A residue processing system and method

Abstract

The present application belongs to the technical field of slurry bed hydrogenation, and discloses a residual oil processing system and method. The system comprises a residual oil hydrogenation reaction device, an oil-gas separation unit, an atmospheric distillation unit, a vacuum distillation unit and a raw oil feeding pipeline. The present application has the technical characteristics of simple structure, improved economic benefits, reduced investment cost and device operation energy consumption, etc.

Description

Technical Field

[0001] This invention belongs to the field of slurry bed hydrogenation technology, and more specifically, relates to a residue oil processing system and method. Background Technology

[0002] Currently, slurry-bed residue hydrotreating units are increasingly widely used in petrochemical production processes due to their high conversion rate of macromolecular hydrocracking and high yield of high-value-added products. More than ten slurry-bed residue hydrotreating technologies have been developed domestically and internationally, including: HDH-plus technology developed jointly by INTEPE and Veba; Uniflex technology developed by UOP (USA); LC-Slurry technology developed by Chevron Lummus (USA); EST technology developed by Enitecnologies; and RMAC technology developed by the China Petroleum & Chemical Research Institute Co., Ltd. According to the report "Current Status and Prospect of Slurry-Bed Residue Hydrotreating Technology," the process flows of existing slurry-bed residue hydrotreating technologies differ slightly, but the following two points are basically consistent: 1. In the feed process, the feedstock is mixed with hydrogen and then enters the slurry-bed reactor for reaction. 2. After cooling and depressurization separation, the heavy slurry enters the vacuum distillation tower, while the light and medium oils enter the atmospheric distillation tower for separating different hydrocarbon fractions.

[0003] However, existing slurry-bed residue hydrotreating technology has the following two problems: 1. Due to the high viscosity of residue oil, it is often blended with one or more distillate oils such as heavy diesel oil and wax oil to facilitate transportation and storage, thereby reducing the viscosity and improving the fluidity of the residue oil. Since the reaction rate of diesel oil and wax oil in the slurry-bed residue hydrotreating reactor is relatively slow, this leads to an increase in the reactor's throughput and energy consumption. Simultaneously, the high temperature and high pressure conditions of the slurry-bed hydrotreating reactor result in higher investment costs and greater difficulty in equipment manufacturing. 2. During slurry-bed hydrotreating, the reaction rate of gums is greater than that of asphaltenes, increasing the concentration difference between asphaltenes and gums. After separation and entry into the vacuum distillation tower, the trays are prone to coking under high temperature and low pressure conditions, clogging the tower and leading to poor unit stability and inability to operate stably for long periods. To solve this problem, some units have installed backup vacuum distillation towers, increasing additional investment costs.

[0004] Therefore, there is an urgent need to propose a new system and method for processing residual oil. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a residue oil processing system and method. This invention features simple structure, improved economic efficiency, reduced investment costs, and lower energy consumption during operation.

[0006] To achieve the above objectives, the present invention provides a residue oil processing system, the system comprising a residue oil hydrogenation reactor, an oil-gas separation unit, an atmospheric distillation unit, a vacuum distillation unit, and a feedstock pipeline;

[0007] The residue hydrotreating reactor is connected to the oil-gas separation unit via a product pipeline.

[0008] The oil-gas separation unit is equipped with a slurry discharge pipeline, a low-separation oil discharge pipeline, a light oil discharge pipeline, and a circulating hydrogen pipeline.

[0009] The low-grade oil discharge pipeline is connected to the atmospheric distillation unit, which is equipped with an atmospheric distillation tower bottom oil discharge pipeline and at least one first light component discharge pipeline.

[0010] The slurry discharge pipeline, the atmospheric distillation tower bottom oil discharge pipeline, and the feed oil pipeline converge and are connected to the vacuum distillation unit. The vacuum distillation unit is equipped with a vacuum distillation tower bottom oil discharge pipeline and at least one second light component discharge pipeline. The outlet of the vacuum distillation tower bottom oil discharge pipeline is divided into two paths: one is used as an external discharge pipeline, and the other is used as a circulating oil pipeline. The fresh hydrogen feed pipeline and the circulating hydrogen pipeline converge to form a total hydrogen feed pipeline, which is then connected to the residue hydrogenation reactor together with the circulating oil pipeline.

