CN219273003U - Continuous preparation system of 1, 4-cyclohexanedimethanol - Google Patents

Abstract

The utility model discloses a continuous system of 1, 4-cyclohexanedimethanol, belonging to the field of cyclohexanedimethanol preparation. The continuous preparation system of the utility model carries out two-step hydrogenation reaction on dimethyl terephthalate in a hydrogenation reactor, and then obtains 1, 4-cyclohexanedimethanol through purification. The system saves the thermal energy consumption of reaction materials through reasonable system streamline design, adopts low-pressure operation and continuous operation, reduces the energy consumption and construction investment cost of equipment, and is beneficial to safe production of the equipment and reduction of equipment investment.

Description

Continuous preparation system of 1, 4-cyclohexanedimethanol

Technical Field

The utility model relates to the field of cyclohexanedimethanol preparation, in particular to a continuous preparation system of 1, 4-cyclohexanedimethanol.

Background

Dimethyl 1, 4-cyclohexanedicarboxylate (DMCD) has a boiling point of 259 ℃ under normal pressure, is insoluble in water, and is soluble in organic solvents such as methanol, ethyl acetate, acetone and the like. DMCD is an important intermediate which is concerned at home and abroad in recent years, is widely used for synthesizing polyester resin, polyamide, alkyd resin and plasticizer, particularly for synthesizing CHDM by hydrogenation, and is an organic intermediate with great development potential and market value.

And CHDM (1, 4-cyclohexanedimethanol) dihydric alcohol with extremely high application value is an excellent monomer for producing high-added-value polyester materials, and the current products mainly depend on import. The CHDM is mainly used for producing polyester fiber, and the polyester fiber is used for partially or completely replacing Ethylene Glycol (EG), and compared with polyethylene terephthalate (PET), the produced polyester fiber has the characteristics of lower density, higher melting point and the like, and has more excellent hydrolytic stability and insulating property. The saturated polyester resin produced in CHDM has many excellent properties not only in paints and coatings but also widely used for producing films, resins for electronic products, insulated wires, and the like. In addition, CHDM may also be used in high performance coatings, high end liquid crystal materials, and the like.

In the prior art, the CHDM adopts a comparatively lagging batch process, has high pressure and high device investment and production cost, is unfavorable for large-scale production of the device, and therefore, a continuous production process system is necessary to be developed.

Disclosure of Invention

The utility model aims to solve the problems in the background technology, and designs a continuous preparation system of 1, 4-cyclohexanedimethanol, which can continuously produce 1, 4-cyclohexanedimethanol, thereby greatly improving the production yield and efficiency of the process.

The utility model provides a continuous preparation system of 1, 4-cyclohexanedimethanol, which comprises the following components: the device comprises a first-stage hydrogenation reactor, a first-stage gas-liquid separator, a second-stage hydrogenation reactor, a second-stage gas-liquid separator and a rectifying tower group;

the primary hydrogenation reactor is provided with a primary material inlet and a primary material outlet, and the primary material outlet is in fluid communication with the primary gas-liquid separator;

the primary gas-liquid separator is provided with a primary gas phase outlet and a primary liquid phase outlet, and the primary liquid phase outlet is in fluid communication with the secondary hydrogenation reactor;

the secondary hydrogenation reactor is provided with a secondary material inlet and a secondary material outlet, and the secondary material outlet is in fluid communication with the rectifying tower group.

In a specific embodiment, the continuous production system further comprises: a first section of hydrogen conveying pipeline, a material melting tank and a second section of hydrogen conveying pipeline;

the material melting tank is provided with a first feeding passage and a first discharging passage;

the first discharging passage is connected with the first-stage hydrogenation reactor, and the first-stage hydrogen conveying pipeline is connected with the first-stage hydrogenation reactor;

the first-stage hydrogenation reactor is provided with a second feeding passage and a second discharging passage, and the second discharging passage is connected with the first-stage gas-liquid separator;

the primary gas-liquid separator is provided with a primary light component passage and a primary liquid phase product passage, and the primary liquid phase product passage is connected with the secondary hydrogenation reactor;

the secondary hydrogenation reactor is provided with a third feeding passage and a third discharging passage, and the third discharging passage is connected with the secondary gas-liquid separator;

the secondary gas-liquid separator is provided with a secondary light component passage and a secondary heavy component passage, and the secondary heavy component passage is connected with the rectifying tower group.

In a specific embodiment, the rectifying column group includes: a methanol recovery tower, a light component separation tower, a recovery tower and a product tower;

wherein the secondary heavy component passage is connected with the methanol recovery tower;

the methanol recovery tower is provided with a methanol passage and a methanol recovery tower heavy component passage, and the methanol recovery tower heavy component passage is connected with the light component separation tower;

the light component separation tower is provided with a separation tower light component passage and a separation tower heavy component passage, the separation tower light component passage is connected with the recovery tower, and the separation tower heavy component passage is connected with the product tower;

the recovery tower is provided with a first discharge passage and a recovery passage;

the product column is provided with a CHDM component outlet line and a second vent path.

