CN218741894U - Production system for preparing benzene by low-temperature and low-pressure dehydrogenation of cyclohexane - Google Patents

Abstract

The utility model provides a production system for preparing benzene by low-temperature and low-pressure cyclohexane dehydrogenation, which comprises a cyclohexane feeding pipe, wherein the cyclohexane feeding pipe is sequentially connected with a cyclohexane preheater, a cyclohexane evaporator and a reaction feeding heat exchanger, the reaction feeding heat exchanger is connected to an upper feeding port of a cyclohexane dehydrogenation reactor, and the bottom of the cyclohexane dehydrogenation reactor is sequentially connected with the reaction feeding heat exchanger, the cyclohexane preheater and a reaction material condenser through pipelines; the reaction material condenser is connected with the gas-liquid separator; the upper end of the gas-liquid separator is connected to a hydrogen compressor through a hydrogen deep cooler; the lower end of the gas-liquid separator is connected to the middle part of the heavy component removal rectifying tower through a heavy component removal tower feeding pump. The utility model discloses can turn into benzene and hydrogen with the byproduct cyclohexane of cyclohexanone device through dehydrogenation, make it obtain effective utilization, realize raw materials and product closed loop circulation in the device, reach the purpose of green, environmental protection, high efficiency, energy-conservation, no waste production, reduce the outsourcing of raw materials benzene and supporting hydrogen plant's production running cost simultaneously.

Description

Production system for preparing benzene by low-temperature and low-pressure dehydrogenation of cyclohexane

[ technical field ] A method for producing a semiconductor device

The utility model relates to a chemicals production technology technical field, concretely relates to production system of low temperature low pressure cyclohexane dehydrogenation preparation benzene.

[ background of the invention ]

Cyclohexane is mainly from a production device for preparing cyclohexanone by a hydration method, and the main production flow is to produce the cyclohexanone by the reactions of raw material benzene hydrogenation, cyclohexene hydration, cyclohexanol dehydrogenation and the like. 20-25% of byproduct cyclohexane is generated in the production process of cyclohexanone by a hydration method, so that the effective utilization rate of the raw material benzene can only reach 75-80%.

[ Utility model ] content

The to-be-solved technical problem of the utility model lies in providing a production system of low temperature low pressure cyclohexane dehydrogenation preparation benzene, can turn into benzene and hydrogen through dehydrogenation by-product cyclohexane of cyclohexanone device, benzene and hydrogen recirculation get back to the cyclohexanone device as the raw materials then, make by-product cyclohexane obtain effective utilization, realize raw materials and product closed loop circulation in the device, reach green, environmental protection, high efficiency, energy-conservation, the purpose that no waste produced, reduce the production running cost of purchasing outward and supporting hydrogen plant of raw materials benzene simultaneously.

The utility model discloses a realize like this:

a production system for preparing benzene by low-temperature and low-pressure cyclohexane dehydrogenation comprises a feed and discharge thermal coupling heat exchange system, a dehydrogenation reaction system, a hydrogen separation and compression system, a de-heavy distillation and separation system and a hot oil heating system;

the discharging thermal coupling heat exchange system comprises a cyclohexane preheater, a cyclohexane evaporator, a reaction feeding heat exchanger and a reaction material condenser; the dehydrogenation reaction system comprises a cyclohexane dehydrogenation reactor; the hydrogen separation and compression system comprises a gas-liquid separator, a hydrogen deep cooler and a hydrogen compressor; the de-heavy distillation separation system comprises a de-heavy tower feed pump and a de-heavy distillation tower; the hot oil heating system comprises a heat conduction oil heating furnace and a heat conduction oil circulating pump;

a cyclohexane feeding pipe is sequentially connected with the cyclohexane preheater, the cyclohexane evaporator and the reaction feeding heat exchanger, the reaction feeding heat exchanger is connected to a feeding port above the cyclohexane dehydrogenation reactor, and the bottom of the cyclohexane dehydrogenation reactor is sequentially connected with the reaction feeding heat exchanger, the cyclohexane preheater and the reaction material condenser through pipelines, so that the raw material and the reaction product are subjected to heat exchange in the discharging thermal coupling heat exchange system;

