Cyclohexanone ammoximation membrane filtration system

Abstract

A cyclohexanone ammoximation membrane filtration system comprises a heterogeneous ammoximation reaction kettle and a cross-flow membrane filter, the upper end and the lower end of the reaction kettle are communicated with a tube pass of the cross-flow membrane filter through a first pipeline, a shell pass of the cross-flow membrane filter is communicated with an extraction tower through a second pipeline, and a kettle liquid circulating pump is mounted on the first pipeline; and a clear liquid discharging stop valve, a clear liquid flowmeter and a clear liquid regulating valve are mounted on the second pipeline. The utility model solves the problems of large discharge amount of clear liquid, membrane pollution, membrane blockage and catalyst leakage and loss in the prior art.

Description

Technical Field

[0001] This utility model relates to the field of chemical production, and in particular to a membrane filtration system used in the ammoniation process of cyclohexanone for the production of caprolactam. Background Technology

[0002] The cyclohexanone ammoniation reaction is a crucial step in the production of caprolactam. Currently, a homogeneous system using tert-butanol as the solvent is primarily employed. The resulting cyclohexanone oxime (or simply oxime) is mixed with tert-butanol, water, etc., and then the catalyst is separated through a cross-flow membrane filter or a dead-end membrane filter for subsequent treatment of the reaction solution. However, this process suffers from problems such as large quantities of clarified liquid, membrane fouling, membrane blockage, and catalyst leakage, which seriously affect the stable and safe operation of the plant. Utility Model Content

[0003] The purpose of this invention is to provide a cyclohexanone ammonium oxime membrane filtration system to solve the problems of large output volume of clarified liquid, membrane fouling, membrane blockage, and catalyst leakage and loss in the existing process.

[0004] To solve the above problems, the technical solution of this utility model is as follows:

[0005] A cyclohexanone ammonium oxime membrane filtration system includes a heterogeneous ammonium oxime reactor and a cross-flow membrane filter. The upper and lower ends of the reactor are connected to the tube side of the cross-flow membrane filter through a first pipe, and the shell side of the cross-flow membrane filter is connected to an extraction tower through a second pipe. A reactor liquid circulation pump is installed on the first pipe, and a clear liquid discharge shut-off valve, a clear liquid flow meter, and a clear liquid regulating valve are installed on the second pipe.

[0006] Furthermore, it also includes a regeneration tank, which is connected to one side of the cross-flow membrane filter via a third pipe, on which a regeneration pump is installed.

[0007] Furthermore, the second pipeline is connected to the backflushing liquid source via a fourth pipeline, and a backflushing shut-off valve is installed on the fourth pipeline.

[0008] Furthermore, a feed pressure gauge and a discharge pressure gauge are installed on the first pipe and the second pipe, respectively.

[0009] Furthermore, a fifth pipe is connected to the first pipe of the reactor liquid circulation pump connected to the cross-flow membrane filter, and a drain valve is installed on the fifth pipe.

[0010] Furthermore, a jacket is provided outside the reactor, with the upper and lower ends of the jacket connected to the air inlet pipe and the exhaust pipe, respectively.

[0011] Furthermore, a pressure-reducing pipe is connected to the top of the reactor to the condenser, and a pressure-reducing valve is installed on the pressure-reducing pipe.

[0012] The beneficial effects of this utility model are as follows:

[0013] 1. Cross-flow membrane filters can simultaneously meet the effluent and oxime requirements of the reaction system, thereby eliminating the need for existing cyclone separation and alkane oxime security filtration systems, simplifying the process flow and equipment of the catalyst filtration system, and reducing the difficulty of operation and equipment investment costs.

[0014] 2. By alternating between high-temperature hot water and high-temperature oxime water as backwashing media, and maintaining high-pressure backwashing with medium-pressure nitrogen, the backwashing effect is greatly improved, the operating cycle of the cross-flow membrane filter is further extended, and production stability is enhanced. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings:

[0016] Figure 1 This is a schematic diagram of the structure of this utility model.

[0017] In the diagram: 1. Adsorption tank; 2. Condensation tank; 3. Pressure reducing valve; 4. Reactor; 5. Regeneration tank; 6. Cross-flow membrane filter; 7. Discharge pressure gauge; 8. Clear liquid flow meter; 9. Reactor liquid circulation pump; 10. Regeneration pump; 11. Feed pressure gauge; 12. Hot water tank; 13. Oxime water clear liquid tank; 14. Extraction tower; 15. Drain valve; 16. Jacket. Detailed Implementation

[0018] 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.

[0019] A cyclohexanone ammonium oxime membrane filtration system includes a heterogeneous ammonium oxime reaction vessel 4 and a cross-flow membrane filter 6. The upper and lower ends of the reaction vessel 4 are connected to the tube side of the cross-flow membrane filter 6 through a first pipe, and the shell side of the cross-flow membrane filter 6 is connected to an extraction tower 14 through a second pipe. A vessel liquid circulation pump 9 is installed on the first pipe, and a clear liquid discharge shut-off valve, a clear liquid flow meter 8, and a clear liquid regulating valve are installed on the second pipe.

[0020] Furthermore, it also includes a regeneration tank 5, which is connected to the side of the cross-flow membrane filter 6 via a third pipe, on which a regeneration pump 10 is installed. After the cross-flow membrane filter 6 is shut off by a valve, the regeneration pump 10 is started, forming a circulation with the heterogeneous ammonium oxime reactor 4 to promote the regeneration of cyclohexanone oxime.

