Heavy naphtha recovery system in coal tar hydrogenation process

Abstract

The utility model belongs to the technical field of coal tar treatment, and relates to a heavy naphtha recovery system in a coal tar hydrogenation process, which comprises a first atmospheric tower, a second atmospheric tower, a first atmospheric pipeline, a second atmospheric pipeline and a connecting pipeline, the normal first pipeline is communicated with the first atmospheric tower; the atmospheric second pipeline is communicated with the second atmospheric tower; one end of the connecting pipeline is communicated with a first normal pipeline, the other end of the connecting pipeline is communicated with a second normal pipeline, and a communicating valve is arranged on the connecting pipeline; according to the heavy naphtha recovery system in the coal tar hydrogenation process, the connecting pipeline is arranged, so that light naphtha flows into the connecting pipeline along the normal first-line pipeline and then flows into the normal second-line pipeline through the connecting pipeline to be extracted, and heavy naphtha is extracted along the outlet end of the normal first-line pipeline; therefore, meaningless deep processing of heavy naphtha without methyl cyclohexane is avoided, and energy consumption of a heavy naphtha recovery system in a coal tar hydrogenation process is reduced.

Description

Technical Field

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

[0002] Coal tar full-fraction hydrogenation is an advanced petroleum processing technology. Through hydrogenation, impurities and harmful components in coal tar can be removed, thereby producing high-value-added naphthenic oil products. In a coal tar full-fraction hydrogenation unit, the first and second atmospheric distillation lines are key material transport channels. The first atmospheric distillation line is mainly responsible for transporting the relatively light fraction after preliminary hydrogenation. These fractions typically contain more cycloalkanes and a small amount of aromatics, which are important raw materials for producing high-quality naphthenic oils. The second atmospheric distillation line is used to transport the slightly heavier fractions, which, after further refining and processing, can be used to produce naphthenic oil products of different grades.

[0003] In existing technologies, the first-stage product is typically integrated into the second-stage pipeline for sale as diesel fuel or as feedstock for the hydrogenation of naphthenic oils. However, subsequent processes require further processing of the first-stage product to separate methylcyclohexane. When heavy naphtha with a distillation range of 145°C–195°C is drawn from the first-stage pipeline, methylcyclohexane cannot exist in the heavy naphtha due to its boiling point of 100.9°C. Therefore, directly integrating the first-stage product into the second-stage pipeline results in a mixture of heavy naphtha and the second-stage product. Further processing of this mixture containing heavy naphtha in subsequent processes is pointless, leading to increased system energy consumption. Utility Model Content

[0004] To address the technical problem that methylcyclohexane cannot exist in heavy naphtha with a distillation range of 145℃ to 195℃, making further processing of mixtures containing heavy naphtha in subsequent processes meaningless and leading to increased system energy consumption, this invention provides a heavy naphtha recovery system in a coal tar hydrogenation process.

[0005] This utility model discloses a heavy naphtha recovery system in a coal tar hydrogenation process. A connecting pipeline connects the first atmospheric pressure tower and the second atmospheric pressure tower. When light naphtha is collected from the first atmospheric pressure tower, the connecting valve is opened, allowing the light naphtha to flow along the first atmospheric pressure tower to the connecting pipeline, and then through the connecting pipeline into the second atmospheric pressure tower for collection. When heavy naphtha is collected from the first atmospheric pressure tower, the connecting valve is closed, allowing the heavy naphtha to be collected from the outlet end of the first atmospheric pressure tower. This avoids unnecessary further processing of heavy naphtha that does not contain methylcyclohexane, thus reducing the energy consumption of the heavy naphtha recovery system in the coal tar hydrogenation process.

[0006] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0007] A heavy naphtha recovery system in a coal tar hydrogenation process includes: a first atmospheric pressure tower, a second atmospheric pressure tower, an atmospheric pressure line 1 pipeline, an atmospheric pressure line 2 pipeline, and connecting pipelines; heavy naphtha or light naphtha is extracted from the side of the first atmospheric pressure tower; diesel oil is extracted from the side of the second atmospheric pressure tower; the system is connected to the first atmospheric pressure tower; the system is connected to the second atmospheric pressure tower; one end of the connecting pipeline is connected to the atmospheric pressure line 1 pipeline, and the other end of the connecting pipeline is connected to the atmospheric pressure line 2 pipeline, and a connecting valve is provided on the connecting pipeline.

