Process and system for the preparation of cyclohexanone oxime

Abstract

This invention relates to the field of production methods for organic chemical raw materials, and discloses a method and system for preparing cyclohexanone oxime. The method includes: (1) mixing cyclohexanone, ammonia, and a circulating catalyst slurry, and reacting the mixture with hydrogen peroxide to undergo an ammoniation reaction to obtain a reaction slurry; (2) mixing the reaction slurry with an organic solvent and performing two-phase separation to obtain an organic phase and an aqueous phase; (3) washing the organic phase with water to obtain a cyclohexanone oxime-rich stream and a first supernatant, separating the cyclohexanone oxime-rich stream to obtain an organic solvent and cyclohexanone oxime; (4) performing membrane filtration on the aqueous phase to obtain a catalyst-rich stream and a second supernatant, returning the catalyst-rich stream to step (1); (5) extracting the first supernatant and / or the second supernatant using the organic solvent obtained in step (3), and returning the resulting organic phase to step (2). This method extends the service life of the catalyst, has good operational stability, and produces high-quality cyclohexanone oxime.

Description

Technical Field

[0001] This invention relates to the field of production methods for organic chemical raw materials, and specifically to a method and system for preparing cyclohexanone oxime. Background Technology

[0002] Cyclohexanone oxime is a crucial organic intermediate in the development of the chemical industry. It is primarily used to produce caprolactam, a key raw material for manufacturing polyamide-6 (nylon-6) fibers and engineering plastics. Nylon-6, due to its excellent abrasion resistance, mechanical properties, and chemical stability, is widely used in the manufacture of tire cords, ropes, mechanical parts, and clothing. With the booming development of these downstream industries, the demand for caprolactam continues to rise, making the preparation technology of cyclohexanone oxime a key research focus in the chemical industry. The traditional method for producing cyclohexanone oxime is the hydroxylamine process, which uses cyclohexanone and hydroxylamine salts (such as hydroxylamine sulfate) as raw materials, reacting them in an acidic medium. This reaction is accompanied by the generation of a large amount of ammonium sulfate as a byproduct, resulting not only in low raw material atom utilization but also extremely high costs for subsequent ammonium sulfate processing. Furthermore, the discharge of large amounts of ammonium sulfate leads to environmental problems such as eutrophication and soil acidification. In addition, the acidic conditions during the reaction process place high demands on the materials used in the reaction equipment, requiring the use of acid-resistant materials, which increases equipment investment and maintenance costs.

[0003] From a green chemistry perspective, developing a more environmentally friendly and efficient method for preparing cyclohexanone oxime has become a research hotspot. Currently, the catalytic ammoniation method is widely used industrially. This method uses titanium silicate molecular sieves as catalysts, and in the presence of a solvent (such as tert-butanol), cyclohexanone reacts with ammonia and hydrogen peroxide to directly generate cyclohexanone oxime. This method has high atom utilization, and the main byproduct is water, which aligns with the principles of green chemistry, reduces environmental pollution, and lowers production costs. In recent years, a novel cyclohexanone ammoniation process without tert-butanol solvent has attracted widespread scientific attention, aiming to overcome the high energy consumption and other technical bottlenecks encountered in traditional solvent systems during the cyclohexanone ammoniation process.

[0004] CN116651013A discloses a solvent-free apparatus and method for preparing cyclohexanone oxime. The method involves first mixing cyclohexanone, gaseous ammonia, and hydrogen peroxide, then reacting them in a reactor. The reaction mixture is then sent to an extraction tower for countercurrent extraction with an extractant. The upper layer after extraction is fed into a flash tank, while the lower layer goes to a purification unit. The extractant is recycled via a recovery component, and the catalyst is recovered and recycled.

[0005] CN117343010A discloses a method for preparing caprolactam through heterogeneous ammonium oximeation and gas-phase rearrangement. In this method, cyclohexanone, hydrogen peroxide, and ammonia react to generate cyclohexanone oxime, which is then mixed with an inert solvent, a reaction solvent is added, and the mixture undergoes evaporation and gas-phase rearrangement to generate caprolactam.

[0006] However, the aforementioned processes generally suffer from poor catalyst stability and rapid deactivation. Furthermore, these processes also involve long preparation and production processes with high energy consumption, leading to increased production costs and reduced production efficiency. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of short catalyst lifespan and difficulty in separating reaction products from the catalyst in existing cyclohexanone oxime production methods, and to provide a method and system for preparing cyclohexanone oxime. The preparation method of this invention significantly extends the catalyst lifespan, exhibits good operational stability, and produces high-quality cyclohexanone oxime products.

[0008] To achieve the above objectives, a first aspect of the present invention provides a method for preparing cyclohexanone oxime, the method comprising the following steps:

[0009] (1) Cyclohexanone, ammonia and recycled catalyst slurry are mixed, and then the mixture is contacted with hydrogen peroxide to carry out an ammonium oxime reaction to obtain a reaction slurry;

[0010] Based on the total amount of cyclohexanone and the circulating catalyst slurry, the mass fraction of cyclohexanone is 2-6%;

[0011] (2) The reaction slurry is mixed with an organic solvent and the two phases are separated to obtain an organic phase containing cyclohexanone oxime and an aqueous phase containing a catalyst.

[0012] The method further includes: heating the reaction slurry before mixing it with the organic solvent; or heating the mixture of the reaction slurry and the organic solvent before performing two-phase separation.

[0013] The mass ratio of organic solvent to cyclohexanone oxime in the reaction slurry is 0.5-5:1;

[0014] (3) The organic phase obtained in step (2) is washed with water to obtain a stream rich in cyclohexanone oxime and a first supernatant. Then the stream rich in cyclohexanone oxime is separated to obtain an organic solvent and a cyclohexanone oxime product.

[0015] (4) The aqueous phase obtained in step (2) is subjected to membrane filtration to obtain a catalyst-rich stream and a second clear liquid; the obtained catalyst-rich stream is returned to step (1) to provide circulating catalyst slurry;

[0016] (5) Extract the first clear liquid and / or the second clear liquid using the organic solvent obtained in step (3), and return the resulting organic phase to step (2) to provide the organic solvent.

[0017] A second aspect of the present invention provides a system for preparing cyclohexanone oxime, the system comprising a reaction unit, a water washing unit, an extraction unit and a product separation unit, wherein the reaction unit comprises at least one reactor, a catalyst separator, a reaction heat exchanger and a membrane filter disposed inside the catalyst separator or connected to the aqueous phase outlet of the catalyst separator;

[0018] The reactor is connected to the circulating catalyst slurry pipeline and the hydrogen peroxide feed pipeline, respectively. The circulating catalyst slurry pipeline is equipped with a cyclohexanone inlet and an ammonia inlet. The reactor is used to contact the cyclohexanone, ammonia and circulating catalyst slurry mixture from the circulating catalyst slurry pipeline with hydrogen peroxide from the hydrogen peroxide feed pipeline to carry out an ammonoximation reaction.

[0019] The reactor and the catalyst separator are connected by a pipeline. A reaction heat exchanger is installed on the pipeline between the reactor and the catalyst separator. The pipeline is equipped with a circulating organic solvent inlet. The catalyst separator is used to separate the reaction slurry from the reactor and the mixed extract material of the organic solvent into two phases.

[0020] The organic phase outlet of the catalyst separator is connected to the water washing unit, the aqueous phase outlet of the water washing unit is connected to the aqueous phase inlet of the extraction unit, and the cyclohexanone oxime-rich outlet of the water washing unit is connected to the cyclohexanone oxime-rich inlet of the product separation unit. The water washing unit is used to wash the organic phase from the catalyst separator.

[0021] The product separation unit's organic solvent outlet is connected to the extraction unit's organic solvent inlet. The product separation unit is used to separate the material rich in cyclohexanone oxime from the water washing unit.

[0022] The catalyst-rich stream outlet of the membrane filter is connected to the reactor via a circulating catalyst slurry pipeline, and the second clear liquid outlet of the membrane filter is connected to the aqueous phase inlet of the extraction unit. The membrane filter is used to filter the aqueous phase separated from the two phases of the catalyst separator, and to send the catalyst-rich stream into the reactor and the second clear liquid into the extraction unit.

[0023] An extraction unit includes at least one extraction tower. The organic solvent outlet of the extraction unit is connected to a pipeline between the reactor and the reaction heat exchanger via a circulating organic solvent pipeline, or to a pipeline between the reaction heat exchanger and the catalyst separator. The extraction unit is used to extract the first clear liquid from the water washing unit and / or the second clear liquid from the membrane filter using the organic solvent from the product separation unit.

[0024] Through the above technical solution, the present invention has the following beneficial effects:

[0025] The method for preparing cyclohexanone oxime provided by this invention involves contacting a mixture of cyclohexanone, ammonia, and a circulating catalyst slurry with hydrogen peroxide. By controlling the concentration of cyclohexanone in the cyclohexanone and the circulating catalyst slurry, as well as the mass ratio of organic solvent to cyclohexanone oxime in the reaction slurry, within a specific range, cyclohexanone remains in a homogeneous state in the circulating catalyst slurry before contacting hydrogen peroxide in the reactor for the ammonoximation reaction. This significantly extends the catalyst's lifespan, improves operational stability, and effectively reduces catalyst consumption while maintaining a high conversion rate of cyclohexanone and selectivity for the cyclohexanone oxime product.

[0026] The ammonium oxime reaction slurry is further mixed with an organic solvent for two-phase separation, achieving separation of the catalyst and reaction products through natural phase separation. The aqueous phase is separated by membrane filtration to achieve separation of the clear liquid and concentration of the catalyst slurry. The catalyst slurry retained by the membrane is returned to the ammonium oxime reactor to continue participating in the reaction, ensuring efficient utilization of the catalyst. By washing and separating the organic phase with water, impurities in cyclohexanone oxime are effectively removed, especially oil-soluble impurities, resulting in a high-quality cyclohexanone oxime product. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a system for preparing cyclohexanone oxime according to a specific embodiment of the present invention.

