A solvent-free cyclohexanone oxime preparation device and method

Abstract

The application provides a solvent-free cyclohexanone oxime preparation device and method, which comprises a mixing reaction assembly, an extraction tower, a catalyst recovery assembly, a flash tank and an extractant recovery assembly; the discharge end of the mixing reaction assembly is communicated with the upper part of the extraction tower, the top of the extraction tower is communicated with the flash tank, the bottom of the flash tank is used for discharging to a refining unit to generate cyclohexanone oxime and is communicated with the middle part of the extraction tower, the low-temperature cyclohexanone oxime concentrated liquid at the bottom of the flash tank flows into the extraction tower according to a preset proportion; the top of the flash tank is communicated with the extractant recovery assembly, the discharge end of the extractant recovery assembly is communicated with the lower part of the extraction tower, the bottom of the extraction tower is communicated with the catalyst recovery assembly, and the discharge end of the catalyst recovery assembly is communicated with the feed end of the mixing reaction assembly; the lower part of the extraction tower is provided with an extractant feed port, and the extractant in the extraction tower is insoluble in water. The application can reduce recovery energy consumption, shorten a process flow, reduce production cost and improve production efficiency.

Description

Technical Field

[0001] This invention relates to the field of chemical preparation technology, and in particular to a solvent-free apparatus and method for preparing cyclohexanone oxime. Background Technology

[0002] Cyclohexanone oxime is an important intermediate in the synthesis of caprolactam. It can be directly generated into caprolactam through the Beckmann rearrangement reaction. Polyamide engineering plastics and nylon 6 materials polymerized from caprolactam monomers have wide applications in daily life.

[0003] Currently, the mainstream process for the industrial production of cyclohexanone oxime is the homogeneous cyclohexanone oximation reaction using tert-butanol as a solvent. Although this method is simple and produces no byproduct ammonium sulfate, the addition of the inert solvent tert-butanol significantly increases the steam consumption for subsequent solvent and product recovery and purification, making the process very lengthy and cumbersome. In the recycling of the catalyst, circulating cooling water heat exchangers are typically used to absorb the reaction heat, which is inefficient and prone to catalyst scaling and pipe blockage, requiring frequent shutdowns for cleaning, reducing production efficiency, and increasing catalyst loss.

[0004] Therefore, there is an urgent need to develop an apparatus for completing the cyclohexanone amination reaction without the need for the inert solvent tert-butanol. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a solvent-free apparatus and method for preparing cyclohexanone oxime, which can reduce energy consumption during recovery, shorten the process flow, reduce production costs, and improve production efficiency.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a solvent-free apparatus for preparing cyclohexanone oxime, comprising a mixing reaction assembly, an extraction tower, a catalyst recovery assembly, a flash tank, and an extractant recovery assembly;

[0008] The discharge end of the mixing reaction assembly is connected to the upper part of the extraction tower, the top of the extraction tower is connected to the flash tank, the bottom of the flash tank is used to discharge to the purification unit to generate cyclohexanone oxime and is connected to the middle part of the extraction tower, and the low-temperature cyclohexanone oxime concentrate at the bottom of the flash tank flows into the extraction tower according to a preset ratio.

[0009] The top of the flash tank is connected to the extractant recovery assembly, the outlet of the extractant recovery assembly is connected to the lower part of the extraction tower, the bottom of the extraction tower is connected to the catalyst recovery assembly, and the outlet of the catalyst recovery assembly is connected to the feed end of the mixing reaction assembly.

[0010] The lower part of the extraction tower is provided with an extractant inlet, and the extractant in the extraction tower is insoluble in water.

