Aromatic hydrocarbon separation and purification device with integrated and optimized internal heat

Abstract

The utility model discloses an aromatic hydrocarbon separation and purification device with integrated and optimized internal heat. The aromatic hydrocarbon separation and purification device comprises a raw oil light component removal tower; a shunting device; a first vertical partition plate is arranged in the low-pressure separation tower, and the low-pressure separation tower comprises a first product outlet, a second product outlet, a first inlet, a first outlet and a first reflux inlet; a second vertical partition plate is arranged in the high-pressure separation tower, and the high-pressure separation tower comprises a third product outlet, a fourth product outlet, a second inlet and a second outlet; a hot end inlet of the first heat exchanger is communicated with the third product outlet, a cold end inlet is communicated with the first outlet, and a cold end outlet is communicated with the first reflux inlet; a hot end inlet of the second heat exchanger is communicated with the third product outlet, a cold end inlet is communicated with the mixture outlet, and a cold end outlet is communicated with the main inlet. According to the invention, benzene and toluene are separated in a single rectifying tower, so that the equipment cost is reduced; heat of high-pressure steam of the high-pressure separation tower is fully utilized, heat integration optimization is achieved, and heat consumption is remarkably reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of aromatic hydrocarbon separation, and in particular relates to an aromatic hydrocarbon separation and purification device with optimized internal heat integration. Background Art

[0002] Toluene and benzene are important chemical raw materials, widely used in industries such as paints, coatings, and rubber. Currently, the industry primarily uses hydrocarbon mixtures such as catalytic reforming gasoline or cracking hydrogenated gasoline as raw materials. After light removal, these mixtures are processed through distillation and adsorption to produce products such as benzene and toluene. Benzene and toluene are each distilled in separate distillation towers.

[0003] In the above-mentioned existing preparation process, benzene and toluene are separated by multiple equipment, which brings about a large investment cost. At the same time, due to the temperature difference between the top and bottom of different distillation towers, heat cannot be directly exchanged and utilized, resulting in a large amount of energy waste, which is not conducive to energy conservation and emission reduction, and causes a large amount of economic losses. Utility Model Content

[0004] The purpose of the present application is to provide an aromatics separation and purification device with optimized internal heat integration, so as to solve the technical problems in the prior art that benzene and toluene are separated by multiple devices, resulting in a large investment cost, and the tops and bottoms of different distillation towers cannot be directly heat exchanged and utilized due to the temperature difference, resulting in a large waste of energy.

[0005] In order to achieve the above objectives, the present application provides an aromatics separation and purification device with optimized internal heat integration, comprising:

[0006] A crude oil light removal tower, including a crude oil inlet and a mixture outlet;

[0007] The diverter device comprises a main inlet, a first diverter outlet and a second diverter outlet;

[0008] A low-pressure separation tower having a first vertical partition disposed therein, wherein the first vertical partition divides the space within the tower into a first pre-separation zone located on one side of the first vertical partition, a first main tower zone on the other side, a first top zone above the first vertical partition, and a first bottom zone below the first vertical partition. The low-pressure separation tower includes a first product outlet and a second product outlet communicating with the first top zone and the first main tower zone, respectively, and a first inlet and a first outlet communicating with the first pre-separation zone and the first bottom zone, respectively. The low-pressure separation tower also includes a first reflux port communicating with the first bottom zone.

[0009] a high-pressure separation tower having a second vertical partition disposed therein, the second vertical partition dividing the tower space into a second pre-separation zone located on one side of the second vertical partition, a second main tower zone on the other side, a second top zone above, and a second bottom zone below; the high-pressure separation tower comprising a third product outlet and a fourth product outlet communicating with the second top zone and the second main tower zone, respectively, and a second inlet and a second outlet communicating with the second pre-separation zone and the second bottom zone, respectively;

[0010] a first heat exchanger, wherein the hot end inlet is connected to the third product outlet, the cold end inlet is connected to the first outlet, and the cold end outlet is connected to the first reflux port, so that the liquid flowing out of the first outlet is partially refluxed to the first bottom area after being heated;

[0011] a second heat exchanger, wherein the hot end inlet is connected to the third product outlet, the cold end inlet is connected to the mixture outlet, and the cold end outlet is connected to the main inlet;

[0012] The first branch outlet and the second branch outlet are communicated with the first inlet and the second inlet respectively.

[0013] In one or more embodiments, the hot end outlet of the first heat exchanger is connected to the hot end inlet of the second heat exchanger.

