Device for refining crude benzene by using reaction heat

By using cyclohexanone amoximetization reaction heat or cyclohexanone oxime rearrangement reaction heat for crude benzene refining, the problem of unused reaction heat in the prior art is solved, and energy saving and consumption reduction in the benzene refining process is achieved, and production costs are reduced.

CN222788461UActive Publication Date: 2025-04-25HUNAN BAILI ENGINEERING SCIENCE AND TECHNOLOGY CO LTD
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Patent Information

Application Number
CN202421351117.X
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-06-13
Publication Date
2025-04-25
Estimated Expiration
2034-06-13

AI Technical Summary

Technical Problem

In the prior art, the reaction heat in the production process of caprolactam cannot be effectively utilized, resulting in high energy consumption and problems of steam consumption and cooling water consumption during the purification of crude benzene.

Method used

The crude benzene is refined by cyclohexanone amoximetization reaction heat or cyclohexanone oxime rearrangement reaction heat, and the reaction heat is used for the isoximetization reaction or rearrangement reaction of benzene through a circulation heater to achieve heat reuse.

Benefits of technology

It reduces steam consumption and cooling water consumption during benzene refining, achieves energy saving, reduces production and operation costs, and improves economic benefits and competitiveness.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model relates to a device for refining crude benzene by using reaction heat, which mainly comprises a cyclohexanone ammoximation reactor or a cyclohexanone oxime rearrangement reactor, a benzene distillation tower, a circulating heater, a benzene steam condenser, a refined benzene cooler, a benzene steam post-condenser, a refined benzene tank, a vacuum pump, pipelines and valves. And extracting reaction heat. According to the utility model, the steam consumption for benzene refining is saved, the consumption of cooling water required for removing reaction heat is reduced, and the aim of saving energy is fulfilled.
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Description

Technical Field

[0001] The utility model belongs to the technical field of caprolactam production, and relates to a device for using cyclohexanone ammoximation reaction heat or cyclohexanone oxime rearrangement reaction heat for crude benzene refining. Background Art

[0002] Caprolactam (abbreviated as CPL) is a basic organic chemical raw material for the production of nylon 6 fiber and nylon 6 engineering plastics. At present, the mainstream production process of caprolactam is to adopt cyclohexanone ammoximation method (cyclohexanone→cyclohexanone oxime) and Beckmann liquid phase rearrangement technology (cyclohexanone oxime→caprolactam); the cyclohexanone ammoximation method is a process in which cyclohexanone, ammonia and hydrogen peroxide are directly reacted to generate cyclohexanone oxime in the presence of tert-butanol as solvent in the presence of a catalyst. Cyclohexanone oxime is subjected to Beckmann liquid phase rearrangement to generate crude caprolactam, and the crude caprolactam is refined to obtain the caprolactam product.

[0003] Both the cyclohexanone ammoximation reaction and the Beckmann rearrangement reaction are highly exothermic reactions. Literature reports that the heat of cyclohexanone ammoximation reaction is 300 kJ / mol oxime, and the heat of Beckmann rearrangement reaction is 188 kJ / mol oxime. Comprehensive utilization of the reaction heat has important economic significance for energy conservation and consumption reduction, as well as carbon emission reduction.

[0004] The extractant crude benzene in the caprolactam production process needs to be refined. Using the heat of cyclohexanone ammoximation reaction or cyclohexanone oxime rearrangement reaction to purify crude benzene can reduce energy consumption. Utility Model Content

[0005] The purpose of the present invention is to utilize the heat of cyclohexanone ammoximation reaction or the heat of cyclohexanone oxime rearrangement reaction for crude benzene refining, and to provide a device for using the reaction heat for crude benzene refining.

[0006] Technical solution of the present invention

[0007] A device for using the heat of cyclohexanone ammoximation reaction for crude benzene refining mainly comprises a cyclohexanone ammoximation reactor, a benzene distillation tower, a circulation heater, a benzene steam condenser, a refined benzene cooler, a benzene steam post-condenser, a refined benzene tank, a vacuum pump, pipelines and valves.

