Crude cyclohexane refining and recycling system
By employing high-pressure settings and multi-stage condensers in the cyclohexane refining and recovery system, the problems of low cyclohexane distillation efficiency and recovery rate have been solved, achieving efficient recovery and purification of cyclohexane, reducing production costs, and improving the economic benefits of enterprises.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HUBEI SANNING CHEM
- Filing Date
- 2025-04-30
- Publication Date
- 2026-05-15
AI Technical Summary
In existing technologies, the efficiency and recovery rate of cyclohexane distillation are relatively low, resulting in high raw material costs, low market prices, and increased operational pressure on enterprises.
A crude cyclohexane refining and recovery system is adopted, including a cyclohexane refining reactor and a cyclohexane distillation column. Combined with high pressure setting and multi-stage condenser, the purity and recovery rate of cyclohexane are improved through multi-stage condensation and distillation separation.
By refining and separating cyclohexane to obtain products with qualified purity, raw material costs are reduced, the company's resilience is enhanced, the value of by-products is increased, and market competitiveness is strengthened.
Smart Images
Figure CN224236790U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of chemical production technology, and in particular to a crude cyclohexane refining and recovery system. Background Technology
[0002] Cyclohexane is an important organic raw material for chemical production, mainly used in the manufacture of cyclohexanol, cyclohexanone, and other chemical raw materials. Cyclohexane is extensively used in the production of cyclohexanone, which primarily involves two processes: cyclohexane oxidation and cyclohexene hydration. In the cyclohexane oxidation process, benzene is completely hydrogenated to produce cyclohexane, which is then oxidized, decomposed, and separated to yield cyclohexanol and cyclohexanone. In the cyclohexene hydration process, benzene is partially and selectively hydrogenated to produce cyclohexene, with cyclohexane being collected as a byproduct.
[0003] Due to its significant advantages over oxidation methods, such as higher yield, less waste, higher safety, and lower energy consumption, the cyclohexane hydration process is widely used in cyclohexane ketone production both domestically and internationally. Most domestic hydration plants completely hydrogenate the byproduct cyclohexane containing unsaturated hydrocarbons, then distill it to obtain a high-purity cyclohexane product for sale. However, with the continuous expansion of domestic hydration plant scale, the market for byproduct cyclohexane has gradually become saturated, and the market price of cyclohexane has fallen below that of the feedstock benzene, increasing the operating pressure on enterprises. Utility Model Content
[0004] This invention provides a crude cyclohexane refining and recovery system, which solves the technical problems of high raw material costs and low cyclohexane distillation efficiency and recovery rate.
[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: a crude cyclohexane refining and recovery system, including a cyclohexane refining reactor and a cyclohexane distillation column. The bottom of the cyclohexane refining reactor is connected to the cyclohexane distillation column via a pipeline. The top of the cyclohexane distillation column is connected to a first reflux tank via a first circulating water condenser and a cyclohexanol distillation column reboiler. The first reflux tank is connected to a methylcyclopentane separation column via a pipeline. The bottom of the methylcyclopentane separation column is connected to the methylcyclopentane distillation column via a pipeline. The bottom of the methylcyclopentane distillation column is connected to the cyclohexane distillation column via a pipeline.
[0006] In a preferred embodiment, the top of the methylcyclopentane separation tower is connected to a second circulating water condenser and a second reflux tank, and the second reflux tank is connected to the light oil tank and the methylcyclopentane separation tower respectively via an electric pump unit.
[0007] In the preferred embodiment, the top of the methylcyclopentane distillation column is connected to a third circulating water condenser and a third reflux tank, and the third reflux tank is connected to the methylcyclopentane product tank and the methylcyclopentane distillation column respectively through an electric pump unit.
[0008] In a preferred embodiment, an electric pump unit is provided between the first reflux tank and the methylcyclopentane separation tower. The electric pump unit connects the low-boiling material to the methylcyclopentane separation tower and the cyclohexane distillation tower via pipelines.
[0009] In the preferred embodiment, the upper side and top of the cyclohexane refining reactor are respectively connected to crude cyclohexane and hydrogen through pipelines.
