阅读说明：本技术 一种水合法环己醇分离的节能装置及方法 (Energy-saving device and method for separating cyclohexanol in hydration method ) 是由 葛春方 王卫华 于 2021-09-30 设计创作，主要内容包括：本发明属于有机物分离技术领域,尤其是涉及一种水合法环己醇分离的节能装置及方法。它包括环己烯分离塔,所述的环己烯分离塔的底部连接环己烯回收塔,环己烯回收塔的顶部连接环己醇分离塔,环己醇分离塔连接水合反应器,所述的环己烯分离塔的顶部连接换热器的热侧进口,换热器的冷侧进口和冷侧出口都与环己醇分离塔的中下部连接。本发明在节省环己烯分离塔塔顶外加冷却负荷的同时,减少了环己醇分离塔的塔底再沸器外加热负荷,降低了能耗。(The invention belongs to the technical field of organic matter separation, and particularly relates to an energy-saving device and method for separating cyclohexanol by a hydration method. The device comprises a cyclohexene separating tower, wherein the bottom of the cyclohexene separating tower is connected with the cyclohexene recovering tower, the top of the cyclohexene recovering tower is connected with a cyclohexanol separating tower, the cyclohexanol separating tower is connected with a hydration reactor, the top of the cyclohexene separating tower is connected with a hot side inlet of a heat exchanger, and a cold side inlet and a cold side outlet of the heat exchanger are connected with the middle lower part of the cyclohexanol separating tower. The invention saves the cooling load applied to the top of the cyclohexene separating tower, reduces the heating load applied to the reboiler at the bottom of the cyclohexanol separating tower, and reduces the energy consumption.)

1. An energy-saving device for separating cyclohexanol by a hydration method comprises a cyclohexene separating tower (1), wherein the bottom of the cyclohexene separating tower (1) is connected with a cyclohexene recovery tower (2), the top of the cyclohexene recovery tower (2) is connected with a cyclohexanol separating tower (3), the cyclohexanol separating tower (3) is connected with a hydration reactor (4),

the device is characterized in that the top of the cyclohexene separating tower (1) is connected with a hot side inlet of a heat exchanger (6), and a cold side inlet and a cold side outlet of the heat exchanger (6) are both connected with the middle lower part of the cyclohexanol separating tower (3).

2. The energy-saving device for separating cyclohexanol in the hydration method according to claim 1, wherein the bottom of the cyclohexene separation column (1) is connected to the middle of the cyclohexene recovery column (2), and the top of the cyclohexene recovery column (2) is connected to the middle upper part of the cyclohexanol separation column (3).

3. An energy-saving method for cyclohexanol separation in hydration process using the energy-saving device for cyclohexanol separation in hydration process according to any one of claims 1 to 2,

conveying a mixed material (5) containing cyclohexane and cyclohexene into a cyclohexene separation tower (1), adding a solvent into the cyclohexene separation tower (1) for extractive distillation, wherein a cyclohexane product is at the tower top, and a cyclohexene-rich solvent-based material flow II is in the tower bottom;

conveying the solvent-based material flow II into a cyclohexene recovery tower (2) for solvent recovery, obtaining a material flow III rich in cyclohexene at the tower top, and obtaining a material flow IV rich in solvent in the tower kettle;

sending the stream III rich in cyclohexene into a cycloethanol separation tower (3), forming a stream VII rich in cyclohexene on the upper part of the cycloethanol separation tower (3), entering a hydration reactor (4), wherein a part of cyclohexene reacts with water to generate cyclohexanol, unreacted cyclohexene is separated from water, an upper oil phase is separated to obtain a stream VIII containing cyclohexanol and cyclohexene, and a water layer is remained in the hydration reactor (4) for continuous hydration reaction;

the material flow VIII flows back to the middle lower part of the cyclohexanol separation tower (3), a material flow VII rich in cyclohexene is continuously extracted from the upper part of the cyclohexanol separation tower (3), a light component material flow V generated by side reaction is extracted from the top of the tower, and a material flow VI rich in cyclohexanol is arranged in the tower kettle;

taking the top gas phase material flow I of the cyclohexene separation tower (1) as a hot side material flow, heating and evaporating the bottom material of the cyclohexanol separation tower in a heat exchanger, discharging a part of condensed cyclohexane to form a material flow IX, and refluxing a part of condensed cyclohexane to the cyclohexene separation tower.

