Cyclohexanone vacuum refining system and technology

Abstract

The invention relates to the technical field of cyclohexanone production, in particular to a cyclohexanone vacuum refining system and process, and aims to solve the problems of large steam consumption, high energy consumption and large wastewater amount of the conventional cyclohexanone vacuum refining system. The cyclohexanone vacuum refining system provided by the invention comprises a vacuum refining unit, and the vacuum refining unit comprises a first condenser, a dry vacuum pump, a second condenser and a reflux tank which are connected in sequence; a gas-phase product sequentially flows through the first condenser, the dry vacuum pump, the second condenser and the reflux tank; cooling water is introduced into the first condenser and the second condenser for condensation. According to the cyclohexanone vacuum refining system provided by the invention, the use of steam is avoided by adopting the dry vacuum pump, the problems of generation of a large amount of wastewater, high energy consumption and complex treatment process caused by the use of steam by a steam jet pump are avoided on the premise of ensuring the vacuum degree, the noise and the operating temperature can be reduced, the complexity of the system is reduced, and the production cost is reduced. And the reliability and the stability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cyclohexanone production, and particularly to a cyclohexanone vacuum refining system and process. Background Art

[0002] In the process route of producing cyclohexanone by the hydration of cyclohexene, benzene is partially hydrogenated under the action of a ruthenium-based catalyst to produce cyclohexene and a small amount of cyclohexane; after separation, cyclohexane can be sold as a by-product, and cyclohexene undergoes a hydration reaction under the action of a silicoaluminate catalyst to produce cyclohexanol. Cyclohexanol dehydrogenates under the action of a copper-zinc catalyst to produce cyclohexanone and hydrogen.

[0003] In the production process of cyclohexanone, the crude alcohol-ketone mixture produced in the dehydrogenation reaction process is sent to the first and second light towers. The light components are distilled out from the top of the tower, condensed and cooled, and then flow into the top reflux tank. The light oil in the reflux tank is pumped out by a pump, part of it is returned to the top of the tower as reflux, and the rest is sent to the light component storage tank. Currently, the tower vacuum operation environment is provided by a first-stage steam jet pump.

[0004] The crude alcohol-ketone at the bottom of the first light tower is sent to the bottom of the ketone tower by a tower bottom pump. After being heated by the reboiler at the bottom of the tower, the gaseous cyclohexanone at the top of the tower is condensed and cooled and then flows into the reflux tank. The cyclohexanone in the reflux tank is pumped out by a pump, part of it is returned to the top of the tower as reflux, and the rest is sent to the cyclohexanone storage tank. Currently, the tower vacuum operation environment is provided by a three-stage steam jet pump.

[0005] The bottom liquid of the ketone tower is sent to the bottom of the alcohol tower by a tower bottom pump. After being heated by the reboiler at the bottom of the tower, the gaseous cyclohexanol at the top of the tower is condensed and cooled and then flows into the top reflux tank. The cyclohexanol in the reflux tank is pumped out by a pump, part of it is returned to the top of the tower as reflux, and the rest is sent to the cyclohexanol storage tank. Currently, the tower vacuum operation environment is provided by a multi-stage steam jet pump.

[0006] When using a steam jet pump, a large amount of steam is consumed, the energy consumption is high and the efficiency is low. Moreover, the steam for injection needs to be condensed by circulating water, which will generate a large amount of wastewater. There are organic substances such as ketones and alcohols in the wastewater. The post-treatment of the wastewater to recover alcohol and ketone requires the use of steam, with high operating energy consumption and complex treatment processes. In addition, during the operation of the steam jet pump, the noise is large and the temperature is high, the operating environment is relatively harsh, and nitrogen needs to be used to supplement the reflux to stabilize the pressure, resulting in a large consumption of nitrogen. At the same time, fluctuations in steam pressure and temperature will affect the system vacuum degree. That is, the existing cyclohexanone vacuum refining system has problems of large steam consumption, high energy consumption, and large amount of wastewater. Summary of the Invention

[0007] The purpose of the present invention is to provide a cyclohexanone vacuum refining system and process to solve the problems of large steam consumption, high energy consumption, and large amount of wastewater in the existing cyclohexanone vacuum refining system.

