A method for treating distillate oil using a stripping and reboiling combined process

Abstract

The present disclosure relates to a method for treating distillate oil by a combined stripping and reboiling process, the method comprising: mixing raw oil, a hydrogen transfer catalyst, and a hydrogen donor, and then feeding the mixture into a reaction unit to carry out a hydrogen transfer reaction to obtain a hydrogen transfer reaction product; subjecting the hydrogen transfer reaction product to a first stripping treatment after heat exchange in a reboiler to obtain a gaseous light component; subjecting the gaseous light component to a flash evaporation treatment after heat exchange in a heat exchanger to obtain a first gaseous phase and a mixed spent agent; subjecting a portion of the mixed spent agent to a second stripping treatment as a spent agent to be stripped to obtain a second gaseous phase and a desulfurized spent agent; subjecting a portion of the desulfurized spent agent to a solvent extraction treatment as a hydrogen donor to be extracted to obtain a purified spent agent. The method disclosed herein can obtain an ultra-low sulfur content spent hydrogen donor that meets the feed requirements of solvent extraction, and can also maintain a high purity of the regenerated hydrogen donor, resulting in a high hydrogen supply efficiency in the reaction.

Description

Technical Field

[0001] The present disclosure relates to the field of petrochemical industry, and in particular to a method for treating distillate oil using a combined stripping and reboiling process. Background Art

[0002] At present, there are four major types of residue oil hydrogenation processes in the world, namely fixed bed, ebullating bed, moving bed and slurry bed residue oil hydrogenation. The advantage of slurry bed hydrogenation technology is that it can process the lowest quality residue oil, even coal, but its reaction system pressure is high, the chemical hydrogen consumption is higher than that of fixed bed, ebullating bed and moving bed, and the equipment investment is high.

[0003] The low-carbon deep processing technology for heavy and inferior residual oil, in the slurry bed residual oil hydrogenation, the reaction system is under high pressure and in the presence of hydrogen, the raw oil has poor properties and severe coking, and due to the low molecular weight of hydrogen, it is easy to escape and leak, causing a large safety risk; at the same time, the device is under high pressure conditions, the equipment investment is high, and the safety risk is high. These have brought great troubles to the stable, safe and long-term operation of the existing slurry bed residual oil hydrogenation device.

[0004] Recent research has used the recycling of hydrogenated distillate in hydrogenation reaction systems as a hydrogen donor to reduce coking. However, the recycling of large amounts of distillate significantly increases the energy consumption and investment of the device. Furthermore, the distillate yield in this section of the hydrogenation reaction is high. As the reaction time increases, the hydrogen-supplying components in the hydrogenated distillate gradually decrease, significantly reducing the hydrogen supply capacity during the reaction and making the coking reduction effect less pronounced.

[0005] Common hydrogen donors include distillates, alcohols, formic acid and its salts, cyclohexene, hydrazine hydrate, triethylsilane, and water. However, existing technologies often utilize recycled hydrogenated distillates or a single chemical injection process. This consumes large amounts of chemicals, leading to increased investment. Some hydrogen donor byproducts are difficult to separate from the product, resulting in substandard product specifications.

[0006] Existing hydrogenation processes are prone to coking when processing ultra-high viscosity and ultra-heavy oils, making them unsuitable for long-term operation. Therefore, a hydrogen donor is required to provide a hydrogen source and conduct the hydrogen transfer reaction at low pressure. However, the purity of the regenerated hydrogen donor decreases over time after multiple cycles. Solvent extraction combined processes can be used to purify the hydrogen donor, but solvent extraction requires very low sulfur content, while the sulfur content of the light fraction in the hydrogenation unit is very high. Conventional processes cannot meet the requirements of the combined process. Summary of the Invention

[0007] The purpose of the present disclosure is to provide a method for treating distillate oil by a combined steam stripping and reboiling process, in order to solve the problems in the prior art of high sulfur content in light components produced by hydrogenation units, low purity of circulating hydrogen supply agents, short lifespan and high energy consumption.

