CN220801977U - 3-Aminopropionitrile high-efficiency rectifying device and continuous production system - Google Patents

Abstract

The application discloses a 3-aminopropionitrile efficient rectifying device and a continuous production system, wherein the rectifying device comprises: the device comprises a first falling film evaporator, a second tube layer evaporator, impurity removal separation equipment and vapor phase cooling equipment; the upper part of the first falling film evaporator is provided with a 3-aminopropionitrile crude product inlet and a spiral distributor, the lower part of the first falling film evaporator is communicated with impurity removal and separation equipment through a first-stage vapor phase pipe, and the bottom of the first falling film evaporator is provided with a first-stage liquid outlet; the second tube layer evaporator is communicated with the first-stage liquid outlet through a liquid-phase material inlet at the top of the second tube layer evaporator, and second-stage distribution equipment is arranged in the liquid-phase material inlet; the lower part of the diode layer evaporator is provided with a second-stage vapor phase pipe communicated with the first-stage vapor phase pipe; the impurity removal and separation equipment comprises a primary corrugated demister and a secondary corrugated demister which are sequentially communicated. The rectification device can rapidly heat and evaporate the 3-aminopropionitrile, purify and separate the 3-aminopropionitrile, thereby improving the purification effect of the 3-aminopropionitrile, simultaneously realizing the continuity of the whole production process, reducing the production cost, and being safe and environment-friendly.

Description

3-Aminopropionitrile high-efficiency rectifying device and continuous production system

Technical Field

The application belongs to the technical field of chemical synthesis, and particularly relates to a 3-aminopropionitrile efficient rectifying device and a continuous production system.

Background

3-Aminopropionitrile, also known as beta-aminopropionitrile, is a liquid with ammonia-like odor, useful as an organic synthesis, pharmaceutical intermediate, such as for the synthesis of multivitamin B; the synthetic route is generally obtained by amination of acrylonitrile.

For example, chinese patent document of application publication No. CN 115677532A discloses a process for the efficient preparation of β -aminopropionitrile from acrylonitrile, which comprises: in a kettle reactor, acrylonitrile and ammonia water react under the action of an ammoniating agent, and after the reaction is ended, the reaction liquid is deaminated and distilled to prepare the beta-aminopropionitrile. The method mainly controls the contents of aldehyde substances and polymerization inhibitor in the acrylonitrile so as to greatly improve the reaction yield of the acrylonitrile and ammonia, and the single pass yield is more than 98 percent; the later purification difficulty is greatly reduced. The post-treatment in the method comprises the following steps: deamination of the reaction solution, reduced pressure distillation to remove light components, and continuous heating to distill out the product.

Currently, the known 3-aminopropionitrile synthesis process is mainly intermittent, or the sectional process is mainly operated, or a method of a partial continuous synthesis process is adopted, such as: through ammoniation, ammonia driving, dehydration and gap kettle type rectification. The purification methods have low automation degree, long heating time, high-boiling byproducts, low continuous level and high safety risk, and 3-aminopropionitrile is easily polymerized by long-time rectification.

Disclosure of utility model

In view of the above, the application aims to provide a 3-aminopropionitrile efficient rectifying device and a continuous production system, and by utilizing the rectifying device provided by the application, 3-aminopropionitrile can be rapidly heated, evaporated, purified and separated, so that the purifying effect of 3-aminopropionitrile is improved, the continuous series connection of the whole production process can be realized, the production cost is reduced, and the device is safe and environment-friendly.

