Device for catalyzing cyclohexanone ammoximation reaction by using water system large-aperture silicon-titanium molecular sieve

Abstract

The utility model relates to the technical field of cyclohexanone-oxime, and particularly provides a device for catalyzing cyclohexanone ammoximation reaction by using a water system large-aperture silicon-titanium molecular sieve. The device comprises an oximation reactor, a bottom discharge port of the oximation reactor is connected to a feed port of a cross-flow membrane filter through a pipeline and a circulating pump, a turbid liquid outlet of the cross-flow membrane filter is connected to a feed port of the oximation reactor through a pipeline, and a clear liquid outlet of the cross-flow membrane filter is connected to a cyclohexanone-oxime refining process. A gas ammonia, cyclohexanone and hydrogen peroxide feeding pipe is also arranged on the pipeline between the turbid liquid outlet and the feeding hole of the oximation reactor; the device further comprises a catalyst preparation system, the system is provided with a catalyst storage tank, the catalyst storage tank is connected to a catalyst feeding tank through a catalyst feeding pump, and the catalyst feeding tank is further connected with a desalted water adding pipe and a catalytic promoter adding pipe. And the discharge port of the catalyst feeding tank is connected between the discharge port of the oximation reactor and the feed port of the cross-flow membrane filter through a pipeline. The ammoximation process of a water system can be realized, the reaction quality is improved, and the cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of cyclohexanone oxime production technology, and relates to green catalysis technology, specifically to a device for the amination and oximation reaction of cyclohexanone catalyzed by aqueous large-pore silicon-titanium molecular sieve. Background Technology

[0002] Currently, there are many technologies for preparing cyclohexanone oxime, a key intermediate in caprolactam production, both domestically and internationally. These mainly include the ammoniation method (HAO), the hydroxylamine phosphate method (HPO), the hydroxylamine sulfate method (HSO), the nitric oxide reduction method (NO), the toluene nitrosation method (SNIA), and the cyclohexane photonitrosyl method (PNC), among which HAO and HPO are the mainstream processes.

[0003] The cyclohexanone ammoniation (HAO) reaction first involves the reaction of ammonia, hydrogen peroxide, and cyclohexanone in a homogeneous system with tert-butanol as the solvent. The reaction proceeds under the action of a TS series titanium-silicon molecular sieve catalyst to generate cyclohexanone oxime (hereinafter referred to as oxime). The resulting tert-butanol-oxime solution (hereinafter referred to as tert-butanol oxime) is filtered through a membrane and then enters the subsequent tert-butanol recovery, toluene extraction, and toluene distillation processes as a clear liquid to obtain pure oxime. The pure oxime undergoes a Beckmann rearrangement reaction to generate caprolactam. The main problems with the tert-butanol system include: (1) The large amount of tert-butanol, the circulating solvent, is added to the reactor, resulting in a large filtration volume in the reactor, a larger number of membrane devices and investment, and the membrane is easily fouled and clogged; (2) As a circulating solvent, tert-butanol requires heat energy for distillation and recovery, resulting in high energy consumption; (3) The single reactor (taking an 80m3 reactor as an example) has a small processing capacity, and the input of cyclohexanone is only about 8 tons / hour; (4) The consumption of titanium-silicon molecular sieve catalyst is relatively high; (5) Tert-butanol is a hazardous chemical with flammable and explosive properties, which increases the safety risk of the equipment. Summary of the Invention

[0004] This invention provides an apparatus for the cyclohexanone ammoniation reaction catalyzed by aqueous macroporous titanium-silicon molecular sieves. The apparatus uses an aqueous macroporous titanium-silicon molecular sieve as the catalyst, titanium-silicon additives for catalyst protection, and water or other green and clean solvents as the reaction solvent. The reaction product cyclohexanone oxime and the catalyst are separated by a multi-stage cross-flow membrane filtration integrated separation device, which simplifies the process flow and equipment investment, and improves the production efficiency and intrinsic safety of the apparatus.