the reaction material condenser is connected with the gas-liquid separator; the upper end of the gas-liquid separator is connected to the hydrogen compressor through a hydrogen deep cooler; the lower end of the gas-liquid separator is connected to the middle part of the de-heavy rectifying tower through the de-heavy tower feed pump;

the lower end of the cyclohexane dehydrogenation reactor is also connected with the heat-conducting oil heating furnace through a heat-conducting oil circulating pump, and the outlet of the heat-conducting oil heating furnace is connected to the upper end of the cyclohexane dehydrogenation reactor.

The utility model has the advantages that:

1. the utility model discloses can turn into benzene and hydrogen through dehydrogenation by-product cyclohexane of cyclohexanone device, benzene and hydrogen recycle get back to the cyclohexanone device as the raw materials then, make by-product cyclohexane effectively utilize, realize raw materials and product closed loop circulation in the device, reach green, environmental protection, high efficiency, energy-conservation, the purpose that no waste produced, reduce the production running cost of purchasing and supporting hydrogen plant outward of raw materials benzene simultaneously. The main products of benzene and hydrogen can be returned to a cyclohexanone device for use through a cyclohexane dehydrogenation and dehydrogenation reaction system, so that the problem of the raw materials of benzene and hydrogen is solved; the byproduct hydrogen can be pumped into a hydrogenation station under pressure, and is applied to hydrogen energy vehicles and the like, so that additional economic benefit is generated.

2. The utility model discloses a process flow is simple, and the cooperation of each equipment is reasonable, can guarantee that cyclohexane conversion is more than or equal to 90%, and benzene selectivity > 99%, reaction conversion rate is high, can also be with reaction material heat recycle as far as, is the green chemical production technology of an environment-friendly type.

[ description of the drawings ]

The invention will be further described with reference to the following examples with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of the process flow of the production system for preparing benzene by low-temperature and low-pressure dehydrogenation of cyclohexane.

The numbering in the figure is as follows:

1. a cyclohexane preheater; 2. a cyclohexane evaporator; 3. a reaction feeding heat exchanger, 4, a cyclohexane dehydrogenation reactor; 5. a reaction material condenser; 6. a gas-liquid separator; 7. a hydrogen deep cooler; 8. a hydrogen compressor; 9. a de-weighting tower feed pump; 10. a heavy component removal rectifying tower; 11. a heat conducting oil heating furnace; 12. a heat transfer oil circulating pump; 13. cyclohexane is fed into the tube.

[ detailed description ] embodiments

The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings and the detailed description. In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected" and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 1, the system for producing benzene by dehydrogenation of cyclohexane at low temperature and low pressure of the present invention comprises a thermal coupling heat exchange system for feeding and discharging materials, a dehydrogenation reaction system, a hydrogen separation and compression system, a de-heavy distillation and separation system, and a hot oil heating system;

the discharging thermal coupling heat exchange system comprises a cyclohexane preheater 1, a cyclohexane evaporator 2, a reaction feeding heat exchanger 3 and a reaction material condenser 5; the dehydrogenation reaction system comprises a cyclohexane dehydrogenation reactor 4; the hydrogen separation and compression system comprises a gas-liquid separator 6, a hydrogen deep cooler 7 and a hydrogen compressor 8; the de-heavy distillation separation system comprises a de-heavy column feed pump 9 and a de-heavy distillation column 10; the hot oil heating system comprises a heat conduction oil heating furnace 11 and a heat conduction oil circulating pump 12;

a cyclohexane feeding pipe 13 is sequentially connected with the cyclohexane preheater 1, the cyclohexane evaporator 2 and the reaction feeding heat exchanger 3, the reaction feeding heat exchanger 3 is connected to a feeding port above the cyclohexane dehydrogenation reactor 4, and the bottom of the cyclohexane dehydrogenation reactor 4 is sequentially connected with the reaction feeding heat exchanger 3, the cyclohexane preheater 1 and the reaction material condenser 5 through pipelines, so that the raw material and the reaction product are subjected to heat exchange in the discharging thermal coupling heat exchange system;

