A device for processing heavy aromatics using two-stage hydrocracking
By adopting a two-stage hydrocracking process in the heavy aromatic hydrocarbon processing device and adding heavy aromatic hydrocarbons into the fractionation tower, the problem of low aromatic potential of heavy naphtha is solved, the aromatic index and value-added product output are improved, and the high-quality raw materials demand for the reforming device is met.
Patent Information
- Application Number
- CN202421340419.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-13
- Publication Date
- 2025-04-08
- Estimated Expiration
- 2034-06-13
AI Technical Summary
When the existing heavy aromatic hydrocarbon processing equipment produces heavy naphtha, the aromatic potential is low, which affects the quality of the raw materials of the reforming equipment.
The second-stage hydrocracking process is adopted, and the aromatic index of heavy naphtha is improved by performing hydrochlorication and hydrocracking reactions in the first and second-stage reactors respectively, and adding heavy aromatic hydrocarbons to the fractionation tower.
The aromatic index of heavy naphtha was increased by 5.5%, aromatic hydrocarbon production was increased, value-added product production was increased, gasoline and diesel and coke production was reduced, and high-quality raw materials were provided for the reforming device.
Smart Images
Figure CN222729719U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a device for processing heavy aromatics, more specifically, to a device for processing heavy aromatics by two-stage hydrocracking, belonging to the field of petrochemical industry. Background Art
[0002] Heavy aromatics come from the heavy aromatic fractionation tower of the aromatics unit. Heavy aromatics were originally designed to be processed in catalytic and delayed coking units to produce coking naphtha, diesel and coke, with poor product benefits. Heavy naphtha from the diesel hydrocracking unit is the main raw material for the reforming unit, but the aromatic potential of this raw material is low. If heavy aromatics can be blended, the aromatic potential of heavy naphtha can be increased, providing high-quality raw materials for the reforming unit. Utility Model Content
[0003] The utility model aims to provide a device for processing heavy aromatics by two-stage hydrocracking, which has the technical characteristics of increasing the output of value-added products, reducing the output of gasoline, diesel and coke, increasing the output of aromatics, and providing high-quality raw materials for the reforming device.
[0004] In order to achieve the above purpose, the utility model is implemented by the following technical solutions:
[0005] A device for processing heavy aromatics by two-stage hydrocracking comprises a No. 1 heating furnace, wherein the feed port of the No. 1 heating furnace is connected to four material pipelines through a delivery pump to respectively deliver heavy aromatics, catalytic diesel, slurry bed diesel and straight-run diesel, the discharge port of the No. 1 heating furnace is connected to the top of a first-stage reactor through a pipeline, the bottom of the first-stage reactor is connected to a separation system through a pipeline, the separation system is connected to the middle of a stripping tower through a pipeline, the bottom of the stripping tower is connected to the middle of a fractionating tower through a pipeline, the upper part of the fractionating tower is connected to a discharge line of a heavy naphtha product, and the bottom of the fractionating tower is connected to a discharge pipeline for delivering a diesel product.
[0006] Preferably, it also includes a No. 2 heating furnace, the feed port of the No. 2 heating furnace is connected to a material pipeline through a delivery pump for conveying diesel from the bottom of the distillation tower, the discharge port of the No. 2 heating furnace is connected to the top of the second-stage reactor through a pipeline, and the bottom of the second-stage reactor is connected to the bottom pipeline of the first-stage reactor through a pipeline to achieve connection with the separation system.
[0007] Preferably, the separation system comprises a hot high-pressure separator, a hot low-pressure separator, a cold high-pressure separator, and a cold low-pressure separator. The top of the hot high-pressure separator is connected to the feed port of the No. 1 heating furnace through a No. 5 pipeline. The No. 5 pipeline is divided into a No. 6 pipeline to be connected to the top of the first-stage reactor. The bottom of the second-stage reactor is connected to the hot low-pressure separator after being merged with the bottom pipeline of the first-stage reactor through a pipeline. The hot low-pressure separator is respectively connected to the hot high-pressure separator and the cold low-pressure separator through pipelines. The cold low-pressure separator is connected to the cold high-pressure separator after being merged with the hot high-pressure separator through a pipeline. The cold high-pressure separator and the cold low-pressure separator are both connected to the stripping tower through pipelines.