In one embodiment, the recycling channel is connected with the material melting tank to form a circulation;

in a specific embodiment, the first-stage light component passage is divided into a first-stage light component branch and a first-stage light component branch, and the first-stage light component branch is communicated with the outside; the first-stage light component two-branch is communicated with the first-stage hydrogen conveying pipeline and then communicated with the first-stage hydrogenation reactor;

in a specific embodiment, the secondary light component passage is divided into a secondary light component first branch and a secondary light component second branch, and the secondary light component first branch is communicated with the outside; the secondary light component secondary branch is communicated with the secondary hydrogenation reactor after being connected with the secondary hydrogen conveying pipeline in parallel;

in a specific embodiment, the primary liquid-phase product passage is divided into a primary liquid-phase product first branch and a primary liquid-phase product second branch, the primary liquid-phase product second branch is communicated with the secondary hydrogenation reactor, and the primary liquid-phase product first branch is communicated with the material melting tank to form a loop.

In a specific embodiment, the theoretical plate number of the methanol recovery tower is 8-26. Optionally 8-15, 15-20, or 20-26. The temperature of the tower top is 10-90 ℃, 10-20 ℃, 20-30 ℃, 30-50 ℃, 50-70 ℃, 70-80 ℃ and 80-90 ℃ are selected. The temperature of the tower kettle is 180-235 ℃, alternatively 180-195 ℃, 195-210 ℃, 210-220 ℃ or 220-235 ℃. The absolute pressure of the tower top operation is 1kPa to 100kPa, alternatively 1kPa to 10kPa,10kPa to 20kPa,20kPa to 30kPa,30kPa to 60kPa or 60kPa to 80kPa,80kPa to 90kPa, or 90kPa to 100kPa.

In a specific embodiment, the theoretical plate number of the light component separation column is 25 to 36. Optionally 25-30 blocks or 30-36 blocks. The temperature of the tower top is 110-150 ℃, and 110-120 ℃ is selected, 120-130 ℃ and 130-150 ℃. The temperature of the tower kettle is 170-220 ℃, and the temperature is 170-180 ℃, 180-210 ℃ or 210-220 ℃ optionally. The absolute pressure of the tower top operation is 1kPa to 30kPa, and 1kPa to 5kPa,5kPa to 10kPa,10kPa to 20kPa and 20kPa to 30kPa can be selected.

In a specific embodiment, the theoretical plate number of the recovery column is 35 to 60. Optionally 35-40 blocks, 40-50 blocks and 50-60 blocks. The temperature of the tower top is 60-120 ℃, and the temperature is 60-70 ℃, 70-90 ℃, 90-110 ℃ or 110-120 ℃ optionally. The temperature of the tower kettle is 170-230 ℃, alternatively 170-180 ℃, 180-200 ℃, 200-220 ℃ or 220-230 ℃. The absolute pressure of the tower top operation is 5kPa to 15kPa, and 5kPa to 10kPa or 10kPa to 15kPa can be selected.

In a specific embodiment, the theoretical plate number of the product column is 18 to 30. Optionally 18-25 blocks or 25-30 blocks. The temperature of the tower top is 80-130 ℃, and the temperature is selected to be 80-90 ℃, 90-110 ℃ and 110-130 ℃. The temperature of the tower kettle is 170-230 ℃, alternatively 170-180 ℃, 180-200 ℃, 200-220 ℃ or 220-230 ℃. The absolute pressure of the tower top operation is 1kPa to 10kPa, and 1kPa to 5kPa or 5kPa to 10kPa can be selected. It is worth noting how the person skilled in the art knows how to adjust the above parameters according to specific needs.

In a specific embodiment, the system further comprises a primary recycle compressor, a primary heat exchanger, and a primary start-up heater;

the front section of the first-stage light component two-branch is connected with the inlet of the first-stage circulating compressor, and the outlet of the first-stage circulating compressor is connected with the rear section of the first-stage light component two-branch;

the first section of hydrogen conveying pipeline is integrated into the front section of the first-stage light component two-branch pipeline;

the first discharging passage is integrated into the rear section of the first-stage light component two-branch to form a second feeding passage;

the first-stage heat exchanger is arranged on the second discharging passage, and the second feeding passage is divided into a first branch of the second feeding passage and a second branch of the second feeding passage after passing through the first-stage heat exchanger;

a branch of the second feeding passage is connected with the primary hydrogenation reactor;

and the second feeding passage branch is connected with the primary start-up heater, combined with the second feeding passage branch and then communicated with the primary hydrogenation reactor.

In a specific embodiment, the system further comprises a primary water cooler, the primary water cooler is located at the downstream of the primary heat exchanger, and the second discharging passage sequentially passes through the primary heat exchanger and the primary water cooler and then is communicated with the primary gas-liquid separator.