[0008] To achieve the above-mentioned objectives, the present disclosure provides a method for treating distillate oil using a stripping and reboiling process, the method comprising: mixing a feedstock oil, a hydrogen transfer catalyst, and a hydrogen donor, and then feeding the mixture into a reaction unit for a hydrogen transfer reaction to obtain a hydrogen transfer reaction product; passing the hydrogen transfer reaction product into a reboiler for heat exchange, and then into a first stripping tower for a first stripping treatment to obtain a gaseous light component and a mixed product; passing the gaseous light component into a heat exchanger for heat exchange, and then into a flash evaporation treatment to obtain a first gas phase and a mixed spent catalyst; allowing a portion of the mixed spent catalyst to enter the heat exchanger for heat exchange with the gaseous light component, and then into a second stripping tower for a second stripping treatment to obtain a second gas phase and a desulfurized spent catalyst; allowing another portion of the mixed spent catalyst to return to the first stripping tower for the first stripping treatment; allowing a portion of the desulfurized spent catalyst to enter a solvent extraction unit for solvent extraction treatment to obtain a purified spent catalyst; allowing another portion of the desulfurized spent catalyst to enter the reboiler for heat exchange with the hydrogen transfer reaction product, and then into the second stripping tower for further second stripping treatment.

[0009] Optionally, the feedstock oil is selected from one or more of vacuum residue, deasphalted oil, atmospheric residue, crude oil fractions with an initial boiling point greater than 350°C and extra-heavy crude oil; the hydrogen donor is selected from one or more of cycloalkanes with a carbon number of 6 to 18 and / or olefins with a carbon number of 6 to 18, preferably one or more of cyclohexane, cyclohexene, cyclohexadiene, methylcyclohexane and decahydronaphthalene; the hydrogen transfer catalyst is selected from one or more of oil-soluble liquid phase catalysts, non-precious metal solid catalysts and precious metal solid catalysts; the non-precious metal in the non-precious metal solid catalyst includes one or more of nickel, molybdenum and iron, and the precious metal in the precious metal solid catalyst includes one or more of platinum, gold, silver, ruthenium, rhodium and palladium.

[0010] Optionally, the hydrogen transfer reaction conditions include: reaction temperature of 150-450° C., reaction pressure of 5-70 bar, reaction time of 0.5-24 h; and a weight ratio of the distillate oil to the hydrogen donor of 1.25-100.

[0011] Optionally, the temperature of the hydrogen transfer reaction product is 150-450°C, and the temperature of the hydrogen transfer reaction product after heat exchange is 50-350°C; the temperature of another part of the desulfurization spent agent is 80-120°C, and the temperature of another part of the desulfurization spent agent after heat exchange is 180-210°C.

[0012] Optionally, the temperature of the gas phase light component is 150-250°C, and the temperature of the gas phase light component after heat exchange is 130-150°C; the temperature of a portion of the mixed spent catalyst is 35-45°C, and the temperature of a portion of the mixed spent catalyst after heat exchange is 180-210°C.

[0013] Optionally, the conditions for the first stripping treatment include: a temperature of 340-390°C, a pressure of 5-20 bar, and a weight ratio of the stripping medium of the first stripping treatment to the hydrogen transfer reaction product of (0.01-1):1; the conditions for the second stripping treatment include: a temperature of 200-350°C, a pressure of 5-20 bar, and a weight ratio of a portion of the mixed spent agent to another portion of the desulfurization spent agent of 1:(0.01-0.9).

[0014] Optionally, the method further comprises, before the flash evaporation treatment, cooling the gaseous light component after heat exchange to 35-45° C. and reducing the pressure to 5-20 bar.

[0015] Optionally, the method further includes sending the mixed product into a distillation tower for separation treatment to obtain a light oil product, a heavy oil product and unconverted oil; returning part of the unconverted oil to the reaction unit for the hydrogen transfer reaction; the distillate cut point between the light oil product and the heavy oil product is 300-360°C, and the distillate cut point between the heavy oil product and the unconverted oil is 480-540°C.

[0016] Optionally, the hydrogen sulfide content of the spent desulfurization agent is 0.1 to 50 ppm, preferably 0.2 to 1 ppm.

[0017] Optionally, the method further includes contacting the purified spent catalyst with hydrogen for hydrogenation regeneration treatment to obtain a regenerated hydrogen donor; returning the regenerated hydrogen donor to the reaction unit to continue the hydrogen transfer reaction; the conditions of the hydrogenation regeneration reaction include: a reaction temperature of 150 to 250° C., a reaction pressure of 5 to 50 bar, and a volume ratio of hydrogen to the purified spent catalyst of (0.1 to 999):1.