the reaction material condenser 5 is connected with the gas-liquid separator 6; the upper end of the gas-liquid separator 6 is connected to the hydrogen compressor 8 through a hydrogen deep cooler 7; the lower end of the gas-liquid separator 6 is connected to the middle part of the heavy component removal rectifying tower 10 through the heavy component removal tower feed pump 9;

the lower end of the cyclohexane dehydrogenation reactor 4 is also connected with the heat conduction oil heating furnace 11 through a heat conduction oil circulating pump 12, and an outlet of the heat conduction oil heating furnace 11 is connected to the upper end of the cyclohexane dehydrogenation reactor 4.

In an embodiment of the present invention, the working process of each system is as follows:

feeding and discharging thermal coupling heat exchange system: the system comprises a cyclohexane preheater 1, a cyclohexane evaporator 2, a reaction feeding heat exchanger 3 and a reaction material condenser 5, and is used for recycling the heat of the reaction materials as much as possible; the raw material enters from a cyclohexane feeding pipe 13, is heated by a cyclohexane preheater 1, then enters a cyclohexane evaporator 2 to ensure that the cyclohexane is completely evaporated into a gas phase (150-180 ℃), enters a reaction feeding heat exchanger 3 to exchange heat with a reaction product from an outlet of a cyclohexane dehydrogenation reactor 4, and cyclohexane steam is heated to a reaction temperature. The reaction product from the cyclohexane dehydrogenation reactor 4 is subjected to gradual heat exchange and temperature reduction through the reaction feeding heat exchanger 3 and the cyclohexane preheater 1, the heat of the reaction product is recycled as much as possible, and finally the temperature is reduced to the normal temperature through the reaction material condenser 5.

A dehydrogenation reaction system: comprises a cyclohexane dehydrogenation reactor 4, which is used for dehydrogenation reaction of cyclohexane to generate benzene and hydrogen; controlling the reaction pressure at 10-100 kpa G and the reaction temperature at 240-320 ℃ in a cyclohexane dehydrogenation reactor 4, so that cyclohexane is subjected to dehydrogenation reaction under the catalytic action of a platinum catalyst to generate benzene and hydrogen; under the condition, the conversion rate of cyclohexane is more than or equal to 90 percent, and the selectivity of benzene is more than 99 percent.

Hot oil heating system: the heat conduction oil heating device comprises a heat conduction oil heating furnace 11 and a heat conduction oil circulating pump 12, and is used for providing heat required by the dehydrogenation reaction of cyclohexane; the heat conducting oil system is a set of closed cycle system, the heat conducting oil in the cyclohexane dehydrogenation reactor 4 is pumped out through a heat conducting oil circulating pump 12, heated by a heat conducting oil heating furnace 11 and then returned to the cyclohexane dehydrogenation reactor 4 for heating the cyclohexane in the cyclohexane dehydrogenation reactor 4. The dehydrogenation of cyclohexane is a strong endothermic reaction, and the heat required by the reaction is provided by the system so as to ensure the smooth operation of the dehydrogenation reaction.

Hydrogen separation compression system: the system comprises a gas-liquid separator 6, a hydrogen deep cooler 7 and a hydrogen compressor 8, and is used for effectively separating hydrogen and benzene generated by reaction; the reaction material is cooled to normal temperature by a reaction material condenser 5, and then separated into gas and liquid phases in a gas-liquid separator 6. Wherein, the hydrogen is recycled as much as possible from the organic materials carried by the hydrogen through a hydrogen deep cooler 7, and is pressurized to a proper pressure through a hydrogen compressor 8 to be sent to hydrogen purification or a hydrogen pipe network for delivery; and the liquid phase part enters a de-heavy rectification separation system.