[0008] Preferably, the material pipeline for conveying diesel fuel at the bottom of the fractionation tower is also connected to the No. 5 pipeline.
[0009] Preferably, the discharge pipeline at the bottom of the distillation tower is divided into pipeline No. 1 and pipeline No. 2, the pipeline No. 1 is connected to a delivery pump for delivering diesel products, the pipeline No. 2 is connected to a heating furnace No. 3, and the heating furnace No. 3 is connected to the distillation tower through a pipeline to form a circulation.
[0010] Preferably, the discharge line at the top of the distillation tower is connected to a reflux tank, the reflux tank is connected to pipeline No. 3 and pipeline No. 4, the pipeline No. 3 is connected to the distillation tower to form a circulation, and the pipeline No. 4 is connected to a delivery pump for delivering heavy naphtha products.
[0011] Preferably, the first-stage reactor and the second-stage reactor are respectively a hydrotreating reactor and a hydrocracking reactor.
[0012] Beneficial effects:
[0013] 1. The process of the present invention can improve the aromatic index (N+2A) of heavy naphtha products by 5.5% by blending heavy aromatics through a first-stage reaction and a second-stage reaction, which is beneficial to increasing the production of aromatics.
[0014] 2. Convert heavy aromatics into heavy naphtha, increase the output of value-added products, and reduce the output of gasoline, diesel and coke.
[0015] 3. The heavy aromatics blending process can be switched flexibly without affecting the stable operation of the device. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a schematic diagram of the overall structure of the utility model. DETAILED DESCRIPTION
[0017] The present invention will be further described below in conjunction with the accompanying drawings, but the present invention is not limited to the following embodiments.
[0018] like Figure 1The figure shows a specific embodiment of a device for processing heavy aromatics by two-stage hydrocracking. The device for processing heavy aromatics by two-stage hydrocracking comprises a first heating furnace 1. The feed port of the first heating furnace 1 is connected to four material pipelines through a delivery pump to respectively deliver heavy aromatics, catalytic diesel, slurry bed diesel, and straight-run diesel. The discharge port of the first heating furnace 1 is connected to the top of a first reactor 2 through a pipeline. The bottom of the first reactor 2 is connected to a separation system 7 through a pipeline. The separation system 7 is connected to the middle of a stripping tower 8 through a pipeline. The bottom of the stripping tower 8 is connected to the middle of the distillation tower 9 through a pipeline, the upper part of the distillation tower 9 is connected to a discharge line for heavy naphtha products, and the bottom of the distillation tower 9 is connected to a discharge pipeline for conveying diesel products; it also includes a No. 2 heating furnace 10, the feed port of the No. 2 heating furnace 10 is connected to a material pipeline through a delivery pump for conveying diesel at the bottom of the distillation tower, the discharge port of the No. 2 heating furnace 10 is connected to the top of the second-stage reactor 11 through a pipeline, and the bottom of the second-stage reactor 11 is connected to the bottom pipeline of the first-stage reactor 2 through a pipeline to achieve connection with the separation system 7. The separation system 7 includes a hot high-pressure separator 3, a hot low-pressure separator 4, a cold high-pressure separator 5, and a cold low-pressure separator 6. The top of the hot high-pressure separator 3 is connected to the feed port of the No. 1 heating furnace 1 through a No. 5 pipeline. The No. 5 pipeline is divided into a No. 6 pipeline to connect to the top of the first-stage reactor 2. The bottom of the second-stage reactor 11 is connected to the hot low-pressure separator 4 after being connected to the bottom pipeline of the first-stage reactor 2 through a pipeline. The hot low-pressure separator 4 is connected to the hot high-pressure separator 3 and the cold low-pressure separator 6 through pipelines respectively. The cold low-pressure separator 6 is connected to the cold high-pressure separator 5 after being connected to the hot high-pressure separator 3 through a pipeline. The cold high-pressure separator 5 and the cold low-pressure separator 6 are both connected to the stripping tower 8 through pipelines. The material pipeline for conveying diesel at the bottom of the fractionation tower is also connected to the No. 5 pipeline. The discharge pipeline at the bottom of the fractionation tower 9 is divided into a No. 1 pipeline and a No. 2 pipeline. The No. 1 pipeline is connected to a delivery pump for delivering diesel products, and the No. 2 pipeline is connected to a No. 3 heating furnace 12, and the No. 3 heating furnace 12 is connected to the fractionation tower 9 through a pipeline to form a cycle. The discharge line at the top of the fractionation tower 9 is connected to a reflux tank 13, and the reflux tank 13 is connected to a No. 3 pipeline and a No. 4 pipeline. The No. 3 pipeline is connected to the fractionation tower 9 to form a cycle, and the No. 4 pipeline is connected to a delivery pump for delivering heavy naphtha products. The first stage reactor 2 and the second stage reactor 11 are respectively a hydrofining reactor and a hydrocracking reactor.
