A process for a heavy oil hydroaromatic extraction combined process

Abstract

The present disclosure relates to a method of heavy oil hydroaromatic extraction combined process, which comprises: mixing a heavy oil raw material, a hydrogen transfer catalyst and a hydrogen donor, and feeding the mixture into a slurry bed reactor to carry out a hydrogen transfer reaction to obtain a hydrogen transfer reaction product; subjecting the hydrogen transfer reaction product to a first separation to obtain a gas phase light component and a mixed oil component; subjecting the mixed oil component to a second separation to obtain a light oil product, a heavy oil product and an unconverted oil; returning at least a part of the unconverted oil to the slurry bed reactor for continuous reaction; subjecting the gas phase light component to a third separation, and feeding the obtained spent hydrogen donor into a solvent extraction tower for extraction treatment to obtain a raffinate oil and a mixed solvent oil; subjecting the mixed solvent oil to a fourth separation to obtain a purified spent hydrogen donor; and subjecting the purified spent hydrogen donor to a hydrogenation regeneration treatment to obtain a regenerated hydrogen donor which is returned to the slurry bed reactor. The method of the present disclosure can increase the pressure of the reaction system, reduce the viscosity of the oil product and reduce coking.

Description

Technical Field

[0001] This disclosure relates to the petrochemical field, and more specifically, to a method for a combined process of heavy oil hydrogenation and aromatics extraction. Background Technology

[0002] Currently, there are four main types of residue hydrotreating processes: fixed-bed, fluidized-bed, moving-bed, and slurry-bed. Slurry-bed hydrotreating technology has the advantage of processing even the lowest quality residue oils, and even coal. However, its reaction system pressure is high, and its chemical hydrogen consumption is higher than that of fixed-bed, fluidized-bed, and moving-bed processes, resulting in higher equipment investment. Therefore, reducing the pressure of the reaction system is crucial for energy conservation and emission reduction in the entire plant.

[0003] Low-carbon deep processing technology for heavy / inferior residue oils involves slurry bed residue oil hydrotreating. In this process, the reaction system is under high pressure and near-hydrogen conditions, resulting in poor feedstock properties and severe coking. Furthermore, due to the low molecular weight of hydrogen, it is prone to escape and leakage, posing significant safety risks. At the same time, the high-pressure conditions of the equipment lead to high investment costs and high safety risks, which greatly complicates the stable, safe, and long-term operation of existing slurry bed residue oil hydrotreating units.

[0004] In existing technologies, the hydroprocess plays a very important role in heavy oil processing and is widely used in refineries. However, with changes in feedstocks, especially when processing ultra-high viscosity and extra-heavy oils, existing technologies are prone to coking during the reaction process, which is not conducive to long-term operation.

[0005] In recent studies, hydrogenated distillate oil has been recycled in existing hydrogenation reaction systems. The distillate oil, acting as a hydrogen donor, can reduce coking during the reaction. However, large-scale recycling of distillate oil significantly increases the energy consumption and investment of the unit. Furthermore, as the reaction time increases, the amount of hydrogen-available component in the hydrogenated distillate oil gradually decreases, resulting in a significant decline in its hydrogen supply capacity and a less pronounced effect in reducing coking. Summary of the Invention

[0006] The purpose of this disclosure is to provide a low-pressure hydrogenation method that is non-hydrogen-dependent, consumes less hydrogen feeder, and has high purity of circulating hydrogen feeder.

[0007] To achieve the above objectives, this disclosure provides a combined process for heavy oil hydrogenation and aromatics extraction. The method includes: feeding heavy oil feedstock, a hydrogen transfer catalyst, and a hydrogen donor into a slurry bed reactor to perform a hydrogen transfer reaction, obtaining hydrogen transfer reaction products; wherein the hydrogen donor is selected from cycloalkanes with 6-20 carbon atoms and / or cycloolefins with 6-18 carbon atoms; subjecting the hydrogen transfer reaction products to a first separation to obtain a gaseous light component and a mixed oil component; subjecting the mixed oil component to a second separation to obtain light oil products, heavy oil products, and unconverted oil; returning at least a portion of the unconverted oil to the slurry bed reactor for further reaction; subjecting the gaseous light component to a third separation to obtain a first gaseous phase and a hydrogen donor to be generated; subjecting the hydrogen donor to a solvent extraction tower for extraction treatment to obtain raffinate oil and mixed solvent oil; subjecting the mixed solvent oil to a fourth separation to obtain a purified hydrogen donor to be generated; subjecting the purified hydrogen donor to hydrogen regeneration treatment, and returning the obtained regenerated hydrogen donor to the slurry bed reactor.