[0014] In one or more embodiments, the feed oil inlet and the mixture outlet are respectively arranged in the middle and bottom of the feed oil light component removal tower, and the feed oil light component removal tower also includes a light component outlet and a light component reflux port arranged at the top of the tower; the aromatics separation and purification device also includes a first condenser, the inlet of the first condenser is connected to the light component outlet, and the outlet is connected to the light component reflux port, so that part of the fluid is condensed by the first condenser and refluxed to the feed oil light component removal tower.

[0015] In one or more embodiments, the crude oil light removal tower also includes a second reflux port arranged at the bottom of the tower, and the second reflux port is connected to the cold end outlet of the second heat exchanger so that the fluid can be partially refluxed to the crude oil light removal tower after being heated by the second heat exchanger.

[0016] In one or more embodiments, the theoretical plate number of the crude oil lightness removal tower is 30 to 40, the reflux ratio is 5.0 to 10.0, and the position of the crude oil inlet is the 10th to 20th plate.

[0017] In one or more embodiments, the low-pressure separation tower further comprises a third reflux port in communication with the first top region;

[0018] The aromatic hydrocarbon separation and purification device also includes a second condenser, the inlet of the second condenser is connected to the first product outlet, and the outlet is connected to the third reflux port, so that the fluid can be partially refluxed to the first top area after being condensed by the second condenser.

[0019] In one or more embodiments, the theoretical number of plates of the low-pressure separation tower is 50 to 60, the top position of the first vertical partition is the 10th to 15th plates, and the bottom position is the 40th to 45th plates. The operating pressure of the low-pressure separation tower is 0.1 to 0.4 MPaA, and the reflux ratio is 8.0 to 14.0.

[0020] In one or more embodiments, the high-pressure separation tower further comprises a fourth reflux port and a fifth reflux port located at the top and bottom of the tower, respectively, and the aromatics separation and purification device further comprises:

[0021] a third condenser, the inlet of which is connected to the hot end outlet of the second heat exchanger, and the outlet of which is connected to the fourth reflux port, so that the fluid partially refluxes to the high-pressure separation tower after being condensed by the third condenser;

[0022] The reboiler has an inlet connected to the second outlet and an outlet connected to the fifth reflux port, so that the fluid can be partially refluxed to the high-pressure separation tower after being vaporized by the reboiler.

[0023] In one or more embodiments, the theoretical number of plates of the high-pressure separation tower is 50 to 60, the top position of the second vertical partition is the 10th to 15th plates, and the bottom position is the 40th to 45th plates. The operating pressure of the high-pressure separation tower is 0.6 to 1.0 MPaA, and the reflux ratio is 20.0 to 25.0.

[0024] In one or more embodiments, a flow ratio between the first branch outlet and the main inlet is 0.4 to 0.8.

[0025] Different from the prior art, the present invention has the following advantages:

[0026] The present application arranges a first vertical partition and a second vertical partition in the low-pressure separation tower and the high-pressure separation tower, respectively. The vertical partitions divide the space in the tower into a pre-separation zone and a main tower zone. The mixture entering the tower can be initially separated into two streams, one of which flows to the top and is separated to obtain benzene, and the other flows to the bottom and is separated to obtain toluene. This realizes the separation of benzene and toluene in a single distillation tower, effectively reducing equipment costs while ensuring product purity.

[0027] By arranging the first heat exchanger and the second heat exchanger, the present application fully utilizes the heat of the high-pressure steam discharged from the top of the high-pressure separation tower to heat the fluid flowing out of the bottom of the low-pressure separation tower and the fluid entering the diversion device, thereby achieving heat integration optimization and significantly reducing heat consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 It is a structural schematic diagram of an embodiment of an aromatic hydrocarbon separation and purification device with internal heat integration optimization in the present application.