[0018] Through the above technical solution, a hydrogen donor is used instead of hydrogen to carry out the hydrogen transfer reaction, which can effectively reduce the viscosity of the oil product and reduce coking. At the same time, the introduction of the hydrogen donor will not affect the product quality, and the hydrogen donor can be recycled, with high economic benefits. The present disclosure uses a combined process of gas and reboiler. On the one hand, the hydrogen transfer reaction product and the gaseous light component are used as heat sources for heat exchange, without the consumption of heat exchange medium or fuel, which can reduce energy consumption. On the other hand, the hydrogen transfer reaction product and the mixed spent catalyst are separately stripped to obtain an ultra-low sulfur content spent hydrogen donor that meets the solvent extraction feed requirements, so that the regenerated hydrogen donor can maintain a high purity, so that it can maintain a high hydrogen supply efficiency during the reaction process.

[0019] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0021] Figure 1 The present invention discloses a process flow chart of a method for treating distillate oil by a combined stripping and reboiling process.

[0022] Description of Reference Numerals

[0023] A, reaction unit; B, solvent extraction unit; C, hydrogenation regeneration unit; P1, first reflux pump; P2, second reflux pump; H1, heat exchanger, H2, water cooler; H3, reboiler; C1, first stripping tower; C2, second stripping tower; C3, fractionation tower; D1, flash evaporation device;

[0024] 1. Feedstock oil and hydrogen transfer catalyst; 2. Hydrogen donor; 3. Hydrogen transfer reaction product; 4. Stripping medium of the first stripping treatment; 5. Hydrogen transfer reaction product after heat exchange; 6. Gas phase light components; 7. Gas phase light components after heat exchange; 8. Gas phase light components after cooling; 9. First gas phase; 10. Mixed spent catalyst; 11. Part of mixed spent catalyst; 12. Another part of mixed spent catalyst; 13. Part of desulfurized spent catalyst; 14. Second gas phase; 15. Desulfurized spent catalyst; 16. Another part of desulfurized spent catalyst; 17. Mixed product; 18. Light oil product; 19. Heavy oil product; 20. Unconverted oil; 21. Part of unconverted oil; 22. Hydrogen; 23. Purified spent catalyst; 24. Regenerated hydrogen donor. DETAILED DESCRIPTION

[0025] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0026] In this disclosure, unless otherwise indicated, the terms "first," "second," and "third" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, features specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this disclosure, "plurality" means two or more, unless otherwise specifically defined.

[0027] The present disclosure provides a method for treating distillate oil using a stripping and reboiling process, which comprises: mixing feedstock oil, a hydrogen transfer catalyst, and a hydrogen donor, and then feeding the mixture into a reaction unit for hydrogen transfer reaction to obtain a hydrogen transfer reaction product; passing the hydrogen transfer reaction product into a reboiler for heat exchange, and then feeding it into a first stripping tower for a first stripping treatment to obtain a gaseous light component and a mixed product; passing the gaseous light component into a heat exchanger for heat exchange, and then feeding it into a flash evaporation treatment to obtain a first gas phase and a mixed spent catalyst; allowing a portion of the mixed spent catalyst to enter the heat exchanger for heat exchange with the gaseous light component, and then feeding it into a second stripping tower for a second stripping treatment to obtain a second gas phase and a desulfurized spent catalyst; allowing another portion of the mixed spent catalyst to return to the first stripping tower for the first stripping treatment; allowing a portion of the desulfurized spent catalyst to enter a solvent extraction unit for solvent extraction treatment to obtain a purified spent catalyst; allowing another portion of the desulfurized spent catalyst to enter the reboiler for heat exchange with the hydrogen transfer reaction product, and then feeding it into the second stripping tower for further second stripping treatment.

[0028] Through the above technical solution, a hydrogen donor is used instead of hydrogen to carry out the hydrogen transfer reaction, which can effectively reduce the viscosity of the oil product and reduce coking. At the same time, the introduction of the hydrogen donor will not affect the product quality, and the hydrogen donor can be recycled, with high economic benefits. The present disclosure uses a combined process of gas and reboiler. On the one hand, the hydrogen transfer reaction product and the gaseous light component are used as heat sources for heat exchange, without the consumption of heat exchange medium or fuel, which can reduce energy consumption. On the other hand, the hydrogen transfer reaction product and the mixed spent catalyst are separately stripped to obtain an ultra-low sulfur content spent hydrogen donor that meets the solvent extraction feed requirements, so that the regenerated hydrogen donor can maintain a high purity, so that it can maintain a high hydrogen supply efficiency during the reaction process.

