Coal tar pretreatment system in coal tar hydrogenation process

Abstract

The utility model belongs to the technical field of coal tar treatment, and relates to a coal tar pretreatment system in a coal tar hydrogenation process, which comprises a first heating unit, a filter unit and a dehydration unit, the first heating unit is used for heating the raw material coal tar; the filtering unit is communicated with the outlet end of the first heating unit and is used for filtering solid particles in the raw material coal tar; the dehydration unit is communicated with the outlet end of the filtering unit and is used for carrying out primary dehydration treatment on the filtered coal tar. According to the utility model, the filter unit is arranged in front of the dehydration unit, solid particles in raw material coal tar are filtered by the filter unit firstly, and then the filtered coal tar flowing out of the filter unit is subjected to primary dehydration treatment by the dehydration unit, so that the solid particles in the raw material coal tar are prevented from blocking the dehydration unit; therefore, oil-water separation is facilitated, the oil-water separation effect is improved, and the net yield of the pretreated and purified coal tar is further improved.

Description

Technical Field

[0001] This utility model relates to the field of coal tar treatment technology, specifically to a coal tar pretreatment system in a coal tar hydrogenation process. Background Technology

[0002] Coal tar hydrogenation is a deep processing technology that converts heavy hydrocarbons in coal tar into light fuel oil or chemical feedstock through hydrocracking. Coal tar pretreatment is a crucial step in the entire hydrogenation process, purifying and adjusting the coal tar to meet the requirements of the hydrogenation process.

[0003] Existing technologies have conducted some research on coal tar pretreatment systems in coal tar hydrogenation processes. See patent application number 202110464642.7, which discloses a coal tar pretreatment device for a coal tar hydrogenation process, comprising: a coal tar pretreatment tower, a demulsification and dehydration mechanism, a separated water collection device, and a coal tar collection device. In this device, coal tar is pretreated by the demulsification and dehydration mechanism. Untreated coal tar is located above an oil-water separation membrane, and the separated water inside the untreated coal tar enters a tank below the oil-water separation membrane through the membrane. The separated water is stored in the separated water collection device, and the separated coal tar is stored in the coal tar collection device.

[0004] Therefore, by combining a coal tar pretreatment tower with a demulsification and dehydration mechanism, coal tar can be dehydrated, thereby adjusting its water content. However, the produced coal tar contains a large amount of solid particles such as coal dust. Directly dehydrating the coal tar can easily clog the oil-water separation equipment due to these solid particles, resulting in poor oil-water separation and a low net yield of pretreated and purified coal tar. Utility Model Content

[0005] To address the technical problem in the prior art that the coal tar produced contains a large amount of solid particles such as coal powder, resulting in poor oil-water separation when the coal tar is directly dehydrated, and low net yield of the pretreated and purified coal tar, this utility model provides a coal tar pretreatment system in a coal tar hydrogenation process.

[0006] The coal tar pretreatment system in the coal tar hydrogenation process of this utility model places the filtration unit before the dehydration unit. The filtration unit first filters the solid particles in the raw coal tar, and then the dehydration unit performs a dehydration treatment on the filtered coal tar flowing out of the filtration unit. This avoids the solid particles in the raw coal tar from clogging the dehydration unit, thereby facilitating oil-water separation, improving the oil-water separation effect, and thus increasing the net yield of the pretreated and purified coal tar.

[0007] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0008] A coal tar pretreatment system in a coal tar hydrogenation process includes: a first heating unit, a filtration unit, and a dehydration unit; the first heating unit is used to heat the raw coal tar; the filtration unit is connected to the outlet end of the first heating unit and is used to filter solid particles in the raw coal tar; the dehydration unit is connected to the outlet end of the filtration unit and is used to perform a primary dehydration treatment on the filtered coal tar.

[0009] In one specific implementation, the first heating unit includes a plurality of heat exchangers connected in sequence, and the outlet end of the last heat exchanger is connected to a filter unit.

[0010] In one specific implementation scheme, the coal tar pretreatment system in the coal tar hydrogenation process further includes a pretreatment unit, which includes a fifth heat exchanger, a centrifuge, and a first booster pump connected in sequence; the inlet end of the fifth heat exchanger receives raw coal tar; and the outlet end of the first booster pump is connected to the inlet end of the first heating unit.