In a specific embodiment, the system further comprises a secondary recycle compressor, a secondary heat exchanger, and a secondary start-up heater;

the front section of the secondary light component secondary branch is connected with the inlet of the secondary circulating compressor, and the outlet of the secondary circulating compressor is connected with the rear section of the secondary light component secondary branch;

the second section hydrogen conveying pipeline is integrated into the front section of the two-stage light component branch circuit;

the first-stage liquid-phase product two branches are merged into the rear section of the second-stage light component two branches to form a third feeding passage;

the second heat exchanger is arranged on the third discharging passage, and the third feeding passage is divided into a first branch of the third feeding passage and a second branch of the third feeding passage after passing through the second heat exchanger;

a branch of the third feeding passage is connected with the secondary hydrogenation reactor;

and the second branch of the third feeding passage is connected with the second-stage startup heater, then is combined with the first branch of the third feeding passage, and is communicated with the second-stage hydrogenation reactor.

In a specific embodiment, the system further comprises a secondary water cooler, the secondary water cooler is located at the downstream of the secondary heat exchanger, and the third discharging passage is communicated with the secondary gas-liquid separator after sequentially passing through the secondary heat exchanger and the secondary water cooler.

In a specific embodiment, the primary hydrogenation reactor and the secondary hydrogenation reactor are each independently selected from at least one of a plate reactor, a tubular reactor and/or a composite reactor;

in a specific embodiment, the primary hydrogenation reactor and the secondary hydrogenation reactor are both: the center is provided with a plate group fixing cavity, and a plate group is arranged in the plate group fixing cavity; a catalyst bed layer is arranged between the outer wall of the plate group fixing cavity and the inner wall of the hydrogenation plate type reactor; and a Ni/Cu type catalyst is filled in the catalyst bed layer of the primary hydrogenation reactor.

The utility model has at least one of the following beneficial effects:

1) The continuous preparation system of 1, 4-cyclohexanedimethanol can continuously produce 1, 4-cyclohexanedimethanol, and the thermal energy consumption of reaction materials is saved through reasonable system streamline design.

2) The process system adopts low-pressure operation and continuous operation, reduces the energy consumption and construction investment cost of equipment, is beneficial to safe production of the equipment and reduces equipment investment.

3) The hydrogenation reactor is preferably a plate reactor, so that the hydrogenation reaction is realized, the characteristic of uniform temperature distribution of the reactor can be fully utilized, and the characteristics of improving the space-time yield of the terephthalyl alcohol and the 1, 4-hexanedialkane dimethyl formate and recycling the reaction heat are achieved. Meanwhile, the utilization coefficient of the catalyst and the volume utilization rate of the reactor are improved, the catalyst loading capacity is increased, and the production capacity of the reactor is improved. The reaction characteristics also obtain the same energy-saving and consumption-reducing effects in the industrialized process.

Drawings

FIG. 1 is a schematic flow chart of a continuous preparation system of 1, 4-cyclohexanedimethanol according to the utility model.

Fig. 2 is a schematic flow chart of the portion a in fig. 1.

Fig. 3 is a schematic flow chart of the portion B in fig. 1.

Reference numerals illustrate:

1A material melting tank

1. First feed passage

3. First discharging passage

16. First section hydrogen conveying pipeline

33. Second section hydrogen conveying pipeline

2A primary hydrogenation reactor

5. Second feed passage

10. A second discharging passage

3A primary heat exchanger

7. Second feed passage two branches

8. A branch of the second feeding path

4A primary start-up heater

5A primary water cooler

6A primary gas-liquid separator

7A primary circulation compressor

13. First-stage light component passage

14. First-stage light component one branch

15. First-stage light component two-branch

17. Front section of first-stage light component two-branch

4. Rear section of first-stage light component two-branch

18. First-stage liquid-phase product passage

19. First-stage liquid-phase product two-branch

20. First-stage liquid-phase product first branch

8A secondary hydrogenation reactor

22. Third feed passage

23. A third feeding path

24. A third feeding passage two branches

27. Third discharging passage

9A secondary heat exchanger

10A two-stage start-up heater

11A secondary water cooler

12A secondary gas-liquid separator

30. Two-stage light component passage

31. Two-stage light component two-branch

34. Front section of two-stage light component two-branch

35. Rear section of two-stage light component two-branch

32. Two-stage light component one branch

36. Two-stage heavy component passage

13A two-stage circulation compressor

14A methanol recovery tower

37. Methanol passage

38. Heavy component passage of methanol recovery tower

15A light component separating tower

39. Light component passage of separation tower

40. Heavy component passage of separation tower

16A recovery tower

41. A first discharge passage

42. Recovery passage

17A product tower

43 CHDM component output pipeline

44. A second discharge passage

Detailed Description

The utility model will be further illustrated with reference to specific examples. It is to be understood that these examples are illustrative of the present utility model and are not intended to limit the scope of the present utility model. Furthermore, it should be understood that after reading the teachings of the present utility model, those skilled in the art may make any changes or modifications to the present utility model, and that such equivalents are intended to fall within the scope of the claims appended hereto.

The experimental procedure, in which no specific conditions are noted in the examples below, is generally followed by conventional conditions such as: manual, or according to the conditions recommended by the manufacturer.

