WO2021208200A1 - Built-in micro-interface ammoximation reaction system and method - Google Patents

Abstract

The present invention provides a built-in micro-interface ammoximation reaction system and method, the system comprising an oximation reactor, a reaction supernatant buffer tank, a tert-butanol recovery tower, an extraction tank, a water washing separator, and a water extraction tower, wherein an external circulation device is provided outside the oximation reactor; a micro-interface unit is provided inside the oximation reactor; an oxime aqueous solution outlet is provided at the bottom of the tert-butanol recovery tower; the extraction tank is provided with a liquid inlet, a light phase outlet, and a water phase outlet; the liquid inlet is connected to the oxime aqueous solution outlet; the light phase outlet is connected to the water washing separator for washing a toluene oxime solution; and the water phase outlet is connected to the water extraction tower for extracting and recovering the oxime in the water phase. In the built-in micro-interface ammoximation reaction system of the present invention, the provision of the micro-interface unit inside the reactor increases the mass transfer area between ammonia gas and a liquid phase material and lowers the reaction temperature and pressure, thereby inhibiting the occurrence of side reactions and increasing oximation reaction efficiency.

Description

A built-in micro-interface ammoximation reaction system and method Technical field

The invention belongs to the technical field of micro-interface strengthening reactions, and specifically relates to a built-in micro-interface ammoximation reaction system and method.

Background technique

As we all know, cyclohexanone oxime is the key intermediate for the synthesis of caprolactam, and caprolactam is an important raw material for the preparation of nylon 6 and engineering plastics. The current preparation process of cyclohexanone oxime mainly uses cyclohexanone, ammonia and hydrogen peroxide under low pressure conditions. Butanol is the solvent, using titanium silicon molecular sieve catalyst to synthesize cyclohexanone oxime in one step in the reactor. The reaction formula is: NH ₃ +H ₂ O ₂ +C ₆ H ₁₀ O=C ₆ H ₁₁ ON+2H ₂ O . The cyclohexanone ammoximation method to prepare cyclohexanone oxime is simple, has no by-product ammonium sulfate, and has no environmental problems. Therefore, it has been favored by the caprolactam industry in recent years. Although the cyclohexanone ammoximation process has obvious technological advantages, it also has some shortcomings. On the one hand, the gas-liquid mass transfer area of the existing oximation reactor is limited. During the reaction process, the reaction mixture of raw materials and ammonia cannot be It is fully mixed, resulting in incomplete conversion of cyclohexanone, low oximation conversion rate, and increasing the occurrence of side reactions; on the other hand, the ammoximation reaction is a strong exothermic reaction (301KJ/mol), and the temperature is too high. The decomposition products of cyclohexanone and cyclohexanone oxime are not easily removed in the subsequent process, which affects the yield and quality of the final product caprolactam.

In order to improve the reaction efficiency of cyclohexanone ammoximation, reduce the raw material consumption of the existing process, improve the quality of cyclohexanone oxime and improve the output and quality of the finished caprolactam, it is necessary to improve the current process.

Summary of the invention

In view of this, the first object of the present invention is to provide a built-in micro-interface ammoximation reaction system. The reaction system is equipped with a micro-interface unit inside the ammoximation reactor. After the micro-interface unit is installed, the ammonia can be removed on the one hand. The gas is dispersed and broken into micro-bubbles with a diameter of micrometers, increasing the phase boundary area between the ammonia gas and the liquid phase material, so that the mass transfer space is fully satisfied, and the residence time of the ammonia gas in the liquid phase is increased, and the ammonia gas is reduced. Consumption, thereby greatly improving the efficiency of the oximation reaction, effectively suppressing side reactions, and significantly reducing the energy consumption of the reaction process; on the other hand, the reaction temperature and pressure are reduced, the decomposition products of cyclohexanone and cyclohexanone oxime are reduced, and the decomposition products of cyclohexanone and cyclohexanone oxime are reduced, and the The output and quality of the final product, caprolactam, reduce energy consumption and improve system safety.