[0019] A process operation is performed through the system structure of this application:
[0020] Straight-run diesel, slurry-bed diesel, catalytic diesel and heavy aromatics are used to form a mixed feedstock;
[0021] After the mixed raw material is mixed with hydrogen, it is pressurized to 12.0MPa and heated to 340℃~380℃, and the hydrofining reaction and hydrocracking reaction are carried out in sequence;
[0022] The cracking reaction products are separated into gas and liquid in the hot and cold high and low separators;
[0023] The reaction oil enters the hydrogen sulfide stripping tower to remove hydrogen sulfide and then enters the fractionation tower;
[0024] The reboiler at the bottom of the distillation tower provides heat source for the distillation tower, cutting the feed to obtain heavy naphtha, crude naphtha and diesel products respectively.
[0025] In the process of the present application, 5% of heavy aromatics can be added to atmospheric and vacuum straight-run diesel, slurry bed diesel and catalytic diesel to form a mixed raw material. The properties of atmospheric and vacuum straight-run diesel, slurry bed diesel, catalytic diesel, heavy aromatics and the designed mixed raw material are compared as shown in Table 1.
[0026] Table 1 Properties of straight-run diesel, slurry-bed diesel, catalytic diesel, heavy aromatics and mixed feedstocks
[0027]
[0028]
[0029] The mixed raw materials are pressurized and heat exchanged, mixed with hydrogen, heated to 340℃~380℃ and enter the reactor filled with refining catalyst and cracking catalyst for hydrofining reaction and hydrocracking reaction. The hydrofining of heavy aromatics releases a large amount of heat, and the hydrofining reaction temperature is controlled to be 1-2℃ lower than before the heavy aromatics are blended. Since the cracking of polycyclic aromatics is difficult, to ensure the same conversion rate, the cracking reaction temperature needs to be controlled to be 0.5-1℃ higher than before the heavy aromatics are blended, and the reaction pressure is consistent with that before and after the heavy aromatics are blended. The obtained reaction product is separated into gas and liquid in the cold and hot high and low separators, and the obtained reaction oil enters the hydrogen sulfide stripping tower to remove hydrogen sulfide and liquefied gas and then enters the distillation tower. The product distillation tower is provided with heat source by the reboiler at the bottom of the product distillation tower. The pressure at the top of the distillation tower is controlled at 0.1Mpa. The product distillation tower has a total of 70 layers of trays, and the feed enters from the 30th layer. The heavy naphtha product is extracted from the 10th layer of trays and directly supplied to the reforming unit as raw material. The crude naphtha is extracted from the top of the tower and recycled into light hydrocarbons for further separation. The diesel product at the bottom of the tower can be circulated to the second-stage reactor for further hydrocracking, and a small amount of diesel product is sent to the ethylene unit.
[0030] The comparison of operating parameters of the existing process and the process of this application is shown in Table 2.
[0031] Table 2 Comparison of operating parameters between existing process and process of the present invention
[0032]
[0033]
[0034] When 5% heavy aromatics are added, the content of polycyclic aromatics in the mixed feedstock increases by 2%, and the aromatic index N+2A in the heavy naphtha product increases by 5.5%. The comparison of the content of polycyclic aromatics in the mixed feedstock and the aromatic index N+2A in the heavy naphtha product before and after adding heavy aromatics is shown in Table 3.