4. The energy-saving method for separating cyclohexanol in the hydration method according to claim 3, wherein the operation pressure at the top of the cyclohexene separation tower is 100-300 kPaA, and the temperature at the top of the cyclohexene separation tower is 80-120 ℃; the operation pressure of the top of the cyclohexanol separation tower is 40-100 kPaA, and the temperature of a tower kettle of the cyclohexanol separation tower is 60-110 ℃.

5. The energy-saving method for separating cyclohexanol in the hydration method according to claim 4, wherein the operation pressure at the top of the cyclohexene separation tower is 130-250 kPaA, and the temperature at the top of the cyclohexene separation tower is 90-110 ℃; the operation pressure of the top of the cyclohexanol separation tower is 60-80 kPaA, and the temperature of a tower kettle of the cyclohexanol separation tower is 80-100 ℃.

6. The energy-saving method for separating cyclohexanol in the hydration method according to claim 3, wherein a reflux ratio of the cyclohexene separation tower is 5 to 20.

7. The method for saving energy in the separation of cyclohexanol in the hydration method according to claim 3, wherein the solvent comprises N, N-dimethylacetamide in an amount of more than 80% by weight.

Technical Field

The invention belongs to the technical field of organic matter separation, and particularly relates to an energy-saving device and method for separating cyclohexanol by a hydration method.

Background

The production route of adipic acid and caprolactam based on the cyclohexene hydration method is the mainstream process in the current industrial production. The production of cyclohexene mostly adopts partial hydrogenation of benzene, and a small amount of cyclohexane can be generated in addition to cyclohexene in the hydrogenation process. Cyclohexene reacts with water after being separated and refined from cyclohexane and benzene to generate cyclohexanol. However, the single-pass conversion rate of the hydration reaction of cyclohexene is low, generally about 10%, so a large amount of unreacted cyclohexene needs to be separated from the reaction product cyclohexanol and then recycled to the hydration reaction, and the energy consumption of the separation process is high.

In order to solve the problem of high energy consumption in the separation process of cyclohexene and cyclohexanol, patent CN104086371A discloses a process for separating cyclohexanol in the production process of cyclohexanone by cyclohexene method, wherein a pressure swing double-effect rectification process is used to separate hydrated cyclohexene and cyclohexanol, and the reboiler heat load can be reduced by about 30% compared with the traditional single-tower cyclohexene/cyclohexanol separation. However, one rectification system is changed into two systems, so that the investment is increased, the operation is also complicated.

Disclosure of Invention

The invention aims to solve the problems and provides an energy-saving device for separating cyclohexanol in a hydration method.

The invention also aims to provide an energy-saving method for separating cyclohexanol in a hydration method.

An energy-saving device for separating cyclohexanol by a hydration method comprises a cyclohexene separation tower, wherein the bottom of the cyclohexene separation tower is connected with a cyclohexene recovery tower, the top of the cyclohexene recovery tower is connected with a cyclohexanol separation tower, the cyclohexanol separation tower is connected with a hydration reactor,

the top of the cyclohexene separating tower is connected with a hot side inlet of the heat exchanger, and a cold side inlet and a cold side outlet of the heat exchanger are both connected with the middle lower part of the cyclohexanol separating tower.

In the energy-saving device for separating cyclohexanol by the hydration method, the bottom of the cyclohexene separation tower is connected with the middle part of the cyclohexene recovery tower, and the top of the cyclohexene recovery tower is connected with the middle upper part of the cyclohexanol separation tower.

An energy-saving method for separating cyclohexanol by a hydration method comprises the steps of conveying a mixed material containing cyclohexane and cyclohexene into a cyclohexene separation tower, adding a solvent into the cyclohexene separation tower for extractive distillation, wherein a cyclohexane product is arranged at the top of the tower, and a solvent-based material flow II rich in cyclohexene is arranged in a tower kettle;

conveying the solvent-based material flow II into a cyclohexene recovery tower for solvent recovery, obtaining a material flow III rich in cyclohexene at the tower top, and obtaining a material flow IV rich in the solvent in the tower bottom;