[0028] Explanation of reference numerals in the attached figures

[0029] 1. Reactor 2. Reaction heat exchanger 3. Catalyst separator

[0030] 4. Membrane filter; 5. Exhaust gas absorption unit; 6. Water washing unit

[0031] 7 Product separation unit 8 Extraction unit 9 Deamination unit

[0032] 10. Circulating catalyst slurry pipeline; 11. Circulating organic solvent pipeline Detailed Implementation

[0033] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0034] The first aspect of this invention provides a method for preparing cyclohexanone oxime, the method comprising the following steps:

[0035] (1) Cyclohexanone, ammonia and recycled catalyst slurry are mixed, and then the mixture is contacted with hydrogen peroxide to carry out an ammonium oxime reaction to obtain a reaction slurry;

[0036] Based on the total amount of cyclohexanone and the circulating catalyst slurry, the mass fraction of cyclohexanone is 2-6%;

[0037] (2) The reaction slurry is mixed with an organic solvent and the two phases are separated to obtain an organic phase containing cyclohexanone oxime and an aqueous phase containing a catalyst.

[0038] The method further includes: heating the reaction slurry before mixing it with the organic solvent; or heating the mixture of the reaction slurry and the organic solvent before performing two-phase separation.

[0039] The mass ratio of organic solvent to cyclohexanone oxime in the reaction slurry is 0.5-5:1;

[0040] (3) The organic phase obtained in step (2) is washed with water to obtain a stream rich in cyclohexanone oxime and a first supernatant. Then the stream rich in cyclohexanone oxime is separated to obtain an organic solvent and a cyclohexanone oxime product.

[0041] (4) The aqueous phase obtained in step (2) is subjected to membrane filtration to obtain a catalyst-rich stream and a second clear liquid; the obtained catalyst-rich stream is returned to step (1) to provide circulating catalyst slurry;

[0042] (5) Extract the first clear liquid and / or the second clear liquid using the organic solvent obtained in step (3), and return the resulting organic phase to step (2) to provide the organic solvent.

[0043] In this invention, a mixture of cyclohexanone, ammonia, and a circulating catalyst slurry is contacted with hydrogen peroxide. By controlling the concentration of cyclohexanone in the cyclohexanone and the circulating catalyst slurry, as well as the mass ratio of organic solvent to cyclohexanone oxime in the reaction slurry, within a specific range, cyclohexanone remains homogeneous in the circulating catalyst slurry before contact with hydrogen peroxide in the ammonoximation reactor, significantly extending the catalyst's lifespan. Further, the ammonoximation reaction slurry is mixed with an organic solvent, allowing cyclohexanone oxime to be extracted into the organic phase, while the catalyst is dispersed in the aqueous phase. Natural phase separation separates the catalyst from the reaction product. Membrane filtration is used to separate the aqueous phase, achieving clear liquid separation and catalyst slurry concentration. The catalyst slurry retained by the membrane is returned to the ammonoximation reactor to continue participating in the reaction. Washing and separating the organic phase effectively removes impurities from the cyclohexanone oxime, resulting in a high-quality cyclohexanone oxime product.

[0044] In some embodiments of the present invention, preferably, based on the total amount of cyclohexanone and the circulating catalyst slurry, the mass fraction of cyclohexanone is 2-6%, specifically 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, and any two of these values, preferably 3-5.5%. Using the above-mentioned preferred mass fraction of cyclohexanone is beneficial for extending the catalyst's lifespan and improving the quality of the cyclohexanone oxime product.

[0045] In this invention, the feed ratio of cyclohexanone to the circulating catalyst slurry is adjusted to ensure that the mass fraction of cyclohexanone meets the aforementioned range. In some embodiments of this invention, preferably, the mass ratio of cyclohexanone to the circulating catalyst slurry is 1:15-50, more preferably 1:16-32. Using the above-mentioned preferred mass ratio is more beneficial for extending the service life of the catalyst.

[0046] In some embodiments of the present invention, preferably, the mass ratio of the organic solvent to the cyclohexanone oxime in the reaction slurry is 0.5-5:1, specifically 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, and any two of these values ​​forming a range, preferably 1-3:1. Using the above-mentioned preferred mass ratio is more conducive to achieving effective separation of the catalyst and reaction products, and also more conducive to controlling the concentration of cyclohexanone oxime in the circulating catalyst slurry.

[0047] In this invention, the concentration of cyclohexanone oxime in the circulating catalyst slurry is controlled by controlling the amount of organic solvent added. In some embodiments of this invention, preferably, the mass fraction of cyclohexanone oxime in the circulating catalyst slurry is 0.1-4%, specifically 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, and any two of these values, preferably 0.5-3%. Adopting the above preferred embodiments is more conducive to improving product quality and extending the catalyst's service life.

[0048] In this invention, there are no particular limitations on the method of mixing cyclohexanone, ammonia and circulating catalyst slurry in step (1), as long as it is ensured that cyclohexanone, ammonia and circulating catalyst slurry have been mixed before contact with hydrogen peroxide.

[0049] In some embodiments of the present invention, preferably, the molar ratio of hydrogen peroxide to cyclohexanone in the ammonium oxime reaction system is 1-1.5:1, more preferably 1-1.3:1. Using the above-mentioned preferred range of molar ratios is beneficial for improving the conversion rate of cyclohexanone and the selectivity of the product.

[0050] In this invention, the ammonium oximation reaction system refers to the total mass of materials in the reactor where the ammonium oximation reaction occurs.

[0051] In this invention, preferably, the hydrogen peroxide is provided by hydrogen peroxide solution. The concentration of hydrogen peroxide in the hydrogen peroxide solution of this invention has a wide range of selection. Preferably, the mass concentration of the hydrogen peroxide is 15-80 wt%, more preferably 20-70 wt%.

[0052] In this invention, the method of adding hydrogen peroxide is not particularly limited. Preferably, it is added to the ammonium oxime reactor via a hydrogen peroxide feed distributor. The form of the hydrogen peroxide feed distributor in this invention is not particularly limited; for example, it can be at least one of a loop type, a branch type, and a nozzle type, preferably a loop type.

[0053] In some embodiments of the present invention, preferably, in the ammonium oxime reaction system, the molar ratio of ammonia to cyclohexanone is 1-1.5:1, more preferably 1-1.3:1;

[0054] In some embodiments of the present invention, preferably, the mass fraction of the catalyst in the circulating catalyst slurry is 0.1%-15%, more preferably 1%-10%.

[0055] In this invention, the type of catalyst has a wide range of selection; various catalysts conventionally used in the art for the production of cyclohexanone oxime via amination of cyclohexanone can be used in this invention. Preferably, the catalyst comprises a titanium silicate molecular sieve, which is preferably selected from at least one of TS-1, TS-2, Ti-ZSM-5, Ti-ZSM-12, Ti-ZSM-48, Ti-β, Ti-MCM-41, Ti-MOR, Ti-MWW, and Ti-SBA-15.

[0056] In this invention, there is no particular limitation on the form of the catalyst. It can be in the form of molecular sieve powder or a shaped catalyst formed by arbitrary shaping. Those skilled in the art can choose according to actual needs.

[0057] In this invention, preferably, no organic solvent is added during the ammonium oxime reaction in step (1). The solvent can be any organic solvent commonly used in the art, such as tert-butanol.

[0058] In this invention, preferably, the circulating catalyst slurry comprises the catalyst-rich stream obtained in step (4) and optionally a slurry containing fresh catalyst.

[0059] In this invention, a slurry containing fresh catalyst can be added intermittently according to specific working conditions. The slurry containing fresh catalyst is a slurry containing fresh catalyst prepared with water.

[0060] In this invention, the conditions for the ammonium oximation reaction have a wide range of selection. Preferably, the conditions for the ammonium oximation reaction include: a reaction temperature of 70-100°C and a reaction pressure of 0-0.5 MPaG. More preferably, the conditions for the ammonium oximation reaction include: a reaction temperature of 80-95°C and a reaction pressure of 0.2-0.4 MPaG.

[0061] In this invention, the type of reactor for the ammonium oximation reaction is not particularly limited. Preferably, the ammonium oximation reaction is carried out in a stirred tank reactor. In this invention, the stirred tank reactor refers to a tank reactor equipped with a stirring device.

[0062] In this invention, the number of ammonia oxime reactors is not particularly limited. Those skilled in the art can select and set one or more reactors according to actual production needs, and two or more reactors can be connected in series. Preferably, the number of reactors is 1-4, and more preferably 1-2.

[0063] In this invention, preferably, each reactor is equipped with a stirring paddle. The type of stirring paddle described in this invention has a wide range of selections. Preferably, the stirring paddle is selected from at least one of paddle-type, propeller-type, and turbine-type.

[0064] In this invention, the number of layers of the stirring paddle has a wide range of selection. Preferably, the number of stirring paddle layers is 1-3.

[0065] In this invention, preferably, each reactor is equipped with a baffle. The number of baffles has a wide range of selection. Preferably, each reactor has 2-6 baffles.

[0066] In this invention, when multiple reactors are connected in series, preferably each reactor is independently connected to the hydrogen peroxide feed line, so that hydrogen peroxide is fed simultaneously by multiple reactors.

[0067] In some embodiments of the present invention, preferably, the method in step (1) further includes: contacting the gas generated by the ammonium oximation reaction with demineralized water to absorb ammonia from the gas, and returning the resulting absorbent to the ammonium oximation reaction in step (1). In the present invention, the amount of demineralized water is not particularly limited, and those skilled in the art can adjust it conventionally according to actual conditions; therefore, no limitation is made here.

