Device for producing methylcyclohexane by using naphtha
By using a combination of a first and second separation tower connected in series, along with a reboiler and a cooling reflux pipeline, the problem of low methylcyclohexane yield in existing technologies has been solved, achieving high-purity extraction and energy cascade utilization, thus improving economic efficiency.
Patent Information
- Application Number
- CN202520545245.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2026-03-10
- Estimated Expiration
- 2035-03-26
AI Technical Summary
Existing technologies obtain methylcyclohexane by directly extracting it from the top of the gravity separation tower, resulting in a low yield of methylcyclohexane in the feedstock naphtha and poor economic benefits.
The first and second fractionation towers are connected in series. The second fractionation tower is used to carry out secondary fractionation based on the difference in boiling points of the components. Combined with a reboiler and a cooling reflux line, the yield and purity of methylcyclohexane are improved.
This method achieves high-purity extraction of methylcyclohexane, improves yield, reduces energy consumption, and enhances the reliability and economic benefits of the equipment.
Smart Images
Figure CN223980109U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of naphtha separation technology, specifically to an apparatus for producing methylcyclohexane from naphtha. Background Technology
[0002] Naphtha, an important petroleum product, is mainly divided into light naphtha and heavy naphtha. Naphtha is primarily used in the production of chemical raw materials, especially as an important raw material for the production of ethylene, propylene, and aromatic chemicals such as benzene, toluene, and xylene.
[0003] In the field of naphtha deep processing, existing technologies employ multi-tower cascade processes to achieve component gradient separation. A typical multi-tower cascade process is as follows: the naphtha feedstock from the light oil removal tower first enters the heavy oil separation tower for preliminary fractionation. Methylcyclohexane is directly collected from the top of the tower, while the heavy oil from the bottom is sent to the heavy oil removal tower for secondary separation. Crude C8 cyclohexane is further collected from the top of the heavy oil removal tower, and the final naphtha product is obtained from the bottom.
[0004] Therefore, it can be seen that the basic components of naphtha can be separated by using a heavy separation tower and a de-heavy separation tower in combination. However, methylcyclohexane accounts for as much as 37% of the mass of the naphtha, which has the potential for high-value utilization. However, the existing process obtains methylcyclohexane by directly extracting it from the top of the heavy separation tower. The effective yield of methylcyclohexane is limited to about 75%, which directly results in nearly a quarter of the methylcyclohexane in the naphtha not being effectively extracted. The low yield of methylcyclohexane leads to poor economic benefits. Utility Model Content
[0005] To address the technical problem in the prior art where obtaining methylcyclohexane by directly extracting it from the top of a gravity separation tower results in a low yield of methylcyclohexane in the raw naphtha, this invention provides an apparatus for producing methylcyclohexane from naphtha.
[0006] This invention relates to an apparatus for producing methylcyclohexane from naphtha. It comprises a first and a second fractionation tower connected in series. The first light component collected from the top of the first fractionation tower enters the second fractionation tower. Utilizing the boiling point differences of the components, the first light component undergoes secondary fractionation in the second fractionation tower, after which methylcyclohexane is collected from the top of the second fractionation tower. This achieves high-purity extraction of methylcyclohexane, improves the effective yield of methylcyclohexane, and thus enhances economic benefits.
[0007] To solve the above-mentioned technical problems, this utility model provides the following technical solution:
[0008] An apparatus for producing methylcyclohexane from naphtha includes a first heavy separation tower and a second heavy separation tower. The first heavy separation tower separates the feedstock naphtha, and collects a first light component at the top of the first heavy separation tower and a first heavy component at the bottom of the first heavy separation tower. The second heavy separation tower is connected to the top of the first heavy separation tower, and the first light component enters the second heavy separation tower for separation. A second light component is collected at the top of the second heavy separation tower and a second heavy component is collected at the bottom of the second heavy separation tower. The second light component is methylcyclohexane.