[0011] According to the present invention, preferably, the feedstock oil pipeline is first connected to the feedstock buffer tank and then merges with the slurry discharge pipeline and the atmospheric distillation tower bottom oil discharge pipeline.

[0012] According to the present invention, preferably, the residue hydrotreating reactor is further connected to a catalyst feed pipeline.

[0013] According to the present invention, preferably, the residue hydrotreating apparatus is provided with at least one residue hydrotreating reactor, and more preferably, the residue hydrotreating reactor is at least one of a slurry bed reactor, a slurry bed reactor, a moving bed reactor, and a fixed bed reactor.

[0014] According to the present invention, preferably, the oil and gas separation unit includes a heavy hydrogenation product separator, a medium hydrogenation product separator, and a hydrogen recovery separator;

[0015] The heavy hydrotreating product separator is used to separate the slurry and gaseous streams from the hydrotreating products of the residue hydrotreating reactor.

[0016] The medium-quality hydrotreating product separator is used to separate the low-grade oil and hydrogen-containing light hydrocarbon fractions in the gaseous stream.

[0017] The hydrogen recovery separator is used to separate circulating hydrogen and light oil in the hydrogen-containing gas phase light hydrocarbon fraction.

[0018] According to the present invention, preferably, the atmospheric distillation unit includes a first heating furnace and an atmospheric distillation column;

[0019] The low-separation oil discharge pipeline is connected to the atmospheric distillation tower via the first heating furnace;

[0020] The bottom oil discharge pipeline of the atmospheric distillation tower and at least one first light component discharge pipeline are installed on the atmospheric distillation tower; the atmospheric distillation tower is the atmospheric distillation tower in the atmospheric and vacuum distillation unit of the refinery (that is, the atmospheric distillation tower can be shared with the atmospheric distillation tower in the atmospheric and vacuum distillation unit of the refinery).

[0021] The first light component discharge pipeline includes at least one of a naphtha discharge pipeline, a light diesel oil discharge pipeline, a heavy diesel oil discharge pipeline, and a dry gas discharge pipeline.

[0022] According to the present invention, preferably, the vacuum distillation unit includes a second heating furnace and a vacuum distillation column;

[0023] The bottom oil discharge pipeline of the atmospheric distillation tower and the feed oil pipeline merge and are connected to the second heater, then merge with the slurry discharge pipeline, and finally connect to the vacuum distillation tower.

[0024] The bottom oil discharge pipeline of the vacuum distillation tower and at least one second light component discharge pipeline are installed on the vacuum distillation tower; the vacuum distillation tower is a vacuum distillation tower in the atmospheric and vacuum distillation unit of the refinery (that is, the vacuum distillation tower can be shared with the vacuum distillation tower in the atmospheric and vacuum distillation unit of the refinery).

[0025] The second light component discharge line includes at least one of a light wax oil discharge line and a heavy wax oil discharge line.

[0026] According to the present invention, preferably, the system further includes a hydrogen heater, and the main hydrogen feed line is connected to the hydrogen heater and then connected to the residue oil hydrogenation reactor together with the circulating oil line.

[0027] Another aspect of the present invention provides a method for processing residual oil, the method employing the above-described system and comprising the following steps:

[0028] S1: The effluent from the residual oil hydrotreating reactor is sent to the oil-gas separation unit, where it is separated to obtain slurry, low-grade oil, light oil, and recycled hydrogen.

[0029] S2: The low-grade oil is sent to the atmospheric distillation unit for atmospheric distillation to obtain atmospheric distillation column bottom oil and the first light component; the slurry, the atmospheric distillation column bottom oil and the feed oil are sent together to the vacuum distillation unit for vacuum distillation to obtain vacuum distillation column bottom oil and the second light component.

[0030] S3: The bottom oil of the vacuum distillation tower is divided into two parts, one part is discharged and the remaining part is used as circulating oil; the circulating hydrogen and fresh hydrogen feed are combined into total hydrogen and sent together with the circulating oil to the residue hydrotreating reactor for hydrotreating reaction.