A heavy component removal, rectification and separation system: comprises a de-heavy column feed pump 9 and a de-heavy rectifying column 10, which are used for rectifying, separating and removing polymers and the like in the side reaction of cyclohexane dehydrogenation, and liquid phase material benzene collected by a gas-liquid separator 6 is sent to the middle part of the de-heavy rectifying column 10 through the de-heavy column feed pump 9; then the heavy components such as side reaction polymers in the reaction material benzene are removed through the separation of a heavy component removal rectifying tower 10, the final product benzene extracted from the tower top is sent to a raw material benzene storage tank, and the heavy components are intermittently extracted from the tower bottom.

The utility model has the advantages that:

1. the utility model discloses can turn into benzene and hydrogen through dehydrogenation by-product cyclohexane of cyclohexanone device, benzene and hydrogen recycle get back to the cyclohexanone device as the raw materials then, make by-product cyclohexane effectively utilize, realize raw materials and product closed loop circulation in the device, reach green, environmental protection, high efficiency, energy-conservation, the purpose that no waste produced, reduce the production running cost of purchasing and supporting hydrogen plant outward of raw materials benzene simultaneously. The main products of benzene and hydrogen can be returned to the cyclohexanone device for use by the cyclohexane dehydrogenation and dehydrogenation reaction system, so that the problem of the raw materials of benzene and hydrogen is solved; the byproduct hydrogen can be pumped into a hydrogenation station under pressure, and is applied to hydrogen energy vehicles and the like, so that additional economic benefit is generated.

2. The utility model discloses a process flow is simple, and the cooperation of each equipment is reasonable, can guarantee that cyclohexane conversion is more than or equal to 90%, and benzene selectivity > 99%, reaction conversion rate is high, can also be with reaction material heat recycle as far as, is the green chemical production technology of an environment-friendly type.

Although specific embodiments of the present invention have been described, it will be understood by those skilled in the art that the specific embodiments described are illustrative only and are not limiting upon the scope of the invention, and that equivalent modifications and variations can be made by those skilled in the art without departing from the spirit of the invention, which is to be limited only by the claims appended hereto.

Claims (1)

1. A production system for preparing benzene by low-temperature and low-pressure cyclohexane dehydrogenation is characterized in that: the system comprises a thermal coupling heat exchange system for feeding and discharging materials, a dehydrogenation reaction system, a hydrogen separation and compression system, a de-heavy rectification and separation system and a hot oil heating system;

the discharge thermal coupling heat exchange system comprises a cyclohexane preheater, a cyclohexane evaporator, a reaction feed heat exchanger and a reaction material condenser; the dehydrogenation reaction system comprises a cyclohexane dehydrogenation reactor; the hydrogen separation and compression system comprises a gas-liquid separator, a hydrogen deep cooler and a hydrogen compressor; the de-heavy distillation separation system comprises a de-heavy tower feed pump and a de-heavy distillation tower; the hot oil heating system comprises a heat conduction oil heating furnace and a heat conduction oil circulating pump;

a cyclohexane feeding pipe is sequentially connected with the cyclohexane preheater, the cyclohexane evaporator and the reaction feeding heat exchanger, the reaction feeding heat exchanger is connected to a feeding port above the cyclohexane dehydrogenation reactor, and the bottom of the cyclohexane dehydrogenation reactor is sequentially connected with the reaction feeding heat exchanger, the cyclohexane preheater and the reaction material condenser through pipelines, so that the raw material and the reaction product are subjected to heat exchange in the discharging thermal coupling heat exchange system;

the reaction material condenser is connected with the gas-liquid separator; the upper end of the gas-liquid separator is connected to the hydrogen compressor through a hydrogen deep cooler; the lower end of the gas-liquid separator is connected to the middle part of the de-heavy rectifying tower through the de-heavy tower feed pump;

the lower end of the cyclohexane dehydrogenation reactor is also connected with the heat-conducting oil heating furnace through a heat-conducting oil circulating pump, and the outlet of the heat-conducting oil heating furnace is connected to the upper end of the cyclohexane dehydrogenation reactor.

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