A production device for coupling ammonia-containing gas to perform ammonium sulfate neutralization reaction

Abstract

The utility model belongs to a kind of production device for coupling ammonia-containing gas to carry out ammonium sulfate neutralization reaction;Including oximation reactor, the import of oximation reactor is connected with cyclohexanone tank, hydrogen peroxide storage tank, solvent tank and catalyst tank respectively, the liquid phase of oximation reactor is connected with solvent extraction column, the gas phase outlet of solvent extraction column is connected with water extraction tower, the liquid phase outlet of water extraction tower is connected with ammonia desorption tower, the gas phase outlet of ammonia desorption tower is connected with neutralization reaction kettle;Liquid ammonia storage tank is connected with first three-way by liquid ammonia vaporizer, first three-way is connected with oximation reactor and neutralization reaction kettle respectively, the tail gas outlet of oximation reactor and neutralization reaction kettle is connected with tail gas treatment unit respectively;Coarse rearrangement liquid tank is connected with the import of neutralization reaction kettle, the caprolactam outlet on neutralization reaction kettle is connected with caprolactam refining system;The liquid phase outlet of neutralization reaction kettle is connected with ammonium sulfate treatment system;It has the characteristics of reducing ammonia usage and sewage treatment difficulty.

Description

Technical Field

[0001] This utility model belongs to the field of caprolactam production technology, and in particular relates to a production device that couples an ammonia-containing gas to carry out an ammonium sulfate neutralization reaction. Background Technology

[0002] Caprolactam is produced from cyclohexanone oxime via the Beckmann rearrangement. Currently, there are two rearrangement technologies: gas-phase rearrangement and liquid-phase rearrangement. The liquid-phase rearrangement process is mature and stable, and the capacity of a single unit is much greater than that of the gas-phase method. At present, there are no gas-phase rearrangement units in China, and all use the liquid-phase rearrangement process. However, the liquid-phase Beckmann rearrangement process uses nicotinic acid as a catalyst, and after the reaction, ammonia is needed to neutralize the by-product ammonium sulfate. This step consumes a large amount of liquid ammonia, resulting in high production costs for caprolactam.

[0003] Therefore, how to reduce the consumption of liquid ammonia in the above-mentioned processes has become an urgent technical problem to be solved. Utility Model Content

[0004] To overcome the above deficiencies, this utility model provides a production apparatus that couples ammonia-containing gas to carry out an ammonium sulfate neutralization reaction, thereby solving the technical problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A production apparatus for coupling ammonia-containing gas to perform an ammonium sulfate neutralization reaction includes an oxime reactor. The inlet of the oxime reactor is connected to a cyclohexanone tank, a hydrogen peroxide storage tank, a solvent tank, and a catalyst tank. The liquid phase of the oxime reactor is connected to a solvent extraction tower, the gas phase outlet of the solvent extraction tower is connected to a water extraction tower, the liquid phase outlet of the water extraction tower is connected to an ammonia desorption tower, and the gas phase outlet of the ammonia desorption tower is connected to a neutralization reactor. A liquid ammonia storage tank is connected to a first three-way valve via a liquid ammonia vaporizer. The second end of the first three-way valve is connected to the oxime reactor, and the third end of the first three-way valve is connected to the neutralization reactor. The tail gas outlets of the oxime reactor and the neutralization reactor are respectively connected to a tail gas treatment unit. A coarse heavy liquid discharge tank is connected to the inlet of the neutralization reactor, and the caprolactam outlet on the neutralization reactor is connected to a caprolactam refining system. The liquid phase outlet of the neutralization reactor is connected to an ammonium sulfate treatment system.

[0006] The beneficial effects of this utility model are as follows: This utility model changes the traditional liquid ammonia feed to gaseous ammonia feed, thereby reducing the consumption of demineralized water in the system and reducing the amount of wastewater produced and discharged in the system. On this basis, by setting up an ammonia desorption tower to desorb the waste liquid produced in the system, the desorbed ammonia gas enters the neutralization reaction vessel for neutralization, thereby reducing the amount of ammonia used and the difficulty of sewage treatment.

[0007] Preferably, the exhaust gas treatment unit includes a scrubbing tower, the gas phase outlet of which is connected to a water scrubbing tower, and the gas phase outlet of which is connected to a gas venting pipeline; the gas phase outlet of the oxime reactor is connected to the inlet of the scrubbing tower, and the gas phase outlet of the neutralization reactor is connected to the inlet of the water scrubbing tower; the scrubbing tower and the solvent extraction tower are respectively connected to the extractant tank via a second three-way valve.