The second object of the present invention is to provide a method for reaction using the above reaction system, which has milder operating conditions, reduces the temperature and pressure of the oximation reaction while ensuring the reaction efficiency, and has high safety performance and energy consumption. Low, achieving a better reaction effect than the existing process.

In order to achieve the above objectives of the present invention, the following technical solutions are specially adopted:

The invention provides a built-in micro-interface ammoximation reaction system, which includes an oximation reactor, a reaction clear liquid buffer tank, a tert-butanol recovery tower, an extraction tank, a water washing separator and a water extraction tower, wherein,

An external circulation device is provided outside the oximation reactor to control the temperature inside the oximation reactor; a micro-interface unit is provided inside the oximation reactor to disperse the crushed gas into micron-level diameter Microbubbles

The bottom of the oximation reactor is connected to the reaction clear liquid buffer tank, and the material from the reaction clear liquid buffer tank is passed through the middle section of the tert-butanol recovery tower for the recovery of tert-butanol, so The bottom of the tert-butanol recovery tower is provided with an oxime aqueous solution outlet, the extraction tank is provided with a liquid inlet, a light phase outlet, and an aqueous phase outlet, and the liquid inlet is connected to the oxime aqueous solution outlet, so The light phase discharge port is connected with the water washing separator for washing the toluene oxime solution, and the water phase discharge port is connected with the water extraction tower for extracting and recovering the oxime in the water phase.

In the prior art, the cyclohexanone ammoximation reaction has the following problems: On the one hand, the gas-liquid mass transfer area of the existing oximation reactor is limited. The conversion of cyclohexanone is incomplete, and the conversion rate of oximation is low, which increases the occurrence of side reactions; on the other hand, the ammoximation reaction is a strong exothermic reaction, and the temperature is too high, which increases the content of cyclohexanone and cyclohexanone oxime. Decomposition products, these products are not easily removed in the subsequent process, which affects the yield and quality of the final product caprolactam. The built-in micro-interface ammoximation reaction system of the present invention can disperse and break the ammonia gas into micro-bubbles with a diameter of micrometers by dispersing and crushing the ammonia gas into micron-level micro-bubbles after installing the micro-interface unit inside the oximation reactor, thereby increasing the separation between the ammonia gas and the liquid phase material. The area of the phase boundary makes the mass transfer space fully satisfied, and increases the residence time of ammonia in the liquid phase, reduces the consumption of ammonia, thereby greatly improving the efficiency of the oximation reaction, effectively inhibiting side reactions, and significantly reducing the cost of the reaction process. Energy consumption; on the other hand, the reaction temperature and pressure are reduced, the decomposition products of cyclohexanone and cyclohexanone oxime are reduced, the yield and quality of the final product caprolactam are improved, and energy consumption is reduced, and system safety is improved.

Further, the micro-interface unit includes a first micro-interface generator and a second micro-interface generator arranged up and down, the first micro-interface generator is connected with an air duct, and the top end of the air duct protrudes from the oxime The liquid level of the chemical reactor is used to recover ammonia, and the side wall of the oximation reactor is also provided with an air inlet, and the end of the air inlet extends into the second micro-interface generator.

Further, the first micro-interface generator is a hydraulic micro-interface generator, the second micro-interface generator is a pneumatic micro-interface generator; the first micro-interface generator and the second micro-interface generator are There are supports for mutual support between the devices. The specific material, shape and number of the supports are not limited, as long as they can achieve a supporting effect, preferably tubular, rod-shaped or plate-shaped. More preferably, the second micro-interface generator is connected to a pipe by welding, threading or flange, and the pipe is fixed inside the oximation reactor. Ammonia gas flows into the interior of the second micro-interface generator to be dispersed and broken into micron-level micro bubbles, which effectively increases the mass transfer area between the ammonia gas and the liquid phase material, reduces the mass transfer resistance, and improves the reaction efficiency.