[0068] In this invention, in step (2), the mixed extract material obtained by mixing the reaction slurry and the organic solvent is subjected to two-phase separation. Cyclohexanone oxime is extracted into the organic solvent as the organic phase, while the catalyst enters the aqueous phase. It should be noted that in this invention, extraction occurs during the mixing process of the reaction slurry and the organic solvent to obtain the mixed extract material.

[0069] In this invention, the type of organic solvent has a wide range of selection; conventional organic solvents that are insoluble or slightly soluble in water can be used in this invention. The organic solvent is selected from at least one of alkanes having 6-12 carbon atoms, cycloalkanes having 5-11 carbon atoms, and aromatics having 6-10 carbon atoms, preferably from at least one of aromatics having 6-10 carbon atoms and cycloalkanes having 6-10 carbon atoms, and more preferably from toluene and / or cyclohexane.

[0070] In some embodiments of the present invention, preferably, the method includes: optionally heating the catalyst-rich stream obtained by membrane filtration. In the present invention, "optionally" means that the catalyst-rich stream obtained by membrane filtration may or may not be heated.

[0071] In this invention, the conditions for the heat treatment have a wide range of selection. Preferably, after the heat treatment, the temperature of the reaction slurry and / or the mixture of the reaction slurry and the organic solvent is 40-85°C, more preferably 50-80°C.

[0072] In this invention, the heat recovered from the reaction slurry and / or the mixture of the reaction slurry and the organic solvent can be reused to improve energy efficiency.

[0073] In some embodiments of the present invention, preferably, the two-phase separation in step (2) is carried out in a catalyst separator.

[0074] In some embodiments of the present invention, preferably, the catalyst separator includes a vessel body and a stirrer, an inner extension tube, and an inner sleeve disposed in the vessel body; the inner sleeve is sleeved inside the inner extension tube, and a gas phase balance port is provided on the side wall of the inner extension tube; the stirring paddle of the stirrer is disposed in the aqueous phase section of the vessel body for stirring the aqueous phase.

[0075] In this invention, the catalyst separator, through the combination of the inner extension tube and the inner sleeve, can reduce the amount of catalyst carried in the organic phase; the stirrer can prevent the catalyst from depositing at the bottom of the vessel, while also ensuring the separation of the organic phase and the water phase, avoiding back mixing of the two phases, and ensuring the continuous and stable separation of the two phases and the circulation of the catalyst.

[0076] In this invention, there is no particular limitation on the installation position of the inner tube. Preferably, the top end of the inner tube is located outside the vessel body, and the bottom end of the inner tube is located inside the vessel body. By positioning the bottom end of the inner tube inside the vessel body, the mixed extract of the reaction slurry obtained from the ammonium oxime reaction and the organic solvent can be transported into the vessel body for two-phase separation.

[0077] In some embodiments of the present invention, preferably, the top end of the inner sleeve is flush with the top end of the inner extension tube, and the top of the annular space formed by the inner sleeve and the inner extension tube is closed.

[0078] In this invention, preferably, the ratio of the length of the inner extension tube to the length of the inner sleeve tube is 30-5:1, more preferably 25-8:1. By optimizing the lengths of the inner extension tube and the inner sleeve tube, catalyst entrainment loss can be reduced.

[0079] In this invention, preferably, the ratio of the length of the inner tube extending below the upper tangent of the reactor body to the vertical distance between the upper and lower tangents of the reactor body is 0.3-0.95:1, more preferably 0.4-0.9:1. By optimizing the position of the inner tube in the reactor body, catalyst oil phase entrainment can be effectively suppressed.

[0080] In this invention, it should be noted that the upper tangent of the vessel body refers to the tangential section at the junction of the upper end cap and the cylinder wall; the lower tangent of the vessel body refers to the tangential section at the junction of the lower end cap and the cylinder wall. In this invention, the portion of the inner tube outside the vessel body has no effect on the separation effect of the catalyst separator.

[0081] In this invention, the rotational speed of the agitator is not particularly limited. The rotational speed is related to the selection of the agitator blade, the ratio of the blade diameter to the inner diameter of the vessel, etc. Those skilled in the art can adjust it according to the actual device structure, as long as it can prevent solid materials from depositing at the bottom of the vessel and avoid back mixing of the organic and aqueous phases. Preferably, the agitator rotational speed is 5-200 rpm.

[0082] In this invention, preferably, the bottom end of the stirrer is provided with a stirring paddle.

[0083] In this invention, the specific type of stirring paddle is not particularly limited; any stirring device capable of preventing solid materials from depositing at the bottom of the vessel is applicable. Preferably, the stirring paddle is selected from at least one of propeller-type stirring paddles, turbine-type stirring paddles, anchor-type stirring paddles, and frame-type stirring paddles.

[0084] In this invention, preferably, the number of layers of the stirring paddle is 1-3.

[0085] In this invention, preferably, an anti-impact baffle is provided at the bottom end of the inner tube. The anti-impact baffle of this invention is used to buffer the mixture of the reaction slurry obtained from the ammonium oxime reaction and the extracted material from the organic solvent.

[0086] In this invention, preferably, an overflow weir is provided at the upper part of the vessel. This invention is used to overflow the organic phase to obtain an organic phase product.

[0087] In this invention, the shape of the overflow weir is not particularly limited. In a preferred embodiment, the overflow weir is an L-shaped plate, one end of which is connected to the inner wall of the vessel.

[0088] In this invention, preferably, a membrane filter is optionally provided inside the catalyst separator.

[0089] In this invention, preferably, the upper part of the vessel is provided with an organic phase outlet, which is connected to the overflow weir.

[0090] In this invention, preferably, the bottom of the vessel is provided with an aqueous phase outlet and an optional turbid liquid outlet.

[0091] In this invention, preferably, the top of the vessel is provided with a gas phase outlet.

[0092] In this invention, preferably, the gas phase balance port is directly connected to the gas phase space at the top of the vessel body, or the gas phase balance port is connected to the gas phase space at the top of the vessel body through a pipeline.

[0093] In this invention, preferably, the shape of the lower end cap of the vessel body is at least one of ellipse, sphere and cone, with cone being the most preferred.

[0094] In this invention, preferably, baffles are provided on the vessel body wall and / or the lower end cap side wall, and preferably, the number of baffles is 2-6.

[0095] In this invention, the conditions for phase separation in step (2) have a wide range of selection. Preferably, the conditions for phase separation include: pressure of 0-500 kPaG and temperature of 40-90℃.

[0096] In this invention, step (3) preferably includes washing the organic phase obtained in step (2) with deionized water. The washing method described in this invention is not particularly limited; any method that can remove impurities from the organic phase is acceptable. Conventional washing methods in the art can be used, and will not be elaborated upon here.

[0097] The present invention does not have a particular limitation on the amount of demineralized water used. Preferably, the mass ratio of the amount of demineralized water to the mass of cyclohexanone oxime in the organic phase containing cyclohexanone oxime is 0.1-1:1.

[0098] In this invention, the washing conditions have a wide range of selection. Preferably, the washing stages in step (3) are 1-5 stages, more preferably 1-3 stages. Using the above-mentioned preferred washing stages is beneficial to effectively remove impurities while reducing production costs.

[0099] In this invention, the separation apparatus in step (3) is not particularly limited; for example, a distillation column can be used for separation. The separation conditions described in this invention have a wide range of options. Preferably, the separation conditions in step (3) include: a pressure of 0-500 kPaG and a temperature of 40-90°C.

[0100] In some embodiments of the present invention, preferably, the membrane filtration in step (4) is carried out in a membrane filter, which is located inside the catalyst separator or connected to the aqueous phase outlet of the catalyst separator.

[0101] In this invention, it should be noted that when the membrane filter is installed inside the catalyst separator, the aqueous phase containing the catalyst obtained from the two-phase separation enters the membrane filter for membrane filtration, and the second clear liquid and the catalyst-rich stream obtained from the membrane filtration are discharged from the aqueous phase outlet and the turbid liquid outlet of the catalyst separator, respectively; when the membrane filter is installed at the location connected to the aqueous phase outlet of the catalyst separator, that is, downstream of the catalyst separator, the aqueous phase containing the catalyst obtained from the two-phase separation is discharged from the aqueous phase outlet of the catalyst separator and sent to the membrane filter for membrane filtration via pipeline.

[0102] In this invention, the composition of the membrane filter is not particularly limited. Preferably, the membrane filter is composed of at least one membrane module. When the membrane filter includes two or more membrane modules, the membrane modules can be connected in parallel and / or in series.

[0103] In this invention, preferably, the membrane filter is disposed inside the catalyst separator, and each membrane module includes a membrane tube and a manifold; or, the membrane filter is disposed downstream of the catalyst separator, and each membrane module includes a housing, a tube sheet, a head and a membrane tube, the membrane tube is placed inside the housing, and tube sheets are provided at both ends of the membrane tube for separating the materials inside and outside the membrane tube.

[0104] In this invention, preferably, when the membrane filter is installed inside the catalyst separator, the membrane filter is positioned below the anti-surge baffle, with one end of the membrane filter closed and the other end connected to the collecting pipe. The advantage of this preferred embodiment is that the membrane filter is submerged in the aqueous phase, preventing the organic phase from entering the clear aqueous solution through the membrane filter.

[0105] In this invention, preferably, the membrane filter is disposed inside the catalyst separator, and the aqueous phase containing the catalyst permeates from the outer surface of the membrane tube to the inner side of the membrane tube to obtain a second clear liquid, which is collected by the collecting pipe and discharged from the aqueous phase outlet of the catalyst separator through the clear liquid discharge pipeline B. The resulting catalyst-rich stream is discharged from the turbid liquid outlet of the catalyst separator.