[0008] To solve the above technical problems, the technical solution provided by the present invention lies in:

[0009] A cyclohexanone vacuum refining system includes a vacuum refining unit, and the vacuum refining unit includes a first condenser, a dry vacuum pump, a second condenser and a reflux tank connected in sequence;

[0010] The gas-phase product flows through the first condenser, the dry vacuum pump, the second condenser and the reflux tank in sequence;

[0011] Cooling water is introduced into the first condenser and the second condenser for condensation.

[0012] Furthermore, the cyclohexanone vacuum refining system further includes a transfer pump, and the transfer pump is used for transferring liquid materials and includes a first screw, a second screw, a slide plate and a pump housing;

[0013] The first screw and the second screw are arranged in parallel in the pump housing to form a twin-screw pump;

[0014] Two slide plates are arranged at both ends of the first screw and the second screw, and both ends of the first screw and the second screw are rotatably installed on the slide plates; the two slide plates are slidably installed in the pump housing and respectively enclose a piston chamber with the pump housing to form a piston pump, and the first screw can reciprocate along its own axis to drive the slide plate to move, thereby changing the volume of the piston chamber.

[0015] Furthermore, the transfer pump further includes a first rotating shaft and a second rotating shaft, the first rotating shaft is connected to the first screw and is coaxially arranged, and the second rotating shaft is connected to the second screw and is coaxially arranged;

[0016] The first rotating shaft rotates around its own axis to drive the second rotating shaft, the first screw and the second screw to rotate around their own axes.

[0017] Furthermore, the transfer pump further includes a first gear and a second gear;

[0018] The first gear is sleeved on the first rotating shaft and is connected to the first rotating shaft, and the second gear is sleeved on the second rotating shaft and is connected to the second rotating shaft;

[0019] The first gear meshes with the second gear.

[0020] Furthermore, the transfer pump further includes a camshaft, a plug rod and a motor shaft;

[0021] The motor shaft is sleeved on the camshaft, the camshaft is connected to the first rotating shaft and is coaxially arranged, and a cam groove is provided on the camshaft;

[0022] The insertion rod is inserted into the motor shaft and the cam groove at the same time. The motor shaft rotates around its own axis to drive the insertion rod to rotate, thereby driving the insertion rod to slide along the cam groove so that the camshaft reciprocates along its own axis direction.

[0023] Furthermore, the delivery pump further includes a conical cover and a locking rod;

[0024] The conical cover is sleeved on the motor shaft, and the locking rod is inserted into the motor shaft and located between the conical cover and the camshaft;

[0025] The conical cover can move along its own axis direction. When the double screw pump is started, both ends of the locking rod respectively abut against the inner wall of the conical cover and the camshaft; when the piston pump is started, the conical cover moves along its own axis direction to move away from the locking rod, and then the locking rod can move along its own axis direction to move away from the camshaft.

[0026] Furthermore, the delivery pump further includes a switching mechanism, and the switching mechanism includes a connecting frame, a first cylinder, a second cylinder, a clamping block and a switching cylinder;

[0027] The conical cover is connected to the connecting frame, and the extending end of the first cylinder is connected to the connecting frame to drive the conical cover to move along its own axis direction; the clamping block is connected to the extending end of the second cylinder, and the second cylinder extends to drive the clamping block to be clamped to the first gear;

[0028] The rodless chamber and the rod chamber of the switching cylinder are respectively communicated with the first cylinder and the second cylinder, and the switching cylinder expands and contracts to drive one of the first cylinder and the second cylinder to extend and the other to retract.

[0029] Furthermore, the switching cylinder includes a cylinder block, a piston plate and an electric telescopic rod;

[0030] The piston plate is inserted into the cylinder block and divides the cylinder block into a rod chamber and a rodless chamber; the electric telescopic rod is connected to the piston plate and is used to drive the piston plate to move in the cylinder block.

[0031] Furthermore, the delivery pump further includes a first extraction pipe, a first discharge pipe, a second extraction pipe and a second discharge pipe;

[0032] The first extraction pipe, the first discharge pipe, the second extraction pipe and the second discharge pipe are all communicated with the inner cavity of the pump housing;

[0033] When the double screw pump works, the liquid flows through the first extraction pipe and the first discharge pipe; when the piston pump works, the liquid flows through the second extraction pipe and the second discharge pipe.

[0034] On the other hand, the present invention provides a cyclohexanone vacuum refining process, which uses the above-mentioned cyclohexanone vacuum refining system and includes the following steps:

[0035] The gaseous product enters the first condenser from the top outlet of the light component removal column, the ketone column or the alcohol column and is condensed into a liquid product. Subsequently, the liquid product is subjected to vacuum distillation by the dry vacuum pump to obtain gaseous cyclohexanone. The gaseous cyclohexanone enters the second condenser, is condensed into a liquid and enters the reflux tank. Finally, the liquid cyclohexanone is pumped out of the reflux tank by a transfer pump.