Further, the reaction system further includes a toluoxime cooler, the type of the toluoxime cooler is a shell-and-tube heat exchanger, one end of the shell side of the toluoxime cooler is connected to the outlet of the oxime aqueous solution, and the other end Connect with the extraction tank. The oxime aqueous solution exits from the oxime aqueous solution outlet and is cooled to a certain temperature by the toluoxime cooler, and then enters the extraction tank for sedimentation and stratification. The shell-and-tube heat exchanger has simple structure, low cost, wide circulation cross section, and easy to clean scale. The shell and tube heat exchanger is made of Hastelloy. Compared with other materials, Hastelloy has better corrosion resistance and thermal stability. Therefore, the use of Hastelloy can increase the life of the heat exchanger.

Further, the bottom of the water washing separator is provided with a washing water circulation pipeline for returning the washing water to the water washing separator for further washing and purification; the washing water circulation pipeline is provided with a washing circulation pump. By setting the washing water circulation pipeline, the washing water can be returned to the water washing separator through the washing water circulation pipeline for multiple washing and purification, thereby avoiding the waste of toluoxime. More advantageously, the washing water volume can be adjusted by setting the washing circulating pump, the load of washing water can be reduced, and the washing effect can be improved.

Further, a recovery pipeline is also provided between the middle of the washing water circulation pipeline and the top of the water extraction tower, and the recovery pipeline is used to separate the washing water from the washing water circulation pipeline with the water. The oxime-containing water from the feed port is passed into the water extraction tower at the same time. The washing water contains about 1% oxime and a small amount of dissolved toluene. After being combined with the oxime-containing water from the water phase discharge port through the washing circulation pump, it is passed into the water extraction tower for multi-stage extraction, thereby recovering the water in the water phase. Oxime.

Further, the water extraction tower is a packed tower, and the packing type is a ceramic Raschig ring. Packed tower has the advantages of large production capacity, high separation efficiency, small pressure drop, small liquid holding capacity, and large operating flexibility. Preferably, the filler material is ceramic Raschig ring. Compared with other filler materials, the ceramic Raschig ring has better corrosion and heat resistance effects.

Further, the reaction system includes a pre-filter and a coalescer connected in sequence, and the pre-filter is connected to the top of the water-washing separator for toluene oxime pre-filtering and entering the coalescer to separate impurities Finish washing. After washing with water, the toluene oxime first enters the pre-filter for filtration, and then enters the coalescer for further separation and purification of impurities, and finally the qualified concentration of toluene oxime is sent to the toluoxime tank; the pre-filter can filter out larger ones in the medium The solid particle impurities can prevent the filter element of the coalescer from clogging, and the filtering precision of the pre-filter is less than or equal to 15 μm.

Further, the reaction system includes an extraction liquid receiving tank connected to the water extraction tower for receiving the organic phase extracted from the top of the water extraction tower. The organic phase extracted from the top of the water extraction tower overflows into the extraction liquid receiving tank, and then returns to the toluoxime cooler by a transfer pump for cooling, and then enters the toluoxime extraction system again for extraction and water washing, thereby avoiding Waste of cyclohexanone oxime.

Further, the reaction system includes a tail gas absorption tower, the tail gas absorption tower is connected to the top of the oximation reactor, the bottom of the tail gas absorption tower is also provided with an absorption liquid outlet, and the absorption liquid outlet is connected to the The oximation reactor is used for the absorption liquid to return to the oximation reactor for utilization.

Further, the middle section of the tert-butanol recovery tower is respectively provided with a liquid inlet and a gas inlet, the liquid inlet is connected to the bottom of the reaction clear liquid buffer tank; the gas inlet is connected to the top of the reaction clear liquid buffer tank connect. The liquid in the reaction clear liquid buffer tank enters the tert-butanol recovery tower from the liquid inlet, and the gas in the reaction clear liquid buffer tank enters the tert-butanol recovery tower from the gas inlet. The gas inlet and the liquid inlet are changed because the material composition in the reaction clear liquid buffer tank is more complicated. Most of the tert-butanol exists in liquid form, and a small amount of it exists in the reaction product in gaseous form. This way, the gas inlet and liquid inlet are set up. The dual-material imports can ensure the full recycling of tert-butanol.