[0106] In this invention, preferably, the membrane filter is located downstream of the catalyst separator. The aqueous phase containing the catalyst enters the membrane filter, and the catalyst-rich stream is obtained by flowing through the center of the membrane tube. The second clear liquid is obtained by permeating into the membrane module housing from the inside of the membrane tube. The second clear liquid enters the clear liquid outlet pipeline A on the housing side and is discharged from the membrane filter through the second clear liquid outlet of the membrane filter.

[0107] In this invention, preferably, both the clear liquid discharge line A and the clear liquid discharge line B are equipped with backwashing lines for backwashing the membrane tubes. In this invention, the medium for the backwashing operation is preferably a second clear liquid and / or water, with the second clear liquid being more preferred.

[0108] In this invention, the filtration accuracy of the membrane tubes in the membrane filter has a wide selection range. Preferably, the filtration accuracy of the membrane tubes in the membrane filter is 0.01-50 μm, more preferably 0.05-10 μm. Using the above-mentioned preferred filtration accuracy is beneficial for effectively separating the circulating catalyst slurry.

[0109] In this invention, the material of the membrane tube in the membrane filter is not particularly limited and can be any material commonly used in membrane filters in the art. Preferably, the material of the membrane tube in the membrane filter is selected from at least one of ceramic, metal, and high-density polyethylene, preferably ceramic and / or metal, and more preferably metal.

[0110] In this invention, the extraction method in step (5) is not particularly limited. Preferably, the extraction method is countercurrent extraction.

[0111] In this invention, the extraction conditions in step (5) have a wide range of selection. Preferably, the extraction temperature is 30-90℃, and more preferably 40-80℃. Using the above-mentioned preferred extraction temperature is beneficial for achieving an efficient extraction process and ensuring the stability of the reaction product and the extractant.

[0112] In this invention, in step (5), preferably, the organic solvent obtained in step (3) is used to extract the first clear liquid and / or the second clear liquid to obtain an organic phase and an aqueous phase.

[0113] In this invention, the aqueous phase obtained by extraction in step (5) contains a small amount of ammonia. Preferably, the method in step (5) further includes: removing ammonia from the aqueous phase obtained by extraction to obtain ammonia water and wastewater; and returning the obtained ammonia water to the ammonia oxime reaction in step (1).

[0114] A second aspect of the present invention provides a system for preparing cyclohexanone oxime, such as... Figure 1As shown, the system includes a reaction unit, a water washing unit 6, an extraction unit 8, and a product separation unit 7. The reaction unit includes at least one reactor 1, a catalyst separator 3, a reaction heat exchanger 2, and a membrane filter 4 disposed inside the catalyst separator or connected to the aqueous phase outlet of the catalyst separator.

[0115] Reactor 1 is connected to the circulating catalyst slurry pipeline 10 and the hydrogen peroxide feed pipeline respectively. The circulating catalyst slurry pipeline is provided with a cyclohexanone inlet and an ammonia inlet. Reactor 1 is used to contact the cyclohexanone, ammonia and circulating catalyst slurry mixture from the circulating catalyst slurry pipeline 10 with hydrogen peroxide from the hydrogen peroxide feed pipeline to carry out an ammonium oxime reaction.

[0116] Reactor 1 and catalyst separator 3 are connected by a pipeline. A reaction heat exchanger 2 is installed on the pipeline between reactor 1 and catalyst separator 3. The pipeline is equipped with an inlet for circulating organic solvent 11. Catalyst separator 3 is used to separate the reaction slurry from reactor 1 and the mixed extract material of organic solvent into two phases.

[0117] The organic phase outlet of catalyst separator 3 is connected to water washing unit 6, the aqueous phase outlet of water washing unit 6 is connected to aqueous phase inlet of extraction unit 8, and the cyclohexanone oxime-rich outlet of water washing unit 6 is connected to the cyclohexanone oxime-rich inlet of product separation unit 7. Water washing unit 6 is used to wash the organic phase from catalyst separator 3.

[0118] The product separation unit 7 is connected to the organic solvent outlet of the extraction unit 8 and is used to separate the material rich in cyclohexanone oxime from the water washing unit 6.

[0119] The catalyst-rich stream outlet of membrane filter 4 is connected to reactor 1 through circulating catalyst slurry pipeline 10. The second clear liquid outlet of membrane filter 4 is connected to the water phase inlet of extraction unit 8. Membrane filter 4 is used to filter the water phase separated from the two phases of catalyst separator 3, and send the catalyst-rich stream into reactor and the second clear liquid into extraction unit 8.

[0120] Extraction unit 8 includes at least one extraction tower. The organic solvent outlet of extraction unit 8 is connected to the pipeline between reactor 2 and reaction heat exchanger 2 via circulating organic solvent pipeline 11, or to the pipeline between reaction heat exchanger 2 and catalyst separator 3. Extraction unit 8 is used to extract the first clear liquid from water washing unit 6 and / or the second clear liquid from membrane filter 4 with organic solvent from product separation unit 7.

[0121] In this invention, preferably, the cyclohexanone feed line and the ammonia feed line are independently connected to the cyclohexanone inlet and the ammonia inlet on the circulating catalyst slurry line, respectively, to provide a mixture of cyclohexanone, ammonia and circulating catalyst slurry to reactor 1.

[0122] In this invention, the number of reactors in the reaction unit is not particularly limited. Those skilled in the art can select and set one or more reactors according to actual production needs, and two or more reactors can be connected in series. Preferably, the number of reactors is 1-4, and more preferably 1-2.

[0123] In this invention, the type of reactor is not particularly limited. Preferably, the reactor is a stirred tank reactor.

[0124] In this invention, when multiple reactors are connected in series, preferably each reactor is independently connected to the hydrogen peroxide feed line, so that hydrogen peroxide is fed simultaneously by multiple reactors.

[0125] In some embodiments of the present invention, preferably, the catalyst separator includes a vessel body and a stirrer, an inner extension tube, and an inner sleeve disposed within the vessel body; the inner sleeve is fitted inside the inner extension tube and is used to convey the mixed extract material of the reaction slurry and organic solvent to the inner extension tube; the inner extension tube is used to convey the mixed extract material of the reaction slurry and organic solvent to the vessel body for two-phase separation; a gas phase balance port is provided on the side wall of the inner extension tube to maintain the gas phase balance of the vessel body; the stirring paddle of the stirrer is disposed in the aqueous phase section of the vessel body to stir the aqueous phase.

[0126] In some embodiments of the present invention, preferably, the top end of the inner tube is located outside the vessel body, and the bottom end of the inner tube is located inside the vessel body.

[0127] In some embodiments of the present invention, preferably, the top end of the inner sleeve is flush with the top end of the inner extension tube, and the top of the annular space formed by the inner sleeve and the inner extension tube is closed.

[0128] In some embodiments of the present invention, preferably, the bottom end of the inner tube is provided with an anti-impact baffle for buffering the mixture of reaction slurry and organic solvent obtained from the ammonium oxime reaction.

[0129] In some embodiments of the present invention, preferably, an overflow weir is provided at the upper part of the vessel body for overflowing the organic phase to obtain the organic phase product.

[0130] In this invention, preferably, the upper part of the vessel is provided with an organic phase outlet, which is connected to the overflow weir.

[0131] In some embodiments of the present invention, preferably, the bottom of the vessel is provided with an aqueous phase outlet and an optional turbid liquid outlet.

[0132] In this invention, preferably, the top of the vessel is provided with a gas phase outlet.

[0133] In this invention, preferably, the gas phase balance port is directly connected to the gas phase space at the top of the vessel body, or the gas phase balance port is connected to the gas phase space at the top of the vessel body through a pipeline.

[0134] In this invention, preferably, the membrane filter comprises at least one membrane module. When the membrane filter comprises two or more membrane modules, the membrane modules may be connected in parallel and / or in series.

[0135] In this invention, preferably, when the membrane filter is installed inside the catalyst separator, each membrane module consists of a membrane tube and a manifold; when the membrane filter is installed downstream of the catalyst separator, each membrane module consists of a housing, a tube sheet, a head, and a membrane tube, with the membrane tube placed inside the housing and tube sheets at both ends of the membrane tube for separating the materials inside and outside the membrane tube.

[0136] In this invention, the filtration accuracy of the membrane tube has a wide selection range. Preferably, the filtration accuracy of the membrane tube in the membrane filter is 0.01-50 μm, and more preferably 0.05-10 μm.

[0137] In this invention, the material of the membrane tube is not particularly limited and can be any material commonly used in membrane filters. Preferably, the material of the membrane tube in the membrane filter is selected from at least one of ceramic, metal, and high-density polyethylene, more preferably ceramic and / or metal, and more preferably metal.

[0138] In some embodiments of the present invention, preferably, a heat exchanger is optionally provided on the circulating catalyst slurry pipeline disposed between the membrane filter and the reactor.

[0139] In some embodiments of the present invention, preferably, the system further includes an ammonia removal unit 9 connected to the aqueous phase outlet of the extraction unit, for separating wastewater and ammonia from the aqueous phase. Preferably, the resulting wastewater is sent to the next process step.

[0140] In some embodiments of the present invention, preferably, the circulating catalyst slurry pipeline is further provided with a circulating ammonia water inlet, and the ammonia water outlet of the deammoniation unit is connected to the circulating ammonia water inlet on the circulating catalyst slurry pipeline for returning ammonia water to the ammonia oxime reaction.

[0141] In some embodiments of the present invention, preferably, the system further includes a tail gas absorption unit 5, wherein the gas phase outlet of the reactor is connected to the tail gas absorption unit, and the liquid phase outlet of the tail gas absorption unit is connected to the reactor, for contacting the gas generated in the reaction with demineralized water to remove ammonia. Preferably, in the present invention, the obtained ammonia-removed gas is sent to the next process.

[0142] The present invention will be described in detail below through embodiments.