[0008] Optionally, the heavy oil feedstock is selected from one or more of vacuum residue, deasphalted oil, atmospheric residue, crude oil fractions with an initial boiling point >350℃, and extra-heavy crude oil; the hydrogen donor is selected from one or more of cyclohexane, cyclohexene, cyclohexadiene, methylcyclohexane, and decahydronaphthalene; the hydrogen transfer catalyst is selected from one or more of oil-soluble catalysts, non-precious metal-based solid powder catalysts, and precious metal-based solid powder catalysts; the non-precious metals in the non-precious metal-based solid powder catalyst include one or more of nickel, molybdenum, and iron, and the precious metals in the precious metal-based solid powder catalyst include one or more of platinum, gold, silver, ruthenium, rhodium, and palladium.

[0009] Optionally, the reaction conditions for the hydrogen transfer reaction include: a reaction temperature of 150~450℃, preferably 420~430℃; a reaction pressure of 5~70 bar, preferably 35~50 bar; a reaction time of 0.5~24h, preferably 0.5~2.5h; and a weight ratio of the heavy oil feedstock to the hydrogen donor of 1.25~100, preferably 2~5.

[0010] Optionally, the first separation is carried out in one or more of a stripping tower, a flash tank, an atmospheric distillation tower, and a vacuum distillation tower; the second separation is carried out in one or more of a stripping tower, a flash tank, an atmospheric distillation tower, and a vacuum distillation tower; the fraction cut-off point of the light oil product and the heavy oil product is 300~360℃, and the fraction cut-off point of the heavy oil product and the unconverted oil is 480~540℃; the third separation is carried out in a stripping tower.

[0011] Optionally, the method further includes feeding at least a portion of the catalyst to be generated into the solvent extraction tower as a hydrogen supply agent to be extracted; the weight ratio of the hydrogen supply agent to be extracted to the hydrogen supply agent to be generated is (0.01~0.99):1; and the hydrogen sulfide content in the hydrogen supply agent to be generated is 0.2~50ppm.

[0012] Optionally, the method further includes feeding the mixed solvent oil into a solvent separation tower for a fourth separation to obtain a purified hydrogen donor and a circulating extraction solvent, and returning the circulating extraction solvent to the extraction tower.

[0013] Optionally, the extraction conditions include: a temperature of 100~250℃, preferably 150~200℃; a pressure of 5~30 bar, preferably 10~20 bar; and an extraction solvent selected from one or more of alcohol ethers, sulfoxides, and sulfones, preferably one or more of diethylene glycol ethers, triethylene glycol ethers, tetraethylene glycol ethers, dimethyl sulfoxides, and sulfolane.

[0014] Optionally, the method further includes pressurizing and heating the mixed feedstock containing the heavy oil feedstock, the hydrogen transfer catalyst and the hydrogen donor to 5-70 bar and to 150-450°C before carrying out the hydrogen transfer reaction.

[0015] Optionally, the method further includes: feeding the purified hydrogen supply agent and hydrogen into a hydrogen supply agent hydrogenation reactor for hydrogenation regeneration treatment to obtain a mixed regenerated hydrogen supply agent; feeding the mixed regenerated hydrogen supply agent into a separation tank for a fifth separation to obtain recycled hydrogen and the regenerated hydrogen supply agent; returning the regenerated hydrogen supply agent to the slurry bed reactor; and returning the recycled hydrogen to the hydrogen supply agent hydrogenation reactor after compression.

[0016] Optionally, the conditions for the hydrogenation regeneration treatment include: a reaction temperature of 150~250℃, preferably 180~220℃; a reaction pressure of 5-50 bar, preferably 25~35 bar; and a volume ratio of hydrogen to the purified hydrogen supply agent of (0.1~999):1.