[0021] Furthermore, the second pipeline is connected to the backwash liquid source via a fourth pipeline, and a backwash shut-off valve is installed on the fourth pipeline. The backwash liquid source includes a hot water tank 12 and an oxime water tank 13. The hot water tank 12 and the oxime water tank 13 are respectively connected to the fourth pipeline via flushing pipes, and electric valves are installed on the flushing pipes. The hot water tank and the oxime water tank are connected to a medium-pressure nitrogen tank. During implementation, the two electric valves are opened and closed alternately, powered by medium-pressure nitrogen, to drive the hot water and oxime water to backwash the cross-flow membrane filter 6, greatly improving the backwashing effect and extending the operating cycle of the cross-flow membrane filter 6.

[0022] Furthermore, a feed pressure gauge 11 and a discharge pressure gauge 7 are respectively installed on the first and second pipes. The pressure difference obtained by the feed pressure gauge 11 and the discharge pressure gauge 7 is used to determine the clogging status of the cross-flow membrane filter 6. Clogging can be used to determine whether the cross-flow membrane filter 6 needs backwashing and whether the cross-flow membrane filter 6 is damaged.

[0023] Furthermore, a fifth pipe is connected to the first pipe of the cross-flow membrane filter 6 connected to the circulating pump 9, and a drain valve 15 is installed on the fifth pipe. In the event of a system malfunction, the drain valve 15 is opened, the circulating pump is started, and the circulating pump discharges the residual liquid of the system into a designated container for storage.

[0024] Furthermore, a jacket 16 is provided outside the reactor 4, with an inlet pipe and an outlet pipe connected to the upper and lower ends of the jacket 16, respectively. During implementation, steam is supplied to the jacket 16 through the inlet pipe and the outlet pipe to maintain the reaction temperature at 92~95℃.

[0025] Furthermore, a pressure-reducing pipe connects the top of the reactor 4 to the condenser 2 and the adsorption tank 1 in sequence, and a pressure-reducing valve 3 is installed on the pressure-reducing pipe. When the pressure exceeds 0.8 MPa, the pressure-reducing valve 3 automatically opens, and the waste gas enters the condenser 2, where the organic matter is condensed into liquid and recovered through cooling. Excess waste gas then enters the activated carbon adsorption tank for adsorption and is discharged.

[0026] The working process of this invention is as follows: The reaction liquid (temperature control range 92~95℃, pressure ~0.8MPa) from the heterogeneous ammonia oxime reaction vessel 4 enters the tube side of the cross-flow membrane filter 6. The flow velocity at the membrane surface is controlled to be no less than 6m / s. Under the thrust of the transmembrane pressure difference, the oxime water permeates through the cross-flow membrane filter layer to the outside of the membrane, while the catalyst is intercepted inside the membrane and circulates back to the reaction vessel 4 with the reaction liquid. The reaction liquid circulates continuously, and the water and reaction product cyclohexanone are continuously removed from the reaction system through the cross-flow membrane filter 6, achieving a balance and stability of the concentrations of water and cyclohexanone oxime in the reaction system. The cross-flow membrane filter 6 is designed with a backwashing system and an online regeneration system for regeneration after the cross-flow membrane filter 6 is removed.

[0027] The embodiments described in this specification are merely examples of implementations of the inventive concept. The scope of protection of this utility model should not be considered as limited to the specific forms described in the embodiments. The scope of protection of this utility model also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims

1. A cyclohexanone ammonium oxime membrane filtration system, characterized in that: It includes a heterogeneous ammonium oxime reaction vessel and a cross-flow membrane filter. The upper and lower ends of the reaction vessel are connected to the tube side of the cross-flow membrane filter through a first pipe, and the shell side of the cross-flow membrane filter is connected to the extraction tower through a second pipe. A vessel liquid circulation pump is installed on the first pipe, and a clear liquid discharge shut-off valve, a clear liquid flow meter, and a clear liquid regulating valve are installed on the second pipe.

2. The cyclohexanone ammonium oxime membrane filtration system according to claim 1, characterized in that: It also includes a regeneration tank, which is connected to one side of the cross-flow membrane filter via a third pipe, on which a regeneration pump is installed.

3. The cyclohexanone ammonium oxime membrane filtration system according to claim 1, characterized in that: The second pipeline is connected to the backflushing liquid source via the fourth pipeline, and a backflushing shut-off valve is installed on the fourth pipeline.

4. A cyclohexanone ammonium oxime membrane filtration system according to any one of claims 1 to 3, characterized in that: A feed pressure gauge and a discharge pressure gauge are installed on the first pipe and the second pipe, respectively.

5. A cyclohexanone ammonium oxime membrane filtration system according to any one of claims 1 to 3, characterized in that: A fifth pipe is connected to the first pipe of the reactor liquid circulation pump and the cross-flow membrane filter, and a drain valve is installed on the fifth pipe.

6. A cyclohexanone ammonium oxime membrane filtration system according to any one of claims 1 to 3, characterized in that: A jacket is provided outside the reactor, with the upper and lower ends of the jacket connected to the air inlet pipe and the air outlet pipe, respectively.

7. A cyclohexanone ammonium oxime membrane filtration system according to any one of claims 1 to 3, characterized in that: The top of the reactor is connected to the condenser and the adsorption tank in sequence through a pressure reducing pipe, and a pressure reducing valve is installed on the pressure reducing pipe.

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