CN112830878A - Synthesis system and method for preparing hexamethylene diamine by hydrogenation of adiponitrile - Google Patents

Synthesis system and method for preparing hexamethylene diamine by hydrogenation of adiponitrile Download PDF

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Publication number
CN112830878A
CN112830878A CN201911163720.9A CN201911163720A CN112830878A CN 112830878 A CN112830878 A CN 112830878A CN 201911163720 A CN201911163720 A CN 201911163720A CN 112830878 A CN112830878 A CN 112830878A
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micro
reaction
adiponitrile
interface generator
interface
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张志炳
周政
孟为民
王宝荣
杨高东
罗华勋
张锋
李磊
杨国强
田洪舟
曹宇
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Nanjing Institute of Microinterface Technology Co Ltd
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Nanjing Institute of Microinterface Technology Co Ltd
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Priority to CN201911163720.9A priority Critical patent/CN112830878A/en
Priority to PCT/CN2020/092588 priority patent/WO2021103457A1/en
Publication of CN112830878A publication Critical patent/CN112830878A/en
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
    • C07C209/44—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of carboxylic acids or esters thereof in presence of ammonia or amines, or by reduction of nitriles, carboxylic acid amides, imines or imino-ethers
    • C07C209/48—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of carboxylic acids or esters thereof in presence of ammonia or amines, or by reduction of nitriles, carboxylic acid amides, imines or imino-ethers by reduction of nitriles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0093—Microreactors, e.g. miniaturised or microfabricated reactors
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
    • C07C209/82—Purification; Separation; Stabilisation; Use of additives
    • C07C209/84—Purification
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C211/00—Compounds containing amino groups bound to a carbon skeleton
    • C07C211/01—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to acyclic carbon atoms
    • C07C211/02—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to acyclic carbon atoms of an acyclic saturated carbon skeleton
    • C07C211/09—Diamines
    • C07C211/12—1,6-Diaminohexanes
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C231/00—Preparation of carboxylic acid amides
    • C07C231/02—Preparation of carboxylic acid amides from carboxylic acids or from esters, anhydrides, or halides thereof by reaction with ammonia or amines
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C233/00—Carboxylic acid amides
    • C07C233/01—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms
    • C07C233/02—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms having nitrogen atoms of carboxamide groups bound to hydrogen atoms or to carbon atoms of unsubstituted hydrocarbon radicals
    • C07C233/04—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms having nitrogen atoms of carboxamide groups bound to hydrogen atoms or to carbon atoms of unsubstituted hydrocarbon radicals with carbon atoms of carboxamide groups bound to acyclic carbon atoms of an acyclic saturated carbon skeleton
    • C07C233/05—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms having nitrogen atoms of carboxamide groups bound to hydrogen atoms or to carbon atoms of unsubstituted hydrocarbon radicals with carbon atoms of carboxamide groups bound to acyclic carbon atoms of an acyclic saturated carbon skeleton having the nitrogen atoms of the carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C253/00—Preparation of carboxylic acid nitriles
    • C07C253/20—Preparation of carboxylic acid nitriles by dehydration of carboxylic acid amides
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C255/00—Carboxylic acid nitriles
    • C07C255/01—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms
    • C07C255/02—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms of an acyclic and saturated carbon skeleton
    • C07C255/04—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms of an acyclic and saturated carbon skeleton containing two cyano groups bound to the carbon skeleton

Abstract

The invention provides a synthesis system and a method for preparing hexamethylene diamine by hydrogenation of adiponitrile. The synthesis system comprises: the device comprises an adiponitrile preparation device, a micro-interface intensifier, a hydrogenation reaction kettle and a rectifying tower which are sequentially connected, wherein hydrogen and adiponitrile prepared from the adiponitrile preparation device are introduced into the micro-interface intensifier. The synthesis system provided by the invention optimizes the reaction route, improves the reaction separation efficiency, improves the mass transfer effect of the reaction phase interface, and further improves the quality and yield of the product.