[0031] In this invention, the method further includes discharging the light oil obtained in step S1 through a light oil discharge pipeline system.

[0032] According to the present invention, preferably, the feedstock oil is at least one of residual oil, wax oil, and deasphalted oil; preferably, the residual oil is atmospheric residual oil containing a flow promoter and / or vacuum residual oil containing a flow promoter, wherein the flow promoter is at least one of gasoline, diesel, light wax oil, and heavy wax oil; more preferably, the blending ratio of the flow promoter in the residual oil is 0% to 60 wt%, and even more preferably 15% to 50 wt%; preferably, the wax oil is vacuum wax oil and / or coking wax oil.

[0033] According to the present invention, preferably, the light oil is a hydrocarbon with a boiling point below 40°C.

[0034] According to the present invention, preferably, the low-separation oil is a liquid phase obtained by separation at a pressure of 2.0 to 17.0 MPa and a temperature of 40 to 350°C.

[0035] According to the present invention, preferably, the slurry is a liquid phase separated at a pressure of 15.0 to 25.0 MPa and a temperature of 300 to 500 °C.

[0036] According to the present invention, preferably, the low-grade oil is first sent to the first heating furnace of the atmospheric distillation unit and heated to 300-450°C, and then sent to the atmospheric distillation column of the atmospheric distillation unit for atmospheric distillation to obtain the bottom oil of the atmospheric distillation column and the first light component.

[0037] According to the present invention, preferably, the bottom oil of the atmospheric distillation tower and the feed oil are sent to the second heating furnace of the vacuum distillation unit to obtain a heated mixture, the temperature of which is 280-400°C; the heated mixture and the slurry are sent together to the vacuum distillation tower of the vacuum distillation unit, and after vacuum distillation, the bottom oil of the vacuum distillation tower and the second light component are obtained.

[0038] According to the present invention, preferably, the bottom oil of the atmospheric distillation column is a fraction with a temperature >300°C.

[0039] According to the present invention, preferably, the bottom oil of the vacuum distillation tower is a fraction with a temperature >400°C.

[0040] According to the present invention, preferably, the first light component includes at least one of top gas, naphtha, light diesel oil, and heavy diesel oil.

[0041] According to the present invention, preferably, the second light component includes at least one of light wax oil and heavy wax oil.

[0042] In this invention, the vacuum distillation bottom oil and the second light component include the residue oil and wax oil generated during the hydrogenation reaction, as well as the residue oil and wax oil carried in by the feedstock oil.

[0043] In this invention, the light wax oil and heavy wax oil in the second light component include the light wax oil and heavy wax oil generated in step S2, as well as the light wax oil and heavy wax oil brought in by the raw material oil.

[0044] According to the present invention, preferably, the feed of the residue hydrotreating reactor further includes a catalyst, wherein the catalyst is at least one selected from molybdenum, nickel, cobalt, molybdenum alloy, nickel alloy, cobalt alloy, molybdenum-containing cobalt alloy, cobalt-containing and / or molybdenum-containing nickel alloy, molybdenum oxide, nickel oxide and cobalt oxide.

[0045] According to the present invention, preferably, the operating conditions of the residue hydrotreating reactor include: a reaction pressure of 15.0 MPa to 25.0 MPa, a reaction temperature of 380°C to 450°C, and a volume hourly space velocity of 0.05 h⁻¹. -1 ~0.2h -1 The hydrogen-to-oil volume ratio is 500–1200:1.

[0046] According to the present invention, preferably, the hydrogenation reaction is at least one of hydrodeoxygenation, hydrodemetallization, hydrodesulfurization, and hydrocracking.

[0047] According to the present invention, preferably, the amount of vacuum distillation tower bottom oil discharged from the system accounts for 1-20% of the total amount of vacuum distillation tower bottom oil, with the remainder used as circulating oil. In the present invention, the circulating oil includes heavy oil with a distillation range >400°C from the feedstock and unreacted oil from step S2.

[0048] The beneficial effects of the technical solution of the present invention are as follows:

[0049] This invention features simple structure, improved economic efficiency, reduced investment costs and energy consumption during device operation.