sending the stream III rich in cyclohexene into a cycloethanol separation tower, forming a stream VII rich in cyclohexene on the upper part of the cycloethanol separation tower, entering a hydration reactor, reacting part of cyclohexene with water to generate cyclohexanol, separating unreacted cyclohexene from water, separating an upper oil phase to obtain a stream VIII containing cyclohexanol and cyclohexene, and remaining a water layer in the hydration reactor for continuous hydration reaction;

refluxing the material flow VIII to the middle lower part of the cyclohexanol separation tower, continuously extracting a material flow VII rich in cyclohexene from the upper part of the cyclohexanol separation tower, extracting a light component material flow V generated by side reaction from the top of the tower, and obtaining a material flow VI rich in cyclohexanol in the tower kettle;

taking the gas phase material flow I at the top of the cyclohexene separation tower as a hot side material flow, heating and evaporating the material at the bottom of the cyclohexanol separation tower in a heat exchanger, discharging a part of condensed cyclohexane to form a material flow IX, and refluxing a part of condensed cyclohexane to the cyclohexene separation tower.

In the energy-saving method for separating cyclohexanol by using a hydration method, the operation pressure at the top of the cyclohexene separation tower is 100-300 kPaA, and the temperature at the top of the cyclohexene separation tower is 80-120 ℃; the operation pressure of the top of the cyclohexanol separation tower is 40-100 kPaA, and the temperature of a tower kettle of the cyclohexanol separation tower is 60-110 ℃.

In the energy-saving method for separating cyclohexanol by using a hydration method, the operation pressure at the top of the cyclohexene separation tower is 130-250 kPaA, and the temperature at the top of the cyclohexene separation tower is 90-110 ℃; the operation pressure at the top of the cyclohexanol separation tower is 60-80 kPaA, and the temperature of a tower kettle of the cyclohexanol separation tower is 80-100 ℃;

in the energy-saving method for separating cyclohexanol by using a hydration method, the reflux ratio of the cyclohexene separation tower is 5-20.

In the energy-saving method for separating cyclohexanol by using a hydration method, the solvent comprises more than 80% of N, N-dimethylacetamide by mass.

Compared with the prior art, the invention has the advantages that:

1. the method for separating cyclohexanol provided by the invention saves the external cooling load on the top of the cyclohexene separating tower, reduces the external heating load of a reboiler at the bottom of the cyclohexanol separating tower, and reduces the energy consumption.

2. The invention is basically similar to the flow of the prior art, the equipment can be simply reconstructed on the basis of the prior art, and the control and operation complexity is equivalent.

Drawings

Fig. 1 is a schematic structural view of the present invention.

Fig. 2 is a schematic diagram of a prior art structure.

In the figure: the device comprises a cyclohexene separating tower 1, a cyclohexene recovery tower 2, a cyclohexanol separating tower 3, a hydration reactor 4, a heat exchanger 6 and a condenser 10.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

As shown in fig. 1, this embodiment provides an energy saving device for separating cyclohexanol by a hydration method, which includes a cyclohexene separating tower 1, a cyclohexene recovery tower 2 is connected to the bottom of the cyclohexene separating tower 1, a cyclohexanol separating tower 3 is connected to the top of the cyclohexene recovery tower 2, the cyclohexanol separating tower 3 is connected to a hydration reactor 4, the top of the cyclohexene separating tower 1 is connected to a hot side inlet of a heat exchanger 6, and a cold side inlet and a cold side outlet of the heat exchanger 6 are both connected to the middle lower part of the cyclohexanol separating tower 3. The heat exchanger can be a commercially available heat exchanger such as a plate heat exchanger, a shell and tube heat exchanger and the like according to the heat exchange amount.

In this embodiment, the top of the cyclohexene separation column 1 is connected to a heat exchanger, so that the top gas-phase stream i, i.e. the gas-phase cyclohexane, exchanges heat with the bottom stream of the cyclohexanol separation column 3, and then the gas-phase cyclohexane forms a liquid phase, and the bottom stream of the cyclohexanol separation column 3 is heated. Therefore, on one hand, a condenser is added on the top of the cyclohexene separating tower 1 for cooling gas-phase cyclohexane, on the other hand, the external heating load of a reboiler at the bottom of the cyclohexanol separating tower is reduced, and the energy consumption is reduced.

In the preferred embodiment, the bottom of the cyclohexene separation column 1 is connected to the middle part of the cyclohexene recovery column 2, and the top of the cyclohexene recovery column 2 is connected to the middle upper part of the hexanol separation column 3.

