add it to the reaction vessel to obtain oil-water mixture A; (2) Add 0.2g of nickel dodecylbenzenesulfonate and 12g of hydrogen donor to the reaction vessel containing oil-water mixture A, and stir and mix at 1500rpm for 30min at 60℃ to obtain oil-water mixture B; wherein, the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3. (3) Add 0.2g of di-tert-butyl peroxide to the reaction vessel containing oil-water mixture B, mix evenly, and stir at 1500rpm for 30min at 60℃ to obtain oil-water mixture C; (4) Tighten the reactor containing the oil-water mixture C and purge it with nitrogen three times to remove air, ensuring that the reactor is oxygen-free. Place the sealed reactor into a muffle furnace at 140°C for hydrothermal pyrolysis reaction for 48 hours. After the reaction is completed, remove the reactor, cool it to room temperature, and separate the oil and water to obtain the modified oil sample.

[0035] Example 2 A heavy oil hydrothermal cracking modifier and viscosity reducer comprises the following components in parts by weight: 0.2 parts free radical initiator, 0.2 parts catalyst, and 12 parts hydrogen donor; wherein the free radical initiator is di-tert-butyl peroxide, the catalyst is nickel dodecylbenzenesulfonate, and the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3.

[0036] The method for modifying and reducing the viscosity of heavy oil using the above-mentioned heavy oil hydrothermal cracking modifier includes the following steps: (1) Mix 100g of heavy oil with 100g of deionized water and add the mixture into the reactor to obtain oil-water mixture A; (2) Add 0.2g of nickel dodecylbenzenesulfonate and 12g of hydrogen donor to the reaction vessel containing oil-water mixture A, and stir and mix at 1500rpm for 30min at 60℃ to obtain oil-water mixture B; wherein, the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3. (3) Add 0.2g of di-tert-butyl peroxide to the reaction vessel containing oil-water mixture B, mix evenly, and stir at 1500rpm for 30min at 60℃ to obtain oil-water mixture C; (4) Tighten the reactor containing the oil-water mixture C and purge it with nitrogen three times to remove air, ensuring that the reactor is oxygen-free. Place the sealed reactor into a muffle furnace at 160°C for hydrothermal pyrolysis reaction for 24 hours. After the reaction is completed, remove the reactor, cool it to room temperature, and separate the oil and water to obtain the modified oil sample.

[0037] Example 3 A heavy oil hydrothermal cracking modifier and viscosity reducer comprises the following components in parts by weight: 0.4 parts of free radical initiator, 0.2 parts of catalyst, and 12 parts of hydrogen donor; wherein the free radical initiator is di-tert-butyl peroxide, the catalyst is nickel dodecylbenzenesulfonate, and the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3.

[0038] The method for modifying and reducing the viscosity of heavy oil using the above-mentioned heavy oil hydrothermal cracking modifier includes the following steps: (1) Mix 100g of heavy oil with 100g of deionized water and add the mixture into the reactor to obtain oil-water mixture A; (2) Add 0.2g of nickel dodecylbenzenesulfonate and 12g of hydrogen donor to the reaction vessel containing oil-water mixture A, and stir and mix at 1500rpm for 30min at 60℃ to obtain oil-water mixture B; wherein, the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3. (3) Add 0.4g of di-tert-butyl peroxide to the reaction vessel containing oil-water mixture B, mix evenly, and stir at 1500rpm for 30min at 60℃ to obtain oil-water mixture C; (4) Tighten the reactor containing the oil-water mixture C and purge it with nitrogen three times to remove air, ensuring that the reactor is oxygen-free. Place the sealed reactor into a muffle furnace at 140°C for hydrothermal pyrolysis reaction for 24 hours. After the reaction is completed, remove the reactor, cool it to room temperature, and separate the oil and water to obtain the modified oil sample.

[0039] Example 4 A heavy oil hydrothermal cracking modifier and viscosity reducer comprises the following components in parts by weight: 0.2 parts of free radical initiator, 0.4 parts of catalyst, and 12 parts of hydrogen donor; wherein the free radical initiator is di-tert-butyl peroxide, the catalyst is nickel dodecylbenzenesulfonate, and the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3.