[0011] In one specific implementation scheme, the coal tar pretreatment system in the coal tar hydrogenation process further includes a first cooling unit, which is a sixth heat exchanger; the sixth heat exchanger is connected to the outlet end of the filtration unit.

[0012] In one specific implementation scheme, the inlet of the first heating unit is connected to the outlet of the first booster pump and the outlet of the filter unit; the outlet of the first heating unit is connected to the inlet of the filter unit and the inlet of the sixth heat exchanger.

[0013] In one specific implementation scheme, the coal tar pretreatment system in the coal tar hydrogenation process further includes a dehydration tower; the dehydration tower is connected to the outlet end of the dehydration unit, and the dehydration tower is used to perform secondary dehydration on the coal tar after primary dehydration.

[0014] In one specific implementation scheme, the coal tar pretreatment system in the coal tar hydrogenation process further includes a second heating unit, which includes a seventh heat exchanger and an eighth heat exchanger connected in sequence; the seventh heat exchanger is connected to the outlet end of the dehydration unit, and the eighth heat exchanger is connected to the inlet end of the dehydration tower.

[0015] In one specific implementation scheme, the coal tar pretreatment system in the coal tar hydrogenation process further includes a reflux unit, which includes a second booster pump and a first air cooler; the second booster pump, a fifth heat exchanger, and the first air cooler are connected in sequence; the second booster pump is connected to the outlet end of the bottom of the dehydration tower.

[0016] In one specific implementation scheme, a second air cooler and a separator are connected in sequence along the direction of the flash vapor flowing out from the top of the dehydration tower; the second air cooler is connected to the outlet end at the top of the dehydration tower.

[0017] In one specific implementation, the pretreatment unit further includes a buffer tank; the buffer tank is placed between the centrifuge and the first booster pump.

[0018] In summary, this utility model has the following beneficial technical effects:

[0019] 1. The coal tar pretreatment system in the coal tar hydrogenation process of this utility model places the filtration unit before the dehydration unit. The filtration unit first filters the solid particles in the raw coal tar, and then the dehydration unit performs a dehydration treatment on the filtered coal tar flowing out of the filtration unit. This avoids the solid particles in the raw coal tar from clogging the dehydration unit, thereby facilitating oil-water separation, improving the oil-water separation effect, and thus increasing the net yield of the pretreated and purified coal tar.

[0020] 2. The coal tar pretreatment system in the coal tar hydrogenation process of this utility model connects the first heat exchanger with the outlet end of the centrifuge and the outlet end of the filter unit, which facilitates heat exchange between the raw coal tar and the filtered coal tar, making full use of heat and thus reducing energy consumption. Attached Figure Description

[0021] Figure 1 This is an overall schematic diagram of the coal tar pretreatment system in the coal tar hydrogenation process of this utility model.

[0022] Explanation of reference numerals in the attached drawings: 1. Filtration unit; 2. Dehydration unit; 3. First heat exchanger; 4. Second heat exchanger; 5. Third heat exchanger; 6. Fourth heat exchanger; 7. Fifth heat exchanger; 8. Centrifuge; 9. First booster pump; 10. Sixth heat exchanger; 11. Dehydration tower; 12. Seventh heat exchanger; 13. Eighth heat exchanger; 14. Second booster pump; 15. First air cooler; 16. Buffer tank. Detailed Implementation

[0023] The technical solution of this utility model will be further explained and described below with reference to the accompanying drawings and embodiments, but this utility model is not limited to the embodiments described below.

[0024] Reference Figure 1 In this invention, the filter unit 1 is placed before the dehydration unit 2. The filter unit 1 first filters the solid particles in the raw coal tar, and then the dehydration unit 2 dehydrates the filtered coal tar flowing out of the filter unit 1. This avoids the solid particles in the raw coal tar from clogging the dehydration unit 2, thereby facilitating oil-water separation, improving the oil-water separation effect, and thus increasing the net yield of the pretreated and purified coal tar.