[0050] Typically, the wax oil added to the residue oil to improve its fluidity does not participate in the reaction after entering the residue oil hydrotreating reactor, leading to an increase in the reactor's throughput. In the method of this invention, the residue oil first passes through an atmospheric distillation tower and a vacuum distillation tower to separate the light fraction, and the heavy components then enter the residue oil hydrotreating reactor. This helps to improve the operating cycle of the vacuum distillation unit, reduce the throughput of the slurry bed hydrotreating reactor, and lower the design load, thus saving energy and reducing investment costs.

[0051] After being heated, the bottom oil of the atmospheric distillation tower is mixed with the slurry. The temperature of the mixture flow can be controlled by adjusting the temperature of the second heater, so that the feed temperature of the vacuum distillation tower can be kept stable, which has the advantage of controllable temperature of the vacuum distillation tower.

[0052] Typically, the feed to a vacuum distillation column includes a slurry. The slurry contains a high concentration of tetrahydrofuran insolubles, which makes the trays of the vacuum distillation column prone to coking and results in a short operating cycle. In the method of this invention, the bottom oil of the atmospheric distillation column can dilute the slurry, reduce the concentration of tetrahydrofuran insolubles, help alleviate scaling in the bottom section of the vacuum distillation column, and has the advantage of increasing the operating cycle of the vacuum distillation column, thereby improving the overall system uptime.

[0053] This invention utilizes the vacuum distillation column and atmospheric distillation column of a refinery's atmospheric and vacuum distillation unit as the vacuum distillation column and atmospheric distillation column in its system, forming a coupled system. This reduces the number of equipment units in the system and the atmospheric and vacuum distillation unit, lowering investment expenditure, energy consumption, and plant footprint, and also reducing carbon emissions. Specifically, since the atmospheric and vacuum distillation unit and the system of this invention share a set of vacuum distillation columns and atmospheric distillation columns, instead of using separate sets, this reduction in the number of units is possible. Therefore, due to reduced fouling and downtime, as well as lower capital costs resulting from the reduced number of units, the coupled system of this invention can provide better plant operability and profitability. Because a single set of vacuum and atmospheric distillation columns is used to fractionate the feed to the atmospheric distillation column, this invention can also minimize total energy requirements. The reduced number of units and energy consumption provides advantages in terms of lower CO2 footprint and smaller plant footprint.

[0054] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0055] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0056] Figure 1 A schematic diagram of a residue oil processing system provided in Embodiment 1 of the present invention is shown.

[0057] Figure 2 A schematic diagram of a slurry bed reactant hydrogenation method provided in Comparative Example 1 of the present invention is shown.

[0058] The annotations in the attached figures are explained as follows:

[0059] 1. Feedstock oil; 2. Fresh feed heater; 3. Mixed feedstock tank; 4. Fresh hydrogen feed; 5. Hydrogen heater; 6. Feed to slurry bed reactor; 7. Slurry bed reactor; 8. Separator of oil-gas separation unit; 9. Gas phase product; 10. Low-grade oil; 11. Slurry; 12. Hydrogen recovery separator; 13. Circulating hydrogen; 14. Light oil; 15. First heater; 16. Atmospheric distillation column; 17. Top dry gas; 18. Naphtha; 19. Diesel; 20. Vacuum distillation column; 21. Light wax oil; 22. Heavy wax oil; 23. Bottom oil of vacuum distillation column; 24. Drain oil; 25. Circulating oil; 26. Catalyst; 27. Outflow product of residue hydrotreating unit; 28. Bottom oil of atmospheric distillation column; 29. ​​Light diesel oil; 30. Heavy diesel oil; 31. Second heater; 32. Feedstock buffer tank. Detailed Implementation

[0060] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0061] Example 1

[0062] This embodiment provides a residual oil processing system, such as Figure 1 As shown, the system includes a residue hydrotreating reactor, an oil-gas separation unit, an atmospheric distillation unit, a vacuum distillation unit, and a feedstock pipeline;

[0063] The residue hydrotreating reactor is connected to the oil-gas separation unit via a product pipeline.