The application provides a 3-aminopropionitrile high-efficiency rectifying device, which comprises: the device comprises a first falling film evaporator, a second tube layer evaporator, impurity removal separation equipment and vapor phase cooling equipment;

The upper part of the first falling film evaporator is provided with a 3-aminopropionitrile crude product inlet, the lower part of the first falling film evaporator is communicated with impurity removal and separation equipment through a first vapor phase pipe, and the bottom of the first falling film evaporator is provided with a first liquid outlet; a spiral distributor is arranged in the inlet of the 3-aminopropionitrile crude product;

The second tube layer evaporator is communicated with the first liquid outlet through a liquid phase material inlet at the top of the second tube layer evaporator, and second distribution equipment is arranged in the liquid phase material inlet; the lower part of the second tube layer evaporator is provided with a second vapor phase tube communicated with the first vapor phase tube;

The impurity removal and separation equipment comprises a first-stage corrugated demister and a second-stage corrugated demister which are sequentially communicated, and the first-stage corrugated demister is communicated with a first vapor phase pipe; the secondary corrugated demister is connected with vapor-phase cooling equipment, and the vapor-phase cooling equipment is used for cooling and refining 3-aminopropionitrile.

Preferably, the second distribution device is a conical distributor.

Preferably, the second tube layer evaporator is in the form of 4-tube parallel connection.

Preferably, the primary corrugated foam remover and the secondary corrugated foam remover are both stainless steel corrugated foam removers, and the secondary corrugated foam removers are provided with temperature control units at 70-80 ℃.

Preferably, the liquid phase outlet of the first-stage corrugated foam remover is connected with the liquid phase material inlet of the second-tube layer evaporator through a liquid phase guide tube.

Preferably, a second liquid outlet is arranged at the bottom of the second tube layer evaporator and is communicated with an additionally arranged decompression conveying pump for continuously outputting high-boiling residual liquid.

The application provides a continuous production system of 3-aminopropionitrile, which comprises the following components:

A reaction device for synthesizing 3-aminopropionitrile by ammonification of acrylonitrile;

A continuous low-boiling-point removing device connected with the reaction device;

The 3-aminopropionitrile high-efficiency rectifying device, wherein the first falling film evaporator is connected with a material outlet of the continuous low-boiling-point removing device.

Preferably, the reaction device is a pipeline reactor for ammonifying to form 3-aminopropionitrile and continuously outputting the reaction liquid.

Preferably, the continuous low-boiling removal device comprises:

Deamination flash equipment connected with the pipeline reactor;

And a material outlet of the multistage serial falling film evaporation equipment is communicated with a first falling film evaporator of the 3-aminopropionitrile efficient rectifying device.

Preferably, the low-boiling outlets of the deamination flash evaporation equipment and the multistage serial falling film evaporation equipment are connected with an additionally arranged ammonia absorption device for cooling, collecting and removing low-boiling impurities.

Compared with the prior art, the embodiment of the application provides a continuous and efficient rectifying device, according to the material composition characteristics of the crude product 3-aminopropionitrile after ammonia driving and dehydration, the crude product 3-aminopropionitrile is uniformly fed by adopting a spiral distributor, so that the risk of pipeline blockage caused by material polymerization is reduced; the crude product materials are rapidly heated and evaporated in a first falling film evaporator, the obtained vapor phase passes through a first vapor phase pipe, a first-stage ripple foam remover and a second-stage ripple foam remover, entrained gas and liquid are subjected to two-stage impurity removal and separation, and finally the vapor phase is cooled and collected by vapor phase cooling equipment to obtain refined 3-aminopropionitrile; at this time, after evaporation through a first falling die, 80-90% of 3-aminopropionitrile in the crude 3-aminopropionitrile is purified, and the rest 10-20% of the material rapidly enters a second tube layer evaporator through secondary distribution, and secondary film evaporation is carried out, and the obtained vapor phase is combined with a first vapor phase tube through a second vapor phase tube and then separated, and cooled, so that the 3-aminopropionitrile refined product is obtained. In the application, the two-stage corrugated demister effectively separates high-boiling entrainment and improves the purity of 3-aminopropionitrile. And the residence time of the whole refined distillation material is about 20 seconds, the high-temperature time is greatly shortened, and meanwhile, the liquid holdup of the equipment is lower, so that the danger caused by high-temperature polymerization is greatly reduced.

Furthermore, the whole reaction and purification process is continuously connected in series, so that the reduction of the production cost is realized, and the method is safe and environment-friendly.