[0011] The beneficial effects of this invention are as follows: The use of a water-insoluble extractant for cyclohexanone oxime extraction avoids the high energy consumption of subsequent solvent recovery and purification, thus reducing energy consumption. Simultaneously, the low-temperature cyclohexanone oxime concentrate at the bottom of the flash tank flows into the extraction tower according to a preset ratio, utilizing the heat difference between the circulating flash evaporation and the system reaction heat to balance the reaction heat. This not only efficiently balances the reaction heat but also allows the extraction tower to function as a heat exchanger, shortening the process flow and reducing production costs. Furthermore, it solves the problems of low efficiency in removing reaction heat from traditional heat exchangers, easy scaling requiring frequent shutdowns for cleaning, and catalyst depletion, thereby improving production efficiency.

[0012] Optionally, the extractant recovery assembly includes a condenser, a buffer tank, and a first circulation pump. The top of the flash tank is connected to one end of the condenser, the other end of the condenser is connected to the buffer tank, the bottom end of the buffer tank serves as the discharge end and is connected to one end of the first circulation pump, and the other end of the first circulation pump is connected to the lower part of the extraction tower.

[0013] As described above, the low-temperature cyclohexanone oxime concentrate in the lower layer of the flash tank is refluxed to balance most of the heat of reaction of the catalyst in the extraction tower. The refluxed extractant, as a low-temperature solution, can also balance part of the heat of reaction to a certain extent, thus achieving final balance of the heat of reaction of the catalyst in the extraction tower, so that the circulating material can be kept at a suitable reaction temperature.

[0014] Optionally, the mixing reaction assembly includes a primary mixer, a secondary mixer, and a reaction vessel connected in sequence, with the bottom of the reaction vessel serving as the discharge end and connected to the upper part of the extraction tower;

[0015] The primary mixer includes a cyclohexanone inlet and a gaseous ammonia inlet, and the secondary mixer includes a hydrogen peroxide inlet.

[0016] Optionally, the catalyst recovery assembly includes a second circulation pump and a filter. The bottom of the extraction tower is connected to one end of the filter via the second circulation pump, and the other end of the filter is connected to the primary mixer as the discharge end.

[0017] As described above, the catalyst exists only in the aqueous phase layer. Compared with the homogeneous ammonium oxime reaction, the filtration membrane system of this reaction device only needs to filter the aqueous phase reaction liquid, without needing to filter the entire working liquid of the reaction system. Therefore, it can reduce the membrane filtration area and reduce membrane tube wear.

[0018] Optionally, the filter is a ceramic membrane filter.

[0019] Optionally, the system also includes a third circulation pump, with the bottom of the flash tank connected to one end of the third circulation pump, and the other end of the third circulation pump used to discharge material to the refining unit to generate cyclohexanone oxime and connected to the middle of the extraction tower.

[0020] Optionally, a pressure reducing valve is provided between the top of the extraction tower and the flash tank.

[0021] In a second aspect, the present invention provides a solvent-free method for preparing cyclohexanone oxime, using the solvent-free cyclohexanone oxime preparation apparatus of the first aspect, comprising the following steps:

[0022] S1. Cyclohexanone, ammonia gas, and hydrogen peroxide are passed through a mixing reaction assembly to obtain a reaction mixture containing cyclohexanone oxime, water, catalyst, and ammonia gas. The reaction mixture is then discharged from the mixing reaction assembly to the upper part of the extraction tower.

[0023] S2. The extractant located at the bottom of the extraction tower performs countercurrent extraction of cyclohexanone oxime in the reaction mixture, such that the catalyst, the water, and the cyclohexanone oxime dissolved in the water are located in the lower layer of the extraction tower, and the extractant and the cyclohexanone oxime insoluble in the water are located in the upper layer of the extraction tower.

[0024] S3. The extractant and water-insoluble cyclohexanone oxime enter the flash tank. After being flash-vaporized, the extractant flows into the extractant recovery component. The cyclohexanone oxime flows to the lower layer of the flash tank and forms a low-temperature cyclohexanone oxime concentrate. The low-temperature cyclohexanone oxime concentrate flows into the extraction tower in a preset ratio to balance the reaction heat in the extraction tower. The remaining proportion is discharged to the purification unit to generate cyclohexanone oxime.