Further, the reaction system includes a tert-butanol reflux tank, the tert-butanol reflux tank is provided with a non-condensable gas outlet, and the non-condensable gas in the tert-butanol reflux tank is mixed with the tail gas through the non-condensable gas outlet Enter the tail gas absorption tower for recycling.

Further, the reaction system further includes a circulating tert-butanol tank, the top of the circulating tert-butanol tank is connected to the bottom of the tert-butanol reflux tank, and the bottom of the circulating tert-butanol tank is connected to the oximation tank. The bottom of the reactor is connected so that tert-butanol can be reused as a reaction solvent. A small part of the condensate in the tert-butanol reflux tank is used for reflux at the top of the tower, and most of the remaining part is fed into the oximation reactor through the circulating tert-butanol tank to be reused as a reaction solvent, which reduces the use cost of tert-butanol.

In addition, the present invention also provides a method of oximation reaction, which includes the following steps:

After the ammonia gas is dispersed and broken into microbubbles, it undergoes a catalytic oximation reaction with the liquid phase materials; the reaction product is collected in a clear liquid mode and then recovered by tert-butanol; the oxime aqueous solution after the tertiary butanol is recovered is then extracted with toluene and washed with water.

Further, the liquid phase materials (including cyclohexanone, hydrogen peroxide and tert-butanol) are first passed into the oximation reactor, and at the same time, ammonia gas is passed into the micro-interface unit set inside the oximation reactor to make it broken After the ammonia gas is dispersed and broken into micro-bubbles with a diameter of micrometers, the ammonia gas undergoes a catalytic oximation reaction with the liquid phase materials.

In the process of the catalytic oximation reaction, the unreacted gas is recovered and used as tail gas, and the reaction product is collected in a clear liquid manner and then enters the reaction clear liquid buffer tank, and then enters the tert-butanol recovery tower for the reaction product The tert-butanol in the oximation reactor is recovered, and the recovered tert-butanol enters the oximation reactor again to be used as the reaction solvent; the oxime aqueous solution after the recovery of the tert-butanol is cooled by the toluoxime cooler and then enters the extraction tank for use The solubility of toluene to oxime extracts the oxime from the aqueous oxime solution into the toluene phase. The toluene oxime solution is separated from the light phase discharge port of the extraction tank and enters the water washing separator, which is completed in the water washing separator and coalescer using desalinated water. After washing with water, qualified toluoxime enters the toluoxime tank from the coalescer to wait for the subsequent treatment process.

Further, the temperature of the oximation reaction is 80-83°C, and the pressure is 0.20-0.25 MPa.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention can disperse and break the ammonia gas into micron-sized micro-bubbles after installing the micro-interface unit inside the oximation reactor, increase the phase boundary area between the ammonia gas and the liquid phase material, and make the mass transfer space sufficient. It satisfies, and increases the residence time of ammonia in the liquid phase, reduces the consumption of ammonia, thereby greatly improving the efficiency of the oximation reaction, effectively inhibiting side reactions, and significantly reducing the energy consumption of the reaction process; on the other hand, it reduces the reaction Temperature and pressure reduce the decomposition products of cyclohexanone and cyclohexanone oxime, increase the yield and quality of the final product caprolactam, reduce energy consumption, and improve system safety.

Description of the drawings

By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only used for the purpose of illustrating the preferred embodiments, and are not considered as a limitation to the present invention. Also, throughout the drawings, the same reference symbols are used to denote the same components. In the attached picture:

FIG. 1 is a schematic structural diagram of a built-in micro-interface ammoximation reaction system provided by an embodiment of the present invention.