[0035] Table 3 Comparison of heavy naphtha product composition between existing process and this application process
[0036]
[0037] Finally, it should be noted that the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by ordinary technicians in this field should be considered as the protection scope of the present invention.
Claims
1. A device for processing heavy aromatics using two-stage hydrocracking, characterized in that: The invention comprises a No. 1 heating furnace (1), wherein the feed port of the No. 1 heating furnace (1) is connected to four material pipelines through a delivery pump to respectively deliver heavy aromatics, catalytic diesel, slurry bed diesel, and straight-run diesel; the discharge port of the No. 1 heating furnace (1) is connected to the top of a first-stage reactor (2) through a pipeline; the bottom of the first-stage reactor (2) is connected to a separation system (7) through a pipeline; the separation system (7) is connected to the middle of a stripping tower (8) through a pipeline; the bottom of the stripping tower (8) is connected to the middle of a fractionating tower (9) through a pipeline; the upper part of the fractionating tower (9) is connected to a discharge line of a heavy naphtha product; and the bottom of the fractionating tower (9) is connected to a discharge pipeline for delivering a diesel product.
2. The device for processing heavy aromatics by two-stage hydrocracking according to claim 1, characterized in that: It also includes a No. 2 heating furnace (10), the feed port of the No. 2 heating furnace (10) is connected to a material pipeline through a delivery pump for delivering diesel at the bottom of the fractionation tower, the discharge port of the No. 2 heating furnace (10) is connected to the top of the second-stage reactor (11) through a pipeline, and the bottom of the second-stage reactor (11) is connected to the bottom pipeline of the first-stage reactor (2) through a pipeline to achieve connection with the separation system (7).
3. The device for processing heavy aromatics by two-stage hydrocracking according to claim 2, characterized in that: The separation system (7) comprises a hot high-pressure separator (3), a hot low-pressure separator (4), a cold high-pressure separator (5), and a cold low-pressure separator (6). The top of the hot high-pressure separator (3) is connected to the feed port of the first heating furnace (1) through a No. 5 pipeline. The No. 5 pipeline is divided into a No. 6 pipeline for connecting to the top of the first-stage reactor (2). The bottom of the second-stage reactor (11) is connected to the hot low-pressure separator (4) after being connected to the bottom pipeline of the first-stage reactor (2) through a pipeline. The hot low-pressure separator (4) is connected to the hot high-pressure separator (3) and the cold low-pressure separator (6) through pipelines respectively. The cold low-pressure separator (6) and the hot high-pressure separator (3) are connected to the cold high-pressure separator (5) after being connected to the cold high-pressure separator (5). The cold high-pressure separator (5) and the cold low-pressure separator (6) are both connected to the stripping tower (8) through pipelines.
4. The device for processing heavy aromatics by two-stage hydrocracking according to claim 3, characterized in that: The material pipeline for transporting diesel fuel at the bottom of the distillation tower is also connected to pipeline No.
5.
5. The device for processing heavy aromatics by two-stage hydrocracking according to claim 1, characterized in that: The discharge pipeline at the bottom of the fractionation tower (9) is divided into a first pipeline and a second pipeline. The first pipeline is connected to a delivery pump for delivering diesel products. The second pipeline is connected to a third heating furnace (12). The third heating furnace (12) is connected to the fractionation tower (9) through a pipeline to form a circulation.
6. A two-stage hydrocracking device for processing heavy aromatics according to claim 1 or 5, characterized in that: The discharge line at the top of the fractionation tower (9) is connected to a reflux tank (13), the reflux tank (13) is connected to a No. 3 pipeline and a No. 4 pipeline, the No. 3 pipeline is connected to the fractionation tower (9) to form a circulation, and the No. 4 pipeline is connected to a delivery pump for delivering heavy naphtha products.
7. The device for processing heavy aromatics by two-stage hydrocracking according to claim 3, characterized in that: The first stage reactor (2) and the second stage reactor (11) are respectively a hydrotreating reactor and a hydrocracking reactor.