[0143]

[0144] Where w% is the mass percentage of the corresponding component in the organic phase from the catalyst separator; 0.867 is the molecular weight ratio of cyclohexanone and cyclohexanone oxime; m(catalyst) is the total amount of catalyst added, g; F(ketone) is the cyclohexanone feed rate, kg / h; t is the unit operating time, h; when calculating catalyst consumption, the ketone conversion rate and oxime selectivity are the algebraic averages of the initial and final conversion rates and selectivities.

[0145] Example 1

[0146] Adopting such Figure 1 The reaction system shown.

[0147] Cyclohexanone, ammonia, and a circulating catalyst slurry were mixed and fed into a reactor. Hydrogen peroxide was introduced into the reactor near the bottom agitator via a feed distributor. The reaction was carried out at 90°C and 0.4 MPaG. The effective volume of the reactor was 3 L, and it contained TS-1 titanium-silicon molecular sieve catalyst. The mass fraction of the catalyst in the circulating catalyst slurry was 2.5%. The cyclohexanone feed rate was 353 g / h, the ammonia feed rate was 67 g / h, and hydrogen peroxide (hydrogen peroxide concentration of 35 wt%) was added. The feed flow rate is 402 g / h, and the circulating catalyst slurry feed rate is 6250 g / h, wherein the mass fraction of cyclohexanone oxime in the circulating catalyst slurry is 1.5%, and the molar ratio of hydrogen peroxide to cyclohexanone in the reaction system is 1.15:1; the obtained reaction product is mixed with toluene for extraction, and the resulting mixed extract is cooled to 70°C by a reaction heat exchanger and then sent to a catalyst separator. The toluene flow rate is 810 g / h, and the mass ratio of toluene to cyclohexanone oxime in the reaction product is 2:1;

[0148] The aqueous phase separated from the catalyst separator is sent to a membrane filter (the membrane filter is equipped with a 10mm diameter, 200mm long sintered metal membrane tube with a filtration accuracy of 0.2μm). The catalyst-rich stream flowing out from the center of the membrane tube is circulated back to the reactor. The second clear liquid, which permeates into the shell from the inside of the membrane tube, is sent to the extraction tower via the clear liquid discharge line. The clear liquid discharge line is equipped with a backwashing line, and the backwashing medium is the second clear liquid. The organic phase separated from the catalyst separator is sent to a water washing tank. The organic phase after water washing in the water washing tank is sent to the toluene oxime separation process. In the toluene oxime separation process, the water-washed organic phase is separated by a distillation column. Cyclohexanone oxime product is obtained from the bottom of the column, and the toluene obtained from the top of the column is sent to the extraction tower.

[0149] The gas phase obtained from the reaction is sent to the tail gas absorption process. In the absorption tower, demineralized water is used to absorb ammonia in the tail gas in a countercurrent manner. The amount of demineralized water added is 71 g / h, the operating pressure is atmospheric pressure, and the absorption liquid is sent to the reaction vessel.

[0150] The first clear liquid (wash water) after washing in the washing tank is mixed with the second clear liquid and sent to the extraction process. In the extraction tower, toluene from the toluene oxime separation process is used to countercurrently extract cyclohexanone oxime from the water (first clear liquid and second clear liquid), where water is the continuous phase and toluene is the dispersed phase. The toluene phase obtained by extraction is mixed with the reaction slurry and then sent to the reaction heat exchanger. The aqueous phase obtained by extraction is sent to the deammoniation tower for deammoniation. The operating pressure is atmospheric pressure. The ammonia water obtained from the top of the tower is recycled back to the reactor, and the wastewater obtained from the bottom of the tower is discharged.

[0151] The reactor is equipped with baffles and a stirrer. The stirrer is a propeller-type stirrer with a stirring speed of 600 rpm.

[0152] The catalyst separator includes a vessel body and a stirrer, an inner extension tube, and an inner sleeve disposed within the vessel body. The top end of the inner extension tube is located outside the vessel body, and the bottom end of the inner extension tube is located inside the vessel body. The ratio of the length of the inner extension tube extending below the upper tangent of the vessel body to the vertical distance between the tangent and the lower tangent of the vessel body is 0.85:1. The inner sleeve is fitted inside the inner extension tube, and the top end of the inner sleeve is flush with the top end of the inner extension tube. The top of the annular space formed by the inner sleeve and the inner extension tube... The vessel is enclosed, with the length ratio of the inner extension tube to the inner sleeve being 15:1. A gas phase balance port is provided on the side wall of the inner extension tube, which is connected to the gas phase space of the vessel body to ensure gas phase balance. The stirring paddle of the stirrer is located in the water phase section of the vessel body, and the stirring paddle has one layer. An anti-impact baffle is provided at the bottom end of the inner extension tube. The vessel body is also provided with an overflow weir (L-shaped plate, one end of which is connected to the inner wall of the vessel body) and an organic phase outlet connected to the overflow weir. A gas phase outlet is provided at the top of the vessel body.

[0153] The operating conditions inside the catalyst separator are: temperature 69℃, pressure 0.4MPaG; the agitator is an anchor agitator with a rotation speed of 180rpm.

[0154] Under the above process conditions, sampling began after 10 hours of operation (the conversion rate and selectivity at this time were the initial conversion rate and selectivity). Afterward, samples of the organic phase output from the catalyst separator and the cyclohexanone oxime product were analyzed every 10 hours. When the cyclohexanone conversion rate decreased to below 99.6%, the feeding of cyclohexanone, ammonia, and hydrogen peroxide was stopped. The conversion rate, selectivity, and purity of the cyclohexanone oxime product at this point were the final conversion rate, final selectivity, and purity of the cyclohexanone oxime product (Table 1). The unit operating time was recorded, and catalyst consumption was calculated. Gas chromatography was used for analysis. The conversion rate, selectivity, catalyst consumption, cyclohexanone oxime product purity, and unit operating time data are shown in Table 1.

[0155] Example 2

[0156] The method described in Example 1 is different except that the circulating catalyst slurry feed rate is changed from 6250 g / h to 5750 g / h.

[0157] Under the above process conditions, sampling began after 10 hours of operation (the conversion rate and selectivity at this time were the initial conversion rate and selectivity). Afterward, samples of the organic phase output from the catalyst separator and the cyclohexanone oxime product were analyzed every 10 hours. When the cyclohexanone conversion rate decreased to below 99.6%, the feeding of cyclohexanone, ammonia, and hydrogen peroxide was stopped. The conversion rate, selectivity, and purity of the cyclohexanone oxime product at this point were the final conversion rate, final selectivity, and purity of the cyclohexanone oxime product (Table 1). The unit operating time was recorded, and catalyst consumption was calculated. Gas chromatography was used for analysis. The conversion rate, selectivity, catalyst consumption, cyclohexanone oxime product purity, and unit operating time data are shown in Table 1.

[0158] Example 3

[0159] Cyclohexanone, ammonia, and a circulating catalyst slurry were mixed and fed into a reactor. Hydrogen peroxide was introduced into the reactor near the bottom agitator via a feed distributor. The reaction was carried out at 95°C and 0.4 MPaG. The effective volume of the reactor was 3 L, and it contained TS-1 titanium-silicon molecular sieve catalyst. The mass fraction of the catalyst in the circulating catalyst slurry was 2.5%. The cyclohexanone feed rate was 353 g / h, the ammonia feed rate was 67 g / h, and hydrogen peroxide (hydrogen peroxide concentration of 35 wt%) was added. The feed flow rate is 402 g / h, and the circulating catalyst slurry feed rate is 6250 g / h, wherein the mass fraction of cyclohexanone oxime in the circulating catalyst slurry is 1.5%, and the molar ratio of hydrogen peroxide to cyclohexanone in the reaction system is 1.15:1; the obtained reaction product is mixed with toluene for extraction, and the resulting mixed extract is cooled to 70°C by a reaction heat exchanger and then sent to a catalyst separator. The toluene flow rate is 810 g / h, and the mass ratio of toluene to cyclohexanone oxime in the reaction product is 2:1;

[0160] The aqueous phase separated from the catalyst separator is sent to a membrane filter (the membrane filter is equipped with a 10mm diameter, 200mm long sintered metal membrane tube with a filtration accuracy of 0.2μm, and the backwash medium is the filtered second clear liquid). The catalyst-rich stream flowing out from the center of the membrane tube is circulated back to the reactor. The second clear liquid that permeates into the shell from the inside of the membrane tube is sent to the extraction tower. The organic phase separated from the catalyst separator is sent to a water washing tank. The organic phase after washing in the water washing tank is sent to the toluene oxime separation process. In the toluene oxime separation process, the water-washed organic phase is separated by a distillation column. Cyclohexanone oxime product is obtained from the bottom of the column, and the toluene obtained from the top of the column is sent to the extraction tower.

[0161] The gas phase obtained from the reaction is sent to the tail gas absorption process. In the absorption tower, demineralized water is used to absorb ammonia in the tail gas in a countercurrent manner. The amount of demineralized water added is 71 g / h, the operating pressure is atmospheric pressure, and the absorption liquid is sent to the reaction vessel.

[0162] The first clear liquid (wash water) after washing in the washing tank is mixed with the second clear liquid and sent to the extraction process. In the extraction tower, toluene from the toluene oxime separation process is used to countercurrently extract cyclohexanone oxime from the water (first clear liquid and second clear liquid), where water is the continuous phase and toluene is the dispersed phase. The toluene phase obtained by extraction is mixed with the reaction slurry and then sent to the reaction heat exchanger. The aqueous phase obtained by extraction is sent to the deammoniation tower for deammoniation. The operating pressure is atmospheric pressure. The ammonia water obtained from the top of the tower is recycled back to the reactor, and the wastewater obtained from the bottom of the tower is discharged.

[0163] The reactor is equipped with baffles and a stirrer. The stirrer is a propeller-type stirrer with a stirring speed of 600 rpm.