Description of the drawings:

10-oximation reactor; 11-air inlet;

12-Outlet; 13-Exhaust gas outlet;

20-Reaction clear liquid buffer tank; 30-tert-butanol recovery tower;

31-liquid import; 32-gas import;

33-Export of oxime aqueous solution; 40-Extraction tank;

41-liquid inlet; 42-light phase outlet;

43-Water phase discharge port; 50-Water washing separator;

60-Water extraction tower; 70-Micro interface unit;

71-The first micro-interface generator; 72-The second micro-interface generator;

80-External filtration device; 90-tert-butanol return tank;

91-Non-condensable gas export; 100-circulating tert-butanol tank;

110-toluene oxime cooler; 120-water washing circulating pump;

130-pre-filter; 140-coalescer;

150-Extraction liquid receiving tank; 160-Exhaust gas absorption tower;

161- Absorbent outlet.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific implementations. However, those skilled in the art will understand that the embodiments described below are part of the embodiments of the present invention, rather than all of them. It is only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention. If no specific conditions are indicated in the examples, it shall be carried out in accordance with the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used without the manufacturer's indication are all conventional products that can be purchased on the market.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the pointed device or element must have a specific orientation or a specific orientation. The structure and operation cannot therefore be understood as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance.

In the description of the present invention, it should be noted that the terms "installed", "connected", and "connected" should be understood in a broad sense unless otherwise clearly specified and limited. For example, they can be fixed or detachable. Connected or integrally connected; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above-mentioned terms in the present invention can be understood in specific situations.

In order to explain the technical solutions of the present invention more clearly, the following description will be given in the form of specific embodiments.

Example

Referring to FIG. 1, it is a built-in micro-interface ammoximation reaction system of an embodiment of the present invention, including an oximation reactor 10, a reaction clear liquid buffer tank 20, a tert-butanol recovery tower 30, an extraction tank 40, and a water washing separator 50 And water extraction tower 60. Wherein, an external circulation device is provided outside the oximation reactor 10 to control the temperature inside the oximation reactor; a micro-interface unit 70 is provided inside the oximation reactor 10 to disperse the crushed gas into micron-level diameters. Specifically, the micro-interface unit 70 includes a first micro-interface generator 71 and a second micro-interface generator 72 arranged up and down, the first micro-interface generator 71 is connected with an air tube, and the top of the air tube extends The liquid level of the oximation reactor 10 is used to recover ammonia gas, and the side wall of the oximation reactor 10 is also provided with an air inlet 11, and the end of the air inlet 11 extends into the second micro-interface generator 72. Preferably, the first micro-interface generator 71 is a hydraulic micro-interface generator, and the second micro-interface generator 72 is a pneumatic micro-interface generator; the first micro-interface generator 71 and the second micro-interface generator 72 are arranged between There are support members for supporting each other. It is understandable that the specific material, shape and number of the support members are not limited, as long as they can achieve a supporting effect. The ammonia gas is introduced into the micro-interface unit 70 to be dispersed and broken into micron-level micro bubbles, which effectively increases the mass transfer area between the ammonia gas and the liquid phase material, reduces the mass transfer resistance, and improves the reaction efficiency.

The bottom of the oximation reactor 10 of this embodiment is provided with a discharge port 12, and the discharge port 12 is connected to the reaction clear liquid buffer tank 20. Preferably, it can be located between the reaction clear liquid buffer tank 20 and the discharge port 12. An external filter device 80 is provided on the connecting pipe to prevent the catalyst from entering the reaction clear liquid buffer tank 20 after the internal filter of the oximation reactor 10 is blocked. The material from the reaction clear liquid buffer tank 20 is introduced from the middle section of the tert-butanol recovery tower 30 for the recovery of tert-butanol. Specifically, the middle section of the tert-butanol recovery tower 30 is provided with a liquid inlet 31 and a gas inlet 32 respectively. The liquid inlet 31 is connected to the bottom of the reaction clear liquid buffer tank 20; the gas inlet 32 is connected to the top of the reaction clear liquid buffer tank 20. The reason why the gas inlet 32 and the liquid inlet 31 are provided at the same time is because the reaction clear liquid buffer tank is The material composition of t-butanol is more complicated. Most of the tert-butanol exists in liquid form, and a small amount is present in the reaction product in gaseous form. In this way, the dual material inlet of gas inlet and liquid inlet can ensure the full recovery and utilization of tert-butanol.