[0029] The feedstock oil used in the present disclosure may be selected from one or more of vacuum residue, deasphalted oil, atmospheric residue, crude oil fractions with an initial boiling point greater than 350° C., and extra-thick crude oil.

[0030] The hydrogen donor used in the present disclosure is a conventional choice in the art and is not subject to special requirements in this application. For example, the hydrogen donor can be selected from distillate oil, alcohol, alkane or olefin after hydrogenation in the hydrogenation reaction system; in one embodiment of the present disclosure, the hydrogen donor can be selected from cycloalkanes with a carbon number of 6 to 18 and / or olefins with a carbon number of 6 to 18, preferably one or more of cyclohexane, cyclohexene, cyclohexadiene, methylcyclohexane and decalin.

[0031] The hydrogen transfer catalyst used in the present disclosure is a conventional choice in the art and is not specifically required in this application. For example, the hydrogen transfer catalyst is selected from one or more of an oil-soluble liquid-phase catalyst, a non-precious metal solid catalyst, and a precious metal solid catalyst; wherein the non-precious metal in the non-precious metal solid catalyst includes one or more of nickel, molybdenum, and iron, and the precious metal in the precious metal solid catalyst includes one or more of platinum, gold, silver, ruthenium, rhodium, and palladium.

[0032] The hydrogen transfer reaction disclosed in the present invention is carried out in a slurry bed reactor, wherein the slurry bed reactor is a conventional choice in the art and is not specifically required in this application.

[0033] In one embodiment, the hydrogen transfer reaction conditions include: a reaction temperature of 150 to 450° C., preferably 300 to 440° C., and more preferably 420 to 430° C.; a reaction pressure of 5 to 70 bar, preferably 20 to 60 bar, and more preferably 35 to 50 bar; a reaction time of 0.5 to 24 h, preferably 0.5 to 12 h, and more preferably 0.5 to 2.5 h; and a weight ratio of the distillate oil to the hydrogen donor of 1.25 to 100, preferably 1.5 to 50, and more preferably 2 to 5.

[0034] In the above-described embodiment, the use of a hydrogen donor in the hydrogen transfer reaction disclosed herein, instead of hydrogen gas as used in the prior art, can reduce the pressure of the hydrogen transfer reaction, effectively lowering oil viscosity and reducing coking. Furthermore, the introduction of the hydrogen donor does not affect product quality. Furthermore, the hydrogen donor can be regenerated and recycled through a subsequent regeneration process, thereby improving economic efficiency. Furthermore, the above-described hydrogen transfer reaction conditions can improve the performance of the hydrogen transfer reaction.

[0035] The present disclosure combines stripping treatment and reboiling treatment to treat the hydrogen transfer reaction product. Specifically, the hydrogen transfer reaction product is heat exchanged in the tube side of the reboiler with another part of the desulfurization spent agent entering the shell side of the reboiler, wherein the temperature of the hydrogen transfer reaction product is 150-450°C and the pressure is 5-70 bar; the temperature of the hydrogen transfer reaction product after heat exchange is 50-350°C and the pressure is 5-50 bar; the temperature of the other part of the desulfurization spent agent is 80-120°C and the pressure is 10-140 bar; the temperature of the other part of the desulfurization spent agent after heat exchange is 180-210°C and the pressure is 5-50 bar.

[0036] The present disclosure sends the hydrogen transfer reaction product after heat exchange into a first stripping tower for a first stripping treatment with a stripping medium, which can separate the hydrogen transfer reaction product into a gaseous light component and a mixed product. The stripping medium is conventionally selected in the art and is not specifically required in this application. For example, in a specific embodiment of the present disclosure, the stripping medium for the first stripping treatment is water vapor.

[0037] In one embodiment, the conditions of the first stripping treatment include: a temperature of 340 to 390°C, preferably 340 to 360°C; a pressure of 5 to 20 bar, preferably 8 to 15 bar; and a weight ratio of the stripping medium of the first stripping treatment to the hydrogen transfer reaction product of (0.01 to 0.9):1, preferably (0.1 to 0.5):1.