[0017] By employing the above-described technical solution and the method disclosed herein, using a hydrogen donor instead of hydrogen in the traditional process can reduce the pressure of the hydrogen transfer reaction, decrease oil viscosity, reduce coking, and increase the safety of the equipment. Combining the hydrogen donor regeneration reaction with the solvent extraction process can purify the hydrogen donor after hydrogen supply. After hydrogen regeneration treatment, a high-purity regenerated hydrogen donor is obtained. Using this combined process can maintain high hydrogen transfer efficiency, increase the content of liquid products, and extend the service life of the circulating hydrogen donor, resulting in high economic benefits.

[0018] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a schematic flow diagram of one embodiment of the combined process for heavy oil hydrogenation and aromatics extraction disclosed herein.

[0021] Explanation of reference numerals in the attached figures

[0022] P1, Feed pump; P2, Hydrogen supply booster pump; F1, Feed heater; F2, Hydrogen supply heater; R1, Slurry bed reactor; R2, Hydrogen supply hydrogenation reactor; D1, Separator; K1, Circulating hydrogen compressor; C1, First stripping tower; C2, Fractionating tower; C3, Second stripping tower; C4, Solvent extraction tower; C5, Solvent separation tower;

[0023] 1. Heavy oil feedstock; 2. Hydrogen transfer catalyst; 3. Hydrogen donor; 4. Mixed feedstock; 5. Preheated mixed feedstock; 6. Hydrogen transfer reaction products; 7. Gas phase light components; 8. Mixed oil components; 9. Light oil products; 10. Heavy oil products; 11. Recycled unconverted oil; 12. First gas phase; 13. Hydrogen donor awaiting extraction; 14. Extraction solvent; 15. Raffinate oil; 16. Mixed solvent oil; 17. Recycled solvent; 18. Purified hydrogen donor awaiting extraction; 19. Hydrogen; 20. Hydrogen donor with restored hydrogen supply capacity; 21. Recycled hydrogen; 22. Compressed recycled hydrogen; 23. Regenerated hydrogen donor; 24. Unconverted oil discharged; 25. Hydrogen donor awaiting extraction; 26. Hydrogen donor awaiting extraction. Detailed Implementation

[0024] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0025] In this disclosure, unless otherwise stated, the terms "first, second, third, fourth, and fifth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first, second, third, fourth, and fifth" may explicitly or implicitly include one or more of that feature.

[0026] This disclosure provides a combined process for heavy oil hydrogenation and aromatics extraction. The method includes: feeding heavy oil feedstock, a hydrogen transfer catalyst, and a hydrogen donor into a slurry bed reactor to perform a hydrogen transfer reaction, obtaining hydrogen transfer reaction products; wherein the hydrogen donor is selected from cycloalkanes with 6-20 carbon atoms and / or cycloolefins with 6-18 carbon atoms; subjecting the hydrogen transfer reaction products to a first separation to obtain a gaseous light component and a mixed oil component; subjecting the mixed oil component to a second separation to obtain light oil products, heavy oil products, and unconverted oil; returning at least a portion of the unconverted oil to the slurry bed reactor for further reaction; subjecting the gaseous light component to a third separation to obtain a first gaseous phase and a hydrogen donor to be generated; subjecting the hydrogen donor to a solvent extraction tower for extraction treatment to obtain raffinate oil and mixed solvent oil; subjecting the mixed solvent oil to a fourth separation to obtain purified hydrogen donor to be generated; subjecting the purified hydrogen donor to hydrogen regeneration treatment, and returning the obtained regenerated hydrogen donor to the slurry bed reactor.

[0027] Through the above technical solution, the method disclosed herein uses a hydrogen donor instead of hydrogen as the reactant in a slurry bed hydrotreating reaction. The reaction system does not introduce hydrogen, and the reaction pressure is lower than that of existing slurry bed residue hydrotreating, effectively reducing the safety and stability of the reaction system. Furthermore, the introduction of the hydrogen donor does not affect product quality and can effectively reduce oil viscosity and coking. Combining the hydrogen donor regeneration reaction with solvent extraction processes can purify the hydrogen donor after hydrogen donation. After hydroregeneration treatment, a high-purity regenerated hydrogen donor is obtained. This combined process can maintain high hydrogen transfer efficiency, increase the content of liquid products, and extend the service life of the circulating hydrogen donor, resulting in high economic benefits.