[0030] As shown in the figure:

[0031] Raw oil light fraction removal tower 100; raw oil inlet 101; mixture outlet 102; light fraction outlet 103; light fraction reflux port 104; second reflux port 105;

[0032] Low-pressure separation tower 200; first vertical partition 201; first pre-separation zone 202; first main tower zone 203; first top zone 204; first bottom zone 205; first product outlet 206; second product outlet 207; first inlet 208; first outlet 209; first reflux port 210; third reflux port 211;

[0033] High-pressure separation tower 300; second vertical baffle 301; second pre-separation zone 302; second main tower zone 303; second top zone 304; second bottom zone 305; second inlet 306; third product outlet 307; fourth product outlet 308; fourth reflux port 309; fifth reflux port 310; second outlet 311;

[0034] Diverter device 400; main inlet 401; first diverter outlet 402; second diverter outlet 403;

[0035] a first heat exchanger 500;

[0036] Second heat exchanger 600;

[0037] First condenser 700

[0038] Second condenser 800;

[0039] The third condenser 900;

[0040] Reboiler 1000. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solutions in this application, the following will clearly and completely describe the technical solutions in the embodiments of this application in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this utility model, not all of them. Based on the embodiments of this utility model, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this utility model.

[0042] In order to solve the problem that in the current aromatics separation process, benzene and toluene are separated by multiple equipment, resulting in large investment costs, and the top and bottom of different distillation towers cannot be directly exchanged and utilized due to the temperature difference, resulting in large energy waste, the applicant has developed a new aromatics separation and purification device. This device significantly reduces heat waste through heat integration optimization, and at the same time uses a single distillation tower to achieve the separation of benzene and toluene, reducing equipment costs.

[0043] Specifically, see Figure 1 , Figure 1 It is a structural schematic diagram of an embodiment of an aromatic hydrocarbon separation and purification device with internal heat integration optimization in the present application.

[0044] like Figure 1 As shown, the device includes a crude oil light removal tower 100, a diversion device 400, a low-pressure separation tower 200 and a high-pressure separation tower 300.

[0045] The feedstock light fraction removal tower 100 includes a feedstock inlet 101 and a mixture outlet 102, which are used to remove light components from the feedstock. The mixture, after light components have been removed, is split by a splitter 400, with one portion entering the low-pressure separation tower 200 and the other entering the high-pressure separation tower 300. In the low-pressure separation tower 200 and the high-pressure separation tower 300, the mixture is separated to produce high-purity benzene and toluene, along with C8 aromatics such as xylene, completing the aromatics separation.

[0046] The following details Figure 1 As shown, in this embodiment, the raw oil inlet 101 and the mixture outlet 102 of the raw oil light component removal tower 100 are arranged in the middle and the bottom respectively, and the raw oil light component removal tower 100 also includes a light component outlet 103 and a light component reflux port 104 arranged at the top.

[0047] The aromatic hydrocarbon separation and purification device also includes a first condenser 700, the inlet of the first condenser 700 is connected to the light component outlet 103, and the outlet is connected to the light component reflux port 104, so that part of the fluid can be condensed by the first condenser 700 and then refluxed to the raw oil light component removal tower 100.

[0048] It can be understood that the light components in the crude oil are converted into gas phase in the tower and discharged from the light component outlet 103 at the top of the tower. The light component part is condensed by the first condenser 700 and then refluxed into the crude oil light removal tower 100; at the same time, the liquid phase mixture is discharged from the mixture outlet 102 at the bottom.

[0049] In one embodiment, the feedstock oil may be a mixture of non-aromatic and aromatic hydrocarbons.

[0050] In one embodiment, the crude oil light-removing tower 100 further includes a second reflux port 105 arranged at the bottom, and the mixture outlet 102 is also connected to the second reflux port 105 to allow part of the liquid phase of the mixture to reflux into the crude oil light-removing tower 100.

[0051] In one embodiment, the theoretical number of plates of the crude oil lightness removal tower 100 is 30 to 40, the reflux ratio is 5.0 to 10.0, and the position of the crude oil inlet 101 is the 10th to 20th plate.

[0052] The diversion device 400 includes a main inlet 401, a first diversion outlet 402 and a second diversion outlet 403, wherein the main inlet 401 is connected to the mixture outlet 102, and the first diversion outlet 402 and the second diversion outlet 403 are respectively connected to the low-pressure separation tower 200 and the high-pressure separation tower 300, thereby dividing the mixture after the light components are removed into two streams, which flow into the low-pressure separation tower 200 and the high-pressure separation tower 300 respectively.

[0053] In one embodiment, the flow ratio between the first branch outlet 402 and the main inlet 401 is 0.4 to 0.8.

[0054] In this embodiment, the low-pressure separation tower 200 and the high-pressure separation tower 300 are arranged in parallel, and the mixture can achieve aromatics separation in both towers, and high-purity benzene is obtained from the top of the tower, high-purity toluene is obtained in the middle of the tower, and C8 aromatics such as xylene are obtained at the bottom of the tower.