Furthermore, the top of the tert-butanol recovery tower 30 is preferably connected to the tert-butanol reflux tank 90 through two overhead condensers, and a reflux pipeline is also provided between the tert-butanol recovery tower 30 and the tert-butanol reflux tank 90 One end of the reflux pipeline is connected to the top of the tert-butanol recovery tower 30, and the other end is connected to the bottom of the tert-butanol reflux tank 90 for returning the substance in the tert-butanol reflux tank 90 to continue separation and purification. Flow, can improve the recovery purity of tert-butanol. In this embodiment, the reaction system further includes a circulating tert-butanol tank 100, the top of the circulating tert-butanol tank 100 is connected to the bottom of the tert-butanol reflux tank 90, and the bottom of the circulating tert-butanol tank 100 is connected to the oximation reactor 10. A small part of the condensate in the tert-butanol reflux tank 90 is used for reflux at the top of the tower, and most of the remaining part is recycled into the oximation reactor 10 through the circulating tert-butanol tank 100 to be reused as a reaction solvent, reducing the t-butanol The cost of use.

The bottom of the tert-butanol recovery tower 30 is provided with an oxime aqueous solution outlet 33, and the extraction tank 40 is provided with a liquid inlet 41, a light phase outlet 42 and a water phase outlet 43, and the liquid inlet 41 is connected to the oxime aqueous solution outlet 33, The light phase discharge port 42 is connected with the water washing separator 50 for washing the toluene oxime solution, and the water phase discharge port 43 is connected with the water extraction tower 60 for extracting and recovering the oxime in the water phase. In this embodiment, a toluoxime cooler 110 is also provided on the pipeline between the oxime aqueous solution outlet 33 and the liquid inlet 41. One end of the toluoxime cooler 110 is connected to the oxime aqueous solution outlet 33, and the other end is connected to the extraction tank. 40 connection. More preferably, the type of the toluene oxime cooler 110 is a shell-and-tube heat exchanger. The shell-and-tube heat exchanger has a simple structure, low cost, wide circulation cross-section, and easy scale cleaning. The shell and tube heat exchanger is made of Hastelloy. Compared with other materials, Hastelloy has better corrosion resistance and thermal stability. Therefore, the use of Hastelloy can increase the life of the heat exchanger.

Furthermore, the bottom of the water washing separator 50 is provided with a washing water circulation pipe for returning the washing water to the water washing separator 50 for washing and purification again; a washing water circulation pump 120 is provided on the washing water circulation pipe. By setting the washing water circulation pipeline, the washing water can be returned to the water washing separator through the washing water circulation pipeline for multiple washing and purification, thereby avoiding the waste of toluoxime. More advantageously, by setting the washing circulation pump 120, the amount of washing water can be adjusted, the load of washing water can be reduced, and the washing effect can be improved. In this embodiment, a recovery pipeline is also provided between the middle of the washing water circulation pipeline and the top of the water extraction tower 60. The recovery pipeline is used to remove the washing water from the washing water circulation pipeline and the water phase discharge port 43. The oxime-containing water is passed into the water extraction tower 60 together. The washing water contains about 1% oxime and a small amount of dissolved toluene. After being combined with the oxime-containing water from the water phase discharge port 43 through the washing circulation pump 120, it is passed into the water extraction tower 60 for multi-stage extraction, thereby recovering the water phase.的oxime. Preferably, the water extraction tower 60 is a packed tower, and the packing type is a ceramic Raschig ring. Packed tower has the advantages of large production capacity, high separation efficiency, small pressure drop, small liquid holding capacity, and large operating flexibility. Ceramic Raschig ring is selected as the filler material. Compared with other filler materials, ceramic Raschig ring has better corrosion resistance and heat resistance. In addition, the reaction system of this embodiment also includes a pre-filter 130 and a coalescer 140 connected in sequence, and the pre-filter 130 is connected to the top of the water washing separator 50 to enter the coalescer 140 after pre-filtration of toluene oxime. The impurities are separated in the water to complete the washing. After washing with water, the toluene oxime enters the pre-filter 130 for filtration, and then enters the coalescer 140 to further separate and purify impurities, and finally send the qualified concentration of toluoxime into the toluoxime tank; the pre-filter 130 can filter out larger media The solid particles of impurities can prevent the filter element of the coalescer from clogging, and the filtration accuracy of the pre-filter is preferably ≤15μm.