[0036] Based on the above technical solutions, the technical effects that the present invention can achieve are as follows:

[0037] The cyclohexanone vacuum refining system provided by the present invention includes a vacuum refining unit. The vacuum refining unit includes a first condenser, a dry vacuum pump, a second condenser and a reflux tank connected in sequence. The gaseous product flows through the first condenser, the dry vacuum pump, the second condenser and the reflux tank in sequence. Cooling water is introduced into the first condenser and the second condenser for condensation.

[0038] The cyclohexanone vacuum refining system provided by the present invention avoids the use of steam by using a dry vacuum pump. Therefore, on the premise of ensuring the vacuum degree, it avoids the problems of generating a large amount of wastewater, high energy consumption and complex treatment process caused by the use of steam in a steam jet pump, and can reduce noise and operating temperature, avoid using nitrogen for pressure stabilization, reduce the complexity of the system, and improve reliability and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0040] Figure 1 It is a schematic structural diagram of a transfer pump;

[0041] Figure 2 A sectional view of the transfer pump;

[0042] Figure 3 It is a schematic structural diagram of a twin screw pump;

[0043] Figure 4 It is a schematic structural diagram of a piston pump;

[0044] Figure 5 It is a flow chart of the cyclohexanone vacuum refining process provided by the embodiment of the present invention.

[0045] Icons: 110, first screw; 120, second screw; 130, slide plate; 140, pump housing; 150, first rotating shaft; 160, second rotating shaft; 170, first gear; 180, second gear; 190, gearbox; 101, piston chamber;

[0046] 210, camshaft; 220, inserting rod; 230, motor shaft; 240, conical cover; 250, locking rod; 260, switching mechanism; 261, connecting frame; 262, first cylinder; 263, second cylinder; 264, clamping block; 265, switching cylinder; 201, cylinder block; 202, piston plate; 203, electric telescopic rod; 270, drive motor;

[0047] 310, first extraction pipe; 320, first discharge pipe; 330, second extraction pipe; 340, second discharge pipe. Specific embodiments

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0049] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0050] The following will describe in detail some embodiments of the present invention in conjunction with the accompanying drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0051] During the cyclohexanone refining process, a steam jet pump needs to be used. When using a steam jet pump, a large amount of steam is consumed, resulting in high energy consumption and low efficiency. Moreover, the steam for injection needs to be condensed by circulating water, generating a large amount of wastewater. There are organic substances such as ketones and alcohols in the wastewater. The post-treatment of the wastewater to recover alcohols and ketones requires steam, resulting in high operating energy consumption and complex treatment processes.

[0052] In view of this, the cyclohexanone vacuum refining system provided by the present invention includes a vacuum refining unit. The vacuum refining unit includes a first condenser, a dry vacuum pump, a second condenser, and a reflux tank connected in sequence; the gas-phase product flows through the first condenser, the dry vacuum pump, the second condenser, and the reflux tank in sequence; cooling water is introduced into the first condenser and the second condenser for condensation.

[0053] The cyclohexanone vacuum refining system provided by the present invention avoids the use of steam by adopting a dry vacuum pump, thereby avoiding the problems of generating a large amount of wastewater, high energy consumption, and complex treatment process caused by the use of steam in a steam jet pump while ensuring the vacuum degree, and can reduce noise and operating temperature, avoid using nitrogen for pressure stabilization, reduce the complexity of the system, and improve reliability and stability.

[0054] The following Figures 1 - 5 will be used to elaborate in detail on the structure and shape of the cyclohexanone vacuum refining system provided in this embodiment:

[0055] In this embodiment, a claw vacuum pump is selected as the dry vacuum pump.

[0056] In this embodiment, by using a dry vacuum pump to replace the steam ejector, the problems of high steam consumption, large amount of wastewater generation, and high energy consumption are solved. There is no oil and water in the pump cavity, and it operates in a pure dry mode. The structure is simple, the vacuum degree meets the requirements of the PID control adaptive system, there is no pollution to the transported materials, clean transportation is achieved and the operating efficiency is high. At the same time, it has the characteristics of high vacuum and large pumping speed. The condensable gas transported can be cleanly condensed and recovered, generating objective economic and environmental benefits. After being verified by safe and stable operation on the same device, the operating energy consumption is only one-third of that of the steam ejector, and the energy-saving and consumption-reducing effect is very prominent. At the same time, a large amount of wastewater discharge is reduced. Among them, the public works consumption when using a steam jet vacuum device is shown in Table 1.