Example 1

Initial driving:

1) The 1, 4-dimethyl terephthalate (DMCD) solvent in the liquid phase material is externally added, and after the reaction is established and circulated, the first-stage liquid phase product contains DMCD, and according to the process requirement, part of the first-stage liquid phase product can be directly circulated and used as the solvent.

2) The primary hydrogenation reaction raw material is heated by a primary starting heater 4A, low-pressure steam is adopted as a heat source, and the hydrogenation raw material from a second feeding path 5 enters a pipeline to be preheated to the inlet temperature of a bed layer by the primary starting heater 4A and then enters a catalyst bed layer from the top of the primary hydrogenation reactor 2A through a second feeding path two-way 7 to carry out hydrogenation reaction.

3) The primary hydrogenation raw material is heated by using a secondary startup heater 10A, low-pressure steam is adopted as a heat source, and the hydrogenation raw material from a third feeding passage 22 enters a second branch 24 of the third feeding passage, is preheated to the inlet temperature of a bed layer by the secondary startup heater 10, and enters a catalyst bed layer from the top of the secondary hydrogenation reactor 8A through a pipeline for hydrogenation reaction.

After start-up, referring to fig. 1-3, the crude DMCD solution in the recycle stream from the first feed path 1, the dimethyl 1, 4-terephthalate and the first liquid phase product side path 20 and the DMT recycle solution in the recycle path 42 are mixed and fed into the feed melting tank 1A, melted and then fed out through the first take-off path 3.

Industrial hydrogen from a first-stage hydrogen conveying pipeline 16 and recycle hydrogen from a first-stage light component two-way branch pipeline 15 are mixed, pressurized by a first-stage recycle compressor 7A and then enter a rear section 4 of the first-stage light component two-way branch pipeline, then mixed with DMT and DMCD mixed solution from a first discharging passage 3 to serve as hydrogenation raw materials, enter a first-stage heat exchanger 3A from a second feeding passage 5, exchange heat with hydrogenation products led out from the bottom of the first-stage hydrogenation reactor 2A, and then enter a catalyst bed layer from the top of the first-stage hydrogenation reactor 2A after being converged by a first-stage recycle compressor 8 of the second feeding passage to perform first-stage catalytic hydrogenation. The hydrogenation reaction product enters the primary gas-liquid separator 6A from the pipeline for gas-liquid separation after exchanging heat with the primary heat exchanger 3A through the second discharging passage 10 and the primary water cooler 5A through the pipeline, the gas phase part enters the primary light component two-branch 15 as circulating gas after passing through the primary light component passage 13 for circulation, and the rest part of gas is discharged outside the boundary region through the primary light component one-branch 14 for further treatment. The liquid phase product in the first-stage gas-liquid separator 6A flows out through the first-stage liquid phase product passage 18, a part of the material is used as solvent, the solvent is circulated into the material melting tank 1A through the first-stage liquid phase product first branch 20 and the pipeline, most of DMCD crude liquid and circulating hydrogen from the rear section 35 of the second-stage light component second branch enter the second-stage hydrogenation reaction second-stage heat exchanger 9A through the third feeding passage 22 to exchange heat with hydrogenation reaction discharge material from the third discharging passage 27, then enter the second-stage hydrogenation reactor 8A through the third feeding passage first branch 23 to carry out hydrogenation reaction, and after the reaction material flows into the second-stage heat exchanger 9A through the third discharging passage 27 to exchange heat with the material imported from the second-stage reactor of the third feeding passage 22, the material enters the second-stage water cooler 11A through the pipeline and then enters the second-stage gas-liquid separator 12A through the pipeline to carry out gas-liquid separation. The gas phase part after phase separation passes through the secondary light component passage 30, and most of the gas phase component passes through the secondary light component secondary passage 31 and is mixed with fresh hydrogen from the second section hydrogen conveying pipeline 33, then enters the secondary recycle compressor 13A through the front section 34 of the secondary light component secondary passage, and the compressed recycle gas enters the secondary hydrogenation reactor 8A through the rear section 35 of the secondary light component secondary passage except that a small amount of gas passes through the secondary light component primary passage 32 and is relaxed to the outside of the boundary region for further treatment.

The liquid phase material in the secondary gas-liquid separator 12A flows out through the secondary heavy component passage 36 and enters the methanol recovery column 14A. The liquid phase light component at the top of the methanol recovery tower 14A enters a methanol passage 37 as a methanol raw material to an external PTA esterifying device, and the liquid phase at the bottom of the tower enters a light component rectifying tower 15A through a recovery tower heavy component passage 38 for separation; the light fraction at the top of the light fraction rectifying column 15A is fed to the recovery column 16A through a separation column light fraction passage 39, and the bottoms alcohol mixture is fed to the product column 17A through a separation column heavy fraction passage 40 for further purification, wherein 1, 4-cyclohexanedimethanol is mainly contained as a product and withdrawn through a CHDM component outlet line 43. The bottoms material is passed through a second discharge passage 44 to the outside of the boundary zone for further processing.