[0025] S4. The extractant is returned to the lower layer of the extraction tower by the extractant recovery component to perform secondary extraction, flash evaporation and recovery of cyclohexanone oxime dissolved in water. This cycle is repeated multiple times until the extraction of all cyclohexanone oxime is completed.

[0026] S5. The catalyst and water in the lower layer of the extraction tower enter the catalyst recovery component. The clear liquid is output from the catalyst recovery component to the wastewater treatment device, and the recovered catalyst concentrate is returned to the mixing reaction component.

[0027] Optionally, in step S4, the extractant recovery component recirculates the extractant back to the lower layer of the extraction tower, specifically by:

[0028] The extractant flows into a buffer tank through a condenser. The non-condensable gases and ammonia in the buffer tank are sent to the tail gas absorption device. The extractant in the buffer tank is returned to the lower layer of the extraction tower by the action of the first circulation pump to balance the heat of reaction in the extraction tower.

[0029] Optionally, in step S1, the reaction mixture containing cyclohexanone oxime, water, catalyst, and gaseous ammonia obtained by passing cyclohexanone, gaseous ammonia, and hydrogen peroxide through a mixing reaction assembly is specifically as follows:

[0030] Cyclohexanone and gaseous ammonia are added to a primary mixer. After the solution is mixed evenly, hydrogen peroxide is added to a secondary mixer for a second mixing. The reaction mixture after the two mixing processes is added from the top to a reaction vessel containing a catalyst to complete the ammonia oxime reaction, so as to obtain a reaction mixture containing cyclohexanone oxime, water, catalyst and gaseous ammonia.

[0031] The technical effects of the solvent-free cyclohexanone oxime preparation method provided in the second aspect are described in the relevant description of the solvent-free cyclohexanone oxime preparation apparatus provided in the first aspect. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of a solvent-free cyclohexanone oxime preparation apparatus according to an embodiment of the present invention;

[0033] Figure 2 This is a schematic flowchart of a solvent-free cyclohexanone oxime preparation method according to an embodiment of the present invention.

[0034] [Explanation of Labels in the Attached Image]

[0035] 1. Primary mixer; 2. Secondary mixer; 3. Reactor; 4. Extraction tower; 5. Pressure reducing valve; 6. Flash tank; 7. Condenser; 8. Buffer tank; 9. First circulation pump; 10. Second circulation pump; 11. Filter; 12. Third circulation pump. Detailed Implementation

[0036] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0037] Example 1

[0038] Currently, the mainstream industrial cyclohexanone amination oxime reaction mainly uses tert-butanol as an organic solvent to improve the solubility of the product cyclohexanone oxime, resulting in high energy consumption and a lengthy process for subsequent solvent and product recovery and purification. Furthermore, the oxime reaction is strongly exothermic, and catalyst recovery and reuse require the removal of reaction heat. Traditional methods for removing reaction heat typically use cooling water heat exchangers, which have poor heat exchange efficiency and are prone to catalyst scaling and pipe blockage. Therefore, this embodiment improves the traditional cyclohexanone oxime preparation apparatus as follows:

[0039] Please refer to Figure 1 A solvent-free apparatus for preparing cyclohexanone oxime includes a mixing reaction assembly, an extraction tower 4, a catalyst recovery assembly, a flash tank 6, an extractant recovery assembly, a third circulation pump 12, and a pressure reducing valve 5.

[0040] like Figure 1 As shown, the discharge end of the mixing reaction component is connected to the upper part of the extraction tower 4. The top of the extraction tower 4 is connected to the flash tank 6 through the pressure reducing valve 5. The bottom of the flash tank 6 is connected to one end of the third circulation pump 12. The other end of the third circulation pump 12 is used to discharge to the purification unit to generate cyclohexanone oxime and is connected to the middle part of the extraction tower 4. The low-temperature cyclohexanone oxime concentrate at the bottom of the flash tank 6 flows into the extraction tower 4 according to a preset ratio. Thus, the low-temperature cyclohexanone oxime concentrate at the bottom of the flash tank 6 flows into the extraction tower 4 according to a preset ratio to balance the heat of reaction by utilizing the heat difference between the circulating flash evaporation and the system reaction heat. This not only efficiently balances the heat of reaction, but the extraction tower 4 also functions as a heat exchanger, thereby shortening the process flow and reducing production costs. It also solves the problems of low efficiency in removing reaction heat by traditional heat exchangers, easy scaling requiring frequent shutdowns for cleaning, and catalyst loss, thereby improving production efficiency.