[0057] Table 1 Public Works Consumption Table Designation number Light towers 1 and 2 Ketone tower Alcohol tower 3 Solvent refining tower Recovery tower Steam consumption 0.54 t / h 5.7 t / h 2.1 t / h 3.9 t / h 2.4 t / h Cooling water consumption 0.54 t / h 5.7 t / h 2.1 t / h 3.9 t / h 2.4 t / h

[0058] When using a steam jet vacuum device and calculating based on an operating time of 8000 h / Y, the annual steam consumption is approximately 14.64 t / h × 8000 h / Y = 117120 t. Correspondingly, the annual wastewater generation amount is calculated at a ratio of 1:1, which is 117120 tons. The dry vacuum pump can greatly reduce steam consumption and wastewater generation, reduce wastewater emissions by 117 tons per year, greatly relieve the pressure of wastewater treatment, and at the same time can achieve the condensation and recovery of tail gas alcohol and ketone, directly reduce the content of condensable substances in the tail gas, and indirectly reduce the treatment cost of the tail gas. By reducing the use of steam and nitrogen, the corresponding steam use cost and wastewater treatment cost are reduced. After deducting the increased power consumption and other costs, more than 22 million yuan can be saved annually.

[0059] In the production of cyclohexanone, organic substances such as ketones and alcohols are involved, and in the wastewater treatment process, wastewater containing ketones and alcohols will also be contacted. These substances have certain corrosiveness. Therefore, the pump needs to have good corrosion resistance to prevent being eroded and damaged by chemical substances, ensure long-term stable operation, and avoid interruption or instability in the production process. When the pump is corroded, significant changes will occur in its appearance, performance, structural integrity, and operation stability, which will not only affect the normal operation of the pump but also may cause potential safety hazards and increase maintenance costs. Therefore, the cyclohexanone vacuum refining system provided in this embodiment further includes a transfer pump for transporting liquid materials.

[0060] Specifically, in this embodiment, the transfer pump includes a twin-screw pump and a piston pump. When the parts of the pump are corroded, its surface becomes rough and the dimensions change, resulting in a decrease in conveying capacity, an increase in fluid flow resistance, etc. At this time, the flow rate of the pump will decrease. Therefore, when it is detected that the flow rate of the twin-screw pump drops to the set value, it is switched to the piston pump for operation to ensure the normal progress of the current production, avoid further damage to the twin-screw pump, and facilitate subsequent maintenance. Obviously, the piston pump can also be used first, and when the flow rate of the piston pump drops to the set value, it is then switched to the screw pump.

[0061] In this embodiment, the transfer pump includes a first screw 110, a second screw 120, a slide plate 130, a pump housing 140, a first rotating shaft 150, a second rotating shaft 160, a first gear 170, a second gear 180, a gearbox 190, a camshaft 210, a motor shaft 230, a conical cover 240, a locking rod 250, and a driving motor 270, as Figure 1 , Figure 2 , Figure 3 shown. Among them, the first screw 110 and the second screw 120 are arranged in parallel in the pump housing 140 to form a twin-screw pump. Specifically, the first screw 110, the first rotating shaft 150, and the camshaft 210 are coaxially arranged and connected in sequence, and the three can be integrally processed; similarly, the second screw 120 and the second rotating shaft 160 are coaxially arranged and connected, and the two can be integrally processed. The first gear 170 is sleeved on the first rotating shaft 150 and connected to the first rotating shaft 150, the second gear 180 is sleeved on the second rotating shaft 160 and connected to the second rotating shaft 160, and the first gear 170 and the second gear 180 are arranged in the gearbox 190 and mesh with each other; the gearbox 190 housing is slidably installed in the pump housing 140 through connection means such as linear guides; the motor shaft 230 is sleeved on the camshaft 210, the conical cover 240 is sleeved on the motor shaft 230, and the locking rod 250 is inserted into the motor shaft 230 and is located between the conical cover 240 and the camshaft 210.