[0009] In one specific implementation scheme, the apparatus for producing methylcyclohexane from naphtha further includes a deweighting tower; the deweighting tower is connected to the bottom of a first heavy fractionation tower, the first heavy component enters the deweighting tower for separation, wherein a third light component is collected at the top of the deweighting tower and a third heavy component is collected at the bottom of the deweighting tower.
[0010] In one specific implementation scheme, the first heavy separation column is equipped with a first main reboiler; one end of the first main reboiler is connected to the bottom of the first heavy separation column, the other end of the first main reboiler is connected to the top of the second heavy separation column, and the heat source of the first main reboiler is the second light component extracted from the top of the second heavy separation column.
[0011] In one specific implementation scheme, the first separation column is further equipped with a first auxiliary reboiler; the first auxiliary reboiler is connected to the bottom of the first separation column, and the heat source of the first auxiliary reboiler is saturated steam.
[0012] In one specific implementation scheme, the second separation column is equipped with a second auxiliary reboiler; the second auxiliary reboiler is connected to the bottom of the second separation column, and the heat source of the second auxiliary reboiler is saturated steam.
[0013] In one specific implementation scheme, the heavy component de-coal column is equipped with a second heavy component reboiler; one end of the second heavy component reboiler is connected to the top of the second heavy component column, the other end of the second heavy component reboiler is connected to the bottom of the heavy component de-coal column, and the heat source of the second heavy component reboiler is the second light component extracted from the top of the second heavy component column.
[0014] In one specific implementation scheme, the heavy component removal tower is further equipped with a first heavy component reboiler; one end of the first heavy component reboiler is connected to the bottom of the heavy component removal tower, and the heat source of the first heavy component reboiler is saturated steam.
[0015] In one specific implementation scheme, the deweighting tower is further equipped with a third heavy component reboiler; the third heavy component reboiler is connected to the bottom of the deweighting tower, and the heat source of the third heavy component reboiler is saturated steam.
[0016] In one specific implementation scheme, the top of the first splitter tower is also connected to the side of the first splitter tower via a first cooling return pipeline.
[0017] In one specific implementation scheme, the top of the second splitter is also connected to the side of the second splitter via a second cooling return pipeline.
[0018] In summary, this utility model has the following beneficial technical effects:
[0019] 1. This utility model relates to an apparatus for producing methylcyclohexane from naphtha. It comprises a first and a second fractionation tower connected in series. The first light component collected from the top of the first fractionation tower enters the second fractionation tower. Utilizing the boiling point differences of the components, the first light component undergoes secondary fractionation in the second fractionation tower, and methylcyclohexane is then collected from the top of the second fractionation tower. This achieves high-purity extraction of methylcyclohexane, improves the effective yield of methylcyclohexane, and thus increases economic benefits.
[0020] 2. The apparatus for producing methylcyclohexane using naphtha of this invention includes a first heavy component reboiler in the first heavy fractionation tower. By utilizing the waste heat of the second light component extracted from the top of the second heavy fractionation tower as a heat source, energy is utilized in a cascade manner, reducing energy consumption. At the same time, a first auxiliary reboiler is set up to cooperate with the first main reboiler, flexibly adjusting the bottom temperature of the first heavy fractionation tower to adapt to different operating conditions.
[0021] 3. In the apparatus for producing methylcyclohexane using naphtha, the third heavy component reboiler, the first heavy component reboiler, and the second heavy component reboiler work together in the heavy separation tower. When the heat supplied by the second heavy component reboiler to the bottom liquid of the heavy separation tower is insufficient, the first and third heavy component reboilers supplement the heat to the heavy separation tower, thereby ensuring the stable operation of the heavy separation tower and improving the reliability of the apparatus.
[0022] 4. The apparatus for producing methylcyclohexane using naphtha of this invention, through the provision of a first cooling reflux pipeline and a second cooling reflux pipeline, facilitates the adjustment of the gas-liquid balance in the first and second separation towers, thereby improving the purity of methylcyclohexane. Attached Figure Description
[0023] Figure 1 This is a process flow diagram of the apparatus for producing methylcyclohexane using naphtha according to this utility model.