[0041] like Figure 1 As shown, the top of the flash tank 6 is connected to the extractant recovery assembly, the outlet of the extractant recovery assembly is connected to the lower part of the extraction tower 4, the bottom of the extraction tower 4 is connected to the catalyst recovery assembly, and the outlet of the catalyst recovery assembly is connected to the feed end of the mixing reaction assembly, so as to complete the recycling of extractant and catalyst.

[0042] In this embodiment, the lower part of the extraction tower 4 is provided with an extractant inlet. Thus, the upper layer of the extraction tower 4 serves as a heat exchange zone to remove the heat of reaction, and the lower layer of the extraction tower 4 serves as an extraction zone to extract cyclohexanone oxime and separate it into the extractant and cyclohexanone oxime in the upper layer and water and catalyst in the lower layer.

[0043] In this embodiment, the extractant in extraction tower 4 is insoluble in water. Preferably, the extractant in this embodiment is cyclohexane. Therefore, using an insoluble extractant for the extraction of cyclohexanone oxime avoids the high energy consumption of subsequent solvent recovery and purification, thus achieving the effect of reducing energy consumption during recovery.

[0044] like Figure 1 As shown, the mixing reaction assembly in this embodiment includes a primary mixer 1, a secondary mixer 2, and a reaction vessel 3 connected in sequence. The bottom of the reaction vessel 3 serves as the discharge end and is connected to the upper part of the extraction tower 4. The primary mixer 1 includes a cyclohexanone inlet and a gaseous ammonia inlet, and the secondary mixer 2 includes a hydrogen peroxide inlet.

[0045] like Figure 1 As shown, the catalyst recovery assembly in this embodiment includes a second circulation pump 10 and a filter 11. The bottom of the extraction tower 4 is connected to one end of the filter 11 via the second circulation pump 10, and the other end of the filter 11 is connected to the primary mixer 1 as the discharge end. Therefore, the catalyst exists only in the aqueous phase. Compared to homogeneous ammonium oxime reaction, the membrane filtration system of this reaction device only needs to filter the aqueous phase reaction liquid, eliminating the need for full filtration of the working liquid of the entire reaction system. This reduces the membrane filtration area and membrane tube wear.

[0046] like Figure 1 As shown, the extractant recovery assembly in this embodiment includes a condenser 7, a buffer tank 8, and a first circulation pump 9. The top of the flash tank 6 is connected to one end of the condenser 7, and the other end of the condenser 7 is connected to the buffer tank 8. The bottom end of the buffer tank 8 serves as the discharge end and is connected to one end of the first circulation pump 9. The other end of the first circulation pump 9 is connected to the lower part of the extraction tower 4. Therefore, since the condensed and refluxed extractant is a low-temperature solution, it can play a cooling role, thus balancing some of the reaction heat to a certain extent. This ultimately achieves a final balance of the reaction heat of the catalyst in the extraction tower 4, allowing the circulating material to be maintained at a suitable reaction temperature.

[0047] In this embodiment, filter 11 is a ceramic membrane filter.

[0048] In this embodiment, the pressure of the pressure reducing valve 5 is maintained at 200-300 kPa.

[0049] Example 2

[0050] Please refer to Figure 1 and Figure 2 A solvent-free method for preparing cyclohexanone oxime, using a solvent-free cyclohexanone oxime preparation apparatus as described in Example 1, is characterized by comprising the following steps:

[0051] S1. Cyclohexanone, ammonia gas, and hydrogen peroxide are passed through a mixing reaction assembly to obtain a reaction mixture containing cyclohexanone oxime, water, catalyst, and ammonia gas. The reaction mixture is then discharged from the mixing reaction assembly to the upper part of the extraction tower 4.