[0008] In one specific implementation scheme, a set of regulating components is respectively provided on the first atmospheric pressure pipeline and the second atmospheric pressure pipeline; the regulating components include an air-cooled unit and a water-cooled unit arranged sequentially along the distillate oil conveying direction, the air-cooled unit and the water-cooled unit on the first atmospheric pressure pipeline are located between the first atmospheric pressure tower and the connecting pipeline, and the air-cooled unit and the water-cooled unit on the second atmospheric pressure pipeline are located between the second atmospheric pressure tower and the connecting pipeline.

[0009] In one specific implementation, the regulating component further includes a booster pump; the booster pump on the first atmospheric pressure line is located between the first atmospheric pressure tower and the air-cooled unit, and the booster pump on the second atmospheric pressure line is located between the second atmospheric pressure tower and the air-cooled unit.

[0010] In one specific implementation, the regulating assembly further includes a first gate valve and a regulating valve connected sequentially along the distillate oil conveying direction; both the first gate valve and the regulating valve are located between the water cooling unit and the connecting pipeline.

[0011] In one specific implementation, the regulating assembly further includes a second gate valve located between the regulating valve and the connecting pipeline.

[0012] In one specific implementation, the regulating component further includes a parallel pipeline and a third gate valve; the parallel pipeline is connected in parallel with a constant first line or a constant second line; the third gate valve is disposed on the parallel pipeline.

[0013] In one specific implementation scheme, the regulating component further includes a fourth gate valve; a fourth gate valve is provided between the booster pump on the first atmospheric line and the first atmospheric tower, and a fourth gate valve is provided between the booster pump on the second atmospheric line and the second atmospheric tower.

[0014] In one specific implementation, a fifth gate valve is provided between the booster pump and the air-cooling unit.

[0015] In one specific implementation scheme, a sixth gate valve is provided at the outlet end of the constant-current pipeline.

[0016] In one specific implementation scheme, multiple flow meters are installed on both the primary and secondary flow lines.

[0017] In summary, this utility model has the following beneficial technical effects:

[0018] 1. The heavy naphtha recovery system in the coal tar hydrogenation process of this utility model is provided with a connecting pipeline connecting the first atmospheric pressure tower and the second atmospheric pressure tower. When light naphtha is collected from the first atmospheric pressure tower, the connecting valve is opened, allowing the light naphtha to flow along the first atmospheric pressure tower to the connecting pipeline, and then flow into the second atmospheric pressure tower for collection. When heavy naphtha is collected from the first atmospheric pressure tower, the connecting valve is closed, allowing the heavy naphtha to be collected from the outlet end of the first atmospheric pressure tower. This avoids meaningless further processing of heavy naphtha that does not contain methylcyclohexane and reduces the energy consumption of the heavy naphtha recovery system in the coal tar hydrogenation process.

[0019] 2. The heavy naphtha recovery system in the coal tar hydrogenation process of this utility model, through the cooperation of air-cooled and water-cooled units, facilitates flexible adjustment of the cooling effect according to the characteristics of different distillate oils and subsequent process requirements, ensuring stable system operation. By connecting the first and second gate valves and the third gate valve in parallel through parallel pipelines, when the first gate valve, the second gate valve, or the regulating valve fails, or when the first or second normal pipeline is not flowing, the distillate oil transport path can be switched to the parallel pipeline, ensuring continuous flow of distillate oil in the heavy naphtha recovery system, thereby reducing production interruption time caused by equipment failure. Attached Figure Description

[0020] Figure 1 This is an overall schematic diagram of the heavy naphtha recovery system in the coal tar hydrogenation process of this utility model.

[0021] Explanation of reference numerals in the attached diagram: 1. First atmospheric pressure tower; 2. Second atmospheric pressure tower; 3. First atmospheric pressure tower pipeline; 4. Second atmospheric pressure tower pipeline; 5. Connecting pipeline; 6. Air-cooled unit; 7. Water-cooled unit; 8. Booster pump; 9. First gate valve; 10. Regulating valve; 11. Second gate valve; 12. Parallel pipeline; 13. Third gate valve; 14. Fourth gate valve; 15. Fifth gate valve; 16. Sixth gate valve; 17. Flow meter. Detailed Implementation

[0022] 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.