[0008] Preferably, the liquid phase outlet of the washing tower is connected to the circulation inlet of the oxime reactor.

[0009] Preferably, the upper part of the water washing tower is provided with a demineralized water supply pipe with a valve, and the liquid phase outlet of the water washing tower is connected to the inlet of the ammonia desorption tower.

[0010] Preferably, the liquid phase outlet of the solvent extraction tower is connected to the extractant recovery system.

[0011] Preferably, the waste liquid outlet of the ammonia desorption tower is connected to the waste liquid circulation unit. The waste liquid circulation unit includes a fourth three-way valve connected to the waste liquid outlet. The second end of the fourth three-way valve is connected to the wastewater tank, and the third end of the fourth three-way valve is connected to the circulation inlet of the water washing tower through a circulating water washing tank and a circulating water washing pump.

[0012] Preferably, a third tee is provided between the circulating water washing pump and the circulating inlet of the water washing tower, and the third end of the third tee is connected to the circulating inlet of the water extraction tower.

[0013] Preferably, the circulation outlet at the bottom of the ammonia desorption tower is connected to the circulation inlet in the middle of the ammonia desorption tower via the desorption tower reboiler.

[0014] Preferably, the gas phase outlet of the water extraction tower is connected to the gas phase inlet of the oxime reactor.

[0015] This utility model has the following advantages: 1. This utility model replaces the traditional liquid ammonia feed with gaseous ammonia feed, thereby reducing the consumption of demineralized water in the system and reducing the amount of wastewater produced and discharged by the system.

[0016] 2. This utility model uses an ammonia desorption tower to desorb the waste liquid produced in the system. The desorbed ammonia gas then enters a neutralization reactor for neutralization, thereby reducing the amount of ammonia used and the difficulty of wastewater treatment.

[0017] 3. In this invention, the gas phase after water extraction in the water extraction tower enters the oximation reactor for further reaction, which can improve the utilization rate of raw materials. Furthermore, the extractant enters the washing tower to recover the organic raw materials from the tail gas in the oximation reactor, and the recovered materials are reintroduced into the autooximation reactor, thereby achieving the characteristic of improving the utilization rate of raw materials.

[0018] 4. This utility model constructs a waste liquid recycling unit, which can desorb ammonia in waste liquid and allow the desorbed ammonia to enter the neutralization reaction vessel, thereby reducing the amount of liquid ammonia used in the liquid ammonia storage tank; at the same time, it uses waste liquid to recover ammonia, avoiding the waste of resources caused by ammonia being discharged through tail gas; that is, the waste liquid recycling unit can effectively recover ammonia from tail gas and waste liquid using waste liquid as a carrier, which can not only save the amount of ammonia used, but also reduce the environmental pollution caused by high ammonia content in discharged waste gas and waste liquid. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model.