[0025] Reference Figure 1 A coal tar pretreatment system for a coal tar hydrogenation process includes: a pretreatment unit, a first heating unit, a filtration unit 1, and a dehydration unit 2; the first heating unit is used to heat the raw coal tar; the filtration unit 1 is connected to the outlet end of the first heating unit and is used to filter solid particles in the raw coal tar; the dehydration unit 2 is connected to the outlet end of the filtration unit 1 and is used to perform a primary dehydration treatment on the filtered coal tar.

[0026] Specifically, the filter unit 1 can be a backwash filter, an activated carbon filter, or a fiber bundle filter. The filter unit 1 can be used to filter solid particles in the raw coal tar. In this embodiment, the filter unit 1 is a backwash filter, which removes solid particles with a particle size greater than 15 μm from the raw coal tar.

[0027] Specifically, the dehydration unit 2 can be an electric desalting tank or a vacuum dehydrator. The filtered coal tar can be dehydrated sequentially through the dehydration unit 2. In this embodiment, the dehydration unit 2 is an electric desalting tank, which removes salt and water from the filtered coal tar, reducing the salt content in the filtered coal tar to below 15 mg / L.

[0028] Reference Figure 1 The pretreatment unit includes a fifth heat exchanger 7, a centrifuge 8, and a first booster pump 9, which are connected sequentially along the flow direction of the raw coal tar. The raw coal tar flows into the inlet of the fifth heat exchanger 7. The outlet of the first booster pump 9 is connected to the inlet of the first heating unit.

[0029] Furthermore, the pretreatment unit also includes a buffer tank 16; the buffer tank 16 is placed between the centrifuge 8 and the first booster pump 9.

[0030] Reference Figure 1 The inlet of the first heating unit is connected to the outlet of the first booster pump 9 and the outlet of the filter unit 1; the outlet of the first heating unit is connected to the inlet of the filter unit 1 and the inlet of the sixth heat exchanger 10.

[0031] Specifically, the first heating unit includes multiple heat exchangers connected sequentially along the flow direction of the raw coal tar. The number of heat exchangers can be two, three, or four, depending on the required temperature of the raw coal tar. In this embodiment, the number of heat exchangers is four. The first heating unit includes a first heat exchanger 3, a second heat exchanger 4, a third heat exchanger 5, and a fourth heat exchanger 6 connected sequentially along the flow direction of the raw coal tar. Through the synergistic action of the first heat exchanger 3, the second heat exchanger 4, the third heat exchanger 5, and the fourth heat exchanger 6, the temperature of the raw coal tar is raised to 145°C to 170°C, improving the fluidity of the raw coal tar and facilitating the filtration of solid particles in the raw coal tar by the filtration unit 1.

[0032] Reference Figure 1 The coal tar pretreatment system in the coal tar hydrogenation process further includes a first cooling unit, which is a sixth heat exchanger 10; the sixth heat exchanger 10 is connected to the outlet end of the filtration unit 1. The filtered coal tar is cooled by the sixth heat exchanger 10, which facilitates the subsequent dehydration treatment of the coal tar by the dehydration unit 2 and improves the dehydration effect.

[0033] Furthermore, the inlet end of the heat exchanger furthest from filter unit 1 is connected to both the outlet end of centrifuge 8 and the outlet end of filter unit 1; the outlet end of the heat exchanger furthest from filter unit 1 is connected to both the inlet end of the adjacent heat exchanger and the inlet end of the sixth heat exchanger 10; in this embodiment, the inlet end of the first heat exchanger 3 is connected to both the outlet end of centrifuge 8 and the outlet end of filter unit 1; the outlet end of the first heat exchanger 3 is connected to both the inlet end of the second heat exchanger 4 and the inlet end of the sixth heat exchanger 10. By connecting the first heat exchanger 3 to the outlet end of centrifuge 8 and the outlet end of filter unit 1, heat exchange between the raw coal tar and the filtered coal tar is facilitated, making full use of heat and reducing energy consumption.

[0034] Reference Figure 1 The coal tar pretreatment system in the coal tar hydrogenation process also includes a dehydration tower 11; the dehydration tower 11 is connected to the outlet end of the dehydration unit 2, and the dehydration tower 11 is used to perform secondary dehydration on the coal tar after primary dehydration, thereby improving the degree of dehydration of the filtered coal tar and obtaining purified coal tar.