Drawings

FIG. 1 is a schematic flow diagram of a continuous production system for 3-aminopropionitrile in some embodiments of the present application;

FIG. 2 is a schematic diagram of a 3-aminopropionitrile high-efficiency rectification apparatus according to some embodiments of the present application.

Detailed Description

The technical disclosure of the present application will be clearly and fully described in connection with the following embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

The application provides a 3-aminopropionitrile high-efficiency rectifying device, which comprises: the device comprises a first falling film evaporator, a second tube layer evaporator, impurity removal separation equipment and vapor phase cooling equipment;

The upper part of the first falling film evaporator is provided with a 3-aminopropionitrile crude product inlet, the lower part of the first falling film evaporator is communicated with impurity removal and separation equipment through a first vapor phase pipe, and the bottom of the first falling film evaporator is provided with a first liquid outlet; a spiral distributor is arranged in the inlet of the 3-aminopropionitrile crude product;

The second tube layer evaporator is communicated with the first liquid outlet through a liquid phase material inlet at the top of the second tube layer evaporator, and second distribution equipment is arranged in the liquid phase material inlet; the lower part of the second tube layer evaporator is provided with a second vapor phase tube communicated with the first vapor phase tube;

The impurity removal and separation equipment comprises a first-stage corrugated demister and a second-stage corrugated demister which are sequentially communicated, and the first-stage corrugated demister is communicated with a first vapor phase pipe; the secondary corrugated demister is connected with vapor-phase cooling equipment, and the vapor-phase cooling equipment is used for cooling and refining 3-aminopropionitrile.

The application further provides a continuous production system of 3-aminopropionitrile, which comprises the following steps:

A reaction device for synthesizing 3-aminopropionitrile by ammonification of acrylonitrile;

A continuous low-boiling-point removing device connected with the reaction device;

The 3-aminopropionitrile high-efficiency rectifying device, wherein the first falling film evaporator is connected with a material outlet of the continuous low-boiling-point removing device.

The rectification device provided by the application can improve the purification effect of 3-aminopropionitrile, further realize the continuous series connection of the whole production process and the device, reduce the production cost and have better safety and environmental protection.

Referring to FIG. 1, FIG. 1 is a schematic flow chart of a continuous production system of 3-aminopropionitrile according to some embodiments of the present application. In the continuous production system of the embodiment of the application, a pipeline reactor is preferably adopted as a reaction device for producing 3-aminopropionitrile; specifically, the prepared ammonia water is cooled to-10 ℃ through an ammonia absorption device, and then is conveyed to a conventional pipeline reactor together with acrylonitrile through a high-pressure feed pump. The volume ratio of ammonia water to acrylonitrile is preferably controlled to be 10:1, carrying out ammonification reaction at the temperature of 100-120 ℃ and the pressure of 3-5 MPa for 7-10 minutes to obtain a reaction solution containing 3-aminopropionitrile (which can be called as 3-aminopropionitrile mixed solution). Wherein, the ammonia water is excessive to ensure complete ammoniation, the catalyst is isopropanol, and the content ratio of the ammonia water used by the catalyst is ammonia: water: the mass ratio of the isopropanol is preferably 3:2:5. the present application is not particularly limited to the pipe reactor, and the obtained reaction liquid can be continuously output to a continuous low-boiling-point removing device.

The continuous low-boiling-point removing device provided by the embodiment of the application specifically comprises: a primary deamination flash tank connected to the pipeline reactor outlet; the multistage serial falling film evaporation equipment connected with the outlet of the first-stage deamination flash tank, namely, serial two-stage, three-stage and four-stage falling film evaporators, is used for continuously removing low-boiling impurities such as ammonia water, catalysts and the like.