[0024] Figure 2 This is a simplified schematic diagram of the apparatus for producing methylcyclohexane using naphtha according to this invention.
[0025] Explanation of reference numerals in the attached diagram: 1. First heavy separation tower; 2. Second heavy separation tower; 3. Heavy separation tower; 4. First main reboiler; 5. First auxiliary reboiler; 6. Second auxiliary reboiler; 7. First heavy component reboiler; 8. Second heavy component reboiler; 9. Third heavy component reboiler; 10. First cooling reflux line; 11. Second cooling reflux line; 12. Third cooling reflux line; 13. Raw material preheater; 14. Standby line. Detailed Implementation
[0026] 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.
[0027] This invention aims to provide an apparatus for producing methylcyclohexane from naphtha. It comprises a first heavy fractionation column 1 and a second heavy fractionation column 2 connected in series. The first light component collected from the top of the first heavy fractionation column 1 enters the second heavy fractionation column 2. Utilizing the boiling point differences of the components, the first light component undergoes secondary fractionation in the second heavy fractionation column 2, and then methylcyclohexane is collected from the top of the second heavy fractionation column 2. This achieves high-purity extraction of methylcyclohexane, improves the effective yield of methylcyclohexane, and thus enhances economic benefits.
[0028] Example 1:
[0029] Reference Figure 1 and Figure 2 An apparatus for producing methylcyclohexane from naphtha includes a first heavy separation tower 1 and a second heavy separation tower 2. Naphtha feedstock collected from the top of the light separation tower enters the first heavy separation tower 1, where it separates the naphtha, resulting in a first light component collected at the top and a first heavy component collected at the bottom. The second heavy separation tower 2 is connected to the top of the first heavy separation tower 1, and a portion of the first light component enters the second heavy separation tower 2 for further separation. A second light component is collected at the top of the second heavy separation tower 2, and a second heavy component is collected at the bottom. The second light component is methylcyclohexane, and the second heavy component is the naphtha product.
[0030] Specifically, both the first and second separation towers can be configured as plate distillation towers, packed towers, membrane separation towers, etc. By selecting appropriate types of first and second separation towers, the purification of the feedstock naphtha can be ensured. Preferably, both the first and second separation towers are plate distillation towers. Plate distillation towers have low resistance, sufficient gas-liquid contact, and high space utilization, thus improving the separation efficiency during the separation of the feedstock naphtha.
[0031] More specifically, the naphtha collected from the top of the light hydrocarbon stripping tower is preheated by the feedstock preheater 13 before entering the first heavy hydrocarbon separation tower 1, which helps to improve the subsequent separation efficiency of the feedstock naphtha. The feedstock preheater 13 is connected to the bottom of the first heavy hydrocarbon separation tower 1. The first heavy component collected from the bottom of the first heavy hydrocarbon separation tower 1 is diverted to the feedstock preheater 13 and mixed with the feedstock naphtha. The first heavy component has a high temperature, thus using the first heavy component to preheat the feedstock naphtha, further realizing the cascade utilization of energy and reducing energy consumption.
[0032] Reference Figure 1 and Figure 2 To revaporize the liquid in the bottom of the first heavy separation column 1 and provide rising steam to the first heavy separation column 1, the first heavy separation column 1 is equipped with a first main reboiler 4 and a first auxiliary reboiler 5. One end of the first main reboiler 4 is connected to the bottom of the first heavy separation column 1, and the other end of the first main reboiler 4 is connected to the top of the second heavy separation column 2. The heat source for the first main reboiler 4 is the second light component collected at the top of the second heavy separation column 2. The first auxiliary reboiler 5 is connected to the bottom of the first heavy separation column 1, and the heat source for the first auxiliary reboiler 5 is medium-pressure saturated steam. The amount of steam entering the bottom of the first heavy separation column 1 is regulated by a steam regulating valve installed on the first auxiliary reboiler 5, thereby regulating the temperature of the liquid in the bottom of the first heavy separation column 1.