[0035] Reference Figure 1The coal tar pretreatment system in the coal tar hydrogenation process further includes a second heating unit. This second heating unit comprises a seventh heat exchanger 12 and an eighth heat exchanger 13, sequentially connected along the flow direction of the filtered coal tar exiting the filtration unit 1. The seventh heat exchanger 12 is connected to the outlet of the dehydration unit 2, and the eighth heat exchanger 13 is connected to the inlet of the dehydration tower 11. The seventh heat exchanger 12 and the eighth heat exchanger 13 facilitate heating the coal tar after primary dehydration, improving its fluidity and thus making it easier for it to enter the dehydration tower 11 for secondary dehydration.

[0036] Reference Figure 1 The coal tar pretreatment system in the coal tar hydrogenation process also includes a reflux unit, which includes a second booster pump 14 and a first air cooler 15; the second booster pump 14, the fifth heat exchanger 7 and the first air cooler 15 are connected in sequence along the flow direction of the purified coal tar flowing out from the bottom of the dehydration tower 11; the second booster pump 14 is connected to the outlet end of the bottom of the dehydration tower 11.

[0037] Specifically, the purified coal tar is pressurized to 0.8 MPa by the second booster pump 14 to facilitate its delivery to subsequent process units. Part of the purified coal tar is cooled to the range of 100℃ to 130℃ by the fifth heat exchanger 7 and then sent to the reaction unit, which refers to the hydrogenation reactor in the coal tar hydrogenation process. Another part of the purified coal tar undergoes a second cooling process by the first air cooler 15, cooling to the range of 80℃ to 90℃ before being sent to the tank area for storage. The second booster pump 14, the fifth heat exchanger 7, and the first air cooler 15 facilitate the reasonable pressurization and cooling of the purified coal tar to meet the needs of different process units.

[0038] Reference Figure 1 The dehydration tower 11 is connected in sequence to a second air cooler and a separator along the flow direction of the flash vapor flowing out from the top of the tower 11; the second air cooler is connected to the outlet end at the top of the dehydration tower 11. The cooperation between the second air cooler and the separator facilitates the condensation and three-phase separation of the flash vapor, recovering the oil and water in the flash vapor, and obtaining dry gas at the same time.

[0039] Specifically, after being cooled by the second air cooler, the flash vapor enters the separator for three-phase separation of oil, gas, and water, which facilitates the recovery and reuse of oil, gas, and water in the flash vapor, thereby improving resource utilization.

[0040] The working principle of the coal tar pretreatment system in the coal tar hydrogenation process of this utility model is as follows: Raw coal tar from the tank farm enters the fifth heat exchanger 7. In the fifth heat exchanger 7, purified coal tar flowing from the outlet of the second booster pump 14 exchanges heat with the raw coal tar, raising the temperature of the raw coal tar. The raw coal tar continues to flow to the centrifuge 8, where, under the action of centrifugal force, the coal tar, oil residue, and ammonia-containing wastewater in the raw coal tar are separated into three phases. The separated coal tar flows by gravity to the buffer tank 16. The coal tar in the buffer tank 16 is pressurized by the first booster pump 9 and flows to the first heat exchanger 3. The coal tar at the first heat exchanger 3 flows sequentially through the first heat exchanger 3, the second heat exchanger 4, the third heat exchanger 5, and the fourth heat exchanger 6 for heating. The coal tar flowing out of the outlet of the fourth heat exchanger 6 flows to the filter unit 1, where the filter unit 1 filters the solid particles in the coal tar. The coal tar flowing out of the outlet of the filter unit 1 flows sequentially through the first heat exchanger... Heat exchanger 3 and the sixth heat exchanger 10 are used for cooling; the filtered coal tar flowing out of the outlet of the sixth heat exchanger 10 flows into the dehydration unit 2, where the filtered coal tar is dehydrated once; the coal tar flowing out of the outlet of the dehydration unit 2 flows sequentially through the seventh heat exchanger 12 and the eighth heat exchanger 13 for heating; the coal tar flowing out of the outlet of the eighth heat exchanger 13 flows into the dehydration tower 11, where the coal tar is flash-dehydrated, and the flash tar discharged from the top outlet of the dehydration tower 11 is dehydrated. After being condensed by the second air cooler, the steam enters the separator, where oil, water, and gas are separated. The purified coal tar is discharged from the top and bottom outlet of the dehydration tower 11. The purified coal tar is pressurized by the second booster pump 14 and flows to the fifth heat exchanger 7. In the fifth heat exchanger 7, the purified coal tar exchanges heat with the raw coal tar, and the temperature of the purified coal tar decreases. After cooling, part of the purified coal tar flows to the reaction unit, and the other part is cooled again by the first air cooler 15 and then flows to the tank area for storage.