[0062] When the transfer pump operates in the state of a twin-screw pump, the conical cover 240 abuts against the locking rod 250 so that the locking rod 250 abuts against the camshaft 210. To increase torque transmission, a plurality of locking rods 250 can be arranged around the axis of the cam, and structures such as patterns can be provided on the surface where the locking rod 250 contacts the camshaft 210 to increase the frictional force. To reduce the friction between the locking rod 250 and the conical cover 240, balls can be provided at one end of the locking rod 250 where it contacts the conical cover 240. During operation, the drive motor 270 drives the motor shaft 230 to rotate around its own axis, and then drives the camshaft 210 to rotate around its own axis through the locking rod 250, and successively drives the first rotating shaft 150, the first screw 110, and the first gear 170 to rotate around their own axes. At the same time, through the meshing of the first gear 170 and the second gear 180, the second gear 180, the second rotating shaft 160, and the second screw 120 are successively driven to rotate around their own axes, so that the first screw 110 and the second screw 120 rotate synchronously to convey the liquid material.

[0063] In this embodiment, the transfer pump further includes a slide plate 130 and an insertion rod 220. As Figure 2 , Figure 4 shown, the two slide plates 130 are respectively arranged at both ends of the first screw 110 and the second screw 120, and both ends of the first screw 110 and the second screw 120 are rotatably installed on the slide plate 130; the two slide plates 130 are slidably installed in the pump housing 140 and respectively enclose a piston chamber 101 with the pump housing 140 to form a piston pump. Specifically, an annular cam groove is provided on the camshaft 210, and the insertion rod 220 is inserted into both the motor shaft 230 and the cam groove and slides along the cam groove.

[0064] When the transfer pump operates in the state of a piston pump, the conical cover 240 moves along its own axis to increase the distance between the inner wall and the end of the locking rod 250, so that the locking rod 250 can move away from the camshaft 210 along its own axis. Therefore, when the drive motor 270 drives the motor shaft 230 to rotate around its own axis, it will not drive the first screw 110 and the second screw 120 to rotate around their own axes. At this time, the motor shaft 230 drives the insertion rod 220 to rotate around the axis of the motor shaft 230 and makes the insertion rod 220 slide along the cam groove, thereby driving the camshaft 210 to reciprocate along its own axis, and then driving the first rotating shaft 150, the first gear 170, and the first screw 110 to reciprocate along their own axes, so as to drive the slide plate 130 to reciprocate to change the volume of the piston chamber 101. At this time, due to the corresponding connection, the second screw 120, the second rotating shaft 160, and the gearbox 190 all reciprocate synchronously.

[0065] In this embodiment, the conical cover 240 and the locking rod 250 can drive the locking rod 250 away from the camshaft 210 through magnetic force, or a spring can be provided to drive the locking rod 250 through the spring force. At this time, the spring can be installed on the motor shaft 230 and connected to the locking rod 250.

[0066] In this embodiment, the transfer pump further includes a switching mechanism 260 for switching between the working states of the twin-screw pump and the piston pump. Specifically, the switching mechanism 260 includes a connecting frame 261, a first cylinder 262, a second cylinder 263, a clamping block 264, and a switching cylinder 265. The switching cylinder 265 includes a cylinder block 201, a piston plate 202, and an electric telescopic rod 203, as Figure 4 described. The conical cover 240 is connected to the connecting frame 261. The first cylinder 262 is installed on the pump housing 140, and the extending end of the first cylinder 262 is connected to the connecting frame 261 to drive the conical cover 240 to move along its own axis. The second cylinder 263 is installed on the gearbox 190, and the clamping block 264 is connected to the extending end of the second cylinder 263. The second cylinder 263 extends to drive the clamping block 264 to be clamped to the first gear 170. The piston plate 202 is inserted into the cylinder block 201 and divides the cylinder block 201 into a rod chamber and a rodless chamber. The electric telescopic rod 203 is connected to the piston plate 202 and is used to drive the piston plate 202 to move within the cylinder block 201. The rodless chamber of the switching cylinder 265 is connected to the rodless chamber of the first cylinder 262, and the rod chamber of the switching cylinder 265 is connected to the rodless chamber of the second cylinder 263.