[0055] Specifically, in order to achieve separation of benzene and toluene in a single distillation tower, in this embodiment, a first vertical baffle 201 and a second vertical baffle 301 are respectively arranged in the low-pressure separation tower 200 and the high-pressure separation tower 300.

[0056] Among them, the first vertical partition 201 divides the tower space inside the low-pressure separation tower 200 into a first pre-separation zone 202 located on one side of the first vertical partition 201, a first main tower zone 203 on the other side, a first top zone 204 above and a first bottom zone 205 below. The low-pressure separation tower 200 includes a first product outlet 206 and a second product outlet 207 respectively connected to the first top zone 204 and the first main tower zone 203, as well as a first inlet 208 and a first outlet 209 respectively connected to the first pre-separation zone 202 and the first bottom zone 205.

[0057] The second vertical partition 301 divides the tower space of the high-pressure separation tower 300 into a second pre-separation zone 302 located on one side of the second vertical partition 301, a second main tower zone 303 on the other side, a second top zone 304 above and a second bottom zone 305 below. The high-pressure separation tower 300 includes a third product outlet 307 and a fourth product outlet 308 respectively connected to the second top zone 304 and the second main tower zone 303, and a second inlet 306 and a second outlet 311 respectively connected to the second pre-separation zone 302 and the second bottom zone 305.

[0058] The first inlet 208 and the second inlet 306 are respectively communicated with the first diversion outlet 402 and the second diversion outlet 403 of the diversion device 400 .

[0059] Based on the above design, when the mixture passes through the crude oil light removal tower 100 and enters the tower, it can be separated by the vertical partition and initially separated into two streams inside the pre-separation area, one of which flows to the top and is separated to obtain benzene, which is discharged from the product outlet at the top of the tower; the other flows to the bottom and is separated to obtain toluene, which is discharged from the product outlet in the middle of the tower; other C8 aromatic hydrocarbons such as xylene are discharged from the outlet at the bottom of the tower, thereby realizing the separation of benzene and toluene in a single distillation tower, effectively reducing equipment costs.

[0060] To achieve reflux, the low-pressure separation tower 200 further includes a first reflux port 210 communicating with the first bottom zone 205 and a third reflux port 211 communicating with the first top zone 204. The first reflux port 210 is connected to the first outlet 209 to partially reflux the fluid flowing out of the bottom of the tower.

[0061] The aromatic hydrocarbon separation and purification device also includes a second condenser 800 , the inlet of the second condenser 800 is connected to the first product outlet 206 , and the outlet is connected to the third reflux port 211 , so that the fluid can partially reflux to the first top area 204 after being condensed by the second condenser 800 .

[0062] In one embodiment, the number of theoretical plates of the low-pressure separation tower 200 is 50 to 60, the top position of the first vertical partition 201 is the 10th to 15th plates, and the bottom position is the 40th to 45th plates. The operating pressure of the low-pressure separation tower 200 is 0.1 to 0.4 MPaA, and the reflux ratio is 8.0 to 14.0.

[0063] In order to achieve reflux, the high-pressure separation tower 300 further includes a fourth reflux port 309 and a fifth reflux port 310 located at the top and bottom of the tower respectively. The aromatic hydrocarbon separation and purification device further includes a third condenser 900 and a reboiler 1000.

[0064] The inlet of the third condenser 900 is connected to the third product outlet 307, and the outlet is connected to the fourth reflux port 309, so that the fluid can be partially refluxed to the high-pressure separation tower 300 after being condensed by the third condenser 900;

[0065] The inlet of the reboiler 1000 is connected to the second outlet 311 , and the outlet is connected to the fifth reflux port 310 , so that the fluid can partially flow back to the high-pressure separation tower 300 after being vaporized by the reboiler 1000 .

[0066] In one embodiment, the high-pressure separation tower 300 has a theoretical plate number of 50 to 60, the top position of the second vertical partition 301 is the 10th to 15th plates, and the bottom position is the 40th to 45th plates. The operating pressure of the high-pressure separation tower 300 is 0.6 to 1.0 MPaA, and the reflux ratio is 20.0 to 25.0.

[0067] In order to fully utilize the heat of the high-pressure steam discharged from the third product outlet 307 and achieve heat integration optimization, a first heat exchanger 500 and a second heat exchanger 600 are further arranged in this embodiment.

