System and method for improving conversion rate of cyclohexanol prepared by cyclohexene hydration

Abstract

The invention belongs to the technical field of cyclohexanol production, and particularly relates to a system and a method for improving the conversion rate of cyclohexanol prepared by cyclohexene hydration. The system for improving the conversion rate of cyclohexanol prepared by cyclohexene hydration comprises an alcohol tower I, a first hydration reactor and a second hydration reactor, a cyclohexene inlet and a side line extraction opening are respectively formed in the side wall of the alcohol tower I; the side line extraction port is communicated with an inlet of a first hydration reactor through a side line pipeline, a micro-interface reactor is arranged on the side line pipeline, a catalyst outlet is formed in the bottom of the first hydration reactor, and the catalyst outlet is communicated with a micro-interface mixing device through a catalyst pipeline; the first hydration reactor is communicated with the second hydration reactor through an overflow pipeline. According to the system and the method, on the premise of not changing the existing process operation, the reaction conversion rate of cyclohexanol prepared by a cyclohexene hydration method is improved, the process operation conditions are optimized, the energy consumption is reduced, and the purpose of improving the productivity is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of cyclohexanol production, and particularly relates to a system and a method for improving the conversion rate of cyclohexene hydration to cyclohexanol. Background Art

[0002] At present, cyclohexane oxidation and cyclohexene hydration are mostly used for industrial cyclohexanol production. Compared with oxidation, hydration has the advantages of low raw material and operation costs, good product quality, safety and environmental protection. In recent years, domestic industrial cyclohexanol production plants have mostly used cyclohexene hydration. The principle of hydration is to partially hydrogenate benzene under the action of ruthenium catalyst to produce cyclohexene (this process is accompanied by the generation of some cyclohexane), and then react cyclohexene with water to produce cyclohexanol.

[0003] At present, the conversion rate of cyclohexene hydration to cyclohexanol is about 9%, and the selectivity is about 99%. In the actual production process, a large amount of unreacted cyclohexene is always circulating in the reaction system, resulting in a slow reaction rate and relatively high energy consumption in the cyclohexene hydration to cyclohexanol reaction. Therefore, in the cyclohexene hydration to cyclohexanol reaction, improving the reaction conversion rate or reaction rate has become a key technology for increasing the load of domestic cyclohexanol plants in recent years.

[0004] At present, the existing technology mainly focuses on improving the reaction conversion rate, and has the following disadvantages: ① The operating temperature of cyclohexene hydration to produce cyclohexanol is about 120℃-130℃. Properly increasing the temperature will have a certain positive effect on improving the reaction conversion rate, but it will also reduce the selectivity of cyclohexanol, generate more by-products, and shorten the life of the hydration catalyst, increasing the system operation cost. ② In order to improve the reaction conversion rate, the industry needs to increase the proportion of the water phase side as much as possible on the basis of not losing the catalyst. The operating space is small, and the lost catalyst can cause the internal structure and pipeline of the distillation tower of the subsequent system to be blocked, and at the same time increase energy consumption. ③ Replace the new hydration catalyst. The current maximum conversion rate of the catalyst on the market can reach 10%, which cannot effectively improve the yield of cyclohexanol. There are catalysts with a conversion rate of 20% in domestic laboratories, but there is no industrial application. At the same time, the cost of replacing the catalyst is high and the workload is large.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a system and method for improving the conversion rate of cyclohexene hydration to cyclohexanol; the system and method improve the reaction conversion rate of cyclohexene hydration to cyclohexanol without changing the existing process operation, optimize the process operation conditions, reduce energy consumption, and achieve the purpose of increasing production capacity.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A system for improving the conversion rate of cyclohexene hydration to cyclohexanol comprises an alcohol tower, a first hydration reactor and a second hydration reactor; the side walls of the alcohol tower are respectively provided with a cyclohexene inlet and a side line production outlet; the side line production outlet is connected with the inlet of the first hydration reactor through a side line pipeline, a micro-interface reactor is arranged on the side line pipeline, a catalyst outlet is arranged at the bottom of the first hydration reactor, and the catalyst outlet is connected with a micro-interface mixing device through a catalyst pipeline; the first hydration reactor and the second hydration reactor are connected through an overflow pipeline.

[0009] Furthermore, a reflux port is provided on the side wall of the first alcohol tower; a mixture outlet is provided on one side of the second hydration reactor, and the mixture outlet is connected to the reflux port through a reflux line.

[0010] Furthermore, the catalyst pipeline is provided with a slurry pump for delivering the catalyst extracted from the catalyst outlet into the micro-interface mixing device.