[0005] The technical solution of this utility model is to provide an apparatus for the molecular sieve catalytic ammonia oxime reaction of cyclohexanone. The apparatus includes an oxime reactor, the bottom outlet of which is connected to the inlet of a cross-flow membrane filter via a pipeline and a circulating pump. The turbid liquid outlet of the cross-flow membrane filter is connected to the inlet of the oxime reactor via a pipeline, and the clear liquid outlet is connected to the cyclohexanone oxime refining process. The pipeline between the turbid liquid outlet and the inlet of the oxime reactor is also equipped with gaseous ammonia, cyclohexanone, and hydrogen peroxide inlet pipes. The apparatus also includes a catalyst preparation system, which is equipped with a catalyst storage tank, which is connected to a catalyst feeding tank via a catalyst feeding pump. The catalyst feeding tank is also connected to a demineralized water inlet pipe and a catalyst aid inlet pipe. The outlet of the catalyst feeding tank is connected to the outlet of the oxime reactor and the inlet of the cross-flow membrane filter via a pipeline.

[0006] Furthermore, the oxime reactor is also equipped with a nitrogen inlet pipe and a tail gas outlet pipe, the tail gas outlet pipe being connected to a tail gas absorption tower.

[0007] Furthermore, the cross-flow membrane filter is a multi-stage cross-flow membrane filter, and the filter membrane tube is a metal membrane tube, a ceramic membrane tube, or a silicon carbide membrane tube; the permeate outlet pipe of the cross-flow membrane filter is connected to the extraction process.

[0008] Furthermore, the gaseous ammonia, cyclohexanone, and hydrogen peroxide feed pipes are respectively connected to the pipeline between the turbid liquid outlet of the cross-flow membrane filter and the feed inlet of the oxime reactor via a gaseous ammonia feed injector, a cyclohexanone feed injector, and a hydrogen peroxide high-shear mixer.

[0009] Furthermore, a heat exchanger is also installed between the turbid liquid outlet of the cross-flow membrane filter and the ammonia feed pipe.

[0010] Furthermore, the heat exchanger is a reboiler for a benzene distillation column, which is connected to the benzene distillation column.

[0011] Furthermore, the catalyst feeding tank is equipped with a double-layer paddle agitator and a level gauge, and the catalyst feeding tank is connected to the inlet pipe of the circulation pump via a catalyst metering pump.

[0012] Furthermore, both the demineralized water inlet pipe and the catalyst additive inlet pipe of the catalyst feeding tank are equipped with flow meters.

[0013] Furthermore, the oxime reactor is equipped with a double-layer paddle stirrer, and the stirrer is equipped with a frequency converter.

[0014] This utility model has the following beneficial effects:

[0015] The apparatus provided by this invention includes a catalyst preparation system. A water-based, macroporous titanium-silicon molecular sieve is used as the catalyst. Water and a catalytic aid are mixed in a catalyst feeding tank to prepare a mixture, which is then mixed with the material from the oxime reactor. A clear liquid containing water and cyclohexanone oxime is separated in a cross-flow membrane filter. The turbid liquid containing the catalyst is then heated in the reboiler of a benzene distillation column and subsequently mixed with gaseous ammonia, cyclohexanone, and hydrogen peroxide before being returned to the oxime reactor for further reaction. This apparatus can use water as a solvent, and the catalyst can be efficiently recycled back to the oxime reactor. Compared to current mainstream tert-butanol-based cyclohexanone ammoniation oxime catalytic reactors, its process flow is reduced, the equipment is simpler, and the operation difficulty is significantly reduced. Furthermore, the use of a water-based titanium-silicon molecular sieve catalyst results in high activity, long lifespan, and low consumption, improving reaction quality. The addition of a benzene distillation column reboiler after the cross-flow membrane filter enables heat coupling of the reaction. Attached Figure Description

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

[0017] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.