[0068] Specifically, the hot end inlet of the first heat exchanger 500 is connected to the third product outlet 307 , the cold end inlet is connected to the first outlet 209 , and the cold end outlet is connected to the first reflux port 210 , so that the liquid flowing out of the first outlet 209 can be partially refluxed to the first bottom area 205 after being heated.

[0069] Based on the above design, the first heat exchanger 500 can fully utilize the high-pressure steam as a heat source to heat the fluid flowing out of the bottom of the low-pressure separation tower 200, and the heated fluid partially flows back into the tower for separation.

[0070] The hot end inlet of the second heat exchanger 600 is connected to the hot end outlet of the first heat exchanger 500 , the hot end outlet is connected to the inlet of the third condenser 900 , the cold end inlet is connected to the mixture outlet 102 , and the cold end outlet is connected to the main inlet 401 and the second reflux port 105 .

[0071] Based on the above design, high-pressure steam is further used as a heat source to heat the mixture at the bottom outlet of the crude oil de-lightening tower 100. Part of the heated mixture enters the diversion device 400 and is diverted into the two separation towers, and the other part flows back into the crude oil de-lightening tower 100; the high-pressure steam passes through the second heat exchanger 600 and enters the third condenser 900, and after condensation, part of it flows back to the high-pressure separation tower 300.

[0072] In this embodiment, the first heat exchanger 500 and the second heat exchanger 600 are arranged in series, that is, the hot end inlet of the second heat exchanger 600 is connected to the hot end outlet of the first heat exchanger 500, and the hot end outlet of the second heat exchanger 600 is connected to the inlet of the third condenser 900, so that the high-pressure steam can heat the fluid flowing out of the bottom of the low-pressure separation tower 200 and the fluid entering the diversion device 400 in turn, and then the high-pressure steam enters the third condenser 900 for condensation, and partially refluxes to the top of the high-pressure separation tower 300.

[0073] Of course, in other embodiments, the high-pressure steam discharged through the third product outlet 307 can also be divided into two streams and transmitted to the hot end inlets of the first heat exchanger 500 and the second heat exchanger 600 respectively, which can also achieve the effect of this embodiment.

[0074] Based on the above arrangement, the heat of the high-pressure steam discharged from the top of the high-pressure separation tower 300 is fully utilized to achieve heat integration optimization and significantly reduce heat consumption.

[0075] The beneficial effects of the technical solution of the present application are further elaborated in detail below with reference to specific embodiments.

[0076] use Figure 1 The aromatic hydrocarbon separation and purification device shown is used to separate aromatic hydrocarbons. The specific parameters are as follows:

[0077] The crude oil lightness removal tower 100 has 35 theoretical plates, the crude oil inlet 101 is located at the 15th plate, the operating pressure is 0.2 MPaA, and the reflux ratio is 6.0; the splitter 400 distributes the flow to the low-pressure separation tower 200 and the high-pressure separation tower 300 in a flow distribution ratio of 6:4; the low-pressure separation tower 200 has 56 theoretical plates, the first inlet 208 is located at the 15th plate, the operating pressure is 0.1 MPaA, the reflux ratio is 11.0, the first vertical baffle 201 is located at the 14th-43rd plate, and the second product outlet 207 is located at the 28th plate; the high-pressure separation tower 300 has 56 theoretical plates, the second inlet 306 is located at the 15th plate, the operating pressure is 0.7 MPaA, the reflux ratio is 22.0, the second vertical baffle 301 is located at the 14th-43rd plate, and the fourth product outlet 308 is located at the 28th plate.

[0078] The components of the raw oil are shown in the table below. The mass purity of the separated product benzene is 99.95wt%, and the mass purity of toluene is 99.51wt%. It can be seen that the technical solution of the present application can ensure the purity of benzene and toluene.

[0079]