[0064] The oil-gas separation unit includes a heavy hydrotreating product separator, a medium hydrotreating product separator, and a hydrogen recovery separator 12. The heavy hydrotreating product separator separates the slurry and gaseous streams from the hydrotreating products of the residue hydrotreating reactor. The medium hydrotreating product separator separates the low-grade oil and hydrogen-containing light hydrocarbon fractions from the gaseous stream. The hydrogen recovery separator separates the circulating hydrogen and light oil from the hydrogen-containing light hydrocarbon fraction. The oil-gas separation unit is equipped with a slurry discharge pipeline, a low-grade oil discharge pipeline, a light oil discharge pipeline, and a circulating hydrogen pipeline.

[0065] The atmospheric distillation unit includes a first heating furnace 15 and an atmospheric distillation tower 16; the low-grade oil discharge pipeline is connected to the atmospheric distillation tower 16 through the first heating furnace 15; the atmospheric distillation tower 16 is provided with an atmospheric distillation tower bottom oil discharge pipeline, a naphtha discharge pipeline, a light diesel oil discharge pipeline, a heavy diesel oil discharge pipeline, and a dry gas discharge pipeline.

[0066] The vacuum distillation unit includes a second heater 31 and a vacuum distillation tower 20. The feedstock oil pipeline is first connected to the feedstock buffer tank 32, then merges with the bottom oil discharge pipeline of the atmospheric distillation tower, and is connected to the second heater 31, then merges with the slurry discharge pipeline, and finally connects to the vacuum distillation tower 20. The vacuum distillation tower 20 is equipped with a vacuum distillation tower bottom oil discharge pipeline, a light wax oil discharge pipeline, and a heavy wax oil discharge pipeline. The outlet of the vacuum distillation tower bottom oil discharge pipeline is divided into two paths: one is used as an external discharge pipeline, and the other is used as a circulating oil pipeline. The fresh hydrogen feed pipeline and the circulating hydrogen pipeline merge into a total hydrogen feed pipeline. The total hydrogen feed pipeline is connected to the hydrogen heater 5, and then connected to the residue hydrogenation reactor together with the circulating oil pipeline.

[0067] The residue hydrotreating reactor is also connected to a catalyst feed pipeline.

[0068] The residue hydrogenation reactor is a slurry bed reactor 7.

[0069] This embodiment also provides a method for processing residual oil, the method employing the above-described system and including the following steps:

[0070] S1: The effluent 27 from the residual oil hydrotreating reactor is sent to the separator 8 of the oil-gas separation unit, where it is separated to obtain slurry 11, low-grade oil 10, light oil 14 (hydrocarbons with a boiling point below 35°C) and recycled hydrogen 13.

[0071] The low-separation oil 10 is a liquid phase obtained by separation at a pressure of 2.0–16.0 MPa and a temperature of 40–350 °C.

[0072] The slurry 11 is a liquid phase obtained by separation at a pressure of 16.0–20.0 MPa and a temperature of 350–430 °C.

[0073] S2: The low-grade oil 10 is first sent to the first heating furnace 15 of the atmospheric distillation unit and heated to 340°C, and then sent to the atmospheric distillation column 16 of the atmospheric distillation unit for atmospheric distillation to obtain atmospheric distillation column bottom oil 28 and the first light component (including column top dry gas 17, naphtha 18, light diesel oil 29 and heavy diesel oil 30).

[0074] The atmospheric distillation column bottom oil 28 and feed oil 1 are sent to the second heater 31 of the vacuum distillation unit to obtain a heated mixture at a temperature of 335°C. The heated mixture and the slurry 11 are then sent to the vacuum distillation column 20 of the vacuum distillation unit for vacuum distillation to obtain vacuum distillation column bottom oil 23 and a second light component (including light wax oil 21 and heavy wax oil 22).

[0075] S3: The bottom oil of the vacuum distillation tower is divided into two parts. One part is discharged (the amount discharged accounts for 10% of the total amount of the bottom oil of the vacuum distillation tower), and the remaining part is used as circulating oil 25. The circulating hydrogen 13 and the fresh hydrogen feed 4 are combined into total hydrogen and then sent to the residue hydrotreating reactor along with the circulating oil 25 and the catalyst 26 for hydrotreating reaction (hydrodeoxygenation, hydrodemetallization, hydrodesulfurization and hydrocracking).