[0023] Reference Figure 1In this invention, a connecting pipeline 5 is provided to connect the first atmospheric pressure pipeline 3 and the second atmospheric pressure pipeline 4. When light naphtha is extracted from the first atmospheric pressure tower 1, the connecting valve is opened, allowing the light naphtha to flow along the first atmospheric pressure pipeline 3 to the connecting pipeline 5, and then flow through the connecting pipeline 5 into the second atmospheric pressure pipeline 4 for extraction. When heavy naphtha is extracted from the first atmospheric pressure tower 1, the connecting valve is closed, allowing the heavy naphtha to be extracted along the outlet end of the first atmospheric pressure pipeline 3. This avoids meaningless further processing of heavy naphtha that does not contain methylcyclohexane and reduces the energy consumption of the heavy naphtha recovery system in the coal tar hydrogenation process.

[0024] Reference Figure 1 A heavy naphtha recovery system in a coal tar hydrogenation process includes: a first atmospheric pressure tower 1, a second atmospheric pressure tower 2, an atmospheric pressure line 3, an atmospheric pressure line 4, and a connecting pipeline 5; heavy naphtha or light naphtha is extracted from the side of the first atmospheric pressure tower 1; diesel oil is extracted from the side of the second atmospheric pressure tower 2; the atmospheric pressure line 3 is connected to the first atmospheric pressure tower 1; the atmospheric pressure line 4 is connected to the second atmospheric pressure tower 2; one end of the connecting pipeline 5 is connected to the atmospheric pressure line 3, the other end of the connecting pipeline 5 is connected to the atmospheric pressure line 4, and a connecting valve is provided on the connecting pipeline 5.

[0025] Specifically, the distillation range of heavy naphtha is 145℃~195℃, that of light naphtha is 80℃~145℃, and that of diesel is 195℃~280℃. When heavy naphtha with a distillation range of 145℃~195℃ is transported via the first atmospheric pipeline 3, methylcyclohexane is not present in the heavy naphtha. The connecting valve is adjusted to the closed state, disconnecting the connection between the first atmospheric pipeline 3 and the second atmospheric pipeline 4, allowing the heavy naphtha to flow along the first atmospheric pipeline 3 to the extraction point. When light naphtha with a distillation range of 80℃~145℃ is transported via the first atmospheric pipeline 3, methylcyclohexane is present in the light naphtha. Further processing of the light naphtha is required to separate the methylcyclohexane. Methylcyclohexane is introduced, and the connecting valve is adjusted to the open state to connect the first atmospheric line 3 and the second atmospheric line 4. Light naphtha flows along the first atmospheric line 3 to the connecting line 5, where it mixes with diesel fuel flowing through the connecting line 5 and the second atmospheric line 4. The mixture of light naphtha and diesel fuel continues to flow along the second atmospheric line 4 until it is extracted. After extraction, the mixture of light naphtha and diesel fuel is further processed to separate methylcyclohexane from the light naphtha, thus achieving effective utilization of different distillate oils.

[0026] Reference Figure 1Each of the first atmospheric pressure pipeline 3 and the second atmospheric pressure pipeline 4 is equipped with a set of regulating components. The regulating components include an air-cooling unit 6 and a water-cooling unit 7 arranged sequentially along the distillate oil conveying direction. The air-cooling unit 6 and water-cooling unit 7 on the first atmospheric pressure pipeline 3 are located between the first atmospheric pressure tower 1 and the connecting pipeline 5, and the air-cooling unit 6 and water-cooling unit 7 on the second atmospheric pressure pipeline 4 are located between the second atmospheric pressure tower 2 and the connecting pipeline 5. In this invention, distillate oil refers to heavy naphtha, light naphtha, or diesel oil. The air-cooling unit 6 provides initial cooling of the distillate oil, lowering its temperature and thus reducing the load on subsequent cooling equipment. The water-cooling unit 7 provides deep cooling of the distillate oil, bringing it to a suitable temperature for subsequent separation, storage, and other operations. The cooperation between the air-cooling unit 6 and the water-cooling unit 7 allows for flexible adjustment of the cooling effect according to the characteristics of different distillate oils and subsequent process requirements, ensuring stable system operation.

[0027] Specifically, the air-cooling unit 6 can be a tubular air cooler, a plate air cooler, or a wet air cooler. The type of air-cooling unit 6 can be selected according to the flow rate and temperature range of the distillate oil being processed, as well as the site environmental conditions. In this embodiment, the air-cooling unit 6 uses a tubular air cooler, which has a simple structure and high heat exchange efficiency. The water-cooling unit 7 can be a shell-and-tube heat exchanger, a spiral plate heat exchanger, or a coaxial heat exchanger. The type of water-cooling unit 7 can be selected according to the flow rate and temperature requirements of the distillate oil being processed, as well as the supply of cooling water. In this embodiment, the water-cooling unit 7 uses a shell-and-tube heat exchanger, which has a large heat exchange area and a compact structure.