[0008] The bottom of the benzene distillation tower is connected to the inlet of the circulation pump, the outlet of the circulation pump is connected to the cold side inlet of the circulation heater, the cold side outlet of the circulation heater is connected to the lower part of the benzene distillation tower, the hot side inlet of the circulation heater is connected to the circulating liquid outlet of the cyclohexanone ammoximation reactor, the hot side outlet of the circulation heater is connected to the inlet of the cyclohexanone ammoximation reactor, the gas phase outlet at the top of the benzene distillation tower is connected to the benzene steam condenser, and the bottom of the benzene distillation tower is also connected to the residual liquid delivery pump;

[0009] The gas phase outlet of the benzene steam condenser is connected to the benzene steam after-condenser, the liquid phase outlet is connected to the crude benzene cooler, and the gas phase outlet of the benzene steam after-condenser is connected to the vacuum pump; the liquid phase outlet of the crude benzene cooler is connected to the refined benzene tank, the gas phase outlet of the crude benzene cooler is connected to the inlet of the benzene steam after-condenser, and the outlet of the refined benzene tank is connected to the inlet of the refined benzene delivery pump.

[0010] A device for using the heat of cyclohexanone oxime rearrangement reaction for crude benzene refining mainly comprises a cyclohexanone oxime rearrangement reactor, a benzene distillation tower, a circulation heater, a benzene steam condenser, a refined benzene cooler, a benzene steam post-condenser, a refined benzene tank, a vacuum pump, pipelines and valves.

[0011] The bottom of the benzene distillation tower is connected to the inlet of the circulation pump, the outlet of the circulation pump is connected to the cold side inlet of the circulation heater, the cold side outlet of the circulation heater is connected to the lower part of the benzene distillation tower, the hot side inlet of the circulation heater is connected to the circulating liquid outlet of the cyclohexanone oxime rearrangement reactor, the hot side outlet of the circulation heater is connected to the inlet of the cyclohexanone oxime rearrangement reactor, the gas phase outlet at the top of the benzene distillation tower is connected to the benzene steam condenser, and the bottom of the benzene distillation tower is also connected to the residual liquid delivery pump;

[0012] The gas phase outlet of the benzene steam condenser is connected to the benzene steam after-condenser, the liquid phase outlet is connected to the crude benzene cooler, and the gas phase outlet of the benzene steam after-condenser is connected to the vacuum pump; the liquid phase outlet of the crude benzene cooler is connected to the refined benzene tank, the gas phase outlet of the crude benzene cooler is connected to the inlet of the benzene steam after-condenser, and the outlet of the refined benzene tank is connected to the inlet of the refined benzene delivery pump.

[0013] The benzene distillation tower is a plate tower or a packed tower, and the operating pressure of the benzene distillation tower is about 10-101 kPa (absolute pressure).

[0014] The circulation heater adopts a plate heat exchanger or a fixed tube plate heat exchanger.

[0015] The circulation heater is arranged in a vertical or horizontal manner.

[0016] Beneficial effects of the utility model

[0017] The utility model utilizes the heat of cyclohexanone ammoximation reaction or cyclohexanone oxime rearrangement reaction to purify crude benzene, and the circulating benzene directly exchanges heat with the ammoximation reaction circulating liquid or rearrangement circulating liquid to extract the reaction heat. The steam consumption of benzene refining is saved, the consumption of cooling water required for reaction heat removal is reduced, the purpose of energy saving is achieved, and thus the economic benefits and competitiveness are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of a device for using reaction heat to purify crude benzene

[0019] In the figure: 1-benzene distillation tower, 2-circulation heater, 3-benzene steam condenser, 4-refined benzene cooler, 5-benzene steam post-condenser, 6-refined benzene tank, 7-residue delivery pump, 8-circulation pump, 9-refined benzene delivery pump, 10-vacuum pump.