The embodiment of the application carries out primary flash evaporation deamination in a primary deamination flash tank, and particularly can deaminate the ammoniated reaction liquid in a conventional flash tank at normal pressure, recycle 80% ammonia at one time by utilizing the characteristic of low boiling point of ammonia, control the temperature at 50-80 ℃, and continuously convey the deaminated solution to the next deamination and dehydration. Flash evaporation is that high-pressure saturated water enters a container with relatively low pressure, and then the saturated water becomes partial saturated water vapor and saturated water under the container pressure due to the sudden pressure reduction; the flash tank functions to provide space for rapid vaporization of the fluid and separation of the vapor and liquid phases.

For the solution after flash evaporation deamination, the embodiment of the application firstly carries out two-stage die-reduction normal-pressure ammonia removal: the deaminated solution is introduced into a second-stage drop-die evaporator for normal-pressure secondary deamination and dehydration, ammonia can be basically stripped, the drop-die liquid phase temperature is preferably controlled at 85-90 ℃, and the materials after the second-stage deamination are continuously conveyed to the next dehydration step and the like.

The embodiment of the application dehydrates and catalysts the materials through a three-stage drop-mode evaporator, specifically, the materials after ammonia water removal enter the drop-mode evaporator for decompression dehydration and partial catalyst removal under the vacuum condition of minus 0.09 to minus 0.08MPa, the temperature of the liquid phase outlet of the drop-mode evaporator can be controlled at 80 to 90 ℃, and the dehydrated materials are continuously conveyed to the next catalyst removal step.

The embodiment of the application adopts a four-stage falling-film evaporator to remove the residual catalyst: preferably, the dehydrated material is subjected to catalyst removal again under the vacuum condition of-0.09 to-0.08 MPa to obtain crude 3-aminopropionitrile; the temperature of the die-down outlet concentrate is preferably 80-90 ℃, and the outlet catalyst residue is less than 1%.

In the conventional falling film evaporation, feed liquid is added from a pipe box on a heating chamber of a falling film evaporator, is uniformly distributed into each heat exchange pipe through liquid distribution and film forming equipment, and flows in a uniform film shape from top to bottom under the action of gravity, vacuum induction and air flow; in the flowing process, the vapor and the liquid phase generated by the heating vaporization of the shell side heating medium enter the gasification separation chamber of the falling film evaporator together, the vapor and the liquid are fully separated, the vapor enters the condenser for condensation (single-effect operation) or enters the next-effect evaporator for being used as the heating medium, thereby realizing multi-effect operation, and the liquid phase is discharged from the liquid phase port.

Because the aminopropionitrile has poor stability in a high-temperature state, the embodiment of the application adopts a continuous multistage falling-film evaporator, and separates low-boiling impurities in a multistage series connection mode, thereby being beneficial to improving the quality and the yield of the 3-aminopropionitrile. The embodiments of the present application may employ falling film evaporation equipment generally known to those skilled in the art; preferably, the application also provides an ammonia absorption device which is connected with the low-boiling outlets of the deamination flash evaporation equipment and the second-level, third-level and fourth-level falling film evaporation equipment, and can cool and recycle the removed low-boiling impurities such as ammonia, thereby realizing the full use of materials and the virtuous circle of the use of materials.

In the embodiment of the application, the materials with low boiling point removed are continuously conveyed to a 3-aminopropionitrile efficient rectifying device in the next step. The crude 3-aminopropionitrile is a material from which low boiling point is removed, the low boiling point is less than 1%, the aminopropionitrile is 80-90%, the high boiling point is 9%, water is less or generally does not exist, and the low boiling point is mainly catalyst residue; the specific composition mass ratio is as follows: 80% of 3-aminopropionitrile, 10% of iminodipropionanitrile and 10% of water.

The structure of the 3-aminopropionitrile efficient rectifying device is shown in fig. 2, 1 is a first falling film evaporator, 11 is a spiral distributor, 12 is a first gasification separation chamber, and 13 is a first vapor phase pipe; 2 is a second tube layer evaporator, 21 is a conical distributor, 22 is a second gasification separation chamber, and 23 is a second vapor phase tube; 3 is impurity removal and separation equipment, 31 is a primary corrugated demister, 32 is a secondary corrugated demister, and 33 is a liquid-phase flow guide pipe; 4 is a vapor phase cooling apparatus.