[0041] The above are all preferred embodiments of this utility model, and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape and principle of this utility model should be included within the scope of protection of this utility model.

Claims

1. A coal tar pre-treatment system in a coal tar hydroprocessing process, characterized by, include: The first heating unit is used to heat the raw coal tar. The filter unit (1) is connected to the outlet end of the first heating unit and is used to filter solid particles in the raw coal tar. And a dehydration unit (2), which is connected to the outlet end of the filter unit (1) for performing a primary dehydration treatment on the filtered coal tar.

2. The coal tar pre-treatment system in a coal tar hydroprocessing process as claimed in claim 1, wherein: The first heating unit includes a plurality of heat exchangers connected in sequence, and the outlet end of the last heat exchanger is connected to the filter unit (1).

3. The coal tar pre-treatment system in coal tar hydroprocessing process as claimed in claim 1 wherein: The coal tar pretreatment system in the coal tar hydrogenation process also includes a pretreatment unit, which includes a fifth heat exchanger (7), a centrifuge (8), and a first booster pump (9) connected in sequence. Raw coal tar flows into the inlet of the fifth heat exchanger (7); The outlet end of the first booster pump (9) is connected to the inlet end of the first heating unit.

4. The coal tar pre-treatment system in a coal tar hydroprocessing process as claimed in claim 3, wherein: The coal tar pretreatment system in the coal tar hydrogenation process also includes a first cooling unit, which is a sixth heat exchanger (10). The sixth heat exchanger (10) is connected to the outlet end of the filter unit (1).

5. The coal tar pre-treatment system in a coal tar hydroprocessing process as claimed in claim 4, wherein: The inlet of the first heating unit is connected to the outlet of the first booster pump (9) and the outlet of the filter unit (1); the outlet of the first heating unit is connected to the inlet of the filter unit (1) and the inlet of the sixth heat exchanger (10).

6. A coal tar pre-treatment system in a coal tar hydroprocessing process according to any one of claims 3 to 5, characterized by: The coal tar pretreatment system in the coal tar hydrogenation process also includes a dehydration tower (11); The dehydration tower (11) is connected to the outlet end of the dehydration unit (2), and the dehydration tower (11) is used to perform secondary dehydration on the coal tar after primary dehydration.

7. The coal tar pre-treatment system in a coal tar hydroprocessing process as claimed in claim 6, wherein: The coal tar pretreatment system in the coal tar hydrogenation process also includes a second heating unit, which includes a seventh heat exchanger (12) and an eighth heat exchanger (13) connected in sequence. The seventh heat exchanger (12) is connected to the outlet end of the dehydration unit (2), and the eighth heat exchanger (13) is connected to the inlet end of the dehydration tower (11).

8. The coal tar pre-treatment system in coal tar hydroprocessing process as claimed in claim 6 wherein: The coal tar pretreatment system in the coal tar hydrogenation process also includes a reflux unit, which includes a second booster pump (14) and a first air cooler (15). The second booster pump (14), the fifth heat exchanger (7), and the first air cooler (15) are connected in sequence; The second booster pump (14) is connected to the outlet end of the bottom of the dehydration tower (11).

9. The coal tar pre-treatment system in a coal tar hydroprocessing process as claimed in claim 8, wherein: The flash vapor flowing out from the top of the dehydration tower (11) is sequentially connected to the second air cooler and the liquid separator; The second air cooler is connected to the outlet end at the top of the dehydration tower (11).

10. The coal tar pre-treatment system in a coal tar hydroprocessing process as claimed in claim 3, wherein: The pretreatment unit also includes a buffer tank (16); The buffer tank (16) is placed between the centrifuge (8) and the first booster pump (9).

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