[0018] like Figure 1 As shown, this utility model provides an apparatus for the cyclohexanone ammoniation reaction catalyzed by a water-based large-pore silicon-titanium molecular sieve. The apparatus includes an oxime reactor 1, whose bottom outlet 1-1 is connected to the inlet of a cross-flow membrane filter 3 via a pipeline and a circulating pump 2. The turbid liquid outlet 3-1 of the cross-flow membrane filter is connected to the inlet 1-2 of the oxime reactor via a pipeline, and the clear liquid outlet 3-2 is connected to the cyclohexanone oxime refining process. The pipeline between the turbid liquid outlet and the inlet of the oxime reactor is also equipped with gaseous ammonia, cyclohexanone, and hydrogen peroxide inlet pipes. The apparatus also includes a catalyst preparation system, which is equipped with a catalyst storage tank 4, which is connected to a catalyst feeding tank 6 via a catalyst feeding pump 5. The catalyst feeding tank is also connected to a demineralized water inlet pipe 6-1 and a catalyst aid inlet pipe 6-2. The outlet 6-3 of the catalyst feeding tank is connected between the outlet of the oxime reactor and the inlet of the cross-flow membrane filter via a pipeline.

[0019] In a preferred embodiment, the oxime reactor is further provided with a nitrogen inlet pipe 1-3 and a tail gas outlet pipe 1-4.

[0020] In some embodiments, the cross-flow membrane filter is a multi-stage cross-flow membrane filter, with each stage equipped with a clear liquid discharge pipe. The filter membrane tubes of the cross-flow membrane filter are metal membrane tubes, ceramic membrane tubes, or silicon carbide membrane tubes; the membrane tube pore size is 50nm~3μm, and the membrane tube outer diameter is 15mm~40mm. It exhibits high permeability to cyclohexanone oxime and water, and high interception rate against the water structured titanium-silicon molecular sieve catalyst, directly separating cyclohexanone oxime, water, and catalyst. The cyclohexanone oxime and water are then removed from the reaction system through the clear liquid discharge pipes. The clear liquid discharge pipes of the multi-stage cross-flow membrane filter converge and are sent to the next process, the cyclohexane extraction tower, to separate cyclohexanone oxime and water. In a preferred embodiment, the parameters of the multi-stage cross-flow membrane filter are set as follows: inlet pressure 0.5MPa(G)~0.7MPa(G), and membrane surface velocity 2m / s~8m / s.

[0021] In a preferred embodiment, the feed pipes for gaseous ammonia, cyclohexanone, and hydrogen peroxide are connected to the pipeline between the outlet of the cross-flow membrane filter and the inlet of the oxime reactor via gaseous ammonia feed injector 7, cyclohexanone feed injector 8, and hydrogen peroxide high-shear mixer 9, respectively. The turbid liquid discharged from the multi-stage cross-flow membrane filter is mixed with gaseous ammonia at gaseous ammonia feed injector 7, then mixed with cyclohexanone at cyclohexanone feed injector 8, and finally mixed with hydrogen peroxide at hydrogen peroxide high-shear mixer 9, resulting in the ammoxime reaction of cyclohexanone to produce the product cyclohexanone oxime. The reaction solution then enters the oxime reactor.

[0022] In some embodiments, a heat exchanger is further provided between the turbid liquid outlet of the cross-flow membrane filter and the ammonia feed pipe. Preferably, the heat exchanger is a benzene distillation column reboiler 10, which is connected to the benzene distillation column 11. The turbid liquid from the cross-flow membrane filter exchanges heat with the material from the benzene distillation column reboiler, making full use of the heat.

[0023] In some embodiments, the catalyst feeding tank is equipped with a double-layer paddle stirrer and a level gauge, and the catalyst feeding tank is connected to the inlet pipe of the circulation pump via a catalyst metering pump 12. In some embodiments, both the demineralized water inlet pipe and the catalyst aid inlet pipe of the catalyst feeding tank are equipped with flow meters. In a preferred embodiment, the catalyst feeding pump adds structured large-pore titanium-silicon molecular sieves to the catalyst feeding tank, and adds a certain amount of demineralized water and catalyst aid (an aqueous solution containing silicon compounds) and stirs them evenly to prepare a catalyst solution with a concentration of not less than 1.5% wt. The prepared catalyst solution is then transported to the inlet pipe of the circulation pump of the oxime reactor via the catalyst metering pump.

[0024] In some embodiments, the oxime reactor is equipped with a double-layer paddle stirrer, and the stirrer is equipped with a frequency converter. Preferably, the stirrer's rotation speed is remotely controlled via the frequency converter; the oxime reactor may also be equipped with remote level transmission, remote temperature transmission, and remote pressure transmission, and the circulation pump is equipped with a frequency converter to remotely control the circulation flow rate; the nitrogen inlet pipe of the oxime reactor is equipped with a flow meter, regulating valve, and shut-off valve, etc.