[0052] In this embodiment, step S1 is the oxime reaction step.

[0053] Specifically, the reaction mixture containing cyclohexanone oxime, water, catalyst, and gaseous ammonia obtained by passing cyclohexanone, gaseous ammonia, and hydrogen peroxide through a mixing reaction assembly is as follows:

[0054] Cyclohexanone and gaseous ammonia are added to the primary mixer 1. After the solution is mixed evenly, hydrogen peroxide is added and the mixture is then introduced into the secondary mixer 2 for secondary mixing. The reaction mixture after the two mixing is added from the top into the reaction vessel 3 containing the catalyst to complete the ammonia oxime reaction, so as to obtain a reaction mixture containing cyclohexanone oxime, water, catalyst and gaseous ammonia.

[0055] S2. The extractant in the lower part of the extraction tower 4 performs countercurrent extraction of cyclohexanone oxime in the reaction mixture, so that the catalyst, water and cyclohexanone oxime dissolved in water are in the lower layer of the extraction tower 4, and the extractant and cyclohexanone oxime insoluble in water are in the upper layer of the extraction tower 4.

[0056] In this embodiment, step S2 is an extraction and layering step.

[0057] In this process, under the influence of density difference and natural gravity, the catalyst, water, and cyclohexanone oxime dissolved in water in the extraction tower 4 are separated into the lower layer, while the extractant and cyclohexanone oxime insoluble in water are separated into the upper layer.

[0058] It should be noted that both the water-insoluble and water-soluble cyclohexanone oximes are cyclohexanone oximes that come out of reactor 3. Since a small amount of cyclohexanone oxime may dissolve in water, they are distinguished and explained separately.

[0059] S3. The extractant and water-insoluble cyclohexanone oxime enter the flash tank 6. After being flash-vaporized, the extractant flows into the extractant recovery component. The cyclohexanone oxime flows to the lower layer of the flash tank 6 and forms a low-temperature cyclohexanone oxime concentrate. The low-temperature cyclohexanone oxime concentrate flows into the extraction tower 4 according to a preset ratio to balance the reaction heat in the extraction tower 4. The remaining proportion is discharged to the purification unit to generate cyclohexanone oxime.

[0060] In this embodiment, step S3 is the discharge and reaction heat balance step.

[0061] Among them, the low-temperature cyclohexanone oxime concentrate located at the bottom of the flash tank 6 is partially pumped from the middle of the extraction tower 4 into the upper organic phase inside the extraction tower 4 by the action of the third circulation pump 12. This part of the reflux liquid is used to finally balance the heat of reaction, so that the circulating material can be kept at a suitable temperature for the reaction, thus replacing the traditional inefficient heat exchanger for heat removal; while the other part is directly discharged into the purification unit to generate the product cyclohexanone oxime.

[0062] S4. The extractant is returned to the lower layer of the extraction tower 4 by the extractant recovery component to perform secondary extraction, flash evaporation and recovery of cyclohexanone oxime dissolved in water. This cycle is repeated multiple times until the extraction of all cyclohexanone oxime is completed.

[0063] In this embodiment, step S4 is the extractant recovery step.

[0064] Specifically, the extractant is returned to the lower layer of extraction tower 4 by the extractant recovery component as follows:

[0065] The extractant flows into the buffer tank 8 through the condenser 7. The non-condensable gas and ammonia in the buffer tank 8 are sent to the tail gas absorption device. The extractant in the buffer tank 8 is returned to the lower layer of the extraction tower 4 by the first circulation pump 9 to balance the heat of reaction in the extraction tower 4.

[0066] Because the reflux rate of the extractant is relatively low, only a portion of the heat of reaction can be balanced. The majority of the heat of reaction is balanced by the lower layer solution of flash tank 6.