[0028] Furthermore, the regulating assembly also includes a booster pump 8; the booster pump 8 on the first atmospheric pressure pipeline 3 is located between the first atmospheric pressure tower 1 and the air-cooling unit 6, and the booster pump 8 on the second atmospheric pressure pipeline 4 is located between the second atmospheric pressure tower 2 and the air-cooling unit 6. The booster pump 8 facilitates overcoming the resistance encountered during the transport of distillate oil in the first atmospheric pressure pipeline 3 or the second atmospheric pressure pipeline 4, ensuring stable transport of distillate oil at a certain pressure and flow rate to meet subsequent process requirements.

[0029] Specifically, the regulating assembly also includes a fourth gate valve 14; a fourth gate valve 14 is installed between the booster pump 8 on the first atmospheric pressure line 3 and the first atmospheric pressure tower 1, and a fourth gate valve 14 is installed between the booster pump 8 on the second atmospheric pressure line 4 and the second atmospheric pressure tower 2. A fifth gate valve 15 is installed between the booster pump 8 and the air-cooling unit 6. By installing a fourth gate valve 14 at the inlet end of the booster pump 8 and a fifth gate valve 15 at the outlet end of the booster pump 8, the connection between the distillate oil and the booster pump 8 can be promptly cut off when the booster pump 8 needs to be inspected, maintained, or malfunctions, ensuring the safe operation of the heavy naphtha recovery system and the smooth progress of maintenance work.

[0030] Furthermore, the regulating assembly also includes a first gate valve 9, a regulating valve 10, and a second gate valve 11 connected sequentially along the distillate oil conveying direction; the first gate valve 9 and the regulating valve 10 are both located between the water cooling unit 7 and the connecting pipeline 5. The second gate valve 11 is located between the regulating valve 10 and the connecting pipeline 5. The flow rate of the distillate oil in the first or second atmospheric pipeline 3 is regulated by the cooperation of the first and second gate valves 11; the flow rate and pressure of the distillate oil in the first or second atmospheric pipeline 4 are precisely regulated by the regulating valve 10, allowing for flexible adjustment according to different production needs, ensuring the stable and efficient operation of the heavy naphtha recovery system.

[0031] Reference Figure 1 A sixth gate valve 16 is installed at the outlet end of the constant-current pipeline 3, and the sixth gate valve 16 is located between the connecting pipeline 5 and the outlet of the constant-current pipeline 3. By installing the sixth gate valve 16 at the outlet end of the constant-current pipeline 3, it is convenient to cut off the flow of distillate oil at the outlet end of the constant-current pipeline 3 in a timely manner when the constant-current pipeline 3 needs to be inspected or maintained, to prevent distillate oil leakage, thereby ensuring the safe operation of the heavy naphtha recovery system.

[0032] Reference Figure 1 Multiple flow meters 17 are installed on both the first and second constant-pressure pipelines 3 and 4. These multiple flow meters 17 facilitate real-time monitoring of the distillate oil flow rate in the first and second constant-pressure pipelines 3 and 4, providing accurate data support for production operators to adjust production parameters promptly and ensure distillate oil quality and production stability.

[0033] Example 2:

[0034] Reference Figure 1 In this embodiment, the heavy naphtha recovery system in the coal tar hydrogenation process, based on embodiment 1, further includes a parallel pipeline 12 and a third gate valve 13 as the regulating component; the parallel pipeline 12 is connected in parallel with the first constant pipeline 3 or the second constant pipeline 4; the third gate valve 13 is installed on the parallel pipeline 12.

[0035] Specifically, when the first gate valve 9, the second gate valve 11, and the regulating valve 10 are working normally, the third gate valve 13 is closed, and the distillate oil does not flow into the parallel pipeline 12; when the first gate valve 9, the second gate valve 11, or the regulating valve 10 malfunctions, causing the first constant line pipeline 3 or the second constant line pipeline 4 to be blocked, the third gate valve 13 is opened, and the distillate oil flows into the parallel pipeline. After the flow rate of the distillate oil is regulated by the third gate valve 13 in the parallel pipeline, it flows back into the first constant line pipeline 3 or the second constant line pipeline 4.

[0036] In this embodiment, the first gate valve 9, the second gate valve 11, and the third gate valve 13 are connected in parallel via the parallel pipeline 12. When the first gate valve 9, the second gate valve 11, or the regulating valve 10 fails, or the first line pipeline 3 or the second line pipeline 4 is not flowing, the distillate oil delivery path can be switched to the parallel pipeline 12 to ensure the continuous flow of distillate oil in the heavy naphtha recovery system, thereby reducing the production interruption time caused by equipment failure.