[0076] The catalyst 26 is a molybdenum-based catalyst;

[0077] The operating conditions of the residue hydrotreating reactor include: reaction pressure 23.0 MPa, reaction temperature 430 °C, and volume hourly space velocity (VHSV) of 0.1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 800:1;

[0078] The raw material oil in Example 1 is raw material 1.

[0079] Example 2

[0080] The only difference between this embodiment and embodiment 1 is that the raw material oil in this embodiment is raw material 2.

[0081] Comparative Example 1

[0082] This comparative example provides a slurry bed reactant hydrogenation method, such as... Figure 2 As shown, the method includes the following steps:

[0083] S1: The effluent 27 from the residual oil hydrotreating unit is sent to the separator 8 of the oil-gas separation unit to separate slurry 11, low-grade oil 10 and gaseous product 9. The gaseous product 9 is separated by the hydrogen recovery separator 12 to obtain recycled hydrogen 13 and light oil (hydrocarbons with a boiling point below 35°C) 14.

[0084] S2: The low-grade oil 10 is sequentially sent to the first heating furnace 15 and the atmospheric distillation tower 16 for atmospheric distillation to obtain atmospheric distillation tower bottom oil 28, tower top dry gas 17, naphtha 18 and diesel 19.

[0085] The bottom oil 28 of the atmospheric distillation tower and the slurry 11 are sent together to the vacuum distillation tower 20. After vacuum distillation, vacuum distillation tower bottom oil 23, light wax oil 21 and heavy wax oil 22 are obtained.

[0086] S3: Divide the bottom oil 23 of the vacuum distillation tower into two parts, one part is discharged externally, and the remaining part is used as circulating oil 25;

[0087] The circulating oil 25, catalyst 26, and feedstock oil heated by the fresh feed heater 2 are sent together to the mixing feed tank 3; the circulating hydrogen 13 and fresh hydrogen feed 4 are heated by the hydrogen heater 5 and sent together with the discharge from the mixing feed tank 3 to the slurry bed reactor 7 for hydrogenation reaction (at least one of hydrodeoxygenation, hydrodemetallization, hydrodesulfurization, and hydrocracking).

[0088] The catalyst used in Comparative Example 1 was the same as that used in Example 1. The operating conditions (temperature, pressure, etc.) for each step in Comparative Example 1 were the same as those in Example 1.

[0089] The raw material oil for Comparative Example 1 is Raw Material 1.

[0090] Comparative Example 2

[0091] The only difference between this comparative example and Comparative Example 1 is that the raw material oil in this comparative example is Raw Material 2.

[0092] Raw material 1: Atmospheric residue oil from Refinery A. The composition and properties of the raw material are shown in Table 1.

[0093] Raw material 2: 80% Refinery B vacuum residue + 20% Refinery B wax oil. The composition and properties of the raw materials are shown in Table 1.

[0094] Table 1

[0095]

[0096] The product composition, equipment energy consumption, and equipment operation cycle of the method of the present invention and the conventional process of the comparative example were compared using raw material 1 and raw material 2 respectively.

[0097] Table 2 shows the test results of raw material 1 in the method of Example 1 of this invention.

[0098]

[0099] Table 3 shows the test results of raw material 2 in the method of Example 2 of this invention.

[0100]

[0101] Table 4 shows the test results of raw material 1 in the conventional process method of Comparative Example 1.

[0102]

[0103] Table 5 shows the test results of raw material 2 in the conventional process method of Comparative Example 2.

[0104]

[0105] As shown in Table 1-5:

[0106] Comparative Example 1 and Comparative Example 1:

[0107] Both methods can achieve the goal of treating residual oil, and the products meet the requirements of downstream equipment.

[0108] The energy consumption of the method of the present invention is reduced by 12.6% compared with the energy consumption of the traditional method.

[0109] The continuous running time of the method of this invention is 61.25% higher than that of the conventional method.

[0110] The overall investment of the method of this invention is reduced by 7.72% compared with the traditional method.