[0033] Specifically, the second light component at the top of the second secondary separation column 2 flows to the first main reboiler 4, while the bottom liquid of the first secondary separation column 1 flows to the first main reboiler 4. The second light component mixes with the bottom liquid of the first secondary separation column 1. The higher temperature of the second light component heats the bottom liquid of the first secondary separation column 1, causing it to re-vaporize. In this embodiment, the heat source for the first main reboiler 4 is the second light component collected from the top of the second secondary separation column 2, achieving energy cascade utilization and reducing energy consumption. Furthermore, the first auxiliary reboiler 5 works in conjunction with the first main reboiler 4, allowing for flexible adjustment of the temperature of the bottom liquid in the first secondary separation column 1 to adapt to different operating conditions.
[0034] Reference Figure 1 and Figure 2 To allow the liquid in the bottom of the second separation column 2 to re-vaporize and provide rising steam to the second separation column 2, the second separation column 2 is equipped with a second auxiliary reboiler 6. The second auxiliary reboiler 6 is connected to the bottom of the second separation column 2, and the heat source for the second auxiliary reboiler 6 is medium-pressure saturated steam. The amount of steam entering the bottom of the second separation column 2 is regulated by a steam regulating valve installed on the second auxiliary reboiler 6, thereby regulating the temperature of the liquid in the bottom of the second separation column 2.
[0035] Specifically, the pressure range of the medium-pressure saturated steam mentioned in this embodiment is 1.0 to 2.5 MPa; the heat source of the first auxiliary reboiler 5 and the second auxiliary reboiler 6 is medium-pressure saturated steam. The temperature difference between the medium-pressure steam and the material in the tower is moderate, which can ensure the vaporization efficiency and avoid component decomposition caused by high temperature.
[0036] More specifically, the types of the first main reboiler 4, the first auxiliary reboiler 5, and the second auxiliary reboiler 6 mentioned in this embodiment are not specifically limited. Fixed tube sheet heat exchangers, floating head heat exchangers, or U-tube heat exchangers can be selected. Operators can choose according to actual needs to ensure that the reboilers provide the necessary heat for the separation of light and heavy components in the column.
[0037] Reference Figure 1 and Figure 2 To enhance the separation effect of the raw material naphtha, the top of the first heavy separation tower 1 is connected to the tower side of the first heavy separation tower 1 via a first cooling reflux pipeline 10. A portion of the first light component is refluxed back to the first heavy separation tower 1 through the first cooling reflux pipeline 10 for further separation. Similarly, the top of the second heavy separation tower 2 is connected to the tower side of the second heavy separation tower 2 via a second cooling reflux pipeline 11. A portion of the second light component is refluxed back to the second heavy separation tower 2 through the second cooling reflux pipeline 11 for further separation. The first cooling reflux pipeline 10 and the second cooling reflux pipeline 11 facilitate further separation of the first and second light components, thereby improving the purity of methylcyclohexane.
[0038] Example 2:
[0039] Reference Figure 1 and Figure 2 This embodiment of the apparatus for producing methylcyclohexane from naphtha, based on Example 1, further utilizes the first heavy component and achieves deeper utilization of the first heavy component. The apparatus also includes a heavy component removal tower 3. The heavy component removal tower 3 is connected to the bottom of the first heavy component removal tower 1. The first heavy component enters the heavy component removal tower 3 for separation. A third light component is collected at the top of the heavy component removal tower 3, and a third heavy component is collected at the bottom of the heavy component removal tower 3.
[0040] Specifically, the third light component, which is crude C8 cyclohexane, is collected at the top of the third heavy component tower; the third heavy component, which is naphtha, is collected at the bottom of the third heavy component tower and is sold externally.
[0041] Furthermore, in order to further enhance the separation effect of the raw naphtha, the third light component is partially refluxed to the de-heavy tower 3 through the third cooling reflux pipeline 12, and the remaining part is directly extracted as crude C8 cyclohexane. The third cooling reflux pipeline 12 facilitates the further separation of the third light component, thereby improving the separation purity of the crude C8 cyclohexane.