[0025] In a specific embodiment, the raw material ammonia has a purity of 99.95% wt, a temperature of 85°C, and a pressure of 0.8 MPa (G); the raw material cyclohexanone has a purity of 99.95%, a temperature of 45°C, and a pressure of 0.7 MPa (G), with an input rate of 11.25 t / h; the raw material hydrogen peroxide has a concentration of 32.5% wt, a temperature of 28°C, and a pressure of 0.7 MPa (G); the inlet pressure of the multi-stage cross-flow membrane filter is 0.65 MPa (G); the catalyst feed tank is 50% full, and the catalyst concentration is 8%. Production is carried out according to the conditions in Table 1.

[0026] Table 1

[0027]

[0028] When the above parameters are controlled, the conversion rate of cyclohexanone oxime can reach 99.91%, and the selectivity is 99.90%.

[0029] The above embodiments describe preferred embodiments of the present invention, but the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, including combining the various technical features in any other way. These simple modifications and combinations should also be considered as the content disclosed by the present invention and all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent should be determined by the appended claims.

Claims

1. An apparatus for the amination and oxime reaction of cyclohexanone catalyzed by a water-based large-pore silica-titanium molecular sieve, characterized in that: The device includes an oxime reactor, whose bottom outlet is connected to the inlet of a cross-flow membrane filter via a pipeline and a circulating pump. The turbid liquid outlet of the cross-flow membrane filter is connected to the inlet of the oxime reactor via a pipeline, and the clear liquid outlet is connected to the cyclohexanone oxime refining process. The pipeline between the turbid liquid outlet and the inlet of the oxime reactor is also equipped with inlet pipes for gaseous ammonia, cyclohexanone, and hydrogen peroxide. The device also includes a catalyst preparation system, which is equipped with a catalyst storage tank, which is connected to a catalyst feeding tank via a catalyst feeding pump. The catalyst feeding tank is also connected to a demineralized water inlet pipe and a catalyst aid inlet pipe. The outlet of the catalyst feeding tank is connected to the outlet of the oxime reactor and the inlet of the cross-flow membrane filter via a pipeline.

2. The apparatus according to claim 1, characterized in that: The oxime reactor is also equipped with a nitrogen inlet pipe and a tail gas outlet pipe, with the tail gas outlet pipe connected to a tail gas absorption tower.

3. The apparatus according to claim 1, characterized in that: The cross-flow membrane filter is a multi-stage cross-flow membrane filter, and the filter membrane tube is a metal membrane tube, a ceramic membrane tube, or a silicon carbide membrane tube; the permeate outlet tube of the cross-flow membrane filter is connected to the extraction process.

4. The apparatus according to claim 1, characterized in that: The gaseous ammonia, cyclohexanone, and hydrogen peroxide feed pipes are connected to the pipeline between the turbid liquid outlet of the cross-flow membrane filter and the feed inlet of the oxime reactor via gaseous ammonia feed injector, cyclohexanone feed injector, and hydrogen peroxide high-shear mixer, respectively.

5. The apparatus according to any one of claims 1 to 4, characterized in that: A heat exchanger is also installed between the turbid liquid outlet of the cross-flow membrane filter and the ammonia feed pipe.

6. The apparatus according to claim 5, characterized in that: The heat exchanger is a reboiler for a benzene distillation column, which is connected to the benzene distillation column.

7. The apparatus according to any one of claims 1 to 4, characterized in that: The catalyst feeding tank is equipped with a double-layer paddle agitator and a level gauge. The catalyst feeding tank is connected to the inlet pipe of the circulating pump via a catalyst metering pump.

8. The apparatus according to any one of claims 1 to 4, characterized in that: Both the demineralized water inlet pipe and the catalyst additive inlet pipe of the catalyst feeding tank are equipped with flow meters.

9. The apparatus according to any one of claims 1 to 4, characterized in that: The oxime reactor is equipped with a double-layer paddle agitator, and the agitator is equipped with a frequency converter.

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