[0040] The method for modifying and reducing the viscosity of heavy oil using the above-mentioned heavy oil hydrothermal cracking modifier includes the following steps: (1) Mix 100g of heavy oil with 50g of deionized water and add it to the reaction vessel to obtain oil-water mixture A; (2) Add 0.4g of nickel dodecylbenzenesulfonate and 12g of hydrogen donor to the reaction vessel containing oil-water mixture A, and stir and mix at 1500rpm for 30min at 60℃ to obtain oil-water mixture B; wherein, the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3. (3) Add 0.2g of di-tert-butyl peroxide to the reaction vessel containing oil-water mixture B, mix evenly, and stir at 1500rpm for 30min at 60℃ to obtain oil-water mixture C; (4) Tighten the reactor containing the oil-water mixture C and purge it with nitrogen three times to remove air, ensuring that the reactor is oxygen-free. Place the sealed reactor into a muffle furnace at 160°C for hydrothermal pyrolysis reaction for 48 hours. After the reaction is completed, remove the reactor, cool it to room temperature, and separate the oil and water to obtain the modified oil sample.

[0041] Example 5 A heavy oil hydrothermal cracking modifier and viscosity reducer comprises the following components in parts by weight: 0.4 parts free radical initiator, 0.4 parts catalyst, and 12 parts hydrogen donor; wherein the free radical initiator is di-tert-butyl peroxide, the catalyst is nickel dodecylbenzenesulfonate, and the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3.

[0042] The method for modifying and reducing the viscosity of heavy oil using the above-mentioned heavy oil hydrothermal cracking modifier includes the following steps: (1) Mix 100g of heavy oil with 100g of deionized water and add the mixture into the reactor to obtain oil-water mixture A; (2) Add 0.4g of nickel dodecylbenzenesulfonate and 12g of hydrogen donor to the reaction vessel containing oil-water mixture A, and stir and mix at 1500rpm for 30min at 60℃ to obtain oil-water mixture B; wherein, the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3. (3) Add 0.4g of di-tert-butyl peroxide to the reaction vessel containing oil-water mixture B, mix evenly, and stir at 1500rpm for 30min at 60℃ to obtain oil-water mixture C; (4) Tighten the reactor containing the oil-water mixture C and purge it with nitrogen three times to remove air, ensuring that the reactor is oxygen-free. Place the sealed reactor into a muffle furnace at 160°C for hydrothermal pyrolysis reaction for 24 hours. After the reaction is completed, remove the reactor, cool it to room temperature, and separate the oil and water to obtain the modified oil sample.

[0043] Example 6 A heavy oil hydrothermal cracking modifier and viscosity reducer comprises the following components in parts by weight: 0.2 parts free radical initiator, 0.2 parts catalyst, and 9 parts hydrogen donor; wherein the free radical initiator is di-tert-butyl peroxide, the catalyst is nickel dodecylbenzenesulfonate, and the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:2.

[0044] The method for modifying and reducing the viscosity of heavy oil using the above-mentioned heavy oil hydrothermal cracking modifier includes the following steps: (1) Mix 100g of heavy oil with 100g of deionized water and add the mixture into the reactor to obtain oil-water mixture A; (2) Add 0.2g of nickel dodecylbenzenesulfonate and 9g of hydrogen donor to the reaction vessel containing oil-water mixture A, and stir and mix at 1500rpm for 30min at 60℃ to obtain oil-water mixture B; wherein, the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:2. (3) Add 0.2g of di-tert-butyl peroxide to the reaction vessel containing oil-water mixture B, mix evenly, and stir at 1500rpm for 30min at 60℃ to obtain oil-water mixture C; (4) Tighten the reactor containing the oil-water mixture C and purge it with nitrogen three times to remove air, ensuring that the reactor is oxygen-free. Place the sealed reactor into a muffle furnace at 160°C for hydrothermal pyrolysis reaction for 24 hours. After the reaction is completed, remove the reactor, cool it to room temperature, and separate the oil and water to obtain the modified oil sample.

[0045] Example 7 A heavy oil hydrothermal cracking modifier and viscosity reducer comprises the following components in parts by weight: 0.2 parts free radical initiator, 0.2 parts catalyst, and 12 parts hydrogen donor; wherein the free radical initiator is di-tert-butyl peroxide, the catalyst is nickel dodecylbenzenesulfonate, and the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:2.