[0067] The number of cycles depends on the actual extraction effect.

[0068] S5. The catalyst and water in the lower layer of the extraction tower 4 enter the catalyst recovery unit. The clear liquid is output from the catalyst recovery unit to the wastewater treatment device, and the recovered catalyst concentrate is returned to the mixing reaction unit.

[0069] In this embodiment, step S5 is the catalyst recovery step.

[0070] The lower aqueous phase and catalyst, after extraction and removal of reaction heat, enter the ceramic membrane filter through the second circulation pump 10. The clear liquid enters the wastewater treatment device. The catalyst concentrate retained by the membrane returns to the reactor 3 through the primary mixer 1 and the secondary mixer 2 to participate in the reaction, thus realizing the recycling of the catalyst.

[0071] In summary, this embodiment employs a water-insoluble extractant for the extraction of cyclohexanone oxime. The heat of reaction is removed through the heat difference generated by the circulating flash evaporation and the reflux of the extractant. Furthermore, the recovery process of the catalyst and extractant is optimized, thereby effectively solving the shortcomings of traditional cyclohexanone oxime preparation devices. This achieves the effects of reducing recovery energy consumption, shortening the process flow, reducing production costs, improving production efficiency, reducing membrane filtration area, and reducing membrane tube wear.

[0072] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0073] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0074] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "over," or "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," or "beneath" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0075] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0076] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A solvent-free apparatus for preparing cyclohexanone oxime, characterized in that, Includes a mixing reaction assembly, an extraction tower, a catalyst recovery assembly, a flash tank, and an extractant recovery assembly; The discharge end of the mixing reaction assembly is connected to the upper part of the extraction tower, the top of the extraction tower is connected to the flash tank, and the bottom of the flash tank is used to discharge to the purification unit to generate cyclohexanone oxime and is connected to the middle part of the extraction tower. The top of the flash tank is connected to the extractant recovery assembly, the outlet of the extractant recovery assembly is connected to the lower part of the extraction tower, the bottom of the extraction tower is connected to the catalyst recovery assembly, and the outlet of the catalyst recovery assembly is connected to the feed end of the mixing reaction assembly. The lower part of the extraction tower is provided with an extractant inlet, and the extractant in the extraction tower is insoluble in water; It also includes a third circulation pump, the bottom of the flash tank is connected to one end of the third circulation pump, and the other end of the third circulation pump is used to discharge material to the refining unit to generate cyclohexanone oxime and is connected to the middle of the extraction tower; Cyclohexanone, ammonia, and hydrogen peroxide are passed through a mixing reaction assembly to obtain a reaction mixture containing cyclohexanone oxime, water, a catalyst, and ammonia. This mixture flows out to the upper part of an extraction tower. In the extraction tower, the extractant at the lower part countercurrently extracts the cyclohexanone oxime from the reaction mixture, resulting in the catalyst, water, and water-soluble cyclohexanone oxime being in the lower layer of the extraction tower, while the extractant and water-insoluble cyclohexanone oxime are in the upper layer. The extractant and water-insoluble cyclohexanone oxime then enter a flash tank. After flash vaporization, the extractant flows into an extractant recovery assembly. The cyclohexanone oxime flows to the lower layer of the flash tank, forming a low-temperature cyclohexanone oxime concentrate. This concentrate flows into the extraction tower at a predetermined ratio to balance the reaction heat within the tower. The remaining concentrate is discharged to a purification unit to generate cyclohexanone oxime.

2. The solvent-free cyclohexanone oxime preparation apparatus according to claim 1, characterized in that, The extractant recovery assembly includes a condenser, a buffer tank, and a first circulation pump. The top of the flash tank is connected to one end of the condenser, the other end of the condenser is connected to the buffer tank, the bottom end of the buffer tank serves as the discharge end and is connected to one end of the first circulation pump, and the other end of the first circulation pump is connected to the lower part of the extraction tower.

