Cyclohexene hydration catalytic distillation production system
By setting filler layers and screen plates on the upper and lower sides of the catalyst layer, the fine catalyst particles entrained by steam are filtered, and the problems of catalyst loss and reaction tower blockage are solved, and efficient cyclohexene hydration production is achieved.
Patent Information
- Application Number
- CN202421786150.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-26
- Publication Date
- 2025-04-29
- Estimated Expiration
- 2034-07-26
AI Technical Summary
The reactor form of the existing cyclohexene direct hydration production device is a secondary series full mixer reactor, where the catalyst powdering leads to loss, and the catalyst of fine particles is entrained by steam, causing the reaction tower to be blocked.
A filler layer and a screen plate are provided on both upper and lower sides of the catalyst layer. The fine catalyst particles entrained by the steam are filtered through the screen plate and the filler layer on both sides of the catalyst to prevent the catalyst from being carried by the steam and stacked to the inlet and outlet of the catalytic distillation reaction tower.
It effectively avoids the blockage problem caused by the catalyst being carried by steam and accumulated, improves the one-way conversion rate of cyclohexene, reduces the circulation of cyclohexene, and reduces energy consumption.
Smart Images
Figure CN222805152U_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of cyclohexanol production, and in particular relates to a cyclohexene hydration catalytic distillation production system. Background Art
[0002] Cyclohexanol is an important organic chemical product that can be used as a solvent, chemical intermediate, etc. It is also a key monomer for the production of caprolactam, adipic acid and its downstream products, and plays an important role in the modern industrial system. Cyclohexanol production methods include cyclohexane oxidation, phenol hydrogenation and cyclohexene hydration. Among them, cyclohexene hydration is the most commonly used production method, which has the advantages of safe and environmentally friendly production route, low production cost and good atom economy.
[0003] The reactor form of the cyclohexene direct hydration production device currently used in industry is a two-stage series fully mixed kettle reactor, but the catalyst pulverization during the reaction will lead to loss, and the fine particles of catalyst will be entrained by steam, which will cause blockage of the reaction tower. Utility Model Content
[0004] In order to solve the problems existing in the above-mentioned prior art, the utility model provides a cyclohexene hydration catalytic distillation production system, in which packing layers and sieve plates are arranged on the upper and lower sides of the catalyst layer, and the fine catalyst particles entrained by steam are filtered through the sieve plates and packing layers on both sides of the catalyst, thereby preventing the catalyst from being carried by the steam and accumulating at the inlet and outlet of the catalytic distillation reaction tower to cause blockage.
[0005] The specific technical solution adopted by the utility model is:
[0006] A cyclohexene hydration catalytic distillation production system comprises a cyclohexene storage tank, a pure water storage tank, a heater and a catalytic distillation reaction tower, wherein the output ends of the cyclohexene storage tank and the pure water storage tank are respectively connected to the input end of the heater, the output end of the heater is connected to the gas phase input end at the bottom of the catalytic distillation reaction tower, the bottom of the catalytic distillation reaction tower is also provided with a liquid phase output end, the top of the catalytic distillation reaction tower is provided with a gas phase output end, and the catalytic distillation reaction tower is provided with a lower packing section, a catalyst layer and an upper packing section in sequence from bottom to top.
[0007] A circulating fan is also provided between the catalytic distillation reaction tower and the heater, the input end of the circulating fan is connected to the gas phase output end of the catalytic distillation reaction tower, and the output end of the circulating fan is connected to the input end of the heater.
[0008] The lower packing section includes a first sieve plate, a lower packing layer and a second sieve plate arranged in sequence from bottom to top, the upper packing layer includes a third sieve plate and an upper packing layer arranged in sequence from bottom to top, and the catalyst layer is located between the second sieve plate and the third sieve plate.
[0009] The liquid phase output end of the catalytic distillation reaction tower is also connected to a flow pump, and the product cyclohexanol is discharged from the catalytic distillation reaction tower by means of the flow pump.
[0010] The catalyst layer uses a granular catalyst with a particle size of φ2-5mm and a porosity of 30-50%.
[0011] The filler porosity of the lower filler layer and the upper filler layer is 80-95%.
[0012] The height ratio of the catalyst layer to the lower packing layer is 2-3:1.
[0013] The height ratio of the catalyst layer to the upper packing layer is 3-4:1.