[0042] Reference Figure 1 and Figure 2 To allow the liquid in the bottom of the heavy component removal tower 3 to vaporize again and provide rising steam to the tower, the heavy component removal tower 3 is equipped with a first heavy component reboiler 7, a second heavy component reboiler 8, and a third heavy component reboiler 9. The top of the second heavy component removal tower 2 and the first main reboiler 4 are both connected to the second heavy component reboiler 8. The other end of the second heavy component reboiler 8 is connected to the bottom of the heavy component removal tower 3. The heat source for the second heavy component reboiler 8 is the second light component collected from the top of the second heavy component removal tower 2. Both the first heavy component reboiler 7 and the third heavy component reboiler 9 are connected to the bottom of the heavy component removal tower 3, and their heat sources are both low-pressure saturated steam.
[0043] Specifically, a portion of the second light component at the top of the second heavy fractionation column 2 flows to the first main reboiler 4, where it exchanges heat with the bottom liquid of the first heavy fractionation column 1; the remaining portion flows to the second heavy component reboiler 8, where it exchanges heat with the bottom liquid of the heavy fractionation column 3. The second light component at the top of the second heavy fractionation column 2 has a high temperature, thus heating the bottom liquid of the heavy fractionation column 3, causing the bottom liquid of the second heavy fractionation column 2 to vaporize again. In this embodiment, the heat source for the second heavy component reboiler 8 is also the second light component at the top of the second heavy fractionation column 2, further realizing energy cascade utilization while reducing energy consumption. Both the first heavy component reboiler 7 and the third heavy component reboiler 9 are equipped with steam regulating valves, which adjust the steam flow to regulate the temperature of the bottom liquid in the heavy fractionation column 3.
[0044] More specifically, when the heat of the second light component flowing to the second heavy component reboiler 8 is insufficient to heat the bottom liquid of the heavy component removal tower 3, this part of the second light component is connected to the second cooling reflux line 11 through the spare line 14, so that the second light component can be directly returned to the second heavy component tower 2 through the second cooling reflux line 11, thereby avoiding unnecessary energy consumption.
[0045] In this embodiment, the third heavy component reboiler 9, the first heavy component reboiler 7, and the second heavy component reboiler 8 cooperate with each other. When the second heavy component reboiler 8 is insufficient to supply heat to the bottom liquid of the heavy separation tower 3, the first heavy component reboiler 7 and the third heavy component reboiler 9 supplement the heat to the heavy separation tower 3, thereby ensuring the stable operation of the heavy separation tower 3.
[0046] Specifically, the pressure range of the low-pressure saturated steam mentioned in this embodiment is 0.2 to 0.5 MPa. By supplementing the heat of the de-weighting tower 3 with low-pressure saturated steam, the heat demand of the de-weighting tower 3 can be met, thus saving costs.
[0047] The types of the first heavy component reboiler 7, the second heavy component reboiler 8, and the third heavy component reboiler 9 mentioned in this embodiment are not specifically limited. Fixed tube sheet heat exchangers, floating head heat exchangers, or U-tube heat exchangers can be selected. Operators can choose according to actual needs to ensure that the reboilers provide the necessary heat for the separation of light and heavy components in the column.
[0048] The working principle of this utility model of an apparatus for producing methylcyclohexane from naphtha is as follows: the raw material naphtha enters the first heavy separation tower 1 for initial separation; the first light component is collected at the top of the first heavy separation tower 1, and the first heavy component is collected at the bottom of the first heavy separation tower 1. The first heavy component enters the de-heavy separation tower 3; the first light component enters the second heavy separation tower 2 for rectification. Utilizing the boiling point difference of each component, the second light component is collected at the top of the second heavy separation tower 2. The second light component is methylcyclohexane. The second heavy component is collected at the bottom of the second heavy separation tower 2; the first heavy component is further separated in the de-heavy separation tower 3. The third light component is collected at the top of the de-heavy separation tower 3, and the third heavy component is collected at the bottom of the de-heavy separation tower 3. The third heavy component is mixed with the first heavy component to produce the naphtha product.