3. The solvent-free cyclohexanone oxime preparation apparatus according to claim 1, characterized in that, The mixing reaction assembly includes a primary mixer, a secondary mixer, and a reaction vessel connected in sequence, with the bottom of the reaction vessel serving as the discharge end and connected to the upper part of the extraction tower; The primary mixer includes a cyclohexanone inlet and a gaseous ammonia inlet, and the secondary mixer includes a hydrogen peroxide inlet.

4. The solvent-free cyclohexanone oxime preparation apparatus according to claim 3, characterized in that, The catalyst recovery assembly includes a second circulation pump and a filter. The bottom of the extraction tower is connected to one end of the filter via the second circulation pump, and the other end of the filter is connected to the primary mixer as the discharge end.

5. The solvent-free cyclohexanone oxime preparation apparatus according to claim 4, characterized in that, The filter is a ceramic membrane filter.

6. The solvent-free cyclohexanone oxime preparation apparatus according to any one of claims 1 to 5, characterized in that, A pressure reducing valve is installed between the top of the extraction tower and the flash tank.

7. A solvent-free method for preparing cyclohexanone oxime, using the solvent-free cyclohexanone oxime preparation apparatus according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Cyclohexanone, ammonia gas, and hydrogen peroxide are passed through a mixing reaction assembly to obtain a reaction mixture containing cyclohexanone oxime, water, catalyst, and ammonia gas. The reaction mixture is then discharged from the mixing reaction assembly to the upper part of the extraction tower. S2. The extractant located at the bottom of the extraction tower performs countercurrent extraction of cyclohexanone oxime in the reaction mixture, such that the catalyst, the water, and the cyclohexanone oxime dissolved in the water are located in the lower layer of the extraction tower, and the extractant and the cyclohexanone oxime insoluble in the water are located in the upper layer of the extraction tower. S3. The extractant and water-insoluble cyclohexanone oxime enter the flash tank. After being flash-vaporized, the extractant flows into the extractant recovery component. The cyclohexanone oxime flows to the lower layer of the flash tank and forms a low-temperature cyclohexanone oxime concentrate. The low-temperature cyclohexanone oxime concentrate flows into the extraction tower in a preset ratio to balance the reaction heat in the extraction tower. The remaining proportion is discharged to the purification unit to generate cyclohexanone oxime. S4. The extractant is returned to the lower layer of the extraction tower by the extractant recovery component to perform secondary extraction, flash evaporation and recovery of cyclohexanone oxime dissolved in water. This cycle is repeated multiple times until the extraction of all cyclohexanone oxime is completed. S5. The catalyst and water in the lower layer of the extraction tower enter the catalyst recovery component. The clear liquid is output from the catalyst recovery component to the wastewater treatment device, and the recovered catalyst concentrate is returned to the mixing reaction component.

8. The method for preparing solvent-free cyclohexanone oxime according to claim 7, characterized in that, In step S4, the extractant recovery component recirculates the extractant back to the lower layer of the extraction tower, specifically as follows: The extractant flows into a buffer tank through a condenser. The non-condensable gases and ammonia in the buffer tank are sent to the tail gas absorption device. The extractant in the buffer tank is returned to the lower layer of the extraction tower by the action of the first circulation pump to balance the heat of reaction in the extraction tower.

9. The method for preparing solvent-free cyclohexanone oxime according to claim 7, characterized in that, In step S1, the reaction mixture containing cyclohexanone oxime, water, catalyst, and gaseous ammonia is obtained by passing cyclohexanone, ammonia, and hydrogen peroxide through a mixing reaction assembly. Specifically, the reaction mixture is as follows: Cyclohexanone and gaseous ammonia are added to a primary mixer. After the solution is mixed evenly, hydrogen peroxide is added to a secondary mixer for a second mixing. The reaction mixture after the two mixing processes is added from the top to a reaction vessel containing a catalyst to complete the ammonia oxime reaction, so as to obtain a reaction mixture containing cyclohexanone oxime, water, catalyst and gaseous ammonia.

Images