[0038] In this embodiment, the higher-temperature hydrogen transfer reaction product is first heat-exchanged with another portion of desulfurization spent catalyst at a lower temperature. This allows the temperature of the hydrogen transfer reaction product to be lowered and the temperature of the other portion of desulfurization spent catalyst to be raised without the use of a cooling medium, thereby reducing energy consumption of the device. The heat-exchanged hydrogen transfer reaction product is then subjected to a first steam stripping treatment, which improves the separation efficiency of the hydrogen transfer reaction product. Furthermore, the use of the above-described first steam stripping treatment conditions can further improve the separation efficiency of the hydrogen transfer reaction product.

[0039] The gas phase light component separated by the first stripping treatment in the present disclosure contains the used hydrogen donor, and the mixed product contains light oil product, heavy oil product and unconverted oil. Therefore, the gas phase light component and the mixed product need to be treated separately.

[0040] In one embodiment, the method further comprises sending the mixed product into a fractionation tower for separation to obtain a light oil product, a heavy oil product, and unconverted oil; the cut point between the light oil product and the heavy oil product is 300-360°C, and the cut point between the heavy oil product and the unconverted oil is 480-540°C. The unconverted oil contains a hydrogen transfer catalyst, so that a portion of the unconverted oil is returned to the reaction unit for the hydrogen transfer reaction, and the remaining portion is sent out of the system.

[0041] In one embodiment, the gaseous light component enters the tube side of the heat exchanger for heat exchange with a portion of the mixed spent catalyst entering the shell side of the heat exchanger, wherein the temperature of the gaseous light component is 150-250°C and the pressure is 5-45 bar; the temperature of the gaseous light component after heat exchange is 130-150°C and the pressure is 5-40 bar; the temperature of a portion of the mixed spent catalyst is 35-45°C and the pressure is 5-40 bar; the temperature of a portion of the mixed spent catalyst after heat exchange is 180-210°C and the pressure is 5-40 bar.

[0042] In one embodiment, the method further includes, prior to the flash evaporation, cooling the heat-exchanged light gaseous component to 35-45°C via a water cooler, reducing the pressure to 5-20 bar via a pressure reducing valve, and then feeding the component into a flash evaporation device for flash evaporation. In this embodiment, the flash tank can be used to separate the mixed spent catalyst from the light gaseous component, and the mixed spent catalyst can be purified through subsequent treatment.

[0043] In one embodiment, the mixed spent agent after heat exchange is fed into a second stripping tower for a second stripping treatment, wherein the stripping medium is conventionally selected in the art and is not specifically required by this application. For example, in this disclosure, the stripping medium used in the second stripping treatment is another portion of desulfurized spent agent; the conditions for the second stripping treatment include: a temperature of 200-350°C, a pressure of 5-20 bar, and a weight ratio of one portion of the mixed spent agent to the other portion of the desulfurized spent agent of 1:(0.01-0.9), preferably 1:(0.1-0.5). In this embodiment, the sulfur content of the desulfurized spent agent obtained by the second stripping treatment is removed by the stripping medium. For example, the hydrogen sulfide content of the desulfurized spent agent obtained by the method of the present disclosure is 0.1-50 ppm, preferably 0.2-1 ppm.

[0044] In order to further improve the ability to remove impurities in the desulfurization spent agent, in one embodiment of the present disclosure, the solvent used for solvent extraction is selected from one or more of alcohol ethers, sulfoxides and sulfones, preferably one or more of diethylene glycol ether, triethylene glycol ether, tetraethylene glycol ether, dimethyl sulfoxide and cyclopentane sulfone; in addition, the conditions for solvent extraction include: temperature of 100-250°C, preferably 150-200°C; pressure of 5-30 bar, preferably 10-20 bar.

[0045] In one embodiment, the method of the present disclosure further includes contacting the purified spent catalyst with hydrogen for hydrogenation regeneration to obtain a regenerated hydrogen donor; and returning the regenerated hydrogen donor to the reaction unit for the hydrogen transfer reaction.

[0046] The hydrogenation regeneration treatment performed in the present disclosure is a conventional choice in the art and is not specifically required in this application. For example, the conditions of the hydrogenation regeneration reaction include: a reaction temperature of 150 to 250° C., preferably 180 to 220° C.; a reaction pressure of 5 to 50 bar, preferably 10 to 30 bar; and a volume ratio of the hydrogen to the purified spent catalyst of (0.1 to 999):1, preferably (50 to 150):1.