[0111] Comparative Example 2 and Comparative Example 2:

[0112] Both methods can achieve the goal of processing 20% ​​wax oil + 80% vacuum residue, and the products meet the requirements of downstream units.

[0113] The energy consumption of the method of the present invention is reduced by 11.0% compared with the energy consumption of the traditional method.

[0114] The continuous running time of the method of this invention is 50% higher than that of the traditional method.

[0115] The overall investment of the method of this invention is reduced by 7.72% compared with the traditional method.

[0116] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A residual oil processing system, characterized in that, The system includes a residue hydrotreating reactor, an oil-gas separation unit, an atmospheric distillation unit, a vacuum distillation unit, and a feedstock pipeline. The residue hydrotreating reactor is connected to the oil-gas separation unit via a product pipeline. The oil-gas separation unit is equipped with a slurry discharge pipeline, a low-separation oil discharge pipeline, a light oil discharge pipeline, and a circulating hydrogen pipeline. The low-grade oil discharge pipeline is connected to the atmospheric distillation unit, which is equipped with an atmospheric distillation tower bottom oil discharge pipeline and at least one first light component discharge pipeline. The slurry discharge pipeline, the atmospheric distillation tower bottom oil discharge pipeline, and the feed oil pipeline converge and are connected to the vacuum distillation unit. The vacuum distillation unit is equipped with a vacuum distillation tower bottom oil discharge pipeline and at least one second light component discharge pipeline. The outlet of the vacuum distillation tower bottom oil discharge pipeline is divided into two paths: one is used as an external discharge pipeline, and the other is used as a circulating oil pipeline. The fresh hydrogen feed pipeline and the circulating hydrogen pipeline converge to form a total hydrogen feed pipeline, which is then connected to the residue hydrogenation reactor together with the circulating oil pipeline.

2. The residual oil processing system according to claim 1, wherein, The feed oil pipeline is first connected to the feed buffer tank and then merges with the slurry discharge pipeline and the bottom oil discharge pipeline of the atmospheric distillation tower. The residue hydrotreating reactor is also connected to a catalyst feed pipeline; The residue hydrotreating apparatus is equipped with at least one residue hydrotreating reactor. Preferably, the residue hydrotreating reactor is at least one of a suspended bed reactor, a slurry bed reactor, a moving bed reactor, and a fixed bed reactor.

3. The residual oil processing system according to claim 1, wherein, The oil and gas separation unit includes a heavy hydrogenation product separator, a medium hydrogenation product separator, and a hydrogen recovery separator. The heavy hydrotreating product separator is used to separate the slurry and gaseous streams from the hydrotreating products of the residue hydrotreating reactor. The medium-quality hydrotreating product separator is used to separate the low-grade oil and hydrogen-containing light hydrocarbon fractions in the gaseous stream. The hydrogen recovery separator is used to separate circulating hydrogen and light oil in the hydrogen-containing gas phase light hydrocarbon fraction.

4. The residual oil processing system according to claim 1, wherein, The atmospheric distillation unit includes a first heating furnace and an atmospheric distillation column; The low-separation oil discharge pipeline is connected to the atmospheric distillation tower via the first heating furnace; The bottom oil discharge pipeline of the atmospheric distillation tower and at least one first light component discharge pipeline are installed on the atmospheric distillation tower; the atmospheric distillation tower is the atmospheric distillation tower in the atmospheric and vacuum distillation unit of the refinery; The first light component discharge pipeline includes at least one of a naphtha discharge pipeline, a light diesel oil discharge pipeline, a heavy diesel oil discharge pipeline, and a dry gas discharge pipeline.

5. The residual oil processing system according to claim 1, wherein, The vacuum distillation unit includes a second heating furnace and a vacuum distillation column; The bottom oil discharge pipeline of the atmospheric distillation tower and the feed oil pipeline merge and are connected to the second heater, then merge with the slurry discharge pipeline, and finally connect to the vacuum distillation tower. The bottom oil discharge pipeline of the vacuum distillation tower and at least one second light component discharge pipeline are installed on the vacuum distillation tower; the vacuum distillation tower is a vacuum distillation tower in the atmospheric and vacuum distillation unit of a refinery. The second light component discharge line includes at least one of a light wax oil discharge line and a heavy wax oil discharge line.