[0020] In the figure: A-crude benzene, B-refined benzene, C-reaction circulating liquid, D-reaction circulating liquid, E-benzene evaporation residue, F-non-condensable gas, G-circulating water, H-chilled water. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings, but is not intended to limit the present invention.

[0022] The device for using the heat of cyclohexanone ammoximation reaction for crude benzene refining is mainly composed of a cyclohexanone ammoximation reactor, a benzene distillation tower, a circulation heater, a benzene steam condenser, a refined benzene cooler, a benzene steam post-condenser, a refined benzene tank, a vacuum pump, pipelines and valves.

[0023] The bottom of the benzene distillation tower is connected to the inlet of the circulation pump, the outlet of the circulation pump is connected to the cold side inlet of the circulation heater, the cold side outlet of the circulation heater is connected to the lower part of the benzene distillation tower, the hot side inlet of the circulation heater is connected to the circulating liquid outlet of the cyclohexanone ammoximation reactor, the outlet of the circulation heater is connected to the cyclohexanone ammoximation reactor, the gas phase outlet at the top of the benzene distillation tower is connected to the benzene steam condenser, and the bottom of the benzene distillation tower is also connected to the residual liquid delivery pump;

[0024] The gas phase outlet of the benzene steam condenser is connected to the benzene steam after-condenser, the liquid phase outlet is connected to the crude benzene cooler, and the gas phase outlet of the benzene steam after-condenser is connected to the vacuum pump; the liquid phase outlet of the crude benzene cooler is connected to the refined benzene tank, the gas phase outlet of the crude benzene cooler is connected to the inlet of the benzene steam after-condenser, and the outlet of the refined benzene tank is connected to the inlet of the refined benzene delivery pump.

[0025] The device for using the heat of cyclohexanone oxime rearrangement reaction for crude benzene refining is mainly composed of a cyclohexanone oxime rearrangement reactor, a benzene distillation tower, a circulation heater, a benzene steam condenser, a refined benzene cooler, a benzene steam post-condenser, a refined benzene tank, a vacuum pump, pipelines and valves.

[0026] The bottom of the benzene distillation tower is connected to the inlet of the circulation pump, the outlet of the circulation pump is connected to the cold side inlet of the circulation heater, the cold side outlet of the circulation heater is connected to the lower part of the benzene distillation tower, the hot side inlet of the circulation heater is connected to the circulating liquid outlet of the cyclohexanone oxime rearrangement reactor, the outlet of the circulation heater is connected to the cyclohexanone oxime rearrangement reactor, the gas phase outlet at the top of the benzene distillation tower is connected to the benzene steam condenser, and the bottom of the benzene distillation tower is also connected to the residual liquid delivery pump;

[0027] The gas phase outlet of the benzene steam condenser is connected to the benzene steam after-condenser, the liquid phase outlet is connected to the crude benzene cooler, and the gas phase outlet of the benzene steam after-condenser is connected to the vacuum pump; the liquid phase outlet of the crude benzene cooler is connected to the refined benzene tank, the gas phase outlet of the crude benzene cooler is connected to the inlet of the benzene steam after-condenser, and the outlet of the refined benzene tank is connected to the inlet of the refined benzene delivery pump.

[0028] Example 1

[0029] The utility model adopts a negative pressure benzene distillation system with an operating pressure of 35kPa (absolute pressure). After being pressurized by a pump, 80t / h crude benzene is sent to the kettle of the benzene distillation tower, mixed with the kettle liquid and transported to the circulating heater by a circulating pump. After heat exchange with the ammonia oximation reaction circulating liquid, the circulating benzene temperature is increased from 52°C to 70°C, and enters the benzene distillation tower for flash evaporation. The top benzene vapor is cooled by a condenser and a cooler to obtain refined benzene, which is transported to the caprolactam extraction process as an extractant by a pump. The heavy components in the crude benzene are left in the kettle and are pressurized and transported to the downstream process for treatment by a residual liquid delivery pump.