It should be understood by those skilled in the art that the cyclohexene separation column 1, the cyclohexene recovery column 2 and the cyclohexanol separation column 3 include an overhead condensing tank, a reflux pump and a reboiler, which are common knowledge in the art and will not be described herein.

Example 2

The embodiment provides an energy-saving method for separating cyclohexanol by a hydration method based on the device provided by the embodiment 1, and the method comprises the steps of conveying a mixed material 5 containing cyclohexane and cyclohexene into a cyclohexene separating tower 1, adding a solvent into the cyclohexene separating tower 1 for extractive distillation, wherein a cyclohexane product is at the top of the tower, and a solvent-based material flow II rich in cyclohexene is in the bottom of the tower;

conveying the solvent-based material flow II into a cyclohexene recovery tower 2 for solvent recovery, obtaining a material flow III rich in cyclohexene at the tower top, and obtaining a material flow IV rich in solvent in the tower bottom;

sending the stream III rich in cyclohexene into a cycloethanol separation tower 3, forming a stream VII rich in cyclohexene on the upper part of the cycloethanol separation tower 3, entering a hydration reactor 4, wherein a part of cyclohexene reacts with water to generate cyclohexanol, unreacted cyclohexene is separated from water, an upper oil phase is separated to obtain a stream VIII containing cyclohexanol and cyclohexene, and a water layer is remained in the hydration reactor 4 for continuous hydration reaction;

the material flow VIII flows back to the middle lower part of the cyclohexanol separation tower 3, a material flow VII rich in cyclohexene is continuously extracted from the upper part of the cyclohexanol separation tower 3, a light component material flow V generated by side reaction is extracted from the top of the tower, and a material flow VI rich in cyclohexanol is arranged in a tower kettle;

taking the gas phase material flow I at the top of the cyclohexene separating tower 1 as a hot side material flow, heating and evaporating the material at the bottom of the cyclohexanol separating tower in a heat exchanger, discharging a part of condensed cyclohexane to form a material flow IX, and refluxing a part of condensed cyclohexane to the cyclohexene separating tower.

In the embodiment, the operation pressure of the top of the cyclohexene separation tower is 100-300 kPaA, and the temperature of the top of the cyclohexene separation tower is 80-120 ℃; the operation pressure of the top of the cyclohexanol separation tower is 40-100 kPaA, and the temperature of a tower kettle of the cyclohexanol separation tower is 60-110 ℃.

In the preferable scheme, the operation pressure at the top of the cyclohexene separation tower is 130-250 kPaA, and the temperature at the top of the cyclohexene separation tower is 90-110 ℃; the operation pressure at the top of the cyclohexanol separation tower is 60-80 kPaA, and the temperature of a tower kettle of the cyclohexanol separation tower is 80-100 ℃;

the reflux ratio of the cyclohexene separating tower is 5-20, and preferably 8-12.

The solvent comprises more than 80% of N, N-dimethylacetamide by mass. That is, the solvent may be a mixed solvent or a single solvent, if the solvent is a single solvent, all of the solvents are N, N-dimethylacetamide, if the solvent is a mixed solvent, the solvent contains more than 80 wt% of N, N-dimethylacetamide, and the other solvents may be one or more of DMF, DMP, and NMP.

Example 3

The embodiment provides an energy-saving method for separating cyclohexanol in a hydration method based on the device provided in embodiment 1, and specifically includes the following steps:

conveying a mixed material 5 containing cyclohexane and cyclohexene into a cyclohexene separation tower 1, adding a solvent into the cyclohexene separation tower 1 for extractive distillation, wherein the solvent is N, N-dimethylacetamide, the weight ratio of the solvent to a mixed material flow is 4-6:1, the operation pressure at the top of the cyclohexene separation tower 1 is 130-250 kPaA, the reflux ratio of the cyclohexene separation tower is 8-12, the temperature at the top of the cyclohexene separation tower is 90-110 ℃, a cyclohexane product is obtained at the top of the tower, and a solvent-based material flow II rich in cyclohexene is obtained in a tower kettle;

conveying the solvent-based material flow II into a cyclohexene recovery tower 2 for solvent recovery, obtaining a material flow III rich in cyclohexene at the tower top, and obtaining a material flow IV rich in solvent in the tower bottom; the operation pressure at the top of the cyclohexene recovery tower 2 is 40-100 kPaA, and the temperature at the top of the cyclohexene recovery tower 2 is 60-110 ℃.