[0164] The catalyst separator includes a vessel body and a stirrer, an inner extension tube, and an inner sleeve disposed within the vessel body. The top end of the inner extension tube is located outside the vessel body, and the bottom end of the inner extension tube is located inside the vessel body. The ratio of the length of the inner extension tube extending below the upper tangent of the vessel body to the vertical distance between the tangent and the lower tangent of the vessel body is 0.85:1. The inner sleeve is fitted inside the inner extension tube, and the top end of the inner sleeve is flush with the top end of the inner extension tube. The top of the annular space formed by the inner sleeve and the inner extension tube... The vessel is enclosed, with the length ratio of the inner extension tube to the inner sleeve being 15:1. A gas phase balance port is provided on the side wall of the inner extension tube, which is connected to the gas phase space of the vessel body to ensure gas phase balance. The stirring paddle of the stirrer is located in the water phase section of the vessel body, and the stirring paddle has one layer. An anti-impact baffle is provided at the bottom end of the inner extension tube. The vessel body is also provided with an overflow weir (L-shaped plate, one end of which is connected to the inner wall of the vessel body) and an organic phase outlet connected to the overflow weir. A gas phase outlet is provided at the top of the vessel body.

[0165] The operating conditions inside the catalyst separator are: temperature 69℃, pressure 0.4MPaG; the agitator is an anchor agitator with a rotation speed of 180rpm.

[0166] Under the above process conditions, sampling began after 10 hours of operation (the conversion rate and selectivity at this time were the initial conversion rate and selectivity). Afterward, samples of the organic phase output from the catalyst separator and the cyclohexanone oxime product were analyzed every 10 hours. When the cyclohexanone conversion rate decreased to below 99.6%, the feeding of cyclohexanone, ammonia, and hydrogen peroxide was stopped. The conversion rate, selectivity, and purity of the cyclohexanone oxime product at this point were the final conversion rate, final selectivity, and purity of the cyclohexanone oxime product (Table 1). The unit operating time was recorded, and catalyst consumption was calculated. Gas chromatography was used for analysis. The conversion rate, selectivity, catalyst consumption, cyclohexanone oxime product purity, and unit operating time data are shown in Table 1.

[0167] Example 4

[0168] Cyclohexanone, ammonia, and a circulating catalyst slurry were mixed and fed into a reactor. Hydrogen peroxide was introduced into the reactor near the bottom agitator via a feed distributor. The reaction was carried out at 90°C and 0.4 MPaG. The effective volume of the reactor was 3 L, and it contained TS-1 titanium-silicon molecular sieve catalyst. The mass fraction of the catalyst in the circulating catalyst slurry was 2%. The feed flow rate of cyclohexanone was 353 g / h, the feed flow rate of ammonia was 67 g / h, and hydrogen peroxide (hydrogen peroxide concentration of 35 wt%) was also fed. The flow rate is 402 g / h, the circulating catalyst slurry feed rate is 6250 g / h, the mass fraction of cyclohexanone oxime in the circulating catalyst slurry is 1.5%, and the molar ratio of hydrogen peroxide to cyclohexanone in the reaction system is 1.15:1; the obtained reaction product is mixed with toluene for extraction, the obtained mixed extract is cooled to 70°C by the reaction heat exchanger, and then sent to the catalyst separator, the toluene flow rate is 810 g / h, and the mass ratio of toluene to cyclohexanone oxime in the reaction product is 2:1;

[0169] The aqueous phase separated from the catalyst separator is sent to a membrane filter (the membrane filter is equipped with a 10mm diameter, 200mm long sintered metal membrane tube with a filtration accuracy of 0.2μm, and the backwash medium is the filtered second clear liquid). The catalyst-rich stream flowing out from the center of the membrane tube is circulated back to the reactor. The second clear liquid that permeates into the shell from the inside of the membrane tube is sent to the extraction tower. The organic phase separated from the catalyst separator is sent to a water washing tank. The organic phase after washing in the water washing tank is sent to the toluene oxime separation process. In the toluene oxime separation process, the water-washed organic phase is separated by a distillation column. Cyclohexanone oxime product is obtained from the bottom of the column, and the toluene obtained from the top of the column is sent to the extraction tower.

[0170] The gas phase obtained from the reaction is sent to the tail gas absorption process. In the absorption tower, demineralized water is used to absorb ammonia in the tail gas in a countercurrent manner. The amount of demineralized water added is 71 g / h, the operating pressure is atmospheric pressure, and the absorption liquid is sent to the reaction vessel.

[0171] The first clear liquid (wash water) after washing in the washing tank is mixed with the second clear liquid and sent to the extraction process. In the extraction tower, toluene from the toluene oxime separation process is used to countercurrently extract cyclohexanone oxime from the water (first clear liquid and second clear liquid), where water is the continuous phase and toluene is the dispersed phase. The toluene phase obtained by extraction is mixed with the reaction slurry and then sent to the reaction heat exchanger. The aqueous phase obtained by extraction is sent to the deammoniation tower for deammoniation. The operating pressure is atmospheric pressure. The ammonia water obtained from the top of the tower is recycled back to the reactor, and the wastewater obtained from the bottom of the tower is discharged.

[0172] The reactor is equipped with baffles and a stirrer. The stirrer is a propeller-type stirrer with a stirring speed of 600 rpm.

[0173] The catalyst separator includes a vessel body and a stirrer, an inner extension tube, and an inner sleeve disposed within the vessel body. The top end of the inner extension tube is located outside the vessel body, and the bottom end of the inner extension tube is located inside the vessel body. The ratio of the length of the inner extension tube extending below the upper tangent of the vessel body to the vertical distance between the tangent and the lower tangent of the vessel body is 0.85:1. The inner sleeve is fitted inside the inner extension tube, and the top end of the inner sleeve is flush with the top end of the inner extension tube. The top of the annular space formed by the inner sleeve and the inner extension tube... The vessel is enclosed, with the length ratio of the inner extension tube to the inner sleeve being 15:1. A gas phase balance port is provided on the side wall of the inner extension tube, which is connected to the gas phase space of the vessel body to ensure gas phase balance. The stirring paddle of the stirrer is located in the water phase section of the vessel body, and the stirring paddle has one layer. An anti-impact baffle is provided at the bottom end of the inner extension tube. The vessel body is also provided with an overflow weir (L-shaped plate, one end of which is connected to the inner wall of the vessel body) and an organic phase outlet connected to the overflow weir. A gas phase outlet is provided at the top of the vessel body.

[0174] The operating conditions inside the catalyst separator are: temperature 69℃, pressure 0.4MPaG; the agitator is an anchor agitator with a rotation speed of 180rpm.

[0175] Under the above process conditions, sampling began after 10 hours of operation (the conversion rate and selectivity at this time were the initial conversion rate and selectivity). Afterward, samples of the organic phase output from the catalyst separator and the cyclohexanone oxime product were analyzed every 10 hours. When the cyclohexanone conversion rate decreased to below 99.6%, the feeding of cyclohexanone, ammonia, and hydrogen peroxide was stopped. The conversion rate, selectivity, and purity of the cyclohexanone oxime product at this point were the final conversion rate, final selectivity, and purity of the cyclohexanone oxime product (Table 1). The unit operating time was recorded, and catalyst consumption was calculated. Gas chromatography was used for analysis. The conversion rate, selectivity, catalyst consumption, cyclohexanone oxime product purity, and unit operating time data are shown in Table 1.

[0176] Example 5

[0177] Cyclohexanone, ammonia, and a circulating catalyst slurry were mixed and fed into a reactor. Hydrogen peroxide was introduced into the reactor near the bottom agitator via a feed distributor. The reaction was carried out at 90°C and 0.4 MPaG. The effective volume of the reactor was 3 L, and it contained TS-1 titanium-silicon molecular sieve catalyst. The mass fraction of the catalyst in the circulating catalyst slurry was 2.5%. The cyclohexanone feed rate was 353 g / h, the ammonia feed rate was 67 g / h, and hydrogen peroxide (hydrogen peroxide concentration of 35 wt%) was added. The feed flow rate is 402 g / h, and the circulating catalyst slurry feed rate is 6250 g / h, wherein the mass fraction of cyclohexanone oxime in the circulating catalyst slurry is 1.5%, and the molar ratio of hydrogen peroxide to cyclohexanone in the reaction system is 1.15:1; the obtained reaction product is mixed with toluene for extraction, and the resulting mixed extract is cooled to 70°C by a reaction heat exchanger and then sent to a catalyst separator. The toluene flow rate is 810 g / h, and the mass ratio of toluene to cyclohexanone oxime in the reaction product is 2:1;

[0178] The catalyst separator is the same as the catalyst separator in Example 1, except that a membrane filter is installed in the water phase space below the height of the anti-surge baffle of the catalyst separator.

[0179] The aqueous phase obtained from the two-phase separation in the catalyst separator enters the aqueous phase space below the height of the anti-surge baffle of the catalyst separator. A membrane filter (the membrane filter is a sintered metal membrane tube with a diameter of 10 mm and a length of 100 mm, and a filtration accuracy of 0.2 μm) is installed in this space. One end of the membrane tube is closed, and the other end is connected to a collecting pipe, which is connected to the outlet of the second clear liquid. The liquid in the aqueous phase permeates from the outer surface of the membrane filter (membrane tube) to the inner surface of the membrane filter (membrane tube) to obtain the second clear liquid. The second clear liquid is collected by the collecting pipe and then sent to the extraction tower. A backwashing line is installed on the clear liquid outlet line, and the backwashing medium is the second clear liquid. The catalyst-rich stream after filtration by the membrane filter is recycled back to the reactor. The organic phase obtained from the two-phase separation in the catalyst separator is sent to a water washing tank. The organic phase after water washing in the water washing tank is sent to the toluene oxime separation process. In the toluene oxime separation process, the organic phase after water washing is separated by a distillation column. Cyclohexanone oxime product is obtained at the bottom of the column, and the toluene obtained at the top of the column is sent to the extraction tower.

