Device for preparing cyclohexanone through phenol hydrogenation

Abstract

The device mainly comprises a hydrogen buffer tank, a phenol preheater, a phenol vaporizer, a hydrogen heat exchanger, a crude alcohol ketone buffer tank, a gas condenser, a crude alcohol ketone cooler, a tail gas condenser, a phenol hydrogenation reactor, a second hydrogen buffer tank and a hydrogen circulating compressor. According to the utility model, heat of a phenol hydrogenation reaction product is subjected to cascade recovery, is firstly used for preheating phenol and then exchanges heat with fed hydrogen, so that the heat is recovered, the consumption of heating steam can be reduced by 30-40%, and meanwhile, the feeding superheater and the phenol vaporizer are arranged as integrated equipment, so that the technological process is reduced, the energy consumption is reduced, and the investment is saved.

Description

Technical Field

[0001] The utility model belongs to the technical field of cyclohexanone production, and relates to a device for preparing cyclohexanone by hydrogenating phenol. Background Art

[0002] Cyclohexanone is an important chemical raw material and is widely used in industrial production and daily life. Cyclohexanone is often divided into two categories according to its downstream uses: amide-use and non-amide-use. Currently, 70% of cyclohexanone is used for the production of polyamides. The commonly used fibers nylon 6 and nylon 66 are prepared from cyclohexanone; in addition, due to the characteristics of high solubility and low volatility of cyclohexanone, it can be used as an organic solvent, that is, non-amide-use cyclohexanone. In addition, cyclohexanone also has a wide range of applications in the pharmaceutical field, anti-aging agents, etc.; for example, drug intermediates such as temarone and caramiphen are prepared by reacting cyclohexanone with cyanoacetic acid and then processed.

[0003] There are mainly three production methods of cyclohexanone: cyclohexane oxidation method, cyclohexene hydration method, and phenol hydrogenation method.

[0004] The cyclohexane oxidation method has been gradually phased out due to its very low single-pass conversion rate, resulting in high energy consumption and serious environmental pollution.

[0005] The cyclohexene hydration method has attracted much attention due to its environmental friendliness. However, its process is long, the production energy consumption is high, and a large amount of cyclohexane is produced as a by-product.

[0006] The production of cyclohexanone by the phenol hydrogenation method has attracted much attention due to its simple production process, short process, and the best product quality. Summary of the Invention

[0007] The purpose of the present invention is to provide a device for preparing cyclohexanone by hydrogenating phenol with a simple process.

[0008] The technical solution of the present invention is as follows:

[0009] An apparatus for producing cyclohexanone by hydrogenating phenol mainly consists of a hydrogen buffer tank, a phenol preheater, a phenol vaporizer, a hydrogen heat exchanger, a crude alcohol-ketone buffer tank, a gas condenser, a crude alcohol-ketone cooler, a tail gas condenser, a phenol hydrogenation reactor, a second hydrogen buffer tank, and a hydrogen recycle compressor. The outlet of the hydrogen buffer tank is connected to the hydrogen heat exchanger, and the cold-side outlet of the hydrogen heat exchanger is connected to the phenol vaporizer; the cold-side outlet of the phenol preheater is connected to the phenol vaporizer, the outlet of the phenol vaporizer is connected to the phenol hydrogenation reactor, the outlet of the phenol hydrogenation reactor is connected to the hot-side inlet of the phenol preheater, the hot-side outlet of the phenol preheater is connected to the hydrogen heat exchanger, and the hot-side liquid phase outlet of the hydrogen heat exchanger is connected to the crude alcohol-ketone buffer tank; the hot-side gas phase outlet of the hydrogen heat exchanger is connected to the gas condenser, the liquid phase outlet of the gas condenser is connected to the crude alcohol-ketone buffer tank, the gas phase outlet of the gas condenser is connected to the tail gas condenser, the liquid phase outlet of the tail gas condenser is connected to the crude alcohol-ketone buffer tank, the gas phase outlet of the gas condenser is connected to the second hydrogen buffer tank, the outlet of the second hydrogen buffer tank is connected to the hydrogen recycle compressor, and the outlet of the hydrogen recycle compressor is connected to the hydrogen buffer tank. The outlet of the crude alcohol-ketone buffer tank is connected to the crude alcohol-ketone cooler.

[0010] The hydrogen buffer tank is provided with a hydrogen interface from an external pipe and a hydrogen interface from cyclohexanol dehydrogenation.

[0011] The phenol preheater is provided with a phenol feed inlet, and phenol from the battery limit enters the phenol preheater.

[0012] The phenol hydrogenation reactor can be a fixed-bed reactor, preferably a shell-and-tube fixed-bed reactor.

[0013] The second hydrogen buffer tank is provided with a hydrogen outlet connected to a hydrogen production device.