In the preferred embodiment of the application, the upper part of the first falling film evaporator 1 is provided with a 3-aminopropionitrile crude product inlet, and a plurality of spiral distributors 11 are arranged above the heating chamber; according to the composition characteristics of the crude product materials, the materials are uniformly distributed and fed through the spiral tube type distributor; the number of distributors is calculated and distributed according to the specific flow. The heating chamber of the first falling film evaporator 1 comprises a plurality of heat exchange tubes, and a first gasification separation chamber 12 is arranged below the heating chamber; the generated steam and liquid phase enter the gasification separation chamber of the first falling film evaporator together, and the steam and the liquid are fully separated. The lower part of the first falling film evaporator 1 is communicated with impurity removal and separation equipment through a first vapor phase pipe 13, and the bottom is provided with a first liquid outlet.

The top of the second tube layer evaporator 2 of the embodiment of the application is provided with a liquid phase material inlet which is communicated with a first liquid outlet of the first falling film evaporator 1. A second distribution device, preferably a conical distributor 21, is arranged in the liquid phase material inlet; according to the problems of low material composition and low material quantity, the second distributing equipment in the application preferably adopts a conical distributor to carry out secondary material distribution. The second distributing equipment is preferably a conical distributor, so that the problem of uneven distribution caused by flow reduction can be better solved.

The heating chamber of the second tube layer evaporator 2 is composed of a plurality of vertical tubes, and preferably, the second tube layer evaporator 2 is in a 4-tube parallel connection mode, so that the problem of uneven distribution caused by flow reduction can be effectively solved. The tube length of the tube layer evaporator is designed according to the feeding quantity and the production capacity, and the number or the diameter of the tube array can be increased if the feeding quantity is large, so that the tube layer evaporator is not limited to the type of the structural form; the structural parameters of the heat exchange tube array and the like of the falling film evaporator can also be adjusted and designed. Below the heating chamber of the second tube layer evaporator 2 is a second gasification separation chamber 22 where a second vapor phase tube 23 is provided in communication with the first vapor phase tube 13. The bottom of the second tube layer evaporator 2 is provided with a second liquid outlet which can be communicated with a decompression conveying pump which is further additionally arranged, so that separated high-boiling residual liquid is continuously output through the decompression conveying pump. According to the embodiment of the application, a falling-film evaporator is adopted for ammonification and dehydration and refining, and the falling-film evaporator has the characteristics of large heat area and short residence time, is small in liquid holdup, effectively reduces the decomposition of 3-aminopropionitrile caused by high temperature, and improves the quality and refining yield of 3-aminopropionitrile.

Referring to fig. 2, the efficient rectifying device according to the embodiment of the present application includes a impurity removing and separating apparatus 3, which includes a primary wave demister 31 and a secondary wave demister 32 that are sequentially connected, where the primary wave demister 31 is connected to a first vapor phase pipe 13; the secondary corrugation demister 32 is connected to a vapor-phase cooling apparatus 4 for cooling the refined 3-aminopropionitrile.

After the first falling film evaporator and the second tube layer evaporator, the embodiment of the application is preferably connected with a two-stage stainless steel corrugated demister, vapor phase is subjected to vapor-liquid separation through the two-stage corrugated demister, and meanwhile, separated liquid enters the second tube layer evaporator through a liquid phase flow guide pipe; the application can continuously and effectively separate the high-boiling entrainment in the vapor phase of the 3-aminopropionitrile crude product, thereby improving the purity of the 3-aminopropionitrile and the efficiency of the continuous process.