6. The residual oil processing system according to claim 1, wherein, The system also includes a hydrogen heater, and the main hydrogen feed line is connected to the hydrogen heater and then connected to the residual oil hydrogenation reactor together with the circulating oil line.

7. A method for processing residual oil, characterized in that, The method employs the system described in any one of claims 1-6 and includes the following steps: S1: The effluent from the residual oil hydrotreating reactor is sent to the oil-gas separation unit, where it is separated to obtain slurry, low-grade oil, light oil, and recycled hydrogen. S2: The low-grade oil is sent to the atmospheric distillation unit for atmospheric distillation to obtain atmospheric distillation column bottom oil and the first light component; the slurry, the atmospheric distillation column bottom oil and the feed oil are sent together to the vacuum distillation unit for vacuum distillation to obtain vacuum distillation column bottom oil and the second light component. S3: The bottom oil of the vacuum distillation tower is divided into two parts, one part is discharged and the remaining part is used as circulating oil; the circulating hydrogen and fresh hydrogen feed are combined into total hydrogen and sent together with the circulating oil to the residue hydrotreating reactor for hydrotreating reaction.

8. The method for processing residual oil according to claim 7, wherein, The feedstock oil is at least one of residue oil, wax oil, and deasphalted oil; Preferably, the residue oil is atmospheric residue oil containing a flow promoter and / or vacuum residue oil containing a flow promoter, wherein the flow promoter is at least one of gasoline, diesel, light wax oil and heavy wax oil, and more preferably, the blending ratio of the flow promoter in the residue oil is 0% to 60 wt%. Preferably, the wax oil is vacuum-pressed wax oil and / or coking wax oil.

9. The method for processing residual oil according to claim 8, wherein, The light oil is a hydrocarbon with a boiling point below 40°C; The low-grade oil is the liquid phase obtained by separation at a pressure of 2.0–17.0 MPa and a temperature of 40–350 °C. The slurry is a liquid phase obtained by separation at a pressure of 15.0–25.0 MPa and a temperature of 300–500 °C.

10. The method for processing residual oil according to claim 8, wherein, The low-grade oil is first sent to the first heating furnace of the atmospheric distillation unit and heated to 300-450°C, and then sent to the atmospheric distillation column of the atmospheric distillation unit for atmospheric distillation to obtain the bottom oil of the atmospheric distillation column and the first light component. The bottom oil and feedstock oil of the atmospheric distillation tower are sent to the second heater of the vacuum distillation unit to obtain a heated mixture at a temperature of 280-400°C. The heated mixture and the slurry are then sent to the vacuum distillation tower of the vacuum distillation unit for vacuum distillation to obtain the bottom oil and the second light component. The bottom oil of the atmospheric distillation tower is a fraction with a temperature >300℃; The bottom oil of the vacuum distillation tower is a fraction with a temperature >400℃; The first light component includes at least one of the following: top gas, naphtha, light diesel oil, and heavy diesel oil; The second light component includes at least one of light wax oil and heavy wax oil.

11. The method for processing residual oil according to claim 8, wherein, The feed to the residue hydrotreating reactor also includes a catalyst, which is at least one of molybdenum, nickel, cobalt, molybdenum alloy, nickel alloy, cobalt alloy, molybdenum-containing cobalt alloy, cobalt-containing and / or molybdenum-containing nickel alloy, molybdenum oxide, nickel oxide and cobalt oxide. The operating conditions of the residue hydrotreating reactor include: reaction pressure of 15.0 MPa to 25.0 MPa, reaction temperature of 380℃ to 450℃, and volume hourly space velocity of 0.05 h⁻¹. -1 ~0.2h -1 The hydrogen-to-oil volume ratio is 500–1200:1; The hydrogenation reaction is at least one of the following: hydrodeoxygenation, hydrodemetallization, hydrodesulfurization, and hydrocracking. The amount of vacuum distillation tower bottom oil discharged from the system accounts for 1-20% of the total amount of vacuum distillation tower bottom oil, and the remainder is used as circulating oil.

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