In this embodiment, the reaction system further includes an extraction liquid receiving tank 150, which is connected to the water extraction tower 60 for receiving the organic phase extracted from the top of the water extraction tower 60. The organic phase extracted from the top of the extraction tower 60 overflows into the extraction liquid receiving tank 150, and then returns to the toluoxime cooler 110 through the transfer pump for cooling, and then enters the toluoxime extraction system again for extraction and water washing, thereby avoiding cyclohexane The waste of ketoxime.

In addition, the top of the oximation reactor 10 is also provided with a tail gas outlet 13, which is connected to the tail gas absorption tower 160. The bottom of the tail gas absorption tower 160 is also provided with an absorption liquid outlet 161, which is connected to the oximation reactor 10 Used for the absorption liquid to return to the oximation reactor for utilization. The tert-butanol reflux tank 90 is provided with a non-condensable gas outlet 91, and the non-condensable gas in the tert-butanol reflux tank 90 is mixed with the tail gas through the non-condensable gas outlet 91 and then enters the tail gas absorption tower 160 for recycling.

The following briefly describes the working process and principle of the built-in micro-interface ammoximation reaction system of the present invention.

Ammonia gas first enters the micro-interface unit 70 through the air inlet 11 to be dispersed and broken into micron-level micro-bubbles. At the same time, the liquid-phase mixed raw materials (including hydrogen peroxide, cyclohexanone, circulating tert-butanol and circulating materials) enter the oximation reactor In 10, the dispersed and broken microbubbles and the liquid phase mixed raw materials are fully emulsified, which effectively increases the mass transfer area of the gas-liquid two-phase and reduces the mass transfer resistance.

As the fully emulsified emulsion undergoes an oximation reaction in the oximation reactor 10 under the action of a catalyst, the temperature in the oximation reactor 10 is 80-83° C. and the pressure is 0.20-0.25 MPa. Among them, the ammoximation reaction is a strongly exothermic reaction, and the temperature inside the reactor is controlled by setting an external circulation pipeline outside the oximation reactor 10.

During the reaction process, unreacted ammonia, alcohol and other gases are cooled from the tail gas outlet 13 and enter the tail gas absorption tower 160. The tail gas absorption tower 160 uses desalinated water to absorb the ammonia and alcohol into the absorption liquid. After the absorption liquid outlet 161 comes out, it enters the oximation reactor 10 for repeated recycling. The oximation reaction products (cyclohexanone oxime, ammonia and a small amount of tert-butanol, etc.) enter the reaction clear liquid buffer tank 20 through the discharge port 12 in a clear liquid manner, and then respectively pass through the liquid inlet 31 of the tert-butanol recovery tower 30. The gas inlet 32 enters the tower for the recovery of tert-butanol. The mixed fraction of water, ammonia and tert-butanol steamed from the top of the tert-butanol recovery tower 30 enters the tert-butanol after being cooled by the condenser at the top of the tower. In the reflux tank 90, the uncooled non-condensable gas is mixed with the tail gas of the oximation reactor 10 through the non-condensable gas outlet 91 and then enters the tail gas absorption tower 160 for ammonia recovery. A small part of the condensate in the tert-butanol reflux tank 90 is used for reflux at the top of the tower, and most of the remaining part is recycled into the oximation reactor 10 through the circulating tert-butanol tank 100 to be reused as a reaction solvent, which reduces the use cost of tert-butanol. .

The aqueous oxime solution exits the oxime aqueous solution outlet 33 of the tert-butanol tower 30 and is cooled to a certain temperature by the toluene cooler 110 and then enters the extraction tank 40. The oxime is extracted from the oxime aqueous solution into the toluene phase by using the solubility of toluene to oxime. , So as to achieve the separation of oxime and water. The toluene oxime solution exits the light phase discharge port 42 of the extraction tank 40 and enters the water washing separator 50, is washed with desalinated water, filtered through the pre-filter 130, and then enters the coalescer 140 for further separation and purification of impurities. The concentration of toluoxime is sent to the toluoxime tank for subsequent processing. Among them, the washing water of the washing separator 50 contains about 1% of oxime and a small amount of dissolved toluene, and the oxime-containing water from the water phase discharge port 43 is combined by the washing circulating pump 120 and then passed into the water extraction tower 60 for multiple stages. Extraction to recover the oxime in the water phase.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it is still The technical solutions recorded in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention .

Claims (10)

1. A built-in micro-interface ammoximation reaction system, which is characterized by comprising an oximation reactor, a reaction clear liquid buffer tank, a tert-butanol recovery tower, an extraction tank, a water washing separator and a water extraction tower, wherein:

   An external circulation device is provided outside the oximation reactor to control the temperature inside the oximation reactor; a micro-interface unit is provided inside the oximation reactor to disperse the crushed gas into micron-level diameter Microbubbles

   The bottom of the oximation reactor is connected to the reaction clear liquid buffer tank, and the material from the reaction clear liquid buffer tank is passed through the middle section of the tert-butanol recovery tower for the recovery of tert-butanol, so The bottom of the tert-butanol recovery tower is provided with an oxime aqueous solution outlet, the extraction tank is provided with a liquid inlet, a light phase outlet, and an aqueous phase outlet, and the liquid inlet is connected to the oxime aqueous solution outlet, so The light phase discharge port is connected with the water washing separator for washing the toluene oxime solution, and the water phase discharge port is connected with the water extraction tower for extracting and recovering the oxime in the water phase.
2. The built-in micro-interface ammoximation reaction system according to claim 1, wherein the micro-interface unit comprises a first micro-interface generator and a second micro-interface generator arranged up and down, and the first micro-interface generator The gas pipe is connected to the gas pipe, and the top of the gas pipe extends from the liquid surface of the oximation reactor for the recovery of ammonia gas. The side wall of the oximation reactor is also provided with an air inlet. The end extends into the second micro-interface generator.
3. The built-in micro-interface ammoximation reaction system according to claim 1, wherein the reaction system further comprises a toluoxime cooler, the type of the toluoxime cooler is a shell-and-tube heat exchanger, and the toluene One end of the shell side of the oxime cooler is connected with the outlet of the oxime aqueous solution, and the other end is connected with the extraction tank.
4. The built-in micro-interface ammoximation reaction system according to claim 1, wherein the bottom of the water washing separator is provided with a washing water circulation pipeline for returning the washing water to the water washing separator for further washing and purification; The washing water circulation pipeline is provided with a washing circulation pump.
5. The built-in micro-interface ammoximation reaction system according to claim 4, wherein a recovery pipeline is also provided between the middle of the washing water circulation pipeline and the top of the water extraction tower, the recovery pipeline It is used to pass the washing water from the washing water circulation pipeline and the oxime-containing water from the water phase discharge port into the water extraction tower together.
6. The built-in micro-interface ammoximation reaction system according to claim 1, wherein the water extraction tower is a packed tower, and the type of packing is a ceramic Raschig ring.
7. The built-in micro-interface ammoximation reaction system according to claims 1-6, wherein the reaction system comprises a pre-filter and a coalescer connected in sequence, and the pre-filter and the water washing separator The top connection is used for toluene oxime pre-filtering and then entering the coalescer to separate impurities to complete the water washing.
8. The built-in micro-interface ammoximation reaction system according to claims 1-6, wherein the reaction system comprises an extracting liquid receiving tank, and the extracting liquid receiving tank is connected to the water extraction tower for receiving The organic phase extracted from the top of the water extraction tower.
9. The oximation reaction method using the built-in micro-interface ammoximation reaction system according to any one of claims 1-8 is characterized in that it comprises the following steps:

   After the ammonia gas is dispersed and broken into microbubbles, it undergoes a catalytic oximation reaction with the liquid phase materials; the reaction product is collected in a clear liquid mode and then recovered by tert-butanol; the oxime aqueous solution after the tertiary butanol is recovered is then extracted with toluene and washed with water.
10. The method according to claim 9, wherein the temperature of the oximation reaction is 80-83°C and the pressure is 0.20-0.25 MPa.

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