[0080] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0081] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. An aromatics separation and purification device with optimized internal heat integration, characterized in that: include: A crude oil light removal tower, including a crude oil inlet and a mixture outlet; The diverter device comprises a main inlet, a first diverter outlet and a second diverter outlet; A low-pressure separation tower having a first vertical partition disposed therein, wherein the first vertical partition divides the space within the tower into a first pre-separation zone located on one side of the first vertical partition, a first main tower zone on the other side, a first top zone above the first vertical partition, and a first bottom zone below the first vertical partition. The low-pressure separation tower includes a first product outlet and a second product outlet communicating with the first top zone and the first main tower zone, respectively, and a first inlet and a first outlet communicating with the first pre-separation zone and the first bottom zone, respectively. The low-pressure separation tower also includes a first reflux port communicating with the first bottom zone. a high-pressure separation tower having a second vertical partition disposed therein, the second vertical partition dividing the tower space into a second pre-separation zone located on one side of the second vertical partition, a second main tower zone on the other side, a second top zone above, and a second bottom zone below; the high-pressure separation tower comprising a third product outlet and a fourth product outlet communicating with the second top zone and the second main tower zone, respectively, and a second inlet and a second outlet communicating with the second pre-separation zone and the second bottom zone, respectively; a first heat exchanger, wherein the hot end inlet is connected to the third product outlet, the cold end inlet is connected to the first outlet, and the cold end outlet is connected to the first reflux port, so that the liquid flowing out of the first outlet is partially refluxed to the first bottom area after being heated; a second heat exchanger, wherein the hot end inlet is connected to the third product outlet, the cold end inlet is connected to the mixture outlet, and the cold end outlet is connected to the main inlet; The first branch outlet and the second branch outlet are communicated with the first inlet and the second inlet respectively.

2. The aromatic hydrocarbon separation and purification device according to claim 1, characterized in that: The hot end outlet of the first heat exchanger is connected to the hot end inlet of the second heat exchanger.

3. The aromatic hydrocarbon separation and purification device according to claim 1, characterized in that: The raw oil inlet and the mixture outlet are respectively arranged in the middle and bottom of the raw oil light component removal tower, and the raw oil light component removal tower also includes a light component outlet and a light component reflux port arranged at the top of the tower; the aromatic hydrocarbon separation and purification device also includes a first condenser, the inlet of the first condenser is connected to the light component outlet, and the outlet is connected to the light component reflux port, so that part of the fluid is condensed by the first condenser and then refluxed to the raw oil light component removal tower.

4. The aromatic hydrocarbon separation and purification device according to claim 3, characterized in that: The crude oil light removal tower also includes a second reflux port arranged at the bottom of the tower, and the second reflux port is connected to the cold end outlet of the second heat exchanger so that the fluid can be partially refluxed to the crude oil light removal tower after being heated by the second heat exchanger.

5. The aromatic hydrocarbon separation and purification device according to claim 4, characterized in that: The theoretical plate number of the raw oil lightness removal tower is 30 to 40, the reflux ratio is 5.0 to 10.0, and the position of the raw oil inlet is the 10th to 20th plate.

6. The aromatic hydrocarbon separation and purification device according to claim 1, characterized in that: The low-pressure separation tower further includes a third reflux port in communication with the first top region; The aromatic hydrocarbon separation and purification device also includes a second condenser, the inlet of the second condenser is connected to the first product outlet, and the outlet is connected to the third reflux port, so that the fluid can be partially refluxed to the first top area after being condensed by the second condenser.

7. The aromatic hydrocarbon separation and purification device according to claim 6, characterized in that: The theoretical number of plates of the low-pressure separation tower is 50 to 60, the top position of the first vertical partition is the 10th to 15th plates, and the bottom position is the 40th to 45th plates. The operating pressure of the low-pressure separation tower is 0.1 to 0.4 MPaA, and the reflux ratio is 8.0 to 14.

0.

8. The aromatic hydrocarbon separation and purification device according to claim 1, characterized in that: The high-pressure separation tower further includes a fourth reflux port and a fifth reflux port located at the top and bottom of the tower, respectively. The aromatic hydrocarbon separation and purification device further includes: a third condenser, the inlet of which is connected to the hot end outlet of the second heat exchanger, and the outlet of which is connected to the fourth reflux port, so that the fluid partially refluxes to the high-pressure separation tower after being condensed by the third condenser; The reboiler has an inlet connected to the second outlet and an outlet connected to the fifth reflux port, so that the fluid can be partially refluxed to the high-pressure separation tower after being vaporized by the reboiler.

9. The aromatic hydrocarbon separation and purification device according to claim 8, characterized in that: The theoretical number of plates of the high-pressure separation tower is 50 to 60, the top position of the second vertical partition is the 10th to 15th plates, and the bottom position is the 40th to 45th plates. The operating pressure of the high-pressure separation tower is 0.6 to 1.0 MPaA, and the reflux ratio is 20.0 to 25.

0.

10. The aromatic hydrocarbon separation and purification device according to any one of claims 1 to 9, characterized in that: The flow ratio between the first branch outlet and the main inlet is 0.4 to 0.8.

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