Sending the material flow III rich in cyclohexene into a cycloethanol separation tower 3, wherein the operation pressure at the top of the cyclohexanol separation tower is 60-80 kPaA, the temperature of a tower kettle of the cyclohexanol separation tower is 80-100 ℃, a material flow VII rich in cyclohexene is formed at the upper part of the cycloethanol separation tower 3 and enters a hydration reactor 4, wherein a part of cyclohexene reacts with water to generate cyclohexanol, unreacted cyclohexene and water are separated, an upper oil phase is separated to obtain a material flow VIII containing cyclohexanol and cyclohexene, and a water layer is remained in the hydration reactor 4 for continuous hydration reaction.

The material flow VIII flows back to the middle lower part of the cyclohexanol separation tower 3, a material flow VII rich in cyclohexene is continuously extracted from the upper part of the cyclohexanol separation tower 3, a light component material flow V generated by side reaction is extracted from the top of the tower, and a material flow VI rich in cyclohexanol is arranged in a tower kettle;

taking the gas phase material flow I at the top of the cyclohexene separating tower 1 as a hot side material flow, heating and evaporating the material at the bottom of the cyclohexanol separating tower in a heat exchanger, discharging a part of condensed cyclohexane to form a material flow IX, and refluxing a part of condensed cyclohexane to the cyclohexene separating tower.

In this embodiment, the top of the cyclohexene separation column 1 is connected to a heat exchanger, so that the top gas-phase stream i, i.e. the gas-phase cyclohexane, exchanges heat with the bottom stream of the cyclohexanol separation column 3, and then the gas-phase cyclohexane forms a liquid phase, and the bottom stream of the cyclohexanol separation column 3 is heated. Therefore, on one hand, a condenser is added on the top of the cyclohexene separating tower 1 for cooling gas-phase cyclohexane, on the other hand, the external heating load of a reboiler at the bottom of the cyclohexanol separating tower is reduced, and the energy consumption is reduced.

Example 4

The embodiment provides an energy-saving method for separating cyclohexanol in a hydration method based on the device provided in embodiment 1, and specifically includes the following steps:

conveying a mixed material 5 containing cyclohexane and cyclohexene into a cyclohexene separation tower 1, adding a solvent into the cyclohexene separation tower for extractive distillation, wherein the solvent is N, N-dimethylacetamide and DMF, the mass parts of the solvent are 88% and 12%, the weight ratio of the solvent to the mixed material flow is 5-5.5:1, the operation pressure at the top of the cyclohexene separation tower 1 is 160-220 kPaA, the reflux ratio of the cyclohexene separation tower is 8-12, the temperature at the top of the cyclohexene separation tower is 95-105 ℃, a cyclohexane product is obtained at the top of the tower, and a solvent-based material flow II rich in cyclohexene is obtained in a tower kettle;

conveying the solvent-based material flow II into a cyclohexene recovery tower 2 for solvent recovery, obtaining a material flow III rich in cyclohexene at the tower top, and obtaining a material flow IV rich in solvent in the tower bottom; the operation pressure at the top of the cyclohexene recovery tower 2 is 40-100 kPaA, and the temperature at the top of the cyclohexene recovery tower 2 is 60-110 ℃.

Sending the material flow III rich in cyclohexene into a cycloethanol separation tower 3, enabling the operation pressure at the top of the cyclohexanol separation tower to be 60-80 kPaA, enabling the temperature of a tower kettle of the cyclohexanol separation tower to be 80-100 ℃, forming a material flow VII rich in cyclohexene on the upper portion of the cycloethanol separation tower 3, enabling the material flow VII to enter a hydration reactor 4, enabling a part of cyclohexene to react with water to generate cyclohexanol in the hydration reactor, separating unreacted cyclohexene from a water layer, separating an upper oil phase to obtain a material flow VIII containing cyclohexanol and cyclohexene, and enabling the water layer to remain in the hydration reactor 4 for continuing hydration reaction; it will be understood by those skilled in the art that the upper middle portion of the hydration reactor 4 is provided with a partition for the purpose of oil-water separation, and the oil layer overflows and the water layer remains in the reactor for further hydration.