[0014] The phenol vaporizer integrates phenol vaporization and feed heating, and functions to vaporize phenol and heat the feed.

[0015] The advantages of the present utility model are as follows:

[0016] 1) The phenol preheater is connected to the outlet of the phenol hydrogenation reactor, so that the heat of the reaction product is fully utilized to preheat phenol.

[0017] 2) The hot-side outlet of the phenol preheater is connected to the hydrogen heat exchanger, which further cools the reaction product and exchanges heat with hydrogen at the same time, saving the steam required for heating hydrogen.

[0018] 3) The hydrogen heat exchanger realizes the functions of heat exchange and separation, separates hydrogen from alcohol-ketone, and reduces the equipment required for separating hydrogen from the reaction product.

[0019] 4) The phenol vaporizer integrates phenol vaporization and feed superheater, functions to vaporize phenol and superheat the feed, optimizes the process flow, reduces the number of equipment units, and lowers the energy consumption. Brief Description of the Drawings

[0020] Figure 1 Schematic diagram of the device for producing cyclohexanone by hydrogenation of phenol according to the present utility model

[0021] In the figure: V-101 - hydrogen buffer tank, V-103 - crude alcohol-ketone buffer tank, V-110 - second hydrogen buffer tank, E-101 - phenol preheater, E-102 - phenol vaporizer, E-103 - hydrogen heat exchanger, E-104 - gas condenser, E-105 - tail gas condenser, E-106 - crude alcohol-ketone cooler, R-101 - phenol hydrogenation reactor, K-101 - hydrogen circulation compressor

[0022] SL - steam, RW - chilled water, CW - circulating water. Detailed Embodiments

[0023] The present invention will be further described below in conjunction with the drawings, but it does not limit the present invention.

[0024] For the device for producing cyclohexanone by hydrogenation of phenol, the outlet of the hydrogen buffer tank is connected to the hydrogen heat exchanger, and the cold-side outlet of the hydrogen heat exchanger is connected to the phenol vaporizer; the cold-side outlet of the phenol preheater is connected to the phenol vaporizer, the outlet of the phenol vaporizer is connected to the phenol hydrogenation reactor, the outlet of the phenol hydrogenation reactor is connected to the hot-side inlet of the phenol preheater, the hot-side outlet of the phenol preheater is connected to the hydrogen heat exchanger, and the hot-side liquid phase outlet of the hydrogen heat exchanger is connected to the crude alcohol-ketone buffer tank; the hot-side gas phase outlet of the hydrogen heat exchanger is connected to the gas condenser, the liquid phase outlet of the gas condenser is connected to the crude alcohol-ketone buffer tank, the gas phase outlet of the gas condenser is connected to the tail gas condenser, the liquid phase outlet of the tail gas condenser is connected to the crude alcohol-ketone buffer tank, the gas phase outlet of the gas condenser is connected to the second hydrogen buffer tank, the outlet of the second hydrogen buffer tank is connected to the hydrogen circulation compressor, the outlet of the hydrogen circulation compressor is connected to the hydrogen buffer tank, and the outlet of the crude alcohol-ketone buffer tank is connected to the crude alcohol-ketone cooler.

[0025] Example 1:

[0026] (1) The raw material phenol is heat-exchanged with the phenol hydrogenation reaction product through the phenol preheater, heated to 120 - 140 °C and then sent to the phenol vaporizer. In the phenol vaporizer, the pressure at the top of the phenol vaporizer is controlled to be 0.2 - 0.25 MPaG. Under the dual action of the phenol hydrogen partial pressure and steam heating, phenol is vaporized into a gas and mixed with hydrogen, and then sent to the upper-feed superheating facility of the phenol vaporizer. In the feed superheating facility, the gas mixture composed of phenol and hydrogen is superheated to 175 - 195 °C and activated, and then sent to the phenol hydrogenation reactor. The molar ratio of phenol to hydrogen in the gas mixture entering the hydrogenation reactor is controlled to be 1:2 - 1:6;

[0027] (2)Control the reaction temperature of the phenol hydrogenation reactor at 180 - 195 °C and the pressure at 0.1 - 0.2 MPaG. In the hydrogenation reactor, phenol is hydrogenated to cyclohexanone, and by-products cyclohexanol are also produced. The hydrogenation reactor is a shell-and-tube fixed-bed isothermal reactor, and the shell-and-tube fixed-bed isothermal reactor is filled with TYPE355 catalyst (catalyst supplier: JOHNSON MATTHEY). The phenol hydrogenation reactor is cooled with boiler feed water to maintain isothermal conditions and generates saturated steam at 0.2 - 0.3 MPaG, which is used to control the temperature in the phenol hydrogenation reactor at 190 °C.