[0014] The beneficial effects of the utility model are:
[0015] 1. The utility model provides packing layers and sieve plates on both sides of the catalyst layer, and filters the fine catalyst particles entrained by steam through the sieve plates and packing layers on both sides of the catalyst, thereby preventing the catalyst from being carried by steam and accumulating at the inlet and outlet of the catalytic distillation reaction tower to cause blockage.
[0016] 2. The catalyst in the utility model is in granular form, and is extruded into a spherical, porous or hollow cylindrical shape using ZSM-5 molecular sieve, thereby avoiding the problem of powdered catalyst pulverization and loss, and the porosity of 30-50% ensures the normal passage of gas. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 This is a process flow chart of the utility model. DETAILED DESCRIPTION
[0018] The utility model is further described below in conjunction with the accompanying drawings and specific embodiments:
[0019] Specific implementation examples Figure 1 As shown, the utility model provides a cyclohexene hydration catalytic distillation production system, including a cyclohexene storage tank, a pure water storage tank, a heater and a catalytic distillation reaction tower, the output ends of the cyclohexene storage tank and the pure water storage tank are respectively connected to the input end of the heater, the output end of the heater is connected to the gas phase input end at the bottom of the catalytic distillation reaction tower, the bottom of the catalytic distillation reaction tower is also provided with a liquid phase output end, the top of the catalytic distillation reaction tower is provided with a gas phase output end, and the catalytic distillation reaction tower is provided with a first sieve plate, a lower packing layer, a second sieve plate, a catalyst layer, a third sieve plate and an upper packing layer in sequence from bottom to top.
[0020] The reactor form of the cyclohexene direct hydration production device currently used in industry is a two-stage series fully mixed kettle reactor. During the reaction, the catalyst is pulverized and lost, and the fine particles of catalyst are entrained by steam, which will cause the reaction tower to be blocked. Therefore, the utility model is provided with packing layers and sieve plates on both sides of the catalyst layer, and the fine particles of catalyst entrained by steam are filtered through the sieve plates and packing layers on both sides of the catalyst, thereby preventing the catalyst from being carried by steam and accumulating at the inlet and outlet of the catalytic distillation reaction tower to cause blockage.
[0021] When in use, first slowly pressurize the system with nitrogen or argon until the system pressure is 0.1-0.3MPa, put 1 / 3 volume of cyclohexanol or cyclohexanol mixed solution into the catalytic distillation reaction tower, start the circulating fan, and after the system circulation is stable, open the reboiler set at the bottom of the catalytic distillation reaction tower, and slowly introduce water vapor. When the bed temperature rises to 100-120℃, slowly introduce cyclohexene steam in proportion to 1 / 3-3 / 4 of the rated flow, and gradually reduce the amount of water vapor until the catalyst layer temperature stabilizes to the required temperature. When the system pressure is too high, the venting operation is carried out in real time through the venting port at the top of the catalytic distillation reaction tower. After the system runs smoothly, gradually reduce the amount of newly added water vapor and cyclohexene to keep the system stable. Through the difference in boiling points, the product and reactant can be separated in real time to improve the single-pass conversion rate. At the same time, through the distillation operation, the concentration of cyclohexanol can be increased, the circulation amount of cyclohexene can be reduced, and the energy consumption can be reduced.
[0022] A circulating fan is also provided between the catalytic distillation reaction tower and the heater, wherein the input end of the circulating fan is connected to the gas phase output end of the catalytic distillation reaction tower, and the output end of the circulating fan is connected to the input end of the heater. By providing the circulating fan, unreacted cyclohexene and water vapor flow out from the top of the catalytic distillation reaction tower, return to the heater through the circulating fan, and mix with new materials, thereby recycling the unreacted cyclohexene and water vapor and improving the overall conversion rate of cyclohexene.
[0023] The liquid phase output end of the catalytic distillation reaction tower is also connected to a flow pump, and the product cyclohexanol is discharged from the catalytic distillation reaction tower by means of the flow pump.
[0024] The catalyst layer uses a granular catalyst with a particle size of φ2-5mm and a porosity of 30-50%. The catalyst in the utility model is granular and is extruded into a spherical, porous or hollow cylindrical shape using ZSM-5 molecular sieve, thereby avoiding the problem of powdered catalyst pulverization and loss, and the 30-50% porosity ensures the normal passage of gas.