[0010] In a preferred embodiment, the bottom of the cyclohexane distillation column is connected to the cyclohexane product tank via an electric pump unit.
[0011] In a preferred embodiment, the bottom of the methylcyclopentane distillation column is connected to the cyclohexane distillation column via an electric pump unit and pipelines.
[0012] In the preferred embodiment, the top pressure of the cyclohexane distillation column is not less than 150 kPa.
[0013] In the preferred embodiment, the top pressure of the methylcyclopentane separation tower is in the range of 0~10 kPa.
[0014] In the preferred embodiment, the top pressure of the methylcyclopentane distillation column is in the range of 0~10 kPa.
[0015] The beneficial effects of this invention are as follows: By refining and separating the crude cyclohexane byproduct of the hydration process to obtain cyclohexane of qualified purity, it can be supplied as raw material to the cyclohexane production unit, greatly saving raw material costs. It also avoids the limitation of the hydration process unit's profitability due to market saturation of cyclohexane, enhancing its resilience. Furthermore, the light oil remaining after cyclohexane purification has low value and is difficult to treat, essentially only suitable for waste oil disposal. The methylcyclopentane in the light oil after crude cyclohexane separation, after separation and purification, has significant economic value, further enhancing the economic efficiency and competitiveness of this unit. Attached Figure Description
[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments:
[0017] Figure 1 This is a flowchart illustrating the present invention.
[0018] Figure 2 This is a schematic diagram of the traditional process flow.
[0019] In the diagram: 1. Hydrogen; 2. Crude cyclohexane; 3. Cyclohexane refining reactor; 4. Cyclohexane distillation column; 5. First circulating water condenser; 6. First reflux tank; 7. Cyclohexane product tank; 8. Low-boiling point; 9. Cyclohexanol distillation column reboiler; 10. Methylcyclopentane separation column; 11. Second circulating water condenser; 12. Second reflux tank; 13. Light oil tank; 14. Methylcyclopentane distillation column; 15. Third circulating water condenser; 16. Third reflux tank; 17. Methylcyclopentane product tank; 18. Electric pump unit. Detailed Implementation
[0020] like Figure 1 A crude cyclohexane refining and recovery system includes a cyclohexane refining reactor 3 and a cyclohexane distillation column 4. The bottom of the cyclohexane refining reactor 3 is connected to the cyclohexane distillation column 4 via a pipeline. The top of the cyclohexane distillation column 4 is connected to a first reflux tank 6 via a first circulating water condenser 5 and a cyclohexanol distillation column reboiler 9. The first reflux tank 6 is connected to a methylcyclopentane separation column 10 via a pipeline. The bottom of the methylcyclopentane separation column 10 is connected to a methylcyclopentane distillation column 14 via a pipeline. The bottom of the methylcyclopentane distillation column 14 is connected to the cyclohexane distillation column 4 via a pipeline.
[0021] Traditional crafts such as Figure 2 The bottom of the cyclohexane refining reactor 3 is connected to the cyclohexane distillation column 4 via a pipeline, and the top of the cyclohexane distillation column 4 is connected to the electric pump unit 18 via the first reflux tank 6. The cyclohexane distillation column 4 is set at atmospheric pressure, but this application sets the cyclohexane distillation column 4 at high pressure to ensure higher overall energy utilization. At the same time, a reboiler 9 for the cyclohexanol distillation column is set to further improve energy utilization. The methylcyclopentane separation column 10 and the methylcyclopentane distillation column 14 are set at atmospheric pressure to ensure stable and efficient production.
[0022] In actual production, this system can reduce the production cost of cyclohexene hydration while ensuring cyclohexane production, and at the same time increase the value of by-products and enhance market competitiveness. Currently, traditional hydration equipment does not have a complete set of equipment and heat utilization scheme for refining and purifying the light oil after cyclohexane separation. The successful application of this project will have an industry-leading and demonstration effect, and has good scientific and technological achievement promotion and application value.