The top material of the recovery tower 16A is taken as light component to be sent to the outside of the boundary zone for further treatment through a first discharge passage 41, and the bottom material of the tower passes through a recovery passage 42 and is recycled to the material melting tank 1A through a pipe for DMT recycling.

The technical details of the present utility model are described in detail by the following examples. The examples are given as preferred embodiments, and serve as further description of the technical features of the present utility model, not as limitation of the present utility model.

Example 2

Referring to FIGS. 1 to 3, a primary hydrogenation reactor 2A (plate fixed bed hydrogenation reactor, inner diameter: 3m, height: 12 m) is centrally disposedThe plate group fixing cavity is internally provided with three groups of plates, each group of 3 plates; a catalyst bed layer is arranged between the outer wall of the plate group fixing cavity and the inner wall of the hydrogenation reactor, and a Ni/Cu catalyst is filled in the catalyst bed layer. The Ni/Cu catalyst adopts Cu6.8wt% -Ni53.2wt% -W0.35wt%/Al ₂ O ₃ 。

Technical grade H conveyed by the first-stage hydrogen conveying pipeline 16 ₂ (purity 99.9 v%) and recycle gas (composition: H) from the first-stage light fraction two-way 15 ₂ :98v％，N ₂ :0.47,CO:0.49v％，H ₂ 0.03v% of O, 1.01 v%) and dimethyl terephthalate (99.9 wt% of DMT) from a material melting tank 1A after being compressed by a primary circulating compressor 7A, and circulating and recycling DMT (3.96 mol% of methyl 4-hydroxymethyl cyclohexane carboxylate, 41.83mol% of DMT, 47.35mol% of CHDM and the other 6.86mol% of DMCD) conveyed by a recycling passage, merging the mixed solution, and then entering a primary heat exchanger 3A of a primary hydrogenation reactor 2A to preheat to 150 ℃, entering the mixed solution from the top of the primary hydrogenation reactor 2A, and then entering a catalyst bed in a mode of uniformly distributing gas and liquid to carry out hydrogenation reaction (the hot spot temperature of the catalyst bed is 160 ℃, the reaction pressure is 4.0MPa, and the liquid hourly space velocity is 0.5 Kg/Kg.h); the hydrogenation product is discharged from the bottom and enters a first-stage heat exchanger 3A and a first-stage water cooler 5A to exchange heat to 30-50 ℃, and then enters a first-stage gas-liquid separator 6A, and gas-liquid separation is carried out.

At the beginning of startup, materials passing through the primary heat exchanger 3A enter the primary startup heater 4A for preheating, and preheated gas is taken as raw material gas to reach the inlet temperature of the catalyst bed layer of the primary hydrogenation reactor 2A and then enter the catalyst bed layer for hydrogenation reaction.

First-order hydrogenation product (composition: H) ₂ ：97.47mol％，N ₂ ：0.46mol％，CO：0.48mol％，H ₂ O:0.05mol%, DMT:0.03mol% of dimethyl 1, 4-cyclohexanedicarboxylate: 1.40mol%, methanol: 0.05mol%, other 0.06 mol%) was separated by the primary gas-liquid separator 6A (inner diameter 2.8m, height 6 m), and most of the gas phase (composition: h ₂ :98v％，N ₂ :0.47,CO:0.49v％，H ₂ O0.03 v%, others 1.01 v%). Through increasingThe pressure and temperature drop enter a compressor for recycling, and only a small part of non-condensable gas is discharged out of the limit as purge gas (the gas accounts for 1.2 v%) for recycling.

Liquid phase (composition: H) extracted from the first-stage gas-liquid separator 6A ₂ :1.77mol% of dimethyl 1, 4-cyclohexanedicarboxylate: 90.13mol%, DMT:1.68mol%, CHDM:1.90mol%, methanol: 1.48mol%, H ₂ O:1.45mol%, p-xylene 0.95mol%, others: 0.64 mol%) of which a part of the material is circulated as solvent into the material melting tank 1A through the liquid-phase product first branch 20, and a large part of the material enters the secondary hydrogenation reactor 8A through the liquid-phase product second branch 19 and the recycle gas from the secondary recycle compressor 13A. The mass ratio of the circulating material to the secondary hydrogenation reaction feed is 1:2.DMT has high melting point and high viscosity, and in order to increase the fluidity of the primary reaction process and improve the mass transfer and heat transfer effects, DMCD with lower viscosity is used as a solvent for recycling, so that the increase of the subsequent separation cost caused by externally introducing the solvent is avoided.