[0049] The preferred embodiments of this utility model 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. An apparatus for producing methylcyclohexane from naphtha, characterized by: Comprising a first heavy fraction column (1) for separating a raw material naphtha, and a first light component is withdrawn at the top of the first heavy fraction column (1), and a first heavy component is withdrawn at the bottom of the first heavy fraction column (1); and a second heavy fraction column (2) which is communicated with the top of the first heavy fraction column (1), and the first light component is introduced into the second heavy fraction column (2) for separation, and a second light component is withdrawn at the top of the second heavy fraction column (2), and a second heavy component is withdrawn at the bottom of the second heavy fraction column (2), and the second light component is methylcyclohexane.
2. The apparatus for producing methylcyclohexane from naphtha according to claim 1, characterized by: The device for producing methylcyclohexane from naphtha further comprises a heavy component removal column (3); The heavy component removal column (3) is communicated with the bottom of the first heavy fraction column (1), and the first heavy component is introduced into the heavy component removal column (3) for separation, and a third light component is withdrawn at the top of the heavy component removal column (3), and a third heavy component is withdrawn at the bottom of the heavy component removal column (3).
3. The apparatus for producing methylcyclohexane from naphtha according to claim 2, characterized by: The first heavy fraction column (1) is provided with a first main reboiler (4); One end of the first main reboiler (4) is communicated with the bottom of the first heavy fraction column (1), the other end of the first main reboiler (4) is communicated with the top of the second heavy fraction column (2), and the heat source of the first main reboiler (4) is the second light component withdrawn at the top of the second heavy fraction column (2).
4. The apparatus for producing methylcyclohexane from naphtha according to claim 3, characterized by: The first heavy fraction column (1) is further provided with a first auxiliary reboiler (5); The first auxiliary reboiler (5) is communicated with the bottom of the first heavy fraction column (1), and the heat source of the first auxiliary reboiler (5) is saturated steam.
5. The apparatus for producing methylcyclohexane from naphtha according to claim 4, characterized by: The second heavy fraction column (2) is provided with a second auxiliary reboiler (6); The second auxiliary reboiler (6) is communicated with the bottom of the second heavy fraction column (2), and the heat source of the second auxiliary reboiler (6) is saturated steam.
6. The apparatus for producing methylcyclohexane from naphtha according to any one of claims 2 to 5, characterized by: The heavy component removal column (3) is provided with a second heavy component reboiler (8); One end of the second heavy component reboiler (8) is communicated with the top of the second heavy fraction column (2), the other end of the second heavy component reboiler (8) is communicated with the bottom of the heavy component removal column (3), and the heat source of the second heavy component reboiler (8) is the second light component withdrawn at the top of the second heavy fraction column (2).
7. The apparatus for producing methylcyclohexane from naphtha according to claim 6, characterized by: The heavy component removal column (3) is further provided with a first heavy component reboiler (7); One end of the first heavy component reboiler (7) is communicated with the bottom of the heavy component removal column (3), and the heat source of the first heavy component reboiler (7) is saturated steam.
8. The apparatus for producing methylcyclohexane from naphtha according to claim 7, characterized by: The heavy component removal column (3) is further provided with a third heavy component reboiler (9); The third heavy component reboiler (9) is communicated with the bottom of the heavy component removal column (3), and the heat source of the third heavy component reboiler (9) is saturated steam.
9. The apparatus for producing methylcyclohexane from naphtha according to claim 1, wherein: The top of the first heavy fraction column (1) is further communicated with the side of the first heavy fraction column (1) through a first cooling reflux pipeline (10).
10. The apparatus for producing methylcyclohexane from naphtha according to claim 1, wherein: The top of the second heavy fraction column (2) is further communicated with the side of the second heavy fraction column (2) through a second cooling reflux pipeline (11).