[0046] The method for modifying and reducing the viscosity of heavy oil using the above-mentioned heavy oil hydrothermal cracking modifier includes the following steps: (1) Mix 100g of heavy oil with 100g of deionized water and add the mixture into the reactor to obtain oil-water mixture A; (2) Add 0.2g of nickel dodecylbenzenesulfonate and 12g of hydrogen donor to the reaction vessel containing oil-water mixture A, and stir and mix at 1500rpm for 30min at 60℃ to obtain oil-water mixture B; wherein, the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:2. (3) Add 0.2g of di-tert-butyl peroxide to the reaction vessel containing oil-water mixture B, mix evenly, and stir at 1500rpm for 30min at 60℃ to obtain oil-water mixture C; (4) Tighten the reactor containing the oil-water mixture C and purge it with nitrogen three times to remove air, ensuring that the reactor is oxygen-free. Place the sealed reactor into a muffle furnace at 160°C for hydrothermal pyrolysis reaction for 24 hours. After the reaction is completed, remove the reactor, cool it to room temperature, and separate the oil and water to obtain the modified oil sample.

[0047] Example 8 A heavy oil hydrothermal cracking modifier and viscosity reducer comprises the following components in parts by weight: 0.2 parts of free radical initiator, 0.2 parts of catalyst, and 12 parts of hydrogen donor; wherein the free radical initiator is azobisisobutyronitrile, the catalyst is nickel dodecylbenzenesulfonate, and the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3.

[0048] The method for modifying and reducing the viscosity of heavy oil using the above-mentioned heavy oil hydrothermal cracking modifier includes the following steps: (1) Mix 100g of heavy oil with 50g of deionized water and add it to the reaction vessel to obtain oil-water mixture A; (2) Add 0.2g of nickel dodecylbenzenesulfonate and 12g of hydrogen donor to the reaction vessel containing oil-water mixture A, and stir and mix at 1500rpm for 30min at 60℃ to obtain oil-water mixture B; wherein, the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3. (3) Add 0.2g of azobisisobutyronitrile to the reaction vessel containing oil-water mixture B, mix evenly, and stir at 1500rpm for 30min at 60℃ to obtain oil-water mixture C; (4) Tighten the reactor containing the oil-water mixture C and purge it with nitrogen three times to remove air, ensuring that the reactor is oxygen-free. Place the sealed reactor into a muffle furnace at 140°C for hydrothermal pyrolysis reaction for 48 hours. After the reaction is completed, remove the reactor, cool it to room temperature, and separate the oil and water to obtain the modified oil sample.

[0049] Example 9 A heavy oil hydrothermal cracking modifier and viscosity reducer comprises the following components in parts by weight: 0.2 parts free radical initiator, 0.2 parts catalyst, and 12 parts hydrogen donor; wherein the free radical initiator is potassium persulfate, the catalyst is nickel dodecylbenzenesulfonate, and the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3.

[0050] The method for modifying and reducing the viscosity of heavy oil using the above-mentioned heavy oil hydrothermal cracking modifier includes the following steps: (1) Mix 100g of heavy oil with 50g of deionized water and add it to the reaction vessel to obtain oil-water mixture A; (2) Add 0.2g of nickel dodecylbenzenesulfonate and 12g of hydrogen donor to the reaction vessel containing oil-water mixture A, and stir and mix at 1500rpm for 30min at 60℃ to obtain oil-water mixture B; wherein, the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3. (3) Add 0.2g of potassium persulfate to the reaction vessel containing oil-water mixture B, mix evenly, and stir at 1500rpm for 30min at 60℃ to obtain oil-water mixture C; (4) Tighten the reactor containing the oil-water mixture C and purge it with nitrogen three times to remove air, ensuring that the reactor is oxygen-free. Place the sealed reactor into a muffle furnace at 140°C for hydrothermal pyrolysis reaction for 48 hours. After the reaction is completed, remove the reactor, cool it to room temperature, and separate the oil and water to obtain the modified oil sample.