Technical grade H ₂ (purity 99.9 v%) and recycle gas (composition: H) from the second gas-liquid separator ₂ :98.52v％，N ₂ 0.16v%, CO 0.15v%, methanol 1.15v%, others 0.02 v%)) is compressed by a second-stage recycle compressor 13A and discharged from a second-stage liquid-phase product branch (composition: h ₂ :1.77mol% of dimethyl 1, 4-cyclohexanedicarboxylate: 90.13mol%, DMT:1.68mol%, CHDM:1.90mol%, methanol: 1.48mol%, H ₂ O:1.45mol%, p-xylene 0.95mol%, others: 0.64 mol%) and then fed into a secondary hydrogenation reaction inlet-outlet heat exchanger of a secondary hydrogenation reactor 8A, and preheated to 160 deg.C, firstly fed into the catalyst bed layer by means of radial flow mode from top of secondary hydrogenation reactor to make secondary hydrogenation reaction, and the catalyst adopts 30wt% Cu/5wt% Zn/Al ₂ O ₃ -SiO ₂ . The hot spot temperature of the catalyst bed is 190 ℃, the reaction pressure is 4.0MPa, and the liquid hourly space velocity is 0.5 Kg/Kg.h); the hydrogenation product is discharged from the bottom and enters a secondary heat exchanger 9A and a secondary water cooler 11A to exchange heat to 30-50 ℃, and then enters a secondary gas-liquid separator 12A, and gas-liquid separation is carried out.

In the initial stage of start-up, the materials passing through the secondary heat exchanger 9A enter the secondary start-up heater 10A for preheating, and the preheated gas is taken as raw material gas to reach the inlet temperature of the catalyst bed layer and then enters the catalyst bed layer for hydrogenation reaction.

Second-stage hydrogenation product (composition: H) ₂ :96.47mol％,N ₂ 0.16mol%; CO 0.15mol%, methanol 2.48mol%, H ₂ O0.04 mol%, CHDM 0.66mol%, and others 0.04 mol%) were separated by a second gas-liquid separator (inner diameter 2m, height 6 m), and most of the gas phase (composition: the composition is as follows: h ₂ :98.52v％，N ₂ 0.16v%, 0.15v% CO, 1.15v% methanol, and 0.02v% others. The gas enters the secondary circulation compressor 13A after pressurization and temperature reduction for recycling, and only a small part of non-condensable gas is discharged out of the boundary as purge gas (the gas accounts for 1.2 v%) for recycling.

Liquid phase (composition: H) extracted from the secondary gas-liquid separator 12A ₂ 0.98mol percent, 64.06mol percent of methanol and H ₂ O1.11 mol%, methyl 4-methylcyclohexane carboxylate 0.49mol%, methyl 4-hydroxymethylcyclohexane carboxylate: 0.26mol%, 4-methyl methylbenzoate: 0.34mol%, CHDM 32.01mol%, DMT 0.59mol%, others: 0.16 mol%) into the methanol recovery column 14A for separation.

In a methanol recovery tower 14A (inner diameter: 2.2m, height: 18m, theoretical plate number: 14, high-efficiency structured packing is filled, tower top temperature is 32 ℃, tower bottom temperature is 216 ℃, absolute pressure of the tower top is 25 kPa), material is fed at a 7 th tower plate, and the methanol recovery tower 14A is discharged from the tower top (composition: methanol: 97.31mol%, H) ₂ O,2.67mol%, others: 0.02 mol%) into the PTA esterification unit; the heavy components (composition: methyl methylcyclohexane formate 1.44mol%, methyl methylcyclohexane methanol 0.76mol%, methyl p-methylbenzoate 0.99mol%, methyl 4-hydroxymethyl cyclohexane formate 0.19mol%, CHDM 94.54mol%, DMCD 0.28wt%, DMT 1.73mol%, high boiling point 0.04 and other components 0.03 mol%) in the bottom of the methanol rectifying tower are fed into the light component separating tower.

In a light component separation tower 15A (with an inner diameter of 2.4m, a height of 29m, a theoretical plate number of 30 blocks, a high-efficiency structured packing filled in, a tower top temperature of 136 ℃, a tower kettle temperature of 193 ℃ and a tower top absolute pressure of 8 kPa), feeding materials at a 15 th column plate, and taking light components (the components of methyl 4-methylcyclohexane formate, 8.78mol%, methyl cyclohexane methanol, 6.4mol%, methyl p-methylbenzoate, 12.53mol%, methyl 4-hydroxymethyl cyclohexane formate, 3.04mol%, CHDM, 33.45mol%, DMCD, 5.04mol%, DMT30.51 mol% and the other components of 0.25 mol%) out of the tower top, and then taking the light components into a recovery tower; the heavy components (composition: CHDM:99.95mol%, high-boiling-point substances 0.05 mol%) in the bottom of the light component removal separation tower enter a product tower 17A.

Product column 17A (inner diameter: 2m, height: 25m, theoretical plate number: 24, high-efficiency structured packing, column top temperature 116 ℃, column bottom temperature 192 ℃, column top absolute pressure 5 kPa), feed plate, 12, column top light component (composition: CHDM:99.99mol%, other: 0.01 mol%) is taken as 1, 4-cyclohexanedimethanol product; the heavy components (composition: CHDM:80.39 mol%) of the tower bottom and the high polymer: 19.61 mol%) enter a reboiling tower for further separation.