[0028] In one embodiment, the heavy oil feedstock is selected from one or more of vacuum residue, deasphalted oil, atmospheric residue, crude oil fractions with an initial boiling point >350°C, and extra-heavy crude oil.

[0029] In one embodiment, the hydrogen donor is selected from cycloalkanes having 6 to 10 carbon atoms and / or cycloolefins having 6 to 10 carbon atoms, preferably one or more of cyclohexane, cyclohexene, cyclohexadiene, methylcyclohexane, and decahydronaphthalene, and more preferably cyclohexane.

[0030] The hydrogen transfer catalyst used in this disclosure is a conventional hydrogen transfer catalyst in the art, and this disclosure does not make any special requirements. For example, the hydrogen transfer catalyst is selected from one or more of oil-soluble catalysts, non-precious metal solid powder catalysts, and precious metal solid powder catalysts, preferably oil-soluble catalysts; wherein, the non-precious metals in the non-precious metal solid powder catalyst include one or more of nickel, molybdenum, and iron, and the precious metals in the precious metal solid powder catalyst include one or more of platinum, gold, silver, ruthenium, rhodium, and palladium.

[0031] In one embodiment, the reaction conditions for the hydrogen transfer reaction include: a reaction temperature of 150~450℃, preferably 300~440℃, more preferably 420~430℃; a reaction pressure of 5~70 bar, preferably 20~60 bar, more preferably 35~50 bar; a reaction time of 0.5~24h, preferably 0.5~12h, more preferably 0.5~2.5h; and a weight ratio of the heavy oil feedstock to the hydrogen donor of 1.25~100, preferably 1.5~20, more preferably 2~5.

[0032] In the above embodiments, using the above reactants and reaction conditions to carry out the hydrogen transfer reaction can increase the reactivity of the hydrogen transfer reaction and reduce the reaction pressure and coking rate.

[0033] In one embodiment, the method further includes, before carrying out the hydrogen transfer reaction, pressurizing the mixed feedstock comprising the heavy oil feedstock, the hydrogen transfer catalyst and the hydrogen donor to 5-70 bar, preferably 20-60 bar, more preferably 35-50 bar; and heating it to 150-450°C, preferably 300-440°C, more preferably 420-430°C.

[0034] In this embodiment, the reactants are first pressurized and preheated, which enables the mixed raw materials to quickly reach the reaction temperature and further improves the reaction performance of the hydrogen transfer reaction.

[0035] The first separation of this disclosure is carried out in one or more of a stripping tower, a flash tank, an atmospheric distillation tower, and a vacuum distillation tower, preferably in a stripping tower. The stripping tower used is a conventional stripping tower in the art, and the stripping medium used is also a conventional choice in the art; this application does not make any special requirements. In one embodiment of this disclosure, the hydrogen transfer reaction product is fed into a stripping tower for separation to obtain a gaseous light component and a mixed oil component.

[0036] In this embodiment, stripping the hydrogen transfer reaction products can effectively separate the mixed oil and the light gas phase components, further enhancing the purity and yield of the product and the regenerated hydrogen donor.

[0037] The third separation in this disclosure is carried out in a stripping tower, which is a conventional stripping tower in the art, and the stripping medium used is also a conventional choice in the art; this application does not make any special requirements. In one embodiment of this disclosure, the gaseous light component is fed into a stripping tower for separation to obtain a first gaseous phase and a hydrogen donor to be generated.

[0038] In one embodiment, the method further includes feeding at least a portion of the catalyst to be generated into the solvent extraction tower as a hydrogen supply agent to be extracted; the weight ratio of the hydrogen supply agent to be extracted to the hydrogen supply agent to be generated is (0.01~0.99):1.

[0039] In the above embodiments, stripping the gaseous light components can remove sulfur from the used hydrogen donor through the stripping medium to obtain a desulfurized, ready-to-use catalyst. The hydrogen sulfide content in the ready-to-use hydrogen donor is reduced to 0.2-50 ppm, preferably below 0.2-1 ppm.

[0040] In one embodiment, the mixed solvent oil is fed into a solvent separation tower for a fourth separation to obtain a purified hydrogen donor and a circulating extraction solvent, and the circulating extraction solvent is returned to the extraction tower to continue to participate in the extraction process.