[0051] Example 10 A heavy oil hydrothermal cracking modifier and viscosity reducer comprises the following components in parts by weight: 0.4 parts free radical initiator, 0.4 parts catalyst, and 12 parts hydrogen donor; wherein the free radical initiator is di-tert-butyl peroxide, the catalyst is ferric dodecylbenzenesulfonate, and the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3.

[0052] The method for modifying and reducing the viscosity of heavy oil using the above-mentioned heavy oil hydrothermal cracking modifier includes the following steps: (1) Mix 100g of heavy oil with 100g of deionized water and add the mixture into the reactor to obtain oil-water mixture A; (2) Add 0.4g of iron dodecylbenzenesulfonate and 12g of hydrogen donor to the reaction vessel containing oil-water mixture A, and stir and mix at 1500rpm for 30min at 60℃ to obtain oil-water mixture B; wherein, the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3. (3) Add 0.4g of di-tert-butyl peroxide to the reaction vessel containing oil-water mixture B, mix evenly, and stir at 1500rpm for 30min at 60℃ to obtain oil-water mixture C; (4) Tighten the reactor containing the oil-water mixture C and purge it with nitrogen three times to remove air, ensuring that the reactor is oxygen-free. Place the sealed reactor into a muffle furnace at 160°C for hydrothermal pyrolysis reaction for 24 hours. After the reaction is completed, remove the reactor, cool it to room temperature, and separate the oil and water to obtain the modified oil sample.

[0053] Example 11 A heavy oil hydrothermal cracking modifier and viscosity reducer comprises the following components in parts by weight: 0.4 parts free radical initiator, 0.4 parts catalyst, and 12 parts hydrogen donor; wherein the free radical initiator is di-tert-butyl peroxide, the catalyst is cobalt dodecylbenzenesulfonate, and the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3.

[0054] The method for modifying and reducing the viscosity of heavy oil using the above-mentioned heavy oil hydrothermal cracking modifier includes the following steps: (1) Mix 100g of heavy oil with 100g of deionized water and add the mixture into the reactor to obtain oil-water mixture A; (2) Add 0.4g of cobalt dodecylbenzenesulfonate and 12g of hydrogen donor to the reaction vessel containing oil-water mixture A, and stir and mix at 1500rpm for 30min at 60℃ to obtain oil-water mixture B; wherein, the hydrogen donor is a mixture of tetrahydronaphthalene and ethanol mixed in a mass ratio of 1:3. (3) Add 0.4g of di-tert-butyl peroxide to the reaction vessel containing oil-water mixture B, mix evenly, and stir at 1500rpm for 30min at 60℃ to obtain oil-water mixture C; (4) Tighten the reactor containing the oil-water mixture C and purge it with nitrogen three times to remove air, ensuring that the reactor is oxygen-free. Place the sealed reactor into a muffle furnace at 160°C for hydrothermal pyrolysis reaction for 24 hours. After the reaction is completed, remove the reactor, cool it to room temperature, and separate the oil and water to obtain the modified oil sample.

[0055] Comparative Example 1 The difference from Example 1 is that no free radical initiator was added.

[0056] Comparative Example 2 The difference from Example 1 is that no hydrogen donor was added.

[0057] Comparative Example 3 The difference from Example 1 is that no catalyst was added.

[0058] Comparative Example 4 The difference from Example 1 is that no free radical initiator and hydrogen donor were added.

[0059] Comparative Example 5 The difference from Example 1 is that no free radical initiator and catalyst were added.

[0060] Comparative Example 6 The difference from Example 1 is that the hydrogen donor used is ethanol, and no tetrahydronaphthalene is added.

[0061] Comparative Example 7 The difference from Example 1 is that the hydrogen donor used is tetrahydronaphthalene, and no ethanol is added.

[0062] Comparative Example 8 The difference from Example 1 is that the mass ratio of tetrahydronaphthalene to ethanol in the hydrogen donor used is 1:1.

[0063] Comparative Example 9 The difference from Example 1 is that the mass ratio of tetrahydronaphthalene to ethanol in the hydrogen donor used is 1:5.

[0064] Comparative Example 10 The difference from Example 1 is that the hydrogen donor is 6 parts.