In a recovery column 16A (inner diameter: 0.8m, height: 30m, theoretical plate number: 50, high-efficiency structured packing is filled, column top temperature: 94 ℃, column bottom temperature: 194 ℃, column top absolute pressure: 10 kPa), the material was fed at 26 th column plate, and column top light component was discharged (composition: H ₂ 0.04mol%, methyl 4-methylcyclohexane carboxylate 43.56mol%, methylcyclohexane methanol: 23.31mol%, 0.79mol% of methyl 4-hydroxymethylcyclohexane formate, 30.92mol% of methyl p-methylbenzoate, 0.77mol% of CHDM, others: 0.61 mol%) is taken off and sent to out-of-limit for further processing. The tower bottom heavy components (composition: 3.96mol% of methyl 4-hydroxymethyl cyclohexane carboxylate, 41.83mol% of DMT, 47.35mol% of CHDM and the other components: 6.86 mol%) are recycled to the material melting tank 1A for further recycling of raw material DMT.

In conclusion, the preparation system can realize continuous operation of the primary catalytic hydrogenation reaction and the secondary catalytic hydrogenation reaction, and the reasonable energy consumption exchange and the reasonable flow path circulation are configured, so that the energy consumption of the device and the investment cost are reduced. In addition, the operation pressure of the preparation system is low, and the energy consumption and the investment cost can be further reduced.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation. The term "comprising" an element defined by the term "comprising" does not exclude the presence of other identical elements in a process, method, article or apparatus that comprises the element.

Although embodiments of the present utility model have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the utility model, the scope of which is defined in the appended claims and their equivalents.

Claims (10)

1. A continuous production system of 1, 4-cyclohexanedimethanol, comprising: the device comprises a first-stage hydrogenation reactor (2A), a first-stage gas-liquid separator (6A), a second-stage hydrogenation reactor (8A), a second-stage gas-liquid separator (12A) and a rectifying tower group;

the primary hydrogenation reactor (2A) is provided with a primary material inlet and a primary material outlet, and the primary material outlet is in fluid communication with the primary gas-liquid separator (6A);

the primary gas-liquid separator (6A) is provided with a primary gas phase outlet and a primary liquid phase outlet, and the primary liquid phase outlet is in fluid communication with the secondary hydrogenation reactor (8A);

the secondary hydrogenation reactor (8A) is provided with a secondary material inlet and a secondary material outlet, and the secondary material outlet is in fluid communication with the rectifying tower group.

2. The continuous production system of 1, 4-cyclohexanedimethanol according to claim 1, further comprising: a first section of hydrogen conveying pipeline (16), a material melting tank (1A) and a second section of hydrogen conveying pipeline (33);

the material melting tank (1A) is provided with a first feeding passage (1) and a first discharging passage (3);

the first discharging passage (3) is connected with the first-stage hydrogenation reactor (2A), and the first-stage hydrogen conveying pipeline (16) is connected with the first-stage hydrogenation reactor (2A);

the first-stage hydrogenation reactor (2A) is provided with a second feeding passage (5) and a second discharging passage (10), and the second discharging passage (10) is connected with the first-stage gas-liquid separator (6A);

the primary gas-liquid separator (6A) is provided with a primary light component passage (13) and a primary liquid phase product passage (18), and the primary liquid phase product passage (18) is connected with the secondary hydrogenation reactor (8A);

the secondary hydrogenation reactor (8A) is provided with a third feeding passage (22) and a third discharging passage (27), and the third discharging passage (27) is connected with the secondary gas-liquid separator (12A);

the secondary gas-liquid separator (12A) is provided with a secondary light component passage (30) and a secondary heavy component passage (36), and the secondary heavy component passage (36) is connected with the rectifying tower group.

3. The continuous production system of 1, 4-cyclohexanedimethanol according to claim 2, characterized in that said rectifying column group comprises: a methanol recovery tower (14A), a light component separation tower (15A), a recovery tower (16A) and a product tower (17A);

wherein the secondary heavy component passage (36) is connected to the methanol recovery column (14A);

the methanol recovery tower (14A) is provided with a methanol passage (37) and a methanol recovery tower heavy component passage (38), and the methanol recovery tower heavy component passage (38) is connected with the light component separation tower (15A);

the light component separation tower (15A) is provided with a separation tower light component passage (39) and a separation tower heavy component passage (40), the separation tower light component passage (39) is connected with the recovery tower (16A), and the separation tower heavy component passage (40) is connected with the product tower (17A);

the recovery tower (16A) is provided with a first discharge passage (41) and a recovery passage (42);

the product column (17A) is provided with a CHDM component output line (43) and a second vent passage (44).