[0020] Legend: 1. Liquid ammonia tank; 2. Liquid ammonia vaporizer; 3. Cyclohexanone tank; 4. Hydrogen peroxide tank; 5. Solvent tank; 6. Catalyst tank; 7. Extractant tank; 8. Oxime reactor; 9. Solvent extraction tower; 10. Water extraction tower; 11. Extractant recovery system; 12. Ammonia desorption tower; 13. Neutralization reactor; 14. Scrubbing tower; 15. Water washing tower; 16. Coarse heavy liquid discharge tank; 17. Ammonium sulfate treatment system; 18. Wastewater tank; 19. Circulating water washing tank; 20. First tee; 21. Second tee; 22. Third tee; 23. Fourth tee; 24. Circulating water washing pump; 25. Desorption tower reboiler; 26. Caprolactam purification system; 27. Gas venting pipeline; 28. Demineralized water replenishment pipeline. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] Reference Figure 1This invention relates to a production apparatus for a coupled ammonia-containing gas-based ammonium sulfate neutralization reaction, comprising an oxime reactor 8. The inlet of the oxime reactor 8 is connected to a cyclohexanone tank 3, a hydrogen peroxide storage tank 4, a solvent tank 5, and a catalyst tank 6. The liquid phase of the oxime reactor 8 is connected to a solvent extraction tower 9, the gas phase outlet of the solvent extraction tower 9 is connected to a water extraction tower 10, the liquid phase outlet of the water extraction tower 10 is connected to an ammonia desorption tower 12, and the gas phase outlet of the ammonia desorption tower 12 is connected to a neutralization reactor 13. A liquid ammonia storage tank is also included. 1. The liquid ammonia vaporizer 2 is connected to the first three-way valve 20. The second end of the first three-way valve 20 is connected to the oxime reactor 8. The third end of the first three-way valve 20 is connected to the neutralization reactor 13. The tail gas outlets of the oxime reactor 8 and the neutralization reactor 13 are respectively connected to the tail gas treatment unit. The coarse heavy liquid discharge tank 16 is connected to the inlet of the neutralization reactor 13. The caprolactam outlet on the neutralization reactor 13 is connected to the caprolactam refining system 26. The liquid phase outlet of the neutralization reactor 13 is connected to the ammonium sulfate treatment system 17. In this invention, the raw material liquid ammonia from the liquid ammonia storage tank 1 enters the liquid ammonia vaporizer 2. After vaporization, the gaseous ammonia is transported through the first three-way valve 20 to the oxime reactor 8 and the neutralization reactor 13, respectively. Cyclohexanone from the cyclohexanone tank 3, hydrogen peroxide from the hydrogen peroxide tank 4, and catalyst from the catalyst tank 6 are transported through corresponding pipelines into the oxime reactor 8 for oxime reaction. The crude cyclohexanone oxime solution after oxime reaction enters the solvent extraction tower 9 for extraction. The extracted gas phase enters the water extraction tower 10. The ammonia-containing solution at the bottom of the water extraction tower 10 enters the ammonia desorption tower 12. The desorbed ammonia gas enters the neutralization reactor... In the neutralization reactor 13, the sulfuric acid-containing heavy discharge liquid in the coarse heavy discharge tank 16 enters the neutralization reactor 13 through a pipeline. The crude ammonium sulfate from the bottom of the neutralization reactor 13 enters the ammonium sulfate treatment system 17. The unreacted ammonia gas from the top of the neutralization reactor 13 enters the tail gas treatment unit. The separated caprolactam enters the caprolactam refining system 26. In the above process, the use of gaseous ammonia feed instead of traditional liquid ammonia can reduce the consumption of demineralized water and the amount of wastewater generated and discharged from the system. Furthermore, gaseous ammonia from the liquid ammonia vaporizer 2 and the ammonia desorption tower 12 can be used in the neutralization reactor 13 to achieve the characteristic of saving ammonia consumption.

[0023] Furthermore, the exhaust gas treatment unit includes a scrubbing tower 14, the gas phase outlet of which is connected to a water scrubbing tower 15, and the gas phase outlet of the water scrubbing tower 15 is connected to a gas exhaust pipe 27; the gas phase outlet of the oxime reactor 8 is connected to the inlet of the scrubbing tower 14, and the gas phase outlet of the neutralization reactor 13 is connected to the inlet of the water scrubbing tower 15; the scrubbing tower 14 and the solvent extraction tower 9 are respectively connected to the extractant tank 7 via a second three-way valve 21. The exhaust gas in this invention mainly comes from the oxime reactor 8 and the neutralization reactor 13. By setting up the scrubbing tower 14, organic matter in the exhaust gas from the oxime reactor 8 can be recovered, and the water scrubbing tower 15 can recover unreacted ammonia from the oxime reactor 8 and the neutralization reactor 13. This setup improves the utilization rate of raw materials and avoids environmental pollution.

[0024] Furthermore, the liquid phase outlet of the washing tower 14 is connected to the circulation inlet of the oxime reactor 8. This arrangement enables the recovery of organic matter before it enters the oxime reactor 8, thereby improving the utilization rate of raw materials.

[0025] Furthermore, the upper part of the water washing tower 15 is equipped with a demineralized water inlet pipe 28 with a valve, and the liquid phase outlet of the water washing tower 15 is connected to the inlet of the ammonia desorption tower 12. This arrangement enables the recovery and reuse of ammonia within the water washing tower 15, improving ammonia utilization while avoiding environmental pollution.

[0026] Furthermore, the liquid phase outlet of the solvent extraction tower 9 is connected to the extractant recovery system 11.

[0027] Furthermore, the waste liquid outlet of the ammonia desorption tower 12 is connected to a waste liquid circulation unit. The waste liquid circulation unit includes a fourth three-way valve 23 connected to the waste liquid outlet. The second end of the fourth three-way valve 23 is connected to the wastewater tank 18, and the third end of the fourth three-way valve 23 is connected to the circulation inlet of the water washing tower 15 via a circulating water washing tank 19 and a circulating water washing pump 24. By setting up the waste liquid circulation unit, the waste liquid can be recycled, reducing the consumption of demineralized water and the amount of wastewater produced and discharged. Simultaneously, in conjunction with the ammonia desorption tower 12, it enables the full recovery of ammonia from the tail gas and waste liquid, thereby reducing ammonia usage and the difficulty of subsequent wastewater and waste gas treatment.