[0023] In a preferred embodiment, the top of the methylcyclopentane separation tower 10 is connected to a second circulating water condenser 11 and a second reflux tank 12. The second reflux tank 12 is connected to the light oil tank 13 and the methylcyclopentane separation tower 10 respectively via an electric pump unit 18.
[0024] The above settings enable further secondary utilization of light oil 13, improving the utilization rate of by-products.
[0025] In a preferred embodiment, the top of the methylcyclopentane distillation column 14 is connected to a third circulating water condenser 15 and a third reflux tank 16. The third reflux tank 16 is connected to the methylcyclopentane product tank 17 and the methylcyclopentane distillation column 14 respectively via an electric pump unit 18.
[0026] After separation, purification, and distillation, methylcyclopentane has good economic value.
[0027] In a preferred embodiment, an electric pump unit 18 is provided between the first reflux tank 6 and the methylcyclopentane separation tower 10. The electric pump unit 18 connects the low-boiling material 8 to the methylcyclopentane separation tower 10 and the cyclohexane distillation tower 4 through pipelines.
[0028] For the unseparated cyclohexane containing over 99% purity and a small amount of methylcyclopentane, the recovered material continues to participate in distillation separation. The methylcyclopentane extracted from the top of the column is also a high-value product, which is a traditional process (such as...). Figure 2 It is not available in China.
[0029] In the preferred embodiment, the upper side and top of the cyclohexane refining reactor 3 are respectively connected to crude cyclohexane 2 and hydrogen 1 via pipelines.
[0030] The cyclohexane processor is a fixed-bed reactor containing a layer of solid nickel catalyst. A spray distributor is installed at the cyclohexane feed to ensure that the cyclohexane is evenly distributed in a mist form on the fixed-bed catalyst. Cyclohexane descends from the hydrogen-filled fixed-bed catalyst bed and undergoes a hydrogenation reaction of unsaturated hydrocarbons. This reaction is adiabatic and exothermic, and the temperature of HA rises during the reaction.
[0031] Hydrogenation principle: Benzene, cyclohexene, and methylcyclopentene react with hydrogen in the presence of a nickel catalyst to produce cyclohexane and methylcyclopentane.
[0032] In the preferred embodiment, the bottom of the cyclohexane distillation column 4 is connected to the cyclohexane product tank 7 via an electric pump unit 18.
[0033] In a preferred embodiment, the bottom of the methylcyclopentane distillation column 14 is connected to the cyclohexane distillation column 4 via an electric pump unit 18 and pipelines.
[0034] The electric pump unit 18 improves the efficiency of material flow and ensures the stability of production cycle time.
[0035] In the preferred embodiment, the top pressure of the cyclohexane distillation column 4 is not less than 150 kPa. The chemical reaction process takes place in the cyclohexane refining reactor 3, using a pressure of 3 MPa and a temperature of approximately 150 °C. The pressurization of the cyclohexane distillation column in this application is to increase the potential energy of the gas phase at the top of the column, facilitating heat exchange and recovery with the reboiler of another column, thereby reducing energy loss and improving overall efficiency.
[0036] In the preferred embodiment, the top pressure of the methylcyclopentane separation tower 10 ranges from 0 to 10 kPa. Atmospheric pressure production meets production needs while saving energy consumption.
[0037] In the preferred embodiment, the top pressure of the methylcyclopentane distillation column 14 ranges from 0 to 10 kPa. Atmospheric pressure production meets production needs while saving energy consumption.
[0038] Process flow description:
[0039] Cyclohexane from the cyclohexane processor feed pump is preheated to approximately 80°C using medium-pressure steam before entering the cyclohexane refining reactor. Hydrogen reacts with cyclohexene, benzene, and methylcyclopentene in the cyclohexane within the A-R401 reactor, using the heat of reaction to raise the reaction temperature to approximately 106°C. The cyclohexane is then stored at the bottom and sent to the cyclohexane distillation column via a pressure differential.