[0028] (3)Feed the hydrogenation reaction product from the bottom of the phenol hydrogenation reactor into the phenol preheater to exchange heat with the feed phenol. After heat exchange, the reaction product enters the hydrogen heat exchanger to exchange heat with the feed hydrogen. The heated hydrogen is sent to the phenol vaporizer. In the hydrogen heat exchanger, hydrogen in the reaction product is separated from the alcohol and ketone. The gas phase enters the gas condenser, and the liquid phase enters the crude alcohol and ketone buffer tank.

[0029] (4)In the gas condenser, further condense the gas with circulating water until the temperature reaches 80 - 100 °C. The liquid phase is discharged to the crude alcohol and ketone buffer tank, and the gas phase continues to enter the tail gas cooler for further cooling to 50 - 60 °C. The liquid phase of the tail gas cooler is discharged to the crude alcohol and ketone buffer tank, and the gas phase is discharged to the second hydrogen buffer tank and then recycled through the hydrogen circulation compressor.

[0030] (5)The alcohol and ketone in the crude alcohol and ketone buffer tank are cooled by the crude alcohol and ketone cooler and then sent to the refining process for refining and separation to obtain cyclohexanone and cyclohexanol. Cyclohexanol is dehydrogenated to obtain cyclohexanone.

[0031] Due to the cascaded recovery of the heat of the phenol hydrogenation reaction product, it is first used for phenol preheating and then exchanges heat with the feed hydrogen, recovering the heat and saving 30 - 40% of the heating steam consumption.

[0032] At the same time, the feed superheater and the phenol vaporizer are set as an integrated device, reducing the process, saving energy consumption, and saving investment.

[0033] The above is only the preferred embodiment of the technology of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. An apparatus for the hydrogenation of phenol to cyclohexanone, mainly composed of a hydrogen buffer tank, a phenol preheater, a phenol vaporizer, a hydrogen heat exchanger, a crude alcohol-ketone buffer tank, a gas condenser, a crude alcohol-ketone cooler, a tail gas condenser, a phenol hydrogenation reactor, a second hydrogen buffer tank, and a hydrogen circulation compressor. The outlet of the hydrogen buffer tank is connected to the hydrogen heat exchanger, and the cold-side outlet of the hydrogen heat exchanger is connected to the phenol vaporizer; the cold-side outlet of the phenol preheater is connected to the phenol vaporizer, the outlet of the phenol vaporizer is connected to the phenol hydrogenation reactor, the outlet of the phenol hydrogenation reactor is connected to the hot-side inlet of the phenol preheater, the hot-side outlet of the phenol preheater is connected to the hydrogen heat exchanger, and the hot-side liquid phase outlet of the hydrogen heat exchanger is connected to the crude alcohol-ketone buffer tank; the hot-side gas phase outlet of the hydrogen heat exchanger is connected to the gas condenser, the liquid phase outlet of the gas condenser is connected to the crude alcohol-ketone buffer tank, the gas phase outlet of the gas condenser is connected to the tail gas condenser, the liquid phase outlet of the tail gas condenser is connected to the crude alcohol-ketone buffer tank, the gas phase outlet of the gas condenser is connected to the second hydrogen buffer tank, the outlet of the second hydrogen buffer tank is connected to the hydrogen circulation compressor, the outlet of the hydrogen circulation compressor is connected to the hydrogen buffer tank, and the outlet of the crude alcohol-ketone buffer tank is connected to the crude alcohol-ketone cooler, and it is characterized in that The outlet of the phenol hydrogenation reactor is connected to the inlet of the hot side of the phenol preheater, and the outlet of the hot side of the phenol preheater is connected to the hydrogen heat exchanger.

2. The device for preparing cyclohexanone by hydrogenating phenol according to claim 1, wherein The hydrogen buffer tank is provided with a hydrogen interface from the outer pipe and a hydrogen interface from cyclohexanol dehydrogenation.

3. The device for preparing cyclohexanone by hydrogenating phenol according to claim 1, characterized in that The phenol preheater is provided with a phenol feed inlet, and phenol from the battery limit enters the phenol preheater.

4. The device for preparing cyclohexanone by hydrogenating phenol according to claim 1, characterized in that The phenol hydrogenation reactor is a fixed-bed reactor.

5. The device for preparing cyclohexanone by hydrogenating phenol according to claim 1, wherein The second hydrogen buffer tank is provided with a hydrogen outlet connected to the hydrogen production unit.

6. The device for preparing cyclohexanone by hydrogenating phenol according to claim 1, characterized in that The phenol vaporizer integrates phenol vaporization and feed superheater.

7. The device for producing cyclohexanone by hydrogenating phenol according to claim 4, wherein The fixed-bed reactor is a shell-and-tube fixed-bed reactor.

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