[0180] The gas phase obtained from the reaction is sent to the tail gas absorption process. In the absorption tower, demineralized water is used to absorb ammonia in the tail gas in a countercurrent manner. The amount of demineralized water added is 71 g / h, the operating pressure is atmospheric pressure, and the absorption liquid is sent to the reaction vessel.

[0181] The first clear liquid (wash water) after washing in the washing tank is mixed with the second clear liquid and sent to the extraction process. In the extraction tower, toluene from the toluene oxime separation process is used to countercurrently extract cyclohexanone oxime from the water (first clear liquid and second clear liquid), where water is the continuous phase and toluene is the dispersed phase. The toluene phase obtained by extraction is mixed with the reaction slurry and then sent to the reaction heat exchanger. The aqueous phase obtained by extraction is sent to the deammoniation tower for deammoniation. The operating pressure is atmospheric pressure. The ammonia water obtained from the top of the tower is recycled back to the reactor, and the wastewater obtained from the bottom of the tower is discharged.

[0182] The reactor is equipped with baffles, and the agitator inside the reactor is a propeller-type agitator with a stirring speed of 600 rpm.

[0183] The operating conditions inside the catalyst separator are: temperature 69℃, pressure 0.4MPaG; the agitator is an anchor agitator with a rotation speed of 180rpm.

[0184] Under the above process conditions, sampling began after 10 hours of operation (the conversion rate and selectivity at this time were the initial conversion rate and selectivity). Afterward, samples of the organic phase output from the catalyst separator and the cyclohexanone oxime product were analyzed every 10 hours. When the cyclohexanone conversion rate decreased to below 99.6%, the feeding of cyclohexanone, ammonia, and hydrogen peroxide was stopped. The conversion rate, selectivity, and purity of the cyclohexanone oxime product at this point were the final conversion rate, final selectivity, and purity of the cyclohexanone oxime product (Table 1). The unit operating time was recorded, and catalyst consumption was calculated. Gas chromatography was used for analysis. The conversion rate, selectivity, catalyst consumption, cyclohexanone oxime product purity, and unit operating time data are shown in Table 1.

[0185] Example 6

[0186] Cyclohexanone, ammonia, and a circulating catalyst slurry were mixed and fed into a reactor. Hydrogen peroxide was introduced into the reactor near the bottom agitator via a feed distributor. The reaction was carried out at 90°C and 0.4 MPaG. The effective volume of the reactor was 3 L, and it contained TS-1 titanium-silicon molecular sieve catalyst. The mass fraction of the catalyst in the circulating catalyst slurry was 2.5%. The cyclohexanone feed rate was 353 g / h, the ammonia feed rate was 67 g / h, and hydrogen peroxide (hydrogen peroxide concentration of 35 wt%) was added. The feed flow rate is 402 g / h, and the circulating catalyst slurry feed rate is 5600 g / h, wherein the mass fraction of cyclohexanone oxime in the circulating catalyst slurry is 2.5%, and the molar ratio of hydrogen peroxide to cyclohexanone in the reaction system is 1.15:1; the obtained reaction product is mixed with toluene for extraction, and the resulting mixed extract is cooled to 70°C by a reaction heat exchanger and then sent to a catalyst separator. The toluene flow rate is 400 g / h, and the mass ratio of toluene to cyclohexanone oxime in the reaction product is 1:1;

[0187] The aqueous phase separated from the catalyst separator is sent to a membrane filter (the membrane filter is equipped with a 10mm diameter, 200mm long sintered metal membrane tube with a filtration accuracy of 0.2μm). The catalyst-rich stream flowing out from the center of the membrane tube is circulated back to the reactor. The second clear liquid, which permeates into the shell from the inside of the membrane tube, is sent to the extraction tower via the clear liquid discharge line. The clear liquid discharge line is equipped with a backwashing line, and the backwashing medium is the second clear liquid. The organic phase separated from the catalyst separator is sent to a water washing tank. The organic phase after water washing in the water washing tank is sent to the toluene oxime separation process. In the toluene oxime separation process, the water-washed organic phase is separated by a distillation column. Cyclohexanone oxime product is obtained from the bottom of the column, and the toluene obtained from the top of the column is sent to the extraction tower.

[0188] The gas phase obtained from the reaction is sent to the tail gas absorption process. In the absorption tower, demineralized water is used to absorb ammonia in the tail gas in a countercurrent manner. The amount of demineralized water added is 71 g / h, the operating pressure is atmospheric pressure, and the absorption liquid is sent to the reaction vessel.

[0189] The first clear liquid (wash water) after washing in the washing tank is mixed with the second clear liquid and sent to the extraction process. In the extraction tower, toluene from the toluene oxime separation process is used to countercurrently extract cyclohexanone oxime from the water (first clear liquid and second clear liquid), where water is the continuous phase and toluene is the dispersed phase. The toluene phase obtained by extraction is mixed with the reaction slurry and then sent to the reaction heat exchanger. The aqueous phase obtained by extraction is sent to the deammoniation tower for deammoniation. The operating pressure is atmospheric pressure. The ammonia water obtained from the top of the tower is recycled back to the reactor, and the wastewater obtained from the bottom of the tower is discharged.

[0190] The reactor is equipped with baffles and a stirrer. The stirrer is a propeller-type stirrer with a stirring speed of 600 rpm.

[0191] The catalyst separator includes a vessel body and a stirrer, an inner extension tube, and an inner sleeve disposed within the vessel body. The top end of the inner extension tube is located outside the vessel body, and the bottom end of the inner extension tube is located inside the vessel body. The ratio of the length of the inner extension tube extending below the upper tangent of the vessel body to the vertical distance between the tangent and the lower tangent of the vessel body is 0.85:1. The inner sleeve is fitted inside the inner extension tube, and the top end of the inner sleeve is flush with the top end of the inner extension tube. The top of the annular space formed by the inner sleeve and the inner extension tube... The vessel is enclosed, with the length ratio of the inner extension tube to the inner sleeve being 15:1. A gas phase balance port is provided on the side wall of the inner extension tube, which is connected to the gas phase space of the vessel body to ensure gas phase balance. The stirring paddle of the stirrer is located in the water phase section of the vessel body, and the stirring paddle has one layer. An anti-impact baffle is provided at the bottom end of the inner extension tube. The vessel body is also provided with an overflow weir (L-shaped plate, one end of which is connected to the inner wall of the vessel body) and an organic phase outlet connected to the overflow weir. A gas phase outlet is provided at the top of the vessel body.

[0192] The operating conditions inside the catalyst separator are: temperature 69℃, pressure 0.4MPaG; the agitator is an anchor agitator with a rotation speed of 180rpm.

[0193] Under the above process conditions, sampling began after 10 hours of operation (the conversion rate and selectivity at this time were the initial conversion rate and selectivity). Afterward, samples of the organic phase output from the catalyst separator and the cyclohexanone oxime product were analyzed every 10 hours. When the cyclohexanone conversion rate decreased to below 99.6%, the feeding of cyclohexanone, ammonia, and hydrogen peroxide was stopped. The conversion rate, selectivity, and purity of the cyclohexanone oxime product at this point were the final conversion rate, final selectivity, and purity of the cyclohexanone oxime product (Table 1). The unit operating time was recorded, and catalyst consumption was calculated. Gas chromatography was used for analysis. The conversion rate, selectivity, catalyst consumption, cyclohexanone oxime product purity, and unit operating time data are shown in Table 1.

[0194] Comparative Example 1

[0195] The method described in Example 1 is different in that hydrogen peroxide is mixed with cyclohexanone, ammonia and circulating catalyst slurry and then fed into the reactor, with the circulating catalyst slurry volume being 2700 g / h.

[0196] Under the above process conditions, sampling began after 10 hours of operation (the conversion rate and selectivity at this time were the initial conversion rate and selectivity). Afterward, samples of the organic phase output from the catalyst separator and the cyclohexanone oxime product were analyzed every 10 hours. When the cyclohexanone conversion rate decreased to below 99.6%, the feeding of cyclohexanone, ammonia, and hydrogen peroxide was stopped. The conversion rate, selectivity, and purity of the cyclohexanone oxime product at this point were the final conversion rate, final selectivity, and purity of the cyclohexanone oxime product (Table 1). The unit operating time was recorded, and catalyst consumption was calculated. Gas chromatography was used for analysis. The conversion rate, selectivity, catalyst consumption, cyclohexanone oxime product purity, and unit operating time data are shown in Table 1.

[0197] Table 1

[0198]

[0199] As can be seen from the results in Table 1, compared with the comparative example, the method for preparing cyclohexanone oxime provided by the present invention significantly reduces catalyst consumption, significantly improves catalyst service life, has good device stability, high cyclohexanone conversion rate and good product selectivity, and the prepared cyclohexanone oxime product has high purity.

[0200] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing cyclohexanone oxime, characterized in that, The method includes the following steps: (1) Cyclohexanone, ammonia and recycled catalyst slurry are mixed, and then the mixture is contacted with hydrogen peroxide to carry out an ammonium oxime reaction to obtain a reaction slurry; Based on the total amount of cyclohexanone and the circulating catalyst slurry, the mass fraction of cyclohexanone is 2-6%; (2) The reaction slurry is mixed with an organic solvent and the two phases are separated to obtain an organic phase containing cyclohexanone oxime and an aqueous phase containing a catalyst. The method further includes: heating the reaction slurry before mixing it with the organic solvent; or heating the mixture of the reaction slurry and the organic solvent before performing two-phase separation. The mass ratio of organic solvent to cyclohexanone oxime in the reaction slurry is 0.5-5:1; (3) The organic phase obtained in step (2) is washed with water to obtain a stream rich in cyclohexanone oxime and a first supernatant. Then the stream rich in cyclohexanone oxime is separated to obtain an organic solvent and a cyclohexanone oxime product. (4) The aqueous phase obtained in step (2) is subjected to membrane filtration to obtain a catalyst-rich stream and a second clear liquid; the obtained catalyst-rich stream is returned to step (1) to provide circulating catalyst slurry; (5) Extract the first clear liquid and / or the second clear liquid using the organic solvent obtained in step (3), and return the resulting organic phase to step (2) to provide the organic solvent.