[0030] The utility model does not consume steam, and the cooling water consumption of the specifications of 0.5MPa.G, 32℃ circulating water supply, 0.35MPa.G, 40℃ circulating return water is 1020t / h; the chilled water consumption of the specifications of 0.5MPa.G, 7℃ chilled water supply, 0.35MPa.G, 12℃ chilled water return is 60t / h; the circulating pump and vacuum pump consume 168.5kW of low-voltage power with specifications of 380V, 50Hz.

[0031] The existing process for refining crude benzene adopts a double-effect evaporation process. The heat of the cyclohexanone ammoximation reaction is taken out through circulating water cooling. The steam consumption at a specification of 0.5MPa.G and 160°C is 7.5t / h; the cooling water consumption at a specification of 0.5MPa.G and 32°C circulating water supply and 0.35MPa.G and 40°C circulating return water is 950t / h. The existing process does not require a circulating pump or a vacuum pump.

[0032]

[0033] Note: Electricity consumption of circulation pump and vacuum pump is calculated only for the difference between the two.

[0034]

[0035] Note: Steam is calculated based on the average market price of 150 yuan / ton; circulating water is calculated based on the average market price of 0.15 yuan / ton; chilled water is calculated based on the average market price of 0.3 yuan / ton; electricity is calculated based on the average market price of 0.6 yuan / kWh; one year is calculated based on 8,000 hours.

[0036] The production and operation cost of the existing process is 10.14 million yuan per year; the production and operation cost of the utility model is 2.1768 million yuan per year. It can be seen that the utility model can save 7.9632 million yuan per year in operating costs.

[0037] Example 2

[0038] The utility model adopts a negative pressure benzene distillation system with an operating pressure of 35kPa (absolute pressure). After being pressurized by a pump, 55t / h crude benzene is sent to the kettle of the benzene distillation tower, mixed with the kettle liquid and then transported to the circulating heater by a circulating pump. After heat exchange with the cyclohexanone oxime rearrangement reaction circulating liquid, the circulating benzene temperature is increased from 55°C to 73°C, and then enters the benzene distillation tower for flash evaporation. The top benzene vapor is cooled by a condenser and a cooler to obtain refined benzene, which is transported to the caprolactam extraction process as an extractant by a pump. The heavy components in the crude benzene are left in the kettle and are pressurized and transported to the downstream process for treatment by a residual liquid delivery pump.

[0039] The utility model does not consume steam, and the cooling water consumption of the specifications of 0.5MPa.G, 32℃ circulating water supply, 0.35MPa.G, 40℃ circulating return water is 702t / h; the chilled water consumption of the specifications of 0.5MPa.G, 7℃ chilled water supply, 0.35MPa.G, 12℃ chilled water return is 40t / h; the circulating pump and the vacuum pump consume 93.5kW of low-voltage electricity with specifications of 380V, 50Hz.

[0040] The existing process for refining crude benzene adopts a double-effect evaporation process. The heat of the cyclohexanone oxime rearrangement reaction is taken out through circulating water cooling. The specification is 0.5MPa.G, and the steam consumption at 160℃ is 5.2t / h; the specification is 0.5MPa.G, 32℃ circulating water supply, and 0.35MPa.G, 40℃ circulating return water, the cooling water consumption is 655t / h; the existing process does not require a circulating pump and a vacuum pump.

[0041]

[0042]

[0043] Note: Electricity consumption of circulation pump and vacuum pump is calculated only for the difference between the two.

[0044]

[0045] Note: Steam is calculated based on the average market price of 150 yuan / ton; circulating water is calculated based on the average market price of 0.15 yuan / ton; chilled water is calculated based on the average market price of 0.3 yuan / ton; electricity is calculated based on the average market price of 0.6 yuan / kWh; one year is calculated based on 8,000 hours.

[0046] The existing process has an annual production cost of 7.026 million yuan, while the utility model has an annual production cost of 1.3872 million yuan. It can be seen that the utility model can save 5.6388 million yuan in operating costs per year.