[0040] Cyclohexane from the cyclohexane processor is distilled at positive pressure in a cyclohexane distillation column. Cyclohexane rich in low-boiling compounds such as methylcyclopentane and nC6 is distilled from the top of the column, exchanges heat with the bottom liquid of the cyclohexanol separator, and the condensed liquid flows into the cyclohexane distillation column reflux tank. Most of this reflux is returned to the cyclohexane distillation column as reflux via the cyclohexane distillation column reflux pump to maintain the concentration of low-boiling compounds at the top of the column. The remainder is sent to the methylcyclopentane light-removal column for distillation at atmospheric pressure. The nC6 in the mixture is distilled from the top of the column and sent to the cyclohexanol low-boiling compound storage tank.
[0041] The purified methylcyclopentane and cyclohexane mixture is drawn from the bottom of the column and sent to the methylcyclopentane purification column for atmospheric pressure distillation. The methylcyclopentane in the mixture is distilled from the top of the column, condensed, and enters the methylcyclopentane distillation column reflux tank. It is then pumped to the methylcyclopentane storage tank by the methylcyclopentane purification column reflux pump, while the cyclohexane in the bottom of the column is pumped back to the cyclohexane distillation column by the bottom pump of the methylcyclopentane purification column.
[0042] The above embodiments are merely preferred technical solutions of this utility model and should not be considered as limitations on this utility model. The protection scope of this utility model should be the technical solution described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the protection scope of this utility model.
Claims
1. A crude cyclohexane refining and recovery system, characterized in that: The system includes a cyclohexane refining reactor (3) and a cyclohexane distillation column (4). The bottom of the cyclohexane refining reactor (3) is connected to the cyclohexane distillation column (4) via a pipeline. The top of the cyclohexane distillation column (4) is connected to the first reflux tank (6) via the first circulating water condenser (5) and the cyclohexanol distillation column reboiler (9). The first reflux tank (6) is connected to the methylcyclopentane separation column (10) via a pipeline. The bottom of the methylcyclopentane separation column (10) is connected to the methylcyclopentane distillation column (14) via a pipeline. The bottom of the methylcyclopentane distillation column (14) is connected to the cyclohexane distillation column (4) via a pipeline.
2. The crude cyclohexane refining and recovery system according to claim 1, characterized in that: The top of the methylcyclopentane separator (10) is connected to the second circulating water condenser (11) and the second reflux tank (12) via an electric pump unit (18). The second reflux tank (12) is connected to the light oil tank (13) and the methylcyclopentane separator (10) via an electric pump unit (18).
3. The crude cyclohexane refining and recovery system according to claim 1, characterized in that: The top of the methylcyclopentane distillation column (14) is connected to the third circulating water condenser (15) and the third reflux tank (16) through the electric pump unit (18), which is connected to the methylcyclopentane product tank (17) and the methylcyclopentane distillation column (14) respectively.
4. The crude cyclohexane refining and recovery system according to claim 1, characterized in that: An electric pump unit (18) is provided between the first reflux tank (6) and the methylcyclopentane separation tower (10). The electric pump unit (18) connects the low-boiling material (8) to the methylcyclopentane separation tower (10) and the cyclohexane distillation tower (4) through pipelines.
5. The crude cyclohexane refining and recovery system according to claim 1, characterized in that: The upper side and top of the cyclohexane refining reactor (3) are connected to crude cyclohexane (2) and hydrogen (1) respectively via pipelines.
6. The crude cyclohexane refining and recovery system according to claim 1, characterized in that: The bottom of the cyclohexane distillation column (4) is connected to the cyclohexane product tank (7) via an electric pump unit (18).
7. The crude cyclohexane refining and recovery system according to claim 1, characterized in that: The bottom of the methylcyclopentane distillation column (14) is connected to the cyclohexane distillation column (4) via an electric pump unit (18) and pipelines.
8. The crude cyclohexane refining and recovery system according to claim 1, characterized in that: The pressure at the top of the cyclohexane distillation column (4) shall not be less than 150 kPa.
9. The crude cyclohexane refining and recovery system according to claim 1, characterized in that: The pressure range at the top of the methylcyclopentane separation tower (10) is 0~10 kPa.
10. The crude cyclohexane refining and recovery system according to claim 1, characterized in that: The pressure range at the top of the methylcyclopentane distillation column (14) is 0~10 kPa.