[0047] In one embodiment, Figure 1 As shown, the method for treating distillate oil by a combined stripping and reboiling process includes:

[0048] Feed the crude oil, hydrogen transfer catalyst 1 and hydrogen donor 2 into reaction unit A for hydrogen transfer reaction to obtain hydrogen transfer reaction product 3; subject the hydrogen transfer reaction product 3 to heat exchange in reboiler H3 to obtain heat-exchanged hydrogen transfer reaction product 5; subject the heat-exchanged hydrogen transfer reaction product 5 to first stripping treatment in first stripping tower C1 and first stripping treatment with stripping medium 4 to obtain gaseous light component 6 and mixed product 17; subject the gaseous light component 6 to heat exchange in heat exchanger H1 to obtain heat-exchanged gaseous light component 7; subject the heat-exchanged gaseous light component 7 to cooling in water cooler H2 to obtain cooled gaseous light component 8; subject the cooled gaseous light component 8 to decompression in pressure reducing valve and then subject it to flash evaporation device D1 for flash evaporation treatment to obtain first gas phase 9 and mixed spent catalyst 10; subject the mixed spent catalyst 10 to first reflux After being pressurized by the pump P1, the mixture is divided into two parts. One part of the mixed spent agent 11 enters the second stripping tower C2 for the second stripping treatment to obtain a second gas phase 14 and a desulfurized spent agent 15. The other part of the mixed spent agent 12 is returned to the first stripping tower C1 to continue the first stripping treatment. The desulfurized spent agent 15 is pressurized by the second reflux pump P2 and divided into two parts. One part of the desulfurized spent agent 13 enters the solvent extraction unit B for the solvent extraction treatment to obtain a purified spent agent 23. The other part of the desulfurized spent agent 16 is returned to the second stripping tower C2 for the second stripping treatment. The purified spent agent 23 is contacted with hydrogen 22 in the hydrogenation regeneration unit C for hydrogenation regeneration treatment to obtain a regenerated hydrogen donor 24. The regenerated hydrogen donor 24 is returned to the reaction unit A to continue the hydrogen transfer reaction. The mixed product 17 enters the fractionation tower C3 for fractionation treatment to obtain a light oil product 18, a heavy oil product 19 and unconverted oil 20, and a portion of the unconverted oil 21 is returned to the reaction unit A for the hydrogen transfer reaction.

[0049] The present disclosure is further illustrated by the following examples, but the present disclosure is not limited thereby. The raw material 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 oil-soluble organic homogeneous molybdenum catalyst. The hydrogen donor used was cyclohexane. All reagents used were of analytical grade unless otherwise specified.

[0050] Table 1 Properties of crude oil

[0051] index Numerical <![CDATA[Density (20 °C) / (g / cm 3 )]]> 1073 Viscosity (20℃) / (mPa·s) 900 Sulfur wt% 3.6 Ni(ppm) 41 V(ppm) 108 Asphaltene wt% 11

[0052] Example 1

[0053] 100 t / h of feedstock oil, a hydrogen transfer catalyst (2 t charged at once, with a flow rate of 0.2 t / h after stable operation) 1, and 10 t / h of a hydrogen donor 2 were fed into reaction unit A for a hydrogen transfer reaction to produce a hydrogen transfer reaction product 3. The hydrogen transfer reaction conditions included a reaction temperature of 425°C, a reaction pressure of 45 bar, a reaction time of 12 hours, and a weight ratio of feedstock oil to hydrogen donor 2 of 5:1. The 110 t / h hydrogen transfer reaction product 3 was then heat exchanged in a reboiler H3 to 320°C to produce a heat-exchanged hydrogen transfer reaction product 5.

[0054] 110 t / h of the heat-exchanged hydrogen transfer reaction product 5 enters the first stripping tower C1 for a first stripping treatment with 2 t / h of the first stripping treatment stripping medium 4 (steam), yielding a gaseous light component 6 and a mixed product 17. The first stripping treatment conditions include a temperature of 390°C, a pressure of 12 bar, and a weight ratio of the first stripping treatment stripping medium 4 to the heat-exchanged hydrogen transfer reaction product 5 of 1:55. Mixed product 17 enters a fractionation tower C3 for fractionation, yielding a light oil product 18, a heavy oil product 19, and unconverted oil 20. A portion of the unconverted oil 21 is returned to reaction unit A for the hydrogen transfer reaction.