[0067] When the transfer pump operates in the state of the twin-screw pump, the electric telescopic rod 203 drives the piston plate 202 to move upward to reduce the volume of the rod chamber and increase the volume of the rodless chamber, thereby increasing the pressure in the rodless chamber of the first cylinder 262. The first cylinder 262 extends to drive the connecting frame 261 and the conical cover 240 to move in the direction close to the gearbox 190, so that the conical cover 240 presses the locking rod 250, causing the locking rod 250 to abut against the camshaft 210. At this time, the drive motor 270 drives the first screw 110 and the second screw 120 to rotate around their own axes. When the first cylinder 262 extends, the second cylinder 263 retracts, and the clamping block 264 moves away from the first gear 170 to ensure the normal rotation of the first gear 170, the first rotating shaft 150, the first screw 110, etc.

[0068] When it is necessary to switch to the piston pump state for operation, the electric telescopic rod 203 drives the piston plate 202 to move downward to increase the volume of the rod chamber and reduce the volume of the rodless chamber, thereby driving the first cylinder 262 to retract and the second cylinder 263 to extend. As a result, the first cylinder 262 drives the conical cover 240 to move away from the gearbox 190, and further the locking rod 250 moves away from the camshaft 210. At the same time, the second cylinder 263 drives the clamping block 264 to be clamped to the second gear 180 to ensure that the first gear 170 cannot rotate. At this time, the drive motor 270 drives the camshaft 210 to reciprocate along its own axis, and further drives the slide plate 130 to reciprocate.

[0069] In this embodiment, the transfer pump further includes a first extraction pipe 310, a first discharge pipe 320, a second extraction pipe 330, and a second discharge pipe 340. The first extraction pipe 310, the first discharge pipe 320, the second extraction pipe 330, and the second discharge pipe 340 are all communicated with the inner cavity of the pump housing 140. When the twin-screw pump operates, the liquid flows through the first extraction pipe 310 and the first discharge pipe 320; when the piston pump operates, the liquid flows through the second extraction pipe 330 and the second discharge pipe 340.

[0070] In this embodiment, the transfer pump further includes a flow meter and a check valve. The flow meter is installed in the first extraction pipe 310 and the second extraction pipe 330 for detecting the liquid flow rate entering the pump housing 140. When the flow rate drops to the set value, the switching mechanism 260 is activated to perform the working state switching to ensure the stable production. Check valves are provided between the first extraction pipe 310, the first discharge pipe 320, the second extraction pipe 330, the second discharge pipe 340 and the inner cavity of the pump housing 140 to ensure the normal operation of the transfer pump.

[0071] Based on the cyclohexanone vacuum refining system provided in this embodiment, a cyclohexanone vacuum refining process is proposed. Using the above cyclohexanone vacuum refining system, it includes the following steps:

[0072] The gaseous product enters the first condenser from the top outlet of the light component removal column, the ketone column or the alcohol column and is condensed into a liquid product. Subsequently, the liquid product is subjected to vacuum distillation by a dry vacuum pump to obtain gaseous cyclohexanone. The gaseous cyclohexanone enters the second condenser and is condensed into a liquid and enters the reflux tank. Finally, the transfer pump pumps out the liquid cyclohexanone from the reflux tank, as Figure 5 shown.

[0073] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cyclohexanone vacuum refining system, characterized in that: A vacuum refining unit is included, wherein the vacuum refining unit includes a first condenser, a dry vacuum pump, a second condenser and a reflux tank connected in sequence; The gas phase product flows through the first condenser, the dry vacuum pump, the second condenser and the reflux tank in sequence; Cooling water is passed into the first condenser and the second condenser to perform condensation.

2. The cyclohexanone vacuum refining system according to claim 1, characterized in that: Also included is a delivery pump, which is used to deliver liquid materials and includes a first screw (110), a second screw (120), a slide plate (130) and a pump housing (140); The first screw (110) and the second screw (120) are arranged in parallel in the pump housing (140) to form a twin-screw pump; The two slide plates (130) are arranged at both ends of the first screw rod (110) and the second screw rod (120), and both ends of the first screw rod (110) and the second screw rod (120) are rotatably mounted on the slide plates (130); the two slide plates (130) are slidably mounted in the pump housing (140) and respectively form a piston cavity (101) with the pump housing (140) to form a piston pump, and the first screw rod (110) can reciprocate along its own axis to drive the slide plates (130) to move, thereby changing the volume of the piston cavity (101).

3. The cyclohexanone vacuum refining system according to claim 2, characterized in that: The delivery pump further comprises a first rotating shaft (150) and a second rotating shaft (160), wherein the first rotating shaft (150) is connected to and coaxially arranged with the first screw (110), and the second rotating shaft (160) is connected to and coaxially arranged with the second screw (120); The first rotating shaft (150) rotates around its own axis to drive the second rotating shaft (160), the first screw rod (110) and the second screw rod (120) to rotate around their own axes.