The embodiment of the application mainly adopts a primary corrugated foam remover 31 to effectively remove entrained liquid; the secondary corrugated demister 32 preferably has a 70-80 ℃ temperature control unit including a temperature control tube array distribution structure that can further remove high boiling impurities. The temperature control unit of the secondary corrugated demister can adopt hot water with the temperature of 70-80 ℃ for constant-temperature condensation, thereby achieving the vapor phase temperature control effect, and particularly can adopt a temperature control unit with the temperature of 70 ℃. The mist droplets are separated by the corrugated demister, and the corresponding size and the like are required to be provided according to the evaporation and refining capacity, for example: the evaporation capacity is larger, the packing size and trays need to be increased, and vice versa, but too much vapor phase resistance will increase, affecting evaporation efficiency. In addition, the temperature of the temperature control unit is 70-80 ℃, and the dynamic adjustment is needed mainly considering that the boiling point of vacuum change can change. In the embodiment of the application, the vapor phase cooling device 4 is mainly a condensing unit, and can cool the vapor phase in vacuum to obtain 3-aminopropionitrile refined products; the present application is not particularly limited in the structure of the vapor phase cooling apparatus.

In addition, the embodiment of the application can also comprise an MVR (mechanical vapor recompression) concentration dehydration device, a crystallization device and a drying device, wherein the refined 3-aminopropionic acid solution is subjected to concentration dehydration, crystallization, drying and the like to obtain a dried finished product 3-aminopropionic acid.

The rectification flow in some embodiments of the application is as follows: conveying the crude product 3-aminopropionitrile after the removal to an inlet of a first falling-film evaporator, uniformly distributing the material through a plurality of spiral distributors, then entering a tube array for falling-film evaporation, enabling the material to stay for about 2-10 seconds, enabling a liquid phase temperature of a first liquid outlet to be about 100 ℃, enabling a vapor phase to pass through a first vapor phase tube, enabling the vapor phase to pass through a first-stage corrugated demister, enabling the vapor phase to pass through a second-stage 70 ℃ temperature-control corrugated demister, enabling entrained gas and liquid to be subjected to two-stage separation, and finally enabling the vapor phase to pass through a vapor phase condenser for cooling and collecting to obtain refined 3-aminopropionitrile; after the first falling-film evaporator acts, 80-90% of 3-aminopropionitrile in the crude 3-aminopropionitrile is purified, the rest 10-20% of the material is rapidly distributed secondarily through a conical distributor, enters a second pipe layer evaporator for secondary film evaporation, vapor phase is combined with a first vapor phase pipe through a second vapor phase pipe and then separated, condensed, 3-aminopropionitrile refined product is obtained, the retention time of liquid phase material of the second pipe layer evaporator is 5-15 seconds, the liquid phase temperature of a second liquid outlet is about 130 ℃, and 3-aminopropionitrile residues in the liquid phase composition of the liquid outlet can be below 0.5% at the moment, and the 3-aminopropionitrile is continuously output through a high-temperature decompression conveying pump.

Wherein, the liquid separated by the primary and secondary demisters passes through the liquid-phase flow guide pipe and enters the second pipe layer evaporator for secondary evaporation.

Further, the embodiment of the application also carries out concentration and dehydration: concentrating and dehydrating the rectified 3-aminopropionic acid refined product under reduced pressure by MVR, controlling the concentration vacuum degree at-0.085 MPa, controlling the liquid phase temperature at 80-90 ℃ and the concentration end point 3-aminopropionic acid content at about 55%, and then further conveying to a crystallization device and a drying device.

Crystallization separation: and cooling the concentrated 3-aminopropionic acid material, centrifuging the material when the temperature of the material is between 0 and 20 ℃ to obtain a wet 3-aminopropionic acid product, and returning the mother liquor to MVR for further concentration and dehydration.

Drying a finished product: and conveying the centrifuged wet 3-aminopropionic acid product through a belt, directly entering an air flow drying device for drying, mixing and packaging through drying to obtain the finished product 3-aminopropionic acid.

In conclusion, the 3-aminopropionitrile continuous fine distillation in the embodiment of the application has high automation degree, low liquid holdup in production, low safety risk, tight combination of all production sections of the process and high product purity.