[0041] In one embodiment, the extraction process conditions include: a temperature of 100~250℃, preferably 150~200℃; and a pressure of 5~30 bar, preferably 10~20 bar.

[0042] In this embodiment, the extraction tower used in this disclosure is a conventional choice in the art and is not specifically required in this application; the extraction solvent used in this disclosure is a conventional choice in the art and is not specifically required in this application. For example, the extraction solvent can be selected from one or more of alcohol ethers, sulfoxides and sulfones, preferably one or more of diethylene glycol ethers, triethylene glycol ethers, tetraethylene glycol ethers, dimethyl sulfoxides and sulfolane, preferably sulfolane.

[0043] In the above embodiments, by using the above extraction processing conditions and apparatus, impurities in the hydrogen supply agent to be generated can be removed, reducing the energy consumption of subsequent hydrogen regeneration processing operations, and reducing the reaction difficulty of subsequent hydrogen regeneration processing.

[0044] In one embodiment, the method further includes: feeding the purified hydrogen supply agent and hydrogen into a hydrogen supply agent hydrogenation reactor for hydrogenation regeneration to obtain a mixed regenerated hydrogen supply agent; feeding the mixed regenerated hydrogen supply agent into a separation tank for a fifth separation to obtain recycled hydrogen and regenerated hydrogen supply agent; returning the regenerated hydrogen supply agent to the slurry bed reactor to continue participating in the hydrogen transfer reaction; and compressing the recycled hydrogen and returning it to the hydrogen supply agent hydrogenation reactor to continue participating in the hydrogenation regeneration process.

[0045] In a further embodiment, before hydrogen regeneration, the purified hydrogen supply agent is heated to 150-250°C, preferably 180-220°C, in a hydrogen supply agent heating furnace, and then mixed with hydrogen.

[0046] In one embodiment, the hydrogenation reactor used in this disclosure is a conventional choice in the art, and this application does not impose any special requirements. The conditions for hydrogenation regeneration treatment in this application include: a reaction temperature of 150~250℃, preferably 180~220℃; a reaction pressure of 5-50 bar, preferably 25~35 bar; a volume ratio of hydrogen to the purified hydrogen-to-be-generated hydrogen-to-be-generated agent of (0.1~999):1; and a ratio of the solvent-extracted hydrogen-to-be-generated agent to the total amount of the hydrogen-to-be-generated agent of 1~99% by weight. Furthermore, the hydrogenation regeneration catalyst used in the hydrogenation regeneration process is a conventional choice in the art; for example, the hydrogenation regeneration catalyst can be a Pt-based solid powder catalyst.

[0047] In the above embodiments, by employing the hydrogen regeneration treatment operation of the hydrogen supply agent, the hydrogen supply agent can be regenerated and returned to the slurry bed reactor for hydrogen transfer reaction, which can further increase economic benefits and hydrogen supply efficiency.

[0048] In one embodiment, the second separation is carried out in one or more of a flash tank, an atmospheric distillation column, and a vacuum distillation column; the cut-off point for the light oil product and the heavy oil product is 300-360°C, and the cut-off point for the heavy oil product and the unconverted oil is 480-540°C. In this embodiment, the mixed oil components are separated to obtain light oil product, heavy oil product, and unconverted oil, wherein the light oil product and the heavy oil product are taken out of the system as liquid products; the unconverted oil is divided into two parts, one part is returned to the slurry bed reactor as circulating unconverted oil containing catalyst, and the other part is taken out of the system as external unconverted oil.

[0049] In a further embodiment, based on the total weight of the unconverted oil, the content of the circulating unconverted oil is 80-100% by weight, and the content of the externally discarded unconverted oil is 0-20% by weight.