[0065] Comparative Example 11 The difference from Example 1 is that the free radical initiator is 0.05 parts.

[0066] Performance testing The viscosity and asphaltene content of the modified oil samples obtained in Examples 1-11 and Comparative Examples 1-11 were measured respectively, and the viscosity reduction rate and asphaltene cracking rate were calculated. The results are shown in Table 1.

[0067] Table 1. Viscosity, viscosity reduction rate, asphaltene content, and asphaltene cracking rate of modified oil samples

[0068] As shown in Table 1, the viscosity reduction rate of the modified oil samples obtained in Examples 1-11 of this invention all reached over 80%, and the asphaltene cracking rate all reached 30%, with a viscosity reduction effect significantly higher than that of Comparative Examples 1-11. This indicates that the present invention uses tetrahydronaphthalene and ethanol mixed in a specific ratio as hydrogen donors, and coordinates them with free radical initiators and catalysts in a specific ratio to construct a ternary synergistic system of "free radical initiator-catalyst-hydrogen donor," which can initiate hydrothermal cracking of heavy oil at a low temperature of 140℃~160℃ and achieve effective hydrothermal cracking modification and viscosity reduction of heavy oil.

Claims

1. A heavy oil hydrothermal cracking modification viscosity reducer, characterized in that, The free radical initiator is selected from any one or several of nickel dodecyl benzene sulfonate, iron dodecyl benzene sulfonate and cobalt dodecyl benzene sulfonate.

2. The heavy oil hydrothermal cracking modification viscosity reducer according to claim 1, characterized in that, The catalyst is selected from any one or several of di-tert-butyl peroxide, azobisisobutyronitrile and potassium persulfate.

3. The heavy oil hydrothermal cracking modification viscosity reducer according to claim 1, characterized in that, The catalyst is selected from any one or several of di-tert-butyl peroxide, azobisisobutyronitrile and potassium persulfate.

4. The heavy oil hydrothermal cracking modification viscosity reducer according to claim 1, characterized in that, The free radical initiator is selected from any one or several of nickel dodecyl benzene sulfonate, iron dodecyl benzene sulfonate and cobalt dodecyl benzene sulfonate.

5. The heavy oil hydrothermal cracking modification viscosity reducer according to any one of claims 1-4, characterized in that, The thick oil hydrothermal cracking modification viscosity reducer has a viscosity reduction rate of greater than 80% and an asphaltene cracking rate of greater than 30% for thick oil hydrothermal cracking modification viscosity reduction at 140-160 DEG C.

6. A method for modifying and reducing the viscosity of heavy oil by hydrothermal cracking, characterized in that, The method comprises the following steps: thick oil and water are mixed to obtain an oil-water mixture A; a catalyst and a hydrogen donor are added to the oil-water mixture A, and mixed uniformly to obtain an oil-water mixture B; the hydrogen donor is a mixture of tetralin and ethanol in a mass ratio of 1:(2-3); a free radical initiator is added to the oil-water mixture B, and mixed uniformly to obtain an oil-water mixture C; the oil-water mixture C is subjected to a hydrothermal cracking reaction under anaerobic conditions at 140-160 DEG C, and after the reaction is completed, the temperature is lowered to room temperature, and the oil-water is separated to obtain a modified oil sample.

7. The heavy oil hydrothermal cracking modification viscosity reduction method according to claim 6, characterized in that, The catalyst is added in an amount of 0.2-0.4% of the mass of the thick oil, the hydrogen donor is added in an amount of 9-12% of the mass of the thick oil, and the free radical initiator is added in an amount of 0.2-0.4% of the mass of the thick oil.

8. The heavy oil hydrothermal cracking upgrading and viscosity reduction method according to claim 6, characterized in that, The catalyst is selected from any one or several of di-tert-butyl peroxide, azobisisobutyronitrile and potassium persulfate.

9. The heavy oil hydrothermal cracking modification viscosity reduction method according to claim 6, characterized in that, The mass ratio of the thick oil to water in the oil-water mixture A is (1-2):

1.

10. The heavy oil hydrothermal cracking upgrading and viscosity reduction method according to claim 6, characterized in that, The reaction time of the hydrothermal cracking reaction is 24-48 h.

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