[0025] The filler porosity of the lower filler layer and the upper filler layer is 80-95%, and the filler is a metal corrugated plate or a stainless steel wire mesh filler.
[0026] The height ratio of the catalyst layer to the lower packing layer is 2-3: 1, and the height ratio of the catalyst layer to the upper packing layer is 3-4: 1. Since the number of catalyst particles that fall is greater than the number that are carried up by steam, the packing layer below needs to filter more catalyst particles, so the lower packing layer is longer, and two sets of sieve plates are set below the catalyst layer.
[0027] 2. Performance Test
[0028] The reaction was carried out in a catalytic distillation experimental device. The catalyst was H-ZSM-5, the loading amount was 80 ml, the catalyst was φ2 mm spherical particles, the reactor diameter was φ20 mm, the catalyst loading height was 250 mm, the lower part was filled with steel mesh, the porosity was 85%, the height was 100 mm, the upper part was filled with steel mesh, the porosity was 85%, the height was 50 mm, and the tower bottom solvent was 500 ml. The cyclohexene flow rate was 70 mol / h, the water vapor flow rate was 150 mol / h, the reaction pressure was 0.1 MPa, the reaction temperature was 140 ° C, and the continuous and stable operation was 50 h. The analysis was performed every 2 h. The cyclohexene conversion rate is shown in Table 1.
[0029] Table 1
[0030] Serial number Conversion Rate % Selectivity% Serial number Conversion Rate % Selectivity% 1 24.62 99.17 13 24.09 99.04 2 24.01 99.68 14 24.34 99.53 3 21.99 99.57 15 22.27 99.08 4 22.55 99.51 16 24.46 99.72 5 22.65 99.75 17 22.02 99.46 6 21.96 99.79 18 21.16 99.27 7 22.92 99.88 19 22.96 99.38 8 23.36 99.17 20 24.40 99.43 9 23.40 99.76 21 24.75 99.86 10 21.75 99.18 22 22.01 99.69 11 24.45 99.76 23 22.13 99.06 12 22.90 99.80 24 23.04 99.87
[0031] It can be seen from Table 1 that when the cyclohexanol is synthesized by the equipment of the utility model, the single-pass conversion rate of cyclohexene reaches more than 20%, which is far higher than the current technology of about 9%, greatly improving the single-pass conversion rate, reducing the circulation amount of cyclohexene, and reducing energy consumption.
Claims
1. A cyclohexene hydration catalytic distillation production system, comprising a cyclohexene storage tank, a pure water storage tank, a heater and a catalytic distillation reaction tower, wherein the output ends of the cyclohexene storage tank and the pure water storage tank are respectively connected to the input end of the heater, the output end of the heater is connected to the gas phase input end at the bottom of the catalytic distillation reaction tower, the bottom of the catalytic distillation reaction tower is also provided with a liquid phase output end, and the top of the catalytic distillation reaction tower is provided with a gas phase output end, characterized in that: The catalytic distillation reaction tower is provided with a first sieve plate, a lower packing layer, a second sieve plate, a catalyst layer, a third sieve plate and an upper packing layer in sequence from bottom to top.
2. A cyclohexene hydration catalytic distillation production system according to claim 1, characterized in that: A circulating fan is also provided between the catalytic distillation reaction tower and the heater, the input end of the circulating fan is connected to the gas phase output end of the catalytic distillation reaction tower, and the output end of the circulating fan is connected to the input end of the heater.
3. A cyclohexene hydration catalytic distillation production system according to claim 1, characterized in that: The liquid phase output end of the catalytic distillation reaction tower is also connected to a flow pump, and the product cyclohexanol is discharged from the catalytic distillation reaction tower by means of the flow pump.
4. A cyclohexene hydration catalytic distillation production system according to claim 1, characterized in that: The catalyst layer uses a granular catalyst with a particle size of φ2-5mm and a porosity of 30-50%.
5. A cyclohexene hydration catalytic distillation production system according to claim 1, characterized in that: The filler porosity of the lower filler layer and the upper filler layer is 80-95%.
6. A cyclohexene hydration catalytic distillation production system according to claim 1, characterized in that: The height ratio of the catalyst layer to the lower packing layer is 2-3:
1.
7. A cyclohexene hydration catalytic distillation production system according to claim 1, characterized in that: The height ratio of the catalyst layer to the upper packing layer is 3-4:1.