[0028] Furthermore, a third tee 22 is provided between the circulating water washing pump 24 and the circulating inlet of the water washing tower 15, and the third end of the third tee 22 is connected to the circulating inlet of the water extraction tower 10.

[0029] Furthermore, the circulation outlet at the bottom of the ammonia desorption tower 12 is connected to the circulation inlet in the middle of the ammonia desorption tower 12 via the desorption tower reboiler 25.

[0030] Furthermore, the gas phase outlet of the water extraction tower 10 is connected to the gas phase inlet of the oxime reactor 8.

[0031] The reaction principle of this invention is as follows: Its reaction principle: (1) Oxime reaction: NH3 + H2O2 + C6H 10 O (cyclohexanone) → C6H 10 NOH (cyclohexanone oxime) + 2H₂O + Q; (2) Ammonia dissolves in water: 2NH3 + H2O → 2NH4OH; (3) Synthesis of ammonium sulfate: 2NH3 + H2SO4 → (NH4)2SO 4。

[0032] The working principle of this utility model is as follows: In this utility model, the raw material liquid ammonia from the liquid ammonia storage tank 1 enters the liquid ammonia vaporizer 2. After the liquid ammonia is vaporized by the liquid ammonia vaporizer 2, the gaseous ammonia is transported to the oxime reactor 8 and the neutralization reaction vessel 13 through the first three-way valve 20 respectively. Cyclohexanone from the cyclohexanone tank 3, hydrogen peroxide from the hydrogen peroxide tank 4, and catalyst from the catalyst tank 6 are respectively transported into the oxime reactor 8 through corresponding pipelines for oxime reaction. The operating temperature of the oxime reactor 8 is 70~90℃, and its operating pressure is 0.1~1. The crude cyclohexanone oxime solution after the oxime reaction enters solvent extraction tower 9 for extraction. The operating temperature of solvent extraction tower 9 is 40~90℃, and the operating pressure is 0.02~1.0MPa. The bottom liquid of solvent extraction tower 9 is collected and sent to extractant recovery system 11 for recovery. The extracted gas phase enters water extraction tower 10 for water extraction. The operating temperature of water extraction tower 10 is 40~70℃, and the operating pressure is 0.01~0.3MPa. The gas phase of water extraction tower 10 is returned to oxime reactor 8, and water... The ammonia-containing solution at the bottom of extraction tower 10 enters ammonia desorption tower 12. The operating temperature of ammonia desorption tower 12 is 600~750℃, and the operating pressure is 0.01~0.2MPa. The aqueous solution at the bottom of ammonia desorption tower 12 is intermittently discharged to wastewater tank 18 according to the operating conditions and water quality of the unit. The desorbed ammonia gas enters neutralization reactor 13. The sulfuric acid-containing heavy discharge liquid in crude heavy discharge tank 16 enters neutralization reactor 13 through a pipeline. The crude ammonium sulfate at the bottom of neutralization reactor 13 enters ammonium sulfate treatment system 17. Neutralization reactor 13... Unreacted ammonia enters the tail gas treatment unit, and the separated caprolactam enters the caprolactam refining system 26. The neutralization reactor 13 operates at a temperature of 50~80℃ and a pressure of 0.01~0.1MPa. The gas phase from the oxime reactor 8 enters the scrubbing tower 14, where it comes into countercurrent contact with the extractant. The organic matter in the gas phase is recovered and then returned to the oxime reactor 8. The scrubbing tower 14 operates at a temperature of 30~50℃ and a pressure of 0.01~0.3MPa. The gas phase in the washing tower 14 and the gas phase in the neutralization reactor 13 both enter the water washing tower 15, where water is used to recover ammonia from the gas phase. The recovered liquid ammonia then enters the ammonia desorption tower 12 for desorption, and the tail gas is discharged through the gas venting pipe 27. In actual use, the ammonia in the ammonia desorption tower 12 can be reused in the circulating water washing tank 19 or sent to the wastewater tank 18 for further treatment, depending on the concentration of the bottom liquid. When reused, the bottom liquid of the ammonia desorption tower 12 enters the circulating water washing tank 19 and is sent to the water extraction tower 10 and the water washing tower 15 by the circulating water washing pump 24 to absorb ammonia. After ammonia absorption, the liquid phase re-enters the ammonia desorption tower 12 for desorption, while the gas phase enters the neutralization reactor 13, and the liquid phase can be circulated.This invention recovers incompletely reacted ammonia from the ammonia oxime reaction process in a caprolactam unit. After absorption and desorption, the ammonia is introduced into a neutralization reactor 13 for neutralization, removing excess sulfuric acid from the rearrangement liquid and achieving the purpose of separating caprolactam. The tail gas of the entire system is discharged in compliance with standards after ammonia removal. This not only solves the environmental protection problem of ammonia-containing tail gas from caprolactam units, but also reduces the consumption of liquid ammonia raw materials in the unit and lowers the production costs of caprolactam production enterprises.