[0055] The gaseous light component 6 is heat exchanged to 110°C in the heat exchanger H1 to obtain a heat-exchanged gaseous light component 7. The heat-exchanged gaseous light component 7 is cooled to 40°C in the water cooler H2 to obtain a cooled gaseous light component 8. The cooled gaseous light component 8 is depressurized to 6 bar by a pressure reducing valve and then enters the flash evaporation device D1 for flash evaporation treatment to obtain a first gas phase 9 and a mixed spent catalyst 10. A portion of the mixed spent catalyst 11 (90 wt%) enters the heat exchanger H1 and exchanges heat with the gaseous light component 6 to 200°C, and then enters the second stripping tower C2 for a second stripping treatment to obtain a second gas phase 14 and a desulfurized spent catalyst 15. Another portion of the mixed spent catalyst 12 (10 wt%) is returned to the first stripping tower C1 to continue the first stripping treatment. The conditions for the second stripping treatment include: a temperature of 340°C, a pressure of 20 bar, and a weight ratio of the portion of the mixed spent catalyst 11 to the portion of the desulfurized spent catalyst 16 of 1:0.2.

[0056] A portion of the spent desulfurization agent 13 (80 wt%) is introduced into the solvent extraction unit B for solvent extraction treatment to obtain a purified spent desulfurization agent 23. Another portion of the spent desulfurization agent 16 (20 wt%) is introduced into the reboiler H3 for heat exchange with the hydrogen transfer reaction product 3 to 150° C., and then introduced into the second stripping tower C2 for a second stripping treatment. The extraction treatment conditions include: a temperature of 150° C., a pressure of 15 bar, and sulfolane as the extraction solvent.

[0057] In the hydrogenation regeneration unit C, the purified spent catalyst 23 was contacted with hydrogen 22 for hydrogenation regeneration, yielding a regenerated hydrogen donor 24. The regenerated hydrogen donor 24 was then returned to the reaction unit A for further hydrogen transfer reaction. The hydrogenation regeneration reaction conditions included a reaction temperature of 200°C, a reaction pressure of 30 bar, and a volume ratio of hydrogen 22 to purified spent catalyst 23 of 50:1. The resulting product specifications are shown in Table 2.

[0058] Comparative Example 1

[0059] The method for treating the distillate oil is the same as that in Example 1, except that the hydrogen donor 2 is replaced with an equivalent amount of hydrogen. The product indicators obtained are shown in Table 2.

[0060] Comparative Example 2

[0061] The method for treating the distillate oil is the same as that in Example 1, except that the mixed spent catalyst obtained by flash evaporating the light gaseous component is directly subjected to solvent extraction. The product indicators are shown in Table 2.

[0062] Table 2 Product properties of Examples and Comparative Examples

[0063]

[0064]

[0065] According to the data in Table 2, it can be seen from the comparison of the data in Example 1 and Comparative Examples 1 to 2 that the method disclosed in the present invention can improve the yield of liquid products and keep the regenerated hydrogen supply agent at a high purity; in addition, the present invention does not consume heat exchange medium or fuel, which can reduce energy consumption. According to the comparison of the data in Example 1 and Comparative Example 1, the use of a hydrogen supply agent instead of hydrogen in the prior art can improve the yield of liquid products and reduce coking. At the same time, the hydrogen supply agent can be recycled and has high economic benefits. According to the comparison of the data in Example 1 and Comparative Example 2, it can be seen that the method for separating the used hydrogen supply agent disclosed in the present invention can keep the regenerated hydrogen supply agent at a high purity and reduce the sulfur content of the hydrogen supply agent to be regenerated entering the solvent extraction unit.