[0037] The working principle of the heavy naphtha recovery system in the coal tar hydrogenation process of this utility model is as follows: When light naphtha is collected from the first atmospheric tower 1, the connecting valve is opened, allowing the light naphtha to flow along the first atmospheric tower 3 to the connecting pipeline 5, and then flow into the second atmospheric tower 4 for collection; when heavy naphtha is collected from the first atmospheric tower 1, the connecting valve is closed, allowing the heavy naphtha to be collected from the outlet end of the first atmospheric tower 3; diesel oil is collected from the second atmospheric tower 2, and the collected diesel oil flows along the second atmospheric tower 4, and is finally collected from the outlet end of the second atmospheric tower 4.

[0038] 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 heavy naphtha recovery system in a coal tar hydroprocessing process, characterized by, include: First atmospheric pressure tower (1), heavy naphtha or light naphtha is extracted from the first atmospheric pressure tower (1); The second atmospheric pressure tower (2) extracts diesel fuel from the second atmospheric pressure tower (2); A constant pressure pipeline (3) is connected to the first atmospheric pressure tower (1); The second atmospheric pressure pipeline (4) is connected to the second atmospheric pressure tower (2); And a connecting pipeline (5), one end of which is connected to the normal first line pipeline (3), and the other end of which is connected to the normal second line pipeline (4), and a connecting valve is provided on the connecting pipeline (5).

2. The heavy naphtha recovery system in a coal tar hydroprocessing process of claim 1, wherein: A set of adjustment components is respectively provided on the first constant line (3) and the second constant line (4); The regulating assembly includes an air-cooled unit (6) and a water-cooled unit (7) arranged sequentially along the distillate oil conveying direction. The air-cooled unit (6) and the water-cooled unit (7) on the first atmospheric pressure pipeline (3) are located between the first atmospheric pressure tower (1) and the connecting pipeline (5). The air-cooled unit (6) and the water-cooled unit (7) on the second atmospheric pressure pipeline (4) are located between the second atmospheric pressure tower (2) and the connecting pipeline (5).

3. The heavy naphtha recovery system in the coal tar hydrogenation process according to claim 2, characterized in that: The regulating assembly also includes a booster pump (8); The booster pump (8) on the first atmospheric pressure pipeline (3) is located between the first atmospheric pressure tower (1) and the air-cooled unit (6), and the booster pump (8) on the second atmospheric pressure pipeline (4) is located between the second atmospheric pressure tower (2) and the air-cooled unit (6).

4. The heavy naphtha recovery system in a coal tar hydroprocessing process of claim 3, wherein: The regulating assembly also includes a first gate valve (9) and a regulating valve (10) connected sequentially along the distillate oil conveying direction; The first gate valve (9) and the regulating valve (10) are both located between the water cooling unit (7) and the connecting pipeline (5).

5. The heavy naphtha recovery system in a coal tar hydroprocessing process of claim 4, wherein: The regulating assembly also includes a second gate valve (11); The second gate valve (11) is located between the regulating valve (10) and the connecting pipeline (5).

6. A heavy naphtha recovery system in a coal tar hydroprocessing process according to any one of claims 3 to 5, characterized by: The regulating assembly also includes a parallel pipe (12) and a third gate valve (13); The parallel pipeline (12) is connected in parallel with the first-line pipeline (3) or the second-line pipeline (4); The third gate valve (13) is installed on the parallel pipeline (12).

7. The heavy naphtha recovery system in a coal tar hydroprocessing process of claim 6, wherein: The regulating assembly also includes a fourth gate valve (14); A fourth gate valve (14) is provided between the booster pump (8) on the first atmospheric line (3) and the first atmospheric tower (1), and a fourth gate valve (14) is provided between the booster pump (8) on the second atmospheric line (4) and the second atmospheric tower (2).

8. The heavy naphtha recovery system in a coal tar hydroprocessing process of claim 7, wherein: A fifth gate valve (15) is provided between the booster pump (8) and the air-cooling unit (6).

9. The heavy naphtha recovery system in a coal tar hydroprocessing process of claim 1, wherein: The outlet end of the constant line pipeline (3) is equipped with a sixth gate valve (16).

10. The heavy naphtha recovery system in a coal tar hydroprocessing process of claim 1, wherein: Multiple flow meters (17) are installed on both the first and second constant pipelines (3 and 4).

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