Examples

Ammoniation: cooling the prepared ammonia water to-10 ℃ (the catalyst is isopropanol) through an ammonia water absorption device, wherein the mass ratio of ammonia water to isopropanol is 3:2:5, then conveying the ammonia water and the acrylonitrile into a pipeline reactor through a high-pressure feed pump, controlling the volume ratio of the ammonia water to the acrylonitrile to be 10:1, carrying out ammonification reaction at 110 ℃ and 4MPa for 7-10 minutes, and continuously outputting the reaction liquid to a deamination flash tank.

Primary deamination: deamination is carried out on the reaction liquid after ammoniation in a flash tank under normal pressure, 80 percent of ammonia is recovered at one time, the temperature is controlled between 50 and 80 ℃, and the deaminated solution is continuously conveyed to the next deamination and dehydration.

Two-stage die-reducing deamination and dehydration: and (3) feeding the deaminated solution into a secondary drop-die evaporator for normal-pressure secondary deamination and dehydration, basically removing ammonia, controlling the drop-die liquid phase temperature at 85-90 ℃, and continuously conveying the ammonia-removed material to the next dehydration.

Three-stage die-reducing decompression dehydration and a catalyst thereof: and (3) under the vacuum condition of minus 0.085MPa, the material subjected to ammonia water removal enters a three-stage drop-die evaporator for decompression dehydration and partial catalyst removal, the temperature of a liquid phase outlet of the drop-die evaporator is controlled at 80-90 ℃, and the dehydrated material is continuously conveyed to the next step of catalyst removal.

Four-stage die-reducing and pressure-reducing catalyst removal: and (3) removing the catalyst from the dehydrated material again under the vacuum condition of-0.085 MPa, wherein the temperature of the concentrated solution at the outlet of the die is 80-90 ℃, and the residue of the catalyst at the outlet is less than 1%. Continuously conveying the materials with low boiling point removed to a 3-aminopropionitrile rectifying device in the next step, wherein the materials consist of: 80% of 3-aminopropionitrile, 10% of iminodipropionanitrile and 10% of water.

And (3) rectifying flow: conveying the crude product 3-aminopropionitrile after the removal to an inlet of a first falling-film evaporator, uniformly distributing the material through a plurality of spiral distributors, then entering a tube array for falling-film evaporation, enabling the material to stay for about 2-10 seconds, enabling a liquid phase temperature of a first liquid outlet to be 100 ℃, enabling a vapor phase to pass through a first vapor phase tube, enabling the vapor phase to pass through a first-stage corrugated demister, enabling the vapor phase to pass through a second-stage 70 ℃ temperature-control corrugated demister, enabling entrained gas and liquid to be subjected to two-stage separation, and finally enabling the vapor phase to pass through a vapor phase condenser for cooling and collecting to obtain refined 3-aminopropionitrile; after the first falling-film evaporator acts, 80-90% of 3-aminopropionitrile in the crude 3-aminopropionitrile is purified, the rest 10-20% of the material is rapidly distributed secondarily through a conical distributor, enters a second tube layer evaporator connected with 4 tubes in parallel for secondary film evaporation, vapor phase is combined with a first vapor phase tube through a second vapor phase tube and then separated, condensed, 3-aminopropionitrile refined products are obtained, the retention time of liquid phase material of the second tube layer evaporator is 5-15 seconds, the liquid phase temperature of a second liquid outlet is 130 ℃, and 3-aminopropionitrile residues are 0.5% in the liquid phase composition of the liquid outlet at the moment, and is continuously output through a high-temperature decompression conveying pump.

Wherein, the liquid separated by the primary and secondary demisters passes through the liquid-phase flow guide pipe and enters the second pipe layer evaporator for secondary evaporation.

The existing gap kettle type refined steaming 3-aminopropionitrile has the high temperature time of 0.5-1 hour and one kettle, namely the high temperature time is as long as 0.5-1 hour, about 2 percent of 3-aminopropionitrile is converted into iminodipropionate in the refined steaming process, and the refined yield of 3-aminopropionitrile is about 97 percent.