[0050] In one implementation, such as Figure 1 As shown, the combined process for heavy oil hydrogenation aromatics extraction includes:

[0051] The mixture of heavy oil feedstock 1 and hydrogen transfer catalyst 2 is mixed with hydrogen donor 3, which is pressurized by hydrogen donor booster pump P2, to obtain mixed feedstock 4. Mixed feedstock 4 is heated by feed heater F1 to obtain preheated mixed feedstock 5. Preheated mixed feedstock 5 is fed into slurry bed reactor R1 for hydrogen transfer reaction to obtain hydrogen transfer reaction product 6. The conditions for hydrogen transfer reaction include: reaction temperature of 150~450℃, reaction pressure of 5~70 bar, reaction time of 0.5~24h, and weight ratio of heavy oil feedstock to hydrogen donor 1.25~100. After being cooled by heat exchange in a cooler, hydrogen transfer reaction product 6 enters the first stripping tower C1 for first separation to obtain gaseous light component 7 and mixed oil component 8. Mixed oil component 8 is then subjected to second separation in fractionation tower C2 to obtain light oil product 9, heavy oil product 10, unconverted circulating oil containing catalyst 11, and unconverted external oil 24. The gaseous light component 7 is further separated by a second stripping tower C3 to obtain a first gaseous phase 12 and a hydrogen supply agent 13. A portion of the hydrogen supply agent 13 is sent to a solvent extraction tower C4 as a hydrogen supply agent 26 to be extracted with an extraction solvent 14, resulting in raffinate oil 15 and mixed solvent oil 16. The other portion is sent out of the system as an external hydrogen supply agent 25. The mixed solvent oil 16 is separated by a solvent separation tower C5 to obtain purified hydrogen supply agent 18 and recycled solvent 17. The extraction conditions include a temperature of 100~250℃ and a pressure of 5~30 bar. The circulating solvent 17 is returned to the solvent extraction tower C4 to continue the extraction process; the purified hydrogen supply agent 18 and hydrogen 19, heated by the hydrogen supply agent heater F2, are introduced into the hydrogen supply agent hydrogenation reactor R2 for hydrogenation reaction; the regenerated hydrogen supply agent 20, which has restored its hydrogen supply capacity, is separated by the separator D1 to obtain circulating hydrogen 21 and regenerated hydrogen supply agent 23; the regenerated hydrogen supply agent 23 is mixed with the hydrogen supply agent 3 and returned to the hydrogen supply agent booster pump P2 for pressurization; the circulating hydrogen 21 is compressed by the circulating hydrogen compressor K1 to obtain compressed circulating hydrogen 22, and the compressed circulating hydrogen 22 is returned to the hydrogen supply agent hydrogenation reactor R2.

[0052] The present disclosure will be further illustrated by the following examples, but the present disclosure is not limited thereto.

[0053] The heavy oil feedstock used in the examples and comparative examples was atmospheric residue oil, the properties of which are shown in Table 1; the hydrogen transfer catalyst used was a self-synthesized Ni / Mo catalyst; the hydrogenation catalyst used was a self-synthesized oil-soluble Mo catalyst; and all reagents used were analytical grade unless otherwise specified.

[0054] Table 1 Properties of Heavy Oil Feedstock

[0055]

[0056] Example 1

[0057] A 100t / h heavy oil feedstock 1, an 8t / h hydrogen donor 3 (cyclohexane, initial charge 100t, stable flow rate 7.2t / h), and a hydrogen transfer catalyst 2 (initial charge 2t, stable flow rate 0.2t / h) are mixed to obtain a mixed feedstock 4. The mixed feedstock 4 is pressurized and heated to 40bar and 425℃ to obtain a preheated mixed feedstock 5. The preheated mixed feedstock 5 is fed into a slurry bed reactor R1 for hydrogen transfer reaction to obtain hydrogen transfer reaction product 6. The conditions for the hydrogen transfer reaction include: reaction temperature of 425℃, reaction pressure of 40bar, reaction time of 20h, and a weight ratio of heavy oil feedstock to hydrogen donor of 2:1.

[0058] The hydrogen transfer reaction product 6, which has been cooled to 350°C by heat exchange in a cooler, is fed into the first stripping tower C1 for the first separation. The stripping medium is steam, which yields a light gas phase component 7 (distillation range <140°C) and a mixed oil component 8 (distillation range >140°C).

[0059] The mixed oil component 8 is fed into the fractionation tower C2 for a second separation to obtain light oil product 9 (distillation range 140~350℃), heavy oil product 10 (distillation range 350~520℃), and unconverted oil containing catalyst (distillation range >520℃). A portion of the unconverted oil (90 wt%) is returned to the slurry bed reactor R1 as recycled unconverted oil 11 to continue participating in the hydrogen transfer reaction, and another portion of the unconverted oil (10 wt%) is discharged from the system as unconverted oil 24.