2. The method according to claim 1, wherein, The mass ratio of the cyclohexanone to the circulating catalyst slurry is 1:15-50, preferably 1:16-32; Preferably, the mass fraction of cyclohexanone is 3-5.5%, based on the total amount of cyclohexanone and the circulating catalyst slurry; Preferably, the mass fraction of cyclohexanone oxime in the circulating catalyst slurry is 0.1-4%, more preferably 0.5-3%; Preferably, the mass ratio of the organic solvent to the cyclohexanone oxime in the reaction slurry is 1-3:

1.

3. The method according to claim 1 or 2, wherein, In the ammonium oxime reaction system, the molar ratio of hydrogen peroxide to cyclohexanone is 1-1.5:1, preferably 1-1.3:1; Preferably, the hydrogen peroxide is provided by hydrogen peroxide solution, wherein the mass concentration of hydrogen peroxide in the hydrogen peroxide solution is 15-80 wt%, preferably 20-70 wt%. Preferably, in the ammonium oxime reaction system, the molar ratio of ammonia to cyclohexanone is 1-1.5:1, more preferably 1-1.3:1; Preferably, the mass fraction of the catalyst in the circulating catalyst slurry is 0.1%-15%, more preferably 1%-10%; Preferably, the catalyst comprises a titanium-silicon molecular sieve, wherein the titanium-silicon molecular sieve is selected from at least one of TS-1, TS-2, Ti-ZSM-5, Ti-ZSM-12, Ti-ZSM-48, Ti-β, Ti-MCM-41, Ti-MOR, Ti-MWW and Ti-SBA-15; Preferably, the organic solvent is selected from at least one of alkanes having 6-12 carbon atoms, cycloalkanes having 5-11 carbon atoms, and aromatics having 6-10 carbon atoms, more preferably from at least one of aromatics having 6-10 carbon atoms and cycloalkanes having 6-10 carbon atoms, and more preferably from toluene and / or cyclohexane.

4. The method according to any one of claims 1-3, wherein, The conditions for the ammonium oxime reaction include: a reaction temperature of 70-100℃, preferably 80-95℃; and a reaction pressure of 0-0.5 MPaG, preferably 0.2-0.4 MPaG. Preferably, the ammonium oxime reaction is carried out in a stirred tank reactor; Preferably, the method in step (1) further includes: contacting the gas generated by the ammonium oximation reaction with demineralized water to remove ammonia, and returning the resulting absorbent to the ammonium oximation reaction in step (1).

5. The method according to any one of claims 1-4, wherein, The method further includes: optionally heating the catalyst-rich stream obtained by membrane filtration; Preferably, in step (2), after heat treatment, the temperature of the reaction slurry and / or the mixture of the reaction slurry and the organic solvent is 40-85°C.

6. The method according to any one of claims 1-5, wherein, The two-phase separation in step (2) is carried out in a catalyst separator; the catalyst separator includes a vessel body and a stirrer, an inner extension tube and an inner sleeve disposed in the vessel body; the inner sleeve is sleeved inside the inner extension tube, and a gas phase balance port is opened on the side wall of the inner extension tube; the stirring paddle of the stirrer is disposed in the aqueous phase section of the vessel body for stirring the aqueous phase; Preferably, the top end of the inner tube is located outside the vessel body, and the bottom end of the inner tube is located inside the vessel body; Preferably, the top end of the inner sleeve is flush with the top end of the inner extension tube, and the top of the annular space formed by the inner sleeve and the inner extension tube is closed. Preferably, an anti-impact baffle is provided at the bottom end of the inner tube; Preferably, the conditions for the two-phase separation in step (2) include: pressure of 0-500 kPaG and temperature of 40-90℃; Preferably, the separation conditions in step (3) include: pressure of 0-500 kPaG and temperature of 40-90℃; Preferably, the water washing stage in step (3) is 1-5 stages, and more preferably 1-3 stages.

7. The method according to any one of claims 1-6, wherein, The membrane filtration in step (4) is carried out in a membrane filter, which is located inside the catalyst separator or connected to the aqueous phase outlet of the catalyst separator; Preferably, the filtration accuracy of the membrane tube in the membrane filter is 0.01-50 μm, and more preferably 0.05-10 μm; Preferably, the membrane tube in the membrane filter is made of at least one of ceramic, metal and high-density polyethylene, preferably ceramic and / or metal, and more preferably metal; Preferably, the extraction method in step (5) is countercurrent extraction; Preferably, the extraction temperature is 30-90℃, and more preferably 40-80℃; Preferably, the method in step (5) further includes: removing ammonia from the aqueous phase obtained by extraction to obtain ammonia water and wastewater; and returning the obtained ammonia water to the ammonia oxime reaction in step (1).

8. A system for preparing cyclohexanone oxime, characterized in that, The system includes a reaction unit, a water washing unit, an extraction unit, and a product separation unit. The reaction unit includes at least one reactor, a catalyst separator, a reaction heat exchanger, and a membrane filter disposed inside the catalyst separator or connected to the aqueous phase outlet of the catalyst separator. The reactor is connected to the circulating catalyst slurry pipeline and the hydrogen peroxide feed pipeline, respectively. The circulating catalyst slurry pipeline is equipped with a cyclohexanone inlet and an ammonia inlet. The reactor is used to contact the cyclohexanone, ammonia and circulating catalyst slurry mixture from the circulating catalyst slurry pipeline with hydrogen peroxide from the hydrogen peroxide feed pipeline to carry out an ammonoximation reaction. The reactor and the catalyst separator are connected by a pipeline. A reaction heat exchanger is installed on the pipeline between the reactor and the catalyst separator. The pipeline is equipped with a circulating organic solvent inlet. The catalyst separator is used to separate the reaction slurry from the reactor and the mixed extract material of the organic solvent into two phases. The organic phase outlet of the catalyst separator is connected to the water washing unit, the aqueous phase outlet of the water washing unit is connected to the aqueous phase inlet of the extraction unit, and the cyclohexanone oxime-rich outlet of the water washing unit is connected to the cyclohexanone oxime-rich inlet of the product separation unit. The water washing unit is used to wash the organic phase from the catalyst separator. The product separation unit's organic solvent outlet is connected to the extraction unit's organic solvent inlet. The product separation unit is used to separate the material rich in cyclohexanone oxime from the water washing unit. The catalyst-rich stream outlet of the membrane filter is connected to the reactor via a circulating catalyst slurry pipeline, and the second clear liquid outlet of the membrane filter is connected to the aqueous phase inlet of the extraction unit. The membrane filter is used to filter the aqueous phase separated from the two phases of the catalyst separator, and to send the catalyst-rich stream into the reactor and the second clear liquid into the extraction unit. An extraction unit includes at least one extraction tower. The organic solvent outlet of the extraction unit is connected to a pipeline between the reactor and the reaction heat exchanger via a circulating organic solvent pipeline, or to a pipeline between the reaction heat exchanger and the catalyst separator. The extraction unit is used to extract the first clear liquid from the water washing unit and / or the second clear liquid from the membrane filter using the organic solvent from the product separation unit.

9. The system according to claim 8, wherein, The reaction unit includes 1-4 reactors, preferably 1-2 reactors; Preferably, the reactor is a stirred tank reactor; Preferably, each reactor is independently connected to a hydrogen peroxide feed line; Preferably, the catalyst separator includes a vessel body and a stirrer, an inner extension tube, and an inner sleeve disposed within the vessel body; the inner sleeve is fitted inside the inner extension tube and is used to convey the mixed extract material of the reaction slurry and organic solvent to the inner extension tube; the inner extension tube is used to convey the mixed extract material of the reaction slurry and organic solvent to the vessel body for two-phase separation to obtain an organic phase and an aqueous phase; a gas phase balance port is provided on the side wall of the inner extension tube to maintain the gas phase balance of the vessel body; the stirring paddle of the stirrer is disposed in the aqueous phase section of the vessel body to stir the aqueous phase; Preferably, the top end of the inner tube is located outside the vessel body, and the bottom end of the inner tube is located inside the vessel body; Preferably, the top end of the inner sleeve is flush with the top end of the inner extension tube, and the top of the annular space formed by the inner sleeve and the inner extension tube is closed. Preferably, the bottom end of the inner tube is provided with an anti-impact baffle to buffer the mixed extraction material of the reaction slurry and organic solvent; Preferably, the filtration accuracy of the membrane tube in the membrane filter is 0.01-50 μm, and more preferably 0.05-10 μm; Preferably, the membrane tube in the membrane filter is made of at least one of ceramic, metal and high-density polyethylene, preferably ceramic and / or metal, and more preferably metal.

10. The system according to claim 9, wherein, A heat exchanger may be optionally installed on the circulating catalyst slurry pipeline between the membrane filter and the reactor; Preferably, the system further includes an ammonia removal unit connected to the aqueous phase outlet of the extraction unit for separating wastewater and ammonia from the aqueous phase; Preferably, the circulating catalyst slurry pipeline is further provided with a circulating ammonia water inlet, and the ammonia water outlet of the deammoniation unit is connected to the circulating ammonia water inlet on the circulating catalyst slurry pipeline for returning ammonia water to the ammonium oxime reaction; Preferably, the system further includes a tail gas absorption unit, with the gas phase outlet of the reactor connected to the tail gas absorption unit and the liquid phase outlet of the tail gas absorption unit connected to the reactor, for contacting the gas generated by the reaction with demineralized water to remove ammonia.

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