[0033] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A production apparatus for coupling ammonia-containing gas to carry out an ammonium sulfate neutralization reaction, comprising an oxime reactor (8), the inlet of which is connected to a cyclohexanone tank (3), a hydrogen peroxide storage tank (4), a solvent tank (5), and a catalyst tank (6), characterized in that: The liquid phase of the oxime reactor (8) is connected to the solvent extraction tower (9), the gas phase outlet of the solvent extraction tower (9) is connected to the water extraction tower (10), the liquid phase outlet of the water extraction tower (10) is connected to the ammonia desorption tower (12), and the gas phase outlet of the ammonia desorption tower (12) is connected to the neutralization reactor (13). The liquid ammonia storage tank (1) is connected to the first three-way valve (20) via the liquid ammonia vaporizer (2). The second end of the first three-way valve (20) is connected to the oxime reactor (8), and the third end of the first three-way valve (20) is connected to the neutralization reactor (13). The tail gas outlets of the oxime reactor (8) and the neutralization reactor (13) are respectively connected to the tail gas treatment unit; The coarse heavy discharge tank (16) is connected to the inlet of the neutralization reactor (13), and the caprolactam outlet on the neutralization reactor (13) is connected to the caprolactam refining system (26); The liquid phase outlet of the neutralization reactor (13) is connected to the ammonium sulfate treatment system (17).

2. The production apparatus for coupling ammonia-containing gas to carry out ammonium sulfate neutralization reaction according to claim 1, characterized in that: The exhaust gas treatment unit includes a scrubbing tower (14), the gas phase outlet of the scrubbing tower (14) is connected to a water scrubbing tower (15), and the gas phase outlet of the water scrubbing tower (15) is connected to a gas exhaust pipe (27). The gas phase outlet of the oxime reactor (8) is connected to the inlet of the scrubbing tower (14), and the gas phase outlet of the neutralization reactor (13) is connected to the inlet of the water scrubbing tower (15). The washing tower (14) and the solvent extraction tower (9) are connected to the extractant tank (7) via the second tee (21).

3. The production apparatus for coupling ammonia-containing gas to carry out ammonium sulfate neutralization reaction according to claim 2, characterized in that: The liquid phase outlet of the washing tower (14) is connected to the circulation inlet of the oxime reactor (8).

4. The production apparatus for coupling ammonia-containing gas to carry out ammonium sulfate neutralization reaction according to claim 2, characterized in that: The upper part of the water washing tower (15) is provided with a demineralized water supply pipe (28) with a valve, and the liquid phase outlet of the water washing tower (15) is connected to the inlet of the ammonia desorption tower (12).

5. The production apparatus for coupling ammonia-containing gas to carry out ammonium sulfate neutralization reaction according to claim 1, characterized in that: The liquid phase outlet of the solvent extraction tower (9) is connected to the extractant recovery system (11).

6. The production apparatus according to claim 4, which couples an ammonia-containing gas to perform an ammonium sulfate neutralization reaction, is characterized in that: The waste liquid outlet of the ammonia desorption tower (12) is connected to the waste liquid circulation unit. The waste liquid circulation unit includes a fourth three-way valve (23) connected to the waste liquid outlet. The second end of the fourth three-way valve (23) is connected to the waste water tank (18). The third end of the fourth three-way valve (23) is connected to the circulation inlet of the water washing tower (15) through the circulating water washing tank (19) and the circulating water washing pump (24).

7. The production apparatus for coupling ammonia-containing gas to carry out ammonium sulfate neutralization reaction according to claim 6, characterized in that: A third tee (22) is provided between the circulating water washing pump (24) and the circulating inlet of the water washing tower (15), and the third end of the third tee (22) is connected to the circulating inlet of the water extraction tower (10).

8. The production apparatus for coupling ammonia-containing gas to carry out ammonium sulfate neutralization reaction according to claim 1, characterized in that: The circulation outlet at the bottom of the ammonia desorption tower (12) is connected to the circulation inlet in the middle of the ammonia desorption tower (12) through the desorption tower reboiler (25).

9. A production apparatus for coupling ammonia-containing gas to carry out an ammonium sulfate neutralization reaction according to claim 1 or 7, characterized in that: The gas phase outlet of the water extraction tower (10) is connected to the gas phase inlet of the oxime reactor (8).

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