4. The cyclohexanone vacuum refining system according to claim 3, characterized in that: The delivery pump further includes a first gear (170) and a second gear (180); The first gear (170) is mounted on the first rotating shaft (150) and connected to the first rotating shaft (150), and the second gear (180) is mounted on the second rotating shaft (160) and connected to the second rotating shaft (160); The first gear (170) is meshed with the second gear (180).

5. The cyclohexanone vacuum refining system according to claim 4, characterized in that: The delivery pump further comprises a cam shaft (210), an insertion rod (220) and a motor shaft (230); The motor shaft (230) is sleeved on the cam shaft (210); the cam shaft (210) is connected to and coaxially arranged with the first rotating shaft (150); and a cam groove is provided on the cam shaft (210); The insertion rod (220) is inserted into the motor shaft (230) and the cam groove at the same time. The motor shaft (230) rotates around its own axis to drive the insertion rod (220) to rotate, thereby driving the insertion rod (220) to slide along the cam groove so that the cam shaft (210) moves back and forth along its own axis.

6. The cyclohexanone vacuum refining system according to claim 5, characterized in that: The delivery pump further comprises a conical cover (240) and a locking rod (250); The conical cover (240) is sleeved on the motor shaft (230), and the locking rod (250) is inserted into the motor shaft (230) and is located between the conical cover (240) and the cam shaft (210); The conical cover (240) is capable of moving along its own axial direction. When the twin-screw pump is started, the two ends of the locking rod (250) respectively abut against the inner wall of the conical cover (240) and the camshaft (210); when the piston pump is started, the conical cover (240) moves along its own axial direction to move away from the locking rod (250), and then the locking rod (250) is capable of moving along its own axial direction to move away from the camshaft (210).

7. The cyclohexanone vacuum refining system according to claim 6, characterized in that: The delivery pump further comprises a switching mechanism (260), wherein the switching mechanism (260) comprises a connecting frame (261), a first cylinder (262), a second cylinder (263), a clamping block (264) and a switching cylinder (265); The conical cover (240) is connected to the connecting frame (261), and the extended end of the first cylinder (262) is connected to the connecting frame (261) to drive the conical cover (240) to move along its own axial direction; the clamping block (264) is connected to the extended end of the second cylinder (263), and the second cylinder (263) is extended to drive the clamping block (264) to clamp the first gear (170); The rod chamber and the rodless chamber of the switching cylinder (265) are respectively connected to the first cylinder (262) and the second cylinder (263), and the switching cylinder (265) is extended and retracted to drive one of the first cylinder (262) and the second cylinder (263) to extend and the other to retract.

8. The cyclohexanone vacuum refining system according to claim 7, characterized in that: The switching cylinder (265) comprises a cylinder body (201), a piston plate (202) and an electric telescopic rod (203); The piston plate (202) is inserted into the cylinder body (201) and divides the cylinder body (201) into a rod chamber and a rodless chamber; the electric telescopic rod (203) is connected to the piston plate (202) and is used to drive the piston plate (202) to move in the cylinder body (201).

9. The cyclohexanone vacuum refining system according to claim 8, characterized in that: The delivery pump further comprises a first extraction pipe (310), a first discharge pipe (320), a second extraction pipe (330) and a second discharge pipe (340); The first extraction pipe (310), the first discharge pipe (320), the second extraction pipe (330) and the second discharge pipe (340) are all in communication with the inner cavity of the pump housing (140); When the twin-screw pump is working, the liquid flows through the first extraction pipe (310) and the first discharge pipe (320); when the piston pump is working, the liquid flows through the second extraction pipe (330) and the second discharge pipe (340).

10. A cyclohexanone vacuum refining process, characterized in that: The cyclohexanone vacuum refining system according to any one of claims 1 to 9 comprises the following steps: The gaseous product enters the first condenser from the top outlet of the light removal tower, ketone tower or alcohol tower to be condensed into a liquid product. Subsequently, the liquid product is subjected to reduced pressure distillation by the dry vacuum pump to obtain gaseous cyclohexanone. The gaseous cyclohexanone enters the second condenser to be condensed into a liquid and enters the reflux tank. Finally, the liquid cyclohexanone is extracted from the reflux tank by a transfer pump.

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