The high-temperature residence time of the whole refined distilled material is 10-30 seconds, for example, about 20 seconds, the high-temperature time is greatly shortened, the liquid holdup of the equipment is low, the danger caused by high-temperature polymerization is greatly reduced, and the controllability and the safety are improved. The process of the embodiment of the application has the advantages of tightly combined production sections, continuous production, high automation degree and continuous fine distillation of 3-aminopropionitrile with the yield close to 99.5%.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. The utility model provides a 3-aminopropionitrile high efficiency rectifier unit which characterized in that includes: the device comprises a first falling film evaporator, a second tube layer evaporator, impurity removal separation equipment and vapor phase cooling equipment;

The upper part of the first falling film evaporator is provided with a 3-aminopropionitrile crude product inlet, the lower part of the first falling film evaporator is communicated with impurity removal and separation equipment through a first vapor phase pipe, and the bottom of the first falling film evaporator is provided with a first liquid outlet; a spiral distributor is arranged in the inlet of the 3-aminopropionitrile crude product;

The second tube layer evaporator is communicated with the first liquid outlet through a liquid phase material inlet at the top of the second tube layer evaporator, and second distribution equipment is arranged in the liquid phase material inlet; the lower part of the second tube layer evaporator is provided with a second vapor phase tube communicated with the first vapor phase tube;

The impurity removal and separation equipment comprises a first-stage corrugated demister and a second-stage corrugated demister which are sequentially communicated, and the first-stage corrugated demister is communicated with a first vapor phase pipe; the secondary corrugated demister is connected with vapor-phase cooling equipment, and the vapor-phase cooling equipment is used for cooling and refining 3-aminopropionitrile.

2. The 3-aminopropionitrile high efficiency rectifying device according to claim 1, wherein the second distributing means is a conical distributor.

3. The 3-aminopropionitrile high efficiency rectifying device according to claim 1, wherein the second tube layer evaporator is in a form of 4 tubes connected in parallel.

4. The 3-aminopropionitrile high-efficiency rectifying device according to claim 1, wherein the primary corrugated demister and the secondary corrugated demister are both stainless steel corrugated demisters, and the secondary corrugated demister is provided with a temperature control unit at 70-80 ℃.

5. The 3-aminopropionitrile high-efficiency rectifying device according to claim 1, wherein the liquid phase outlet of the primary corrugated demister is connected with the liquid phase material inlet of the second tube layer evaporator through a liquid phase guide tube.

6. The 3-aminopropionitrile high-efficiency rectifying device according to claim 1, wherein a second liquid outlet is arranged at the bottom of the second tube layer evaporator and is communicated with an additionally arranged decompression conveying pump for continuously outputting high-boiling residual liquid.

7. A continuous production system for 3-aminopropionitrile, comprising:

A reaction device for synthesizing 3-aminopropionitrile by ammonification of acrylonitrile;

A continuous low-boiling-point removing device connected with the reaction device;

The 3-aminopropionitrile high efficiency rectifying device according to any one of claims 1 to 6, wherein the first falling film evaporator is connected with a material outlet of the continuous low boiling removal device.

8. The continuous production system of 3-aminopropionitrile according to claim 7, wherein the reaction device is a pipeline reactor for ammonifying to form 3-aminopropionitrile and continuously outputting a reaction liquid.

9. The continuous production system of 3-aminopropionitrile according to claim 8, wherein the continuous removal low boiling device comprises:

Deamination flash equipment connected with the pipeline reactor;

And a material outlet of the multistage serial falling film evaporation equipment is communicated with a first falling film evaporator of the 3-aminopropionitrile efficient rectifying device.

10. The continuous production system of 3-aminopropionitrile according to claim 9, wherein the low-boiling outlet of the deamination flash evaporation equipment and the multistage serial falling film evaporation equipment is connected with an additionally arranged ammonia absorption device for cooling and collecting removed low-boiling impurities.