[0011] Furthermore, a side line pump is provided on the side line pipeline.

[0012] Furthermore, the alcohol tower is a distillation tower.

[0013] In addition, the present invention also provides a method for improving the conversion rate of cyclohexene hydration to cyclohexanol, using the above system, comprising the following steps:

[0014] S1. Cyclohexene produced by the upstream unit is sent to the alcohol tower for rectification. The light component is taken out from the top of the tower and returned to the upstream unit. The high-purity cyclohexene is taken out from the side line and fully mixed with the catalyst taken out from the bottom of the first hydration reactor through a micro-interface mixing device and then sent to the first hydration reactor for the first hydration reaction.

[0015] S2, sending the cyclohexanol generated by the first hydration reaction together with the unreacted cyclohexene into the second hydration reaction zone for a second hydration reaction;

[0016] S3. The cyclohexanol generated by the secondary hydration reaction and the unreacted cyclohexene are continuously returned to the alcohol first tower for distillation separation. The separated cyclohexanol is discharged from the bottom of the tower and then enters the subsequent purification. The separated cyclohexene is continuously taken out from the side line and then sent to the first hydration reactor for reuse.

[0017] Furthermore, in step S1, the catalyst is aluminosilicate.

[0018] Furthermore, the purity of the high-purity cyclohexene is 97%.

[0019] Compared with the closest prior art, the technical solution provided by the present invention has the following excellent effects:

[0020] (1) The system and method for improving the conversion rate of cyclohexene hydration to cyclohexanol of the present invention increase the anti-fluctuation ability of the catalyst system without changing the existing process operation, improve the reaction conversion rate of cyclohexene hydration to cyclohexanol, optimize the process operation conditions, save operating costs, reduce energy consumption, and achieve the purpose of increasing production capacity;

[0021] (2) The process is simple, energy consumption is low, and equipment failure is easy to inspect and repair. In some special working conditions, it can serve as a barrier to safe work and reduce or avoid the probability of enterprise accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. Among them:

[0023] Figure 1 The schematic diagram of the system for improving the conversion rate of cyclohexene hydration to cyclohexanol according to the present invention.

[0024] In the figure: 1-alcohol tower; 2-first hydration reactor; 3-second hydration reactor; 11-cyclohexene inlet; 12-side line production outlet; 13-reflux outlet; 101-side line pump; 4-micro-interface mixing device; 21-catalyst outlet; 20-catalyst pipeline; 201-slurry pump; 30-overflow pipeline; 31-mixture outlet; 40-reflux pipeline. DETAILED DESCRIPTION

[0025] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0026] In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present invention. The terms "connected" and "connected" used in the present invention should be understood in a broad sense. For example, they can be fixed connections or detachable connections; they can be directly connected or indirectly connected through intermediate components. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0027] According to a first aspect of the present invention, there is provided a system for improving the conversion rate of cyclohexene hydration to cyclohexanol, such as Figure 1As shown; it includes an alcohol tower 1, a first hydration reactor 2 and a second hydration reactor 3; the side walls of the alcohol tower 1 are respectively provided with a cyclohexene inlet 11 and a side line outlet 12, the side line outlet 12 is connected to the inlet of the first hydration reactor 2 through a side line pipeline 10, the side line pipeline 10 is provided with a side line pump 101 and a micro-interface mixing device 4, the bottom of the first hydration reactor 2 is provided with a catalyst outlet 21, the catalyst outlet 21 is connected to the micro-interface mixing device 4 through a catalyst pipeline 20; a slurry pump 201 is provided on the catalyst pipeline 20 for sending the catalyst produced from the catalyst outlet into the micro-interface mixing device 4; the first hydration reactor 2 and the second hydration reactor 3 are connected through an overflow pipeline 30; wherein, a reflux port 13 is also provided on the side wall of the alcohol tower 1; a mixture outlet 31 is provided on one side of the second hydration reactor 3, and the mixture outlet 31 is connected to the reflux port 13 through a reflux pipeline 40. It should be noted that the alcohol tower 1 described in the present invention is a conventional distillation tower, and the micro-interface mixing device 4 is also a conventional device in the art, so they will not be described in detail here.