[0066] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0067] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0068] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for treating distillate oil by a stripping and reboiling combined process, characterized in that: The method includes: A feedstock oil, a hydrogen transfer catalyst, and a hydrogen donor are mixed and fed into a reaction unit for hydrogen transfer reaction to obtain a hydrogen transfer reaction product; the hydrogen donor is selected from cycloalkanes with 6 to 18 carbon atoms and / or olefins with 6 to 18 carbon atoms; the conditions of the hydrogen transfer reaction include: a reaction temperature of 150 to 450° C., a reaction pressure of 5 to 70 bar, and a reaction time of 0.5 to 24 hours; and a weight ratio of the feedstock oil to the hydrogen donor is 1.25 to 100; The hydrogen transfer reaction product enters a reboiler for heat exchange and then enters a first stripping tower for a first stripping treatment to obtain a gaseous light component and a mixed product; the conditions of the first stripping treatment include: a temperature of 340-390° C., a pressure of 5-20 bar, and a weight ratio of a stripping medium for the first stripping treatment to the hydrogen transfer reaction product of (0.01-1):1; The light component in the gas phase enters a heat exchanger for heat exchange and then undergoes flash evaporation to obtain a first gas phase and a mixed spent catalyst; A portion of the mixed spent catalyst enters the heat exchanger for heat exchange with the gas phase light component and then enters the second stripping tower for a second stripping treatment to obtain a second gas phase and a desulfurized spent catalyst; another portion of the mixed spent catalyst returns to the first stripping tower for the first stripping treatment; the conditions of the second stripping treatment include: a temperature of 200-350° C., a pressure of 5-20 bar, and a weight ratio of the portion of the mixed spent catalyst to the portion of the desulfurized spent catalyst of 1:(0.01-0.9); A portion of the desulfurization spent agent enters the solvent extraction unit for solvent extraction treatment to obtain purified spent agent; another portion of the desulfurization spent agent enters the reboiler for heat exchange with the hydrogen transfer reaction product and then returns to the second stripping tower to continue the second stripping treatment.

2. The method according to claim 1, characterized in that The raw oil is selected from one or more of vacuum residue, deasphalted oil, atmospheric residue, crude oil fractions with an initial boiling point greater than 350°C, and extra-thick crude oil; The hydrogen donor is selected from one or more of cyclohexane, cyclohexene, cyclohexadiene, methylcyclohexane and decalin; The hydrogen transfer catalyst is selected from one or more of an oil-soluble liquid phase catalyst, a non-precious metal solid catalyst and a precious metal solid catalyst; the non-precious metal in the non-precious metal solid catalyst includes one or more of nickel, molybdenum and iron, and the precious metal in the precious metal solid catalyst includes one or more of platinum, gold, silver, ruthenium, rhodium and palladium.

3. The method according to claim 1, characterized in that The temperature of the hydrogen transfer reaction product is 150-450° C., and the temperature of the hydrogen transfer reaction product after heat exchange is 50-350° C.; The temperature of the other part of the desulfurization spent agent is 80-120°C; the temperature of the other part of the desulfurization spent agent after heat exchange is 180-210°C.

4. The method according to claim 3, characterized in that The temperature of the gaseous light component is 150-250°C, and the temperature of the gaseous light component after heat exchange is 130-150°C; The temperature of a portion of the mixed spent catalyst is 35-45° C., and the temperature of a portion of the mixed spent catalyst after heat exchange is 180-210° C.

5. The method according to claim 1, wherein The method further includes, before the flash evaporation treatment, cooling the gas phase light component after heat exchange to 35-45° C. and reducing the pressure to 5-20 bar.

6. The method according to claim 1, characterized in that The method further comprises sending the mixed product into a fractionation tower for separation to obtain a light oil product, a heavy oil product and unconverted oil; returning a portion of the unconverted oil to the reaction unit for the hydrogen transfer reaction; The distillation cut point between the light oil product and the heavy oil product is 300-360°C, and the distillation cut point between the heavy oil product and the unconverted oil is 480-540°C.

7. The method according to claim 1, characterized in that The hydrogen sulfide content of the spent desulfurization agent is 0.1-50 ppm.

8. The method according to claim 7, characterized in that The hydrogen sulfide content of the spent desulfurization agent is 0.2-1 ppm.

9. The method according to claim 7, characterized in that The method further includes contacting the purified spent catalyst with hydrogen to perform hydrogenation regeneration treatment to obtain a regenerated hydrogen donor; returning the regenerated hydrogen donor to the reaction unit to perform the hydrogen transfer reaction; The conditions of the hydrogenation regeneration reaction include: a reaction temperature of 150-250° C., a reaction pressure of 5-50 bar, and a volume ratio of the hydrogen to the spent catalyst of the purification process of (0.1-999):1.

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