[0047] The above is only a preferred implementation of the technology of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A device for using reaction heat for crude benzene refining, mainly composed of a cyclohexanone ammoximation reactor, a benzene distillation tower, a circulation heater, a benzene steam condenser, a refined benzene cooler, a benzene steam post-condenser, a refined benzene tank, a vacuum pump, pipelines and valves; The bottom of the benzene distillation tower is connected to the inlet of the circulation pump, the outlet of the circulation pump is connected to the inlet of the cold side of the circulation heater, the outlet of the cold side of the circulation heater is connected to the lower part of the benzene distillation tower, the inlet of the hot side of the circulation heater is connected to the circulating liquid outlet of the cyclohexanone ammoximation reactor, the outlet of the circulation heater is connected to the cyclohexanone ammoximation reactor, the gas phase outlet at the top of the benzene distillation tower is connected to the benzene steam condenser, and the bottom of the benzene distillation tower is also connected to the residual liquid delivery pump; the gas phase outlet of the benzene steam condenser is connected to the benzene steam post-condenser, the liquid phase outlet is connected to the crude benzene cooler, and the gas phase outlet of the benzene steam post-condenser is connected to the vacuum pump; the liquid phase outlet of the crude benzene cooler is connected to the refined benzene tank, the gas phase outlet of the crude benzene cooler is connected to the inlet of the benzene steam post-condenser, and the outlet of the refined benzene tank is connected to the inlet of the refined benzene delivery pump; Features: The hot side inlet of the circulation heater is connected to the circulating liquid outlet of the cyclohexanone ammoximation reactor, and the hot side outlet of the circulation heater is connected to the inlet of the cyclohexanone ammoximation reactor.

2. A device for using reaction heat for crude benzene refining, mainly consisting of a cyclohexanone oxime rearrangement reactor, a benzene distillation tower, a circulation heater, a benzene steam condenser, a refined benzene cooler, a benzene steam post-condenser, a refined benzene tank, a vacuum pump, pipelines and valves; The bottom of the benzene distillation tower is connected to the inlet of the circulation pump, the outlet of the circulation pump is connected to the inlet of the cold side of the circulation heater, the outlet of the cold side of the circulation heater is connected to the lower part of the benzene distillation tower, the inlet of the hot side of the circulation heater is connected to the circulating liquid outlet of the cyclohexanone oxime rearrangement reactor, the outlet of the circulation heater is connected to the cyclohexanone oxime rearrangement reactor, the gas phase outlet at the top of the benzene distillation tower is connected to the benzene steam condenser, and the bottom of the benzene distillation tower is also connected to the residual liquid delivery pump; the gas phase outlet of the benzene steam condenser is connected to the benzene steam post-condenser, the liquid phase outlet is connected to the crude benzene cooler, and the gas phase outlet of the benzene steam post-condenser is connected to the vacuum pump; the liquid phase outlet of the crude benzene cooler is connected to the refined benzene tank, the gas phase outlet of the crude benzene cooler is connected to the inlet of the benzene steam post-condenser, and the outlet of the refined benzene tank is connected to the inlet of the refined benzene delivery pump; Features: The hot side inlet of the circulation heater is connected to the circulating liquid outlet of the cyclohexanone oxime rearrangement reactor, and the hot side outlet of the circulation heater is connected to the inlet of the cyclohexanone oxime rearrangement reactor.

3. The device for using the reaction heat for crude benzene refining according to claim 1 or 2, characterized in that The benzene distillation tower adopts a plate tower or a packed tower.

4. The device for using the reaction heat for crude benzene refining according to claim 1 or 2, characterized in that The circulation heater adopts a plate heat exchanger or a fixed tube plate heat exchanger.

5. The device for using the reaction heat for crude benzene refining according to claim 1 or 2, characterized in that The circulation heater is arranged in a vertical or horizontal manner.