[0028] The method for improving the conversion rate of cyclohexene hydration to cyclohexanol using the system of the present invention is as follows:

[0029] The cyclohexene produced by the upstream unit is sent to the alcohol tower 1 for distillation. The light component is taken out from the top of the tower and returned to the upstream unit. The high-purity cyclohexene (purity is about 97%) is taken out from the side line and fully mixed with the catalyst (aluminosilicate) taken out from the bottom of the first hydration reactor 2 through the micro-interface mixing device 4 and then sent to the first hydration reactor 2 for the first hydration reaction. Part of the cyclohexene reacts with water in the first hydration reactor 2 to generate cyclohexanol (in the first hydration reaction, the cyclohexene conversion rate is about 6%). The cyclohexanol generated by the first hydration reaction and the unreacted cyclohexene are sent to the second hydration reaction zone 3 together for a second hydration reaction (the conversion rate of cyclohexene in the two hydration reactions is about 9%); the cyclohexanol generated by the second hydration reaction and the unreacted cyclohexene are continuously returned to the alcohol first tower 1 for distillation separation, and the separated cyclohexanol (with a purity of about 10.5%) is discharged from the bottom of the tower and then enters subsequent purification, and the separated cyclohexene is continuously taken out from the side line and sent to the first hydration reactor 2 for reuse.

[0030] The present invention mainly mixes the hydrated catalyst slurry and cyclohexene in advance outside the reactor through a micro-interface mixing device, thereby increasing the contact area between cyclohexene, water and the catalyst, strengthening the mass transfer process, and thus improving the conversion rate, as follows:

[0031] (I) Pre-mixing of hydrated catalyst slurry and cyclohexene outside the reactor

[0032] The catalyst at the bottom of the first hydration reactor is extracted by a slurry pump and sent to the micro-interface mixing device together with the cyclohexene delivered by the alcohol tower sideline pump. The micro-interface mixing device is used to disperse the hydrated catalyst slurry and cyclohexene into small particles and small droplets, increase the contact area of ​​the materials, strengthen the mass transfer process, extend the residence time of the materials and the catalyst, and increase the reaction rate.

[0033] (II) Re-separation of hydrated catalyst slurry and cyclohexene

[0034] The mixed hydrated catalyst slurry and cyclohexene are sent to the first hydration reactor, where they are mixed for the second time and enter the upper grid plate of the reactor. Since the materials are in a relatively static state in the grid plate, cyclohexene is separated from the hydrated catalyst slurry by gravity according to the density difference, and the hydrated catalyst slurry is sent back to the micro-interface mixing device through the reactor bottom slurry pump; cyclohexene and cyclohexanol are sent to the second hydration reactor and the subsequent distillation system.

[0035] Experimental Example 1

[0036] The present embodiment provides a system for improving the conversion rate of cyclohexene hydration to cyclohexanol, comprising an alcohol tower, a first hydration reactor and a second water reactor; a cyclohexene inlet and a side line production outlet are respectively provided on the side walls of the alcohol tower, the side line production outlet is connected to the inlet of the first hydration reactor through a side line pipeline, a side line pump and a micro-interface mixing device are provided on the side line pipeline, a catalyst outlet is provided at the bottom of the first hydration reactor, the catalyst outlet is connected to the micro-interface mixing device through a catalyst pipeline; a slurry pump is provided on the catalyst pipeline to send the catalyst produced from the catalyst outlet into the micro-interface mixing device; the first hydration reactor and the second hydration reactor are connected through an overflow pipeline; wherein a reflux port is also provided on the side wall of the alcohol tower; a mixture outlet is provided on one side of the second hydration reactor, and the mixture outlet is connected to the reflux port through a reflux pipeline.

[0037] This embodiment also provides a method for improving the conversion rate of cyclohexene hydration to cyclohexanol using the above system, comprising the following steps:

[0038] The cyclohexene produced by the upstream unit is sent to the alcohol tower for rectification. The light component is extracted from the top of the tower and returned to the upstream unit. The high-purity cyclohexene (purity of about 97%) is extracted from the side line and fully mixed with the catalyst (aluminosilicate) extracted from the bottom of the first hydration reactor through a micro-interface mixing device and then sent to the first hydration reactor for the first hydration reaction. Part of the cyclohexene reacts with water in the first hydration reactor to generate cyclohexanol (in the first hydration reaction, the cyclohexene conversion rate is about 6%). The cyclohexanol generated by the first hydration reaction is sent to the second hydration reaction zone together with the unreacted cyclohexene for the second hydration reaction (the conversion rate of cyclohexene in the two hydration reactions is about 9%); the cyclohexanol generated by the second hydration reaction and the unreacted cyclohexene are continuously returned to the alcohol tower for rectification and separation. The separated cyclohexanol (purity of about 10.5%) is discharged from the bottom of the tower and then enters the subsequent purification. The separated cyclohexene is continuously extracted from the side line and sent to the first hydration reactor for reuse.