4. A continuous production system of 1, 4-cyclohexanedimethanol according to claim 3, characterized in that said recovery passage (42) is connected to said material melting tank (1A) forming a cycle;

and/or the first-stage light component passage (13) is divided into a first-stage light component branch (14) and a first-stage light component branch (15), and the first-stage light component branch (14) is communicated with the outside; the first-stage light component two-way branch (15) is communicated with the first-stage hydrogen conveying pipeline (16) and then communicated with the first-stage hydrogenation reactor (2A);

and/or the secondary light component passage (30) is divided into a secondary light component first branch (32) and a secondary light component second branch (31), and the secondary light component first branch (32) is communicated with the outside; the secondary light component secondary branch (31) is communicated with the secondary hydrogenation reactor (8A) after being connected with the second section hydrogen conveying pipeline (33);

and/or the primary liquid-phase product passage (18) is divided into a primary liquid-phase product first branch (20) and a primary liquid-phase product second branch (19), the primary liquid-phase product second branch (19) is communicated with the secondary hydrogenation reactor (8A), and the primary liquid-phase product first branch (20) is communicated with the material melting tank (1A) to form a loop.

5. The continuous production system of 1, 4-cyclohexanedimethanol according to claim 3, wherein the theoretical plate number of the methanol recovery column (14A) is 8 to 26;

and/or the theoretical plate number of the light component separation tower (15A) is 25-36;

and/or the theoretical plate number of the recovery tower (16A) is 35-60;

and/or the theoretical plate number of the product column (17A) is 18-30.

6. A continuous production system of 1, 4-cyclohexanedimethanol according to claim 3, characterized in that the system further comprises a primary recycle compressor (7A), a primary heat exchanger (3A) and a primary start-up heater (4A);

the front section (17) of the first-stage light component two-branch is connected with the inlet of the first-stage circulating compressor (7A), and the outlet of the first-stage circulating compressor (7A) is connected with the rear section (4) of the first-stage light component two-branch;

the first section hydrogen conveying pipeline (16) is integrated into the front section (17) of the first-stage light component two-branch pipeline;

the first discharging passage (3) is integrated into the rear section (4) of the first-stage light component two-branch to form a second feeding passage (5);

the primary heat exchanger (3A) is arranged on the second discharging passage (10), and the second feeding passage (5) is divided into a first branch (8) of the second feeding passage and a second branch (7) of the second feeding passage after passing through the primary heat exchanger (3A);

a branch (8) of the second feeding passage is connected with the first-stage hydrogenation reactor (2A);

the second feeding passage branch (7) is connected with the first-stage startup heater (4A) and then combined with the second feeding passage branch (8) and then communicated with the first-stage hydrogenation reactor (2A).

7. The continuous production system of 1, 4-cyclohexanedimethanol according to claim 6, characterized in that,

the system further comprises a primary water cooler (5A), the primary water cooler (5A) is located at the downstream of the primary heat exchanger (3A), and the second discharging passage (10) is communicated with the primary gas-liquid separator (6A) after sequentially passing through the primary heat exchanger (3A) and the primary water cooler (5A).

8. A continuous production system of 1, 4-cyclohexanedimethanol according to claim 3, characterized in that the system further comprises a secondary recycle compressor (13A), a secondary heat exchanger (9A) and a secondary start-up heater (10A);

the front section (34) of the secondary light component secondary branch is connected with the inlet of the secondary circulating compressor (13A), and the outlet of the secondary circulating compressor (13A) is connected with the rear section (35) of the secondary light component secondary branch;

the second section hydrogen conveying pipeline (33) is integrated into the front section (34) of the two-stage light component two-branch pipeline;

the first-stage liquid-phase product two-branch (19) is integrated into the rear section (35) of the second-stage light component two-branch to form a third feeding passage (22);

the second heat exchanger (9A) is arranged on the third discharging passage (27), and the third feeding passage (22) is divided into a first third feeding passage branch (23) and a second third feeding passage branch (24) after passing through the second heat exchanger (9A);

a branch (23) of the third feeding path is connected with the secondary hydrogenation reactor (8A);

the second branch (24) of the third feeding passage is connected with the second-stage start-up heater (10A), combined with the first branch (23) of the third feeding passage and communicated with the second-stage hydrogenation reactor (8A).

9. The continuous production system of 1, 4-cyclohexanedimethanol according to claim 8, further comprising a secondary water cooler (11A), wherein the secondary water cooler (11A) is located downstream of the secondary heat exchanger (9A), and wherein the third discharge passage (27) is in communication with the secondary gas-liquid separator (12A) after passing through the secondary heat exchanger (9A) and the secondary water cooler (11A) in sequence.

10. Continuous production system of 1, 4-cyclohexanedimethanol according to any one of claims 1 to 9, characterized in that the primary hydrogenation reactor (2A) and the secondary hydrogenation reactor (8A) are each independently selected from at least one of a plate reactor, a tube reactor and/or a complex reactor;

and/or, the primary hydrogenation reactor (2A) and the secondary hydrogenation reactor (8A) are: the center is provided with a plate group fixing cavity, and a plate group is arranged in the plate group fixing cavity; a catalyst bed layer is arranged between the outer wall of the plate group fixing cavity and the inner wall of the hydrogenation plate type reactor; and a Ni/Cu type catalyst is filled in the catalyst bed layer of the primary hydrogenation reactor.

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