[0060] The light vapor component 7 is introduced into the second stripping tower C3 for third separation. The stripping medium is steam, yielding the first vapor phase 12 (distillation range <60℃) and the hydrogen donor 13 (distillation range 60~140℃). A portion of the hydrogen donor 13 is sent to the solvent extraction tower C4 as the hydrogen donor 26 to be extracted, yielding raffinate oil 15 and mixed solvent oil 16. The remaining portion of the hydrogen donor 13 is sent out of the system as the external hydrogen donor 25. The weight ratio of the hydrogen donor 26 to the hydrogen donor 13 is 0.9:1. The extraction conditions include a reaction temperature of 160℃, a reaction pressure of 15 bar, and sulfolane as the extraction solvent 14. The mixed solvent oil 16 is desorbed in the solvent separation tower C5 to obtain purified hydrogen donor 18 and recycled solvent 17. The recycled solvent 17 is returned to the solvent extraction tower C4. The purified hydrogen supply agent 18, heated to 200℃ in the hydrogen supply agent heater F2, is mixed with hydrogen gas 19 and then fed into the hydrogen supply agent hydrogenation reactor R2. Under the catalysis of the hydrogenation catalyst, it undergoes hydrogenation regeneration treatment at 200℃ and 30 bar. The regenerated hydrogen supply agent 23, obtained by separating the hydrogen supply agent 20 (which restores its hydrogen supply capacity) in the separator D1, is returned to the slurry bed reactor R1 for further reaction. The separated circulating hydrogen gas 21 is compressed by the circulating hydrogen compressor K1 to obtain compressed circulating hydrogen gas 22, which is then returned to the hydrogen supply agent hydrogenation reactor R2 to continue participating in the reaction. The properties of the product oil are shown in Table 2.

[0061] Comparative Example 1

[0062] The combined process for heavy oil hydrogenation aromatics extraction is the same as in Example 1, except that hydrogen is used instead of hydrogen donor for hydrogen transfer reaction. The product indicators are shown in Table 2.

[0063] Comparative Example 2

[0064] The combined process for heavy oil hydrogenation aromatics extraction is the same as in Example 1, except that no extraction process is performed. The product indicators obtained are shown in Table 2.

[0065] Table 2. Product properties of Example 1 and Comparative Example 1

[0066]

[0067] As shown in Table 2, a comparison of the data from Example 1 and Comparative Examples 1-2 reveals that the method described in this disclosure, compared to conventional methods using hydrogen, can improve the yield of liquid products, reduce coking, and enhance the safety of the method. A comparison of the data from Example 1 and Comparative Example 2 shows that combining the hydrogen regeneration treatment of the hydrogen donor with solvent extraction treatment can improve the purity and lifespan of the circulating hydrogen donor, and enhance the efficiency of the hydrogen transfer reaction.

[0068] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0069] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0070] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for combined heavy oil hydrogenation aromatics extraction, characterized in that, The method includes: Heavy oil feedstock, hydrogen transfer catalyst, and hydrogen donor are fed into a slurry bed reactor to carry out a hydrogen transfer reaction, yielding hydrogen transfer reaction products. The hydrogen donor is selected from cycloalkanes with 6-20 carbon atoms and / or cycloolefins with 6-18 carbon atoms. The reaction conditions for the hydrogen transfer reaction include: a reaction temperature of 150-450℃, a reaction pressure of 5-70 bar, a reaction time of 0.5-24 h, and a weight ratio of heavy oil feedstock to hydrogen donor of 1.25-100. The hydrogen transfer reaction products are subjected to a first separation to obtain a gaseous light component and a mixed oil component; The mixed oil components are subjected to a second separation to obtain light oil product, heavy oil product, and unconverted oil; at least a portion of the unconverted oil is returned to the slurry bed reactor for further reaction. The gaseous light components are subjected to a third separation to obtain a first gaseous phase and a hydrogen-donating agent to be generated; the hydrogen-donating agent to be generated is then fed into a solvent extraction tower for extraction to obtain raffinate oil and mixed solvent oil; the mixed solvent oil is then subjected to a fourth separation to obtain purified hydrogen-donating agent; the extraction conditions include: a temperature of 100~250℃, a pressure of 5~30 bar, and the extraction solvent is selected from one or more of alcohol ethers, sulfoxides, and sulfones. The purified hydrogen supply agent is subjected to hydrogen regeneration treatment, and the resulting regenerated hydrogen supply agent is returned to the slurry bed reactor.