[0039] Test Example 1

[0040] The cyclohexanone workshop of a chemical enterprise adopts the system for improving the conversion rate of cyclohexene hydration to cyclohexanol in Example 1, which is marked as set A; and adopts a system which is different from Example 1 only in that a micro-interface mixing device is not provided, which is marked as set B; and then collects the operation data of multiple times in different time periods to form a report as shown in Table 1:

[0041] Table 1

[0042] 1st time 2nd time 3rd 4th 5th 6th A set conversion rate 10.61 10.9 9.85 10.03 10.11 10.44 B set conversion rate 8.74 9.75 10.22 9.86 9.67 10.3 Operation load 70％ 72％ 72％ 72％ 100％ 100％ 7th 8th 9th 10th 11th 12th A set conversion rate 9.89 9.5 9.0 10.03 8.91 9.18 B set conversion rate 9.7 9.45 8.29 10.31 9.16 9.04 Operation load 100％ 102％ 67％ 102％ 102％ 102％ 13th 14th 15th 16th 17th 18th A set conversion rate 9.92 10.12 9.03 9.99 10.36 9.26 B set conversion rate 9.72 9.84 9.03 9.35 10.04 9.12 Operation load 102％ 102％ 80％ 102％ 103％ 103％ 19th A set conversion rate 9.66 B set conversion rate 9.73 Operation load 103％

[0043] From the operation data in Table 1, it can be seen that the operation data of the hydration reaction of set A is slightly better than that of set B. In this case, the micro-interface mixing device can indeed enhance the mixing effect of cyclohexene and catalyst, and to a certain extent, it can promote the hydration reaction, resulting in a high conversion rate of set A. Micro-mixing technology can indeed improve the mixing effect of catalyst and material, and have a certain positive effect on the hydration reaction.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A system for improving the conversion rate of cyclohexene hydration to cyclohexanol, characterized in that: The invention comprises an alcohol tower, a first hydration reactor and a second hydration reactor; the side wall of the alcohol tower is respectively provided with a cyclohexene inlet and a side line production outlet; the side line production outlet is connected with the inlet of the first hydration reactor through a side line pipeline, a micro-interface reactor is arranged on the side line pipeline, a catalyst outlet is arranged at the bottom of the first hydration reactor, and the catalyst outlet is connected with a micro-interface mixing device through a catalyst pipeline; the first hydration reactor and the second hydration reactor are connected through an overflow pipeline.

2. The system for improving the conversion rate of cyclohexene hydration to cyclohexanol according to claim 1, characterized in that: The side wall of the alcohol tower is also provided with a reflux port; one side of the second hydration reactor is provided with a mixture outlet, and the mixture outlet is connected with the reflux port through a reflux pipeline.

3. The system for improving the conversion rate of cyclohexene hydration to cyclohexanol according to claim 1, characterized in that: The catalyst pipeline is provided with a slurry pump for delivering the catalyst extracted from the catalyst outlet into the micro-interface mixing device.

4. The system for improving the conversion rate of cyclohexene hydration to cyclohexanol according to claim 1, characterized in that: A side line pump is arranged on the side line pipeline.

5. The system for improving the conversion rate of cyclohexene hydration to cyclohexanol according to claim 1, characterized in that: The alcohol tower is a distillation tower.

6. A method for improving the conversion rate of cyclohexene hydration to cyclohexanol, characterized in that: The system according to any one of claims 1 to 5 comprises the following steps: S1. Cyclohexene produced by the upstream unit is sent to the alcohol tower for rectification. The light component is taken out from the top of the tower and returned to the upstream unit. The high-purity cyclohexene is taken out from the side line and fully mixed with the catalyst taken out from the bottom of the first hydration reactor through a micro-interface mixing device and then sent to the first hydration reactor for the first hydration reaction. S2, sending the cyclohexanol generated by the first hydration reaction together with the unreacted cyclohexene into the second hydration reaction zone for a second hydration reaction; S3. The cyclohexanol generated by the secondary hydration reaction and the unreacted cyclohexene are continuously returned to the alcohol first tower for distillation separation. The separated cyclohexanol is discharged from the bottom of the tower and then enters the subsequent purification. The separated cyclohexene is continuously taken out from the side line and then sent to the first hydration reactor for reuse.

7. The method for improving the conversion rate of cyclohexene hydration to cyclohexanol according to claim 6, characterized in that: In step S1, the catalyst is aluminosilicate.

8. The method for improving the conversion rate of cyclohexene hydration to cyclohexanol according to claim 6, characterized in that: In step S1, the purity of the high-purity cyclohexene is 97%.

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