The material flow VIII flows back to the middle lower part of the cyclohexanol separation tower 3, a material flow VII rich in cyclohexene is continuously extracted from the upper part of the cyclohexanol separation tower 3, a light component material flow V generated by side reaction is extracted from the top of the tower, and a material flow VI rich in cyclohexanol is arranged in a tower kettle;

taking the gas phase material flow I at the top of the cyclohexene separating tower 1 as a hot side material flow, heating and evaporating the material at the bottom of the cyclohexanol separating tower in a heat exchanger, discharging a part of condensed cyclohexane to form a material flow IX, and refluxing a part of condensed cyclohexane to the cyclohexene separating tower.

In this embodiment, the top of the cyclohexene separation column 1 is connected to a heat exchanger, so that the top gas-phase stream i, i.e. the gas-phase cyclohexane, exchanges heat with the bottom stream of the cyclohexanol separation column 3, and then the gas-phase cyclohexane forms a liquid phase, and the bottom stream of the cyclohexanol separation column 3 is heated. Therefore, on one hand, a condenser is added on the top of the cyclohexene separating tower 1 for cooling gas-phase cyclohexane, on the other hand, the external heating load of a reboiler at the bottom of the cyclohexanol separating tower is reduced, and the energy consumption is reduced.

Comparative example 1

As shown in fig. 2, a mixed material containing cyclohexane and cyclohexene is conveyed into a cyclohexene separation tower 1, then a solvent is added into the cyclohexene separation tower for extractive distillation, wherein the solvent is N, N-dimethylacetamide and DMF, the mass parts of the solvents are 88% and 12%, the weight ratio of the solvent to the mixed material flow is 5-5.5:1, the operation pressure at the top of the cyclohexene separation tower 1 is 160-220 kPaA, the reflux ratio of the cyclohexene separation tower is 8-12, the temperature at the top of the cyclohexene separation tower is 95-105 ℃, a cyclohexane product is obtained at the top of the tower, a gas phase material flow I at the top of the tower is formed, and after being cooled by an additional condenser 10, a liquid material flow is formed and refluxed to the upper part of the cyclohexene separation tower 1, and a solvent base material flow II rich in cyclohexene is formed in the bottom of the tower;

conveying the solvent-based material flow II into a cyclohexene recovery tower 2 for solvent recovery, obtaining a material flow III rich in cyclohexene at the tower top, and obtaining a material flow IV rich in solvent in the tower bottom; the operation pressure at the top of the cyclohexene recovery tower 2 is 40-100 kPaA, and the temperature at the top of the cyclohexene recovery tower 2 is 60-110 ℃.

Sending the material flow III rich in cyclohexene into a cycloethanol separation tower 3, enabling the operation pressure at the top of the cyclohexanol separation tower to be 60-80 kPaA, enabling the temperature of a tower kettle of the cyclohexanol separation tower to be 80-100 ℃, forming a material flow VII rich in cyclohexene on the upper portion of the cycloethanol separation tower 3, enabling the material flow VII to enter a hydration reactor 4, enabling a part of cyclohexene to react with water to generate cyclohexanol, separating unreacted cyclohexene from water, separating an upper oil phase to obtain a material flow VIII containing cyclohexanol and cyclohexene, and enabling a water layer to remain in the hydration reactor 4 for continuous hydration reaction.

And the material flow VIII flows back to the middle lower part of the cyclohexanol separation tower 3, the material flow VII rich in cyclohexene is continuously extracted from the upper part of the cyclohexanol separation tower 3, the light component material flow V generated by side reaction is extracted from the top of the tower, and the material flow VI rich in cyclohexanol is arranged in the tower kettle.

Load comparison

Taking a conventional 10-million ton/year cyclohexanol plant as an example, the ethylene glycol separation column 3 of examples 2-4 was heated by a reboiler, compared with comparative example 1, i.e., a conventional art, by reboiler heating and ethylene glycol cooling duty.

Therefore, the method can completely save cooling load, namely the load of cooling the gas phase material flow I at the top of the cyclohexene separating tower 1, and can save the heat load of a reboiler in the cyclohexanol separating tower 3 by the heat exchange of the gas phase material flow I at the top of the cyclohexene separating tower 3 on the material at the bottom of the cyclohexanol separating tower 3, thus saving 3500KW of comprehensive energy saving 7000 KW.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit of the invention.