2. The method according to claim 1, characterized in that, The heavy oil feedstock is selected from one or more of vacuum residue, deasphalted oil, atmospheric residue, crude oil fractions with a primary boiling point >350℃, and extra-heavy crude oil. The hydrogen donor is selected from one or more of cyclohexane, cyclohexene, cyclohexadiene, methylcyclohexane, and decahydronaphthalene. The hydrogen transfer catalyst is selected from one or more of oil-soluble catalysts, non-precious metal solid powder catalysts, and precious metal solid powder catalysts; the non-precious metals in the non-precious metal solid powder catalyst include one or more of nickel, molybdenum, and iron, and the precious metals in the precious metal solid powder catalyst include one or more of platinum, gold, silver, ruthenium, rhodium, and palladium.

3. The method according to claim 1, characterized in that, The reaction conditions for the hydrogen transfer reaction include: a reaction temperature of 420~430℃, a reaction pressure of 35~50 bar, a reaction time of 0.5~2.5 h, and a weight ratio of the heavy oil feedstock to the hydrogen donor of 2~5.

4. The method according to claim 1, characterized in that, The first separation is carried out in one or more of the following: a stripping tower, a flash tank, an atmospheric distillation tower, and a vacuum distillation tower; The second separation is carried out in one or more of the following: stripping tower, flash tank, atmospheric distillation tower, and vacuum distillation tower; the cut-off point of the light oil product and the heavy oil product is 300~360℃, and the cut-off point of the heavy oil product and the unconverted oil is 480~540℃. The third separation is carried out in a stripping tower.

5. The method according to claim 1, characterized in that, The method further includes feeding at least a portion of the catalyst to be generated into the solvent extraction tower as a hydrogen supply agent to be extracted; the weight ratio of the hydrogen supply agent to be extracted to the hydrogen supply agent to be generated is (0.01~0.99):1; The hydrogen sulfide content in the hydrogen supply agent is 0.2~50ppm.

6. The method according to claim 1, characterized in that, The method further includes feeding the mixed solvent oil into a solvent separation tower for a fourth separation to obtain a purified hydrogen donor and a circulating extraction solvent, and returning the circulating extraction solvent to the extraction tower.

7. The method according to claim 1, characterized in that, The extraction conditions include: a temperature of 150-200°C, a pressure of 10-20 bar, and an extraction solvent selected from one or more of diethylene glycol ether, triethylene glycol ether, tetraethylene glycol ether, dimethyl sulfoxide, and sulfolane.

8. The method according to claim 1, characterized in that, The method further includes, prior to the hydrogen transfer reaction, pressurizing the mixture containing the heavy oil feedstock, the hydrogen transfer catalyst, and the hydrogen donor to 5-70 bar and heating it to 150-450°C.

9. The method according to claim 1, characterized in that, The method further includes feeding the purified hydrogen supply agent and hydrogen into a hydrogen supply agent hydrogenation reactor for hydrogenation regeneration treatment to obtain a mixed regenerated hydrogen supply agent; The mixed regenerated hydrogen supply agent is fed into a separator for a fifth separation to obtain recycled hydrogen and the regenerated hydrogen supply agent; the regenerated hydrogen supply agent is returned to the slurry bed reactor; the recycled hydrogen is compressed and returned to the hydrogen supply agent hydrogenation reactor.

10. The method according to claim 9, characterized in that, The conditions for the hydrogenation regeneration treatment include: a reaction temperature of 150~250℃, a reaction pressure of 5-50 bar, and a volume ratio of hydrogen to the purified hydrogen supply agent of (0.1~999):

1.

11. The method according to claim 10, characterized in that, The conditions for the hydrogenation regeneration treatment include: a reaction temperature of 180~220℃ and a reaction pressure of 25~35 bar.

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