Description

Synthesis system and method for preparing hexamethylene diamine by hydrogenation of adiponitrile
Technical Field
The invention relates to the field of hexamethylene diamine preparation, and particularly relates to a synthesis system and a method for preparing hexamethylene diamine by hydrogenation of adiponitrile.
Background
Hexamethylene diamine is an important raw material for chemical synthesis, and is mainly used for producing nylon 66 and 610 resins. The production process of hexamethylene diamine mainly comprises a caprolactam method, a butadiene method and an adiponitrile catalytic hydrogenation method. The caprolactam method and the butadiene method are only suitable for small-scale production and are gradually eliminated due to higher production cost, and the method for preparing the hexamethylene diamine by the catalytic hydrogenation of the adiponitrile is widely applied due to simple process, high product quality and low production cost.
The method for preparing hexanediamine by catalytic hydrogenation of adiponitrile is divided into a high-pressure method and a low-pressure method in industry. Wherein, the low-pressure method adopts a nickel-based catalyst, the reaction temperature is about 70-100 ℃, the pressure is about 1.8-2.7MPa, and the selectivity of the hexamethylene diamine reaches 99%. The high pressure process also employs a nickel-based catalyst with a reaction temperature of between about 100 ℃ and 200 ℃ and a pressure of between about 3 MPa and 8 MPa.
However, in the production process of hexamethylenediamine, no matter a high-pressure method or a low-pressure method, some side reactions also occur, main byproducts include azepane, aminocapronitrile, 1, 2-diaminocyclohexane, N-ethylhexamethylenediamine, aminomethyl cyclopentane and the like, wherein the azepane, 1, 2-diaminocyclohexane, N-ethylhexamethylenediamine and the like are difficult to separate from the hexamethylenediamine, and the mixture also contains excessive components such as ethanol, sodium hydroxide, nickel-based catalysts and the like, and the existence of the substances can affect the high-quality refined hexamethylenediamine of a final product and the product quality of downstream users, such as indexes of chromaticity, purity and the like.
In addition, the degree of influence of the interfacial area on the volume mass transfer coefficient is large in the reaction process, but the mass transfer efficiency of the reaction devices such as the kettle type reactor, the tubular reactor, the tower type reactor and the like in the prior art is generally low, so that breakthrough progress is difficult to be made in the reaction efficiency, the reaction efficiency in the reaction process is influenced, and the reaction yield and the raw material conversion rate are difficult to be greatly improved.
In view of the above, the present invention is particularly proposed.
Disclosure of Invention
The first purpose of the invention is to provide a synthesis system for preparing hexamethylene diamine by hydrogenation of adiponitrile, which optimizes a reaction route, improves reaction separation efficiency, improves mass transfer effect of a reaction phase interface by arranging a micro interface intensifier and a micro interface generator, reduces energy consumption and production cost, reduces generation of byproducts, obviously improves reaction efficiency in a reaction process, further improves product quality and yield, and also plays a role in saving equipment cost and equipment floor space.
The second purpose of the invention is to provide a method for synthesizing hexamethylene diamine by adopting the synthesis system, and the synthesized hexamethylene diamine product has good quality, high yield and improved selectivity.
In order to achieve the above purpose of the present invention, the following technical solutions are adopted:
the invention provides a synthesis system for preparing hexamethylene diamine by hydrogenation of adiponitrile, which comprises: the system comprises an adiponitrile preparation device, a micro-interface intensifier, a hydrogenation reaction kettle and a rectifying tower which are sequentially connected, wherein hydrogen and adiponitrile prepared from the adiponitrile preparation device are introduced into the micro-interface intensifier;
adiponitrile preparation facilities includes ammoniation reactor and reaction rectifying column, be provided with raw materials import and reaction feed liquid export on the ammoniation reactor, the raw materials import includes the ammonia import, be provided with first micro-interface generator and the second micro-interface generator of arranging from top to bottom in the ammoniation reactor, let in the first micro-interface generator and follow the reaction feed liquid that the reaction feed liquid export circulated back, first micro-interface generator is connected with the air duct, stretch out the top of air duct ammoniation reactor liquid level is used for retrieving the ammonia, the end of ammonia import extends to in the second micro-interface generator.
In the prior art, in the production process of hexamethylene diamine, side reactions are more, and the influence degree of a phase interface area in the reaction process on a volume mass transfer coefficient is larger, but reaction devices such as a kettle type reactor, a tubular reactor, a tower type reactor and the like in the prior art are generally low in mass transfer efficiency, so that breakthrough progress is difficult to be made in reaction efficiency, the reaction efficiency in the reaction process is influenced, and the reaction yield and the raw material conversion rate are difficult to be greatly improved.
According to the invention, the micro-interface intensifier is additionally arranged in front of the hydrogenation reaction kettle, so that after hydrogen and adiponitrile are introduced into the micro-interface intensifier, mass transfer enhancement, dispersion and crushing are realized in the micro-interface intensifier, and after micro bubbles are formed by crushing, the hydrogen and the adiponitrile are introduced into the hydrogenation reaction kettle from the micro-interface intensifier to carry out further hydrogenation reaction.
The micro-interface intensifier is of a pneumatic type, and the mass transfer effect is improved in a mode that hydrogen is introduced into the micro-interface intensifier and then is in contact with adiponitrile and then is broken into micro bubbles.
In the adiponitrile preparation device, in order to better realize the circulation of the reaction feed liquid returned from the reaction feed liquid outlet, a reaction feed liquid inlet is preferably arranged at the top of the first micro-interface generator, the reaction feed liquid inlet is connected with the reaction feed liquid outlet through a circulation pipeline, and a circulation pump for providing power is preferably arranged on the circulation pipeline.
In addition, the first micro-interface generator is connected with a gas-guide tube, because a part of ammonia gas is leaked above the liquid surface in the reaction process. In order to fully recover the ammonia gas, a mode of arranging the gas guide tube can be utilized, so that the ammonia gas is sucked into the first micro-interface generator along the gas guide tube and is fully contacted with reaction liquid, severe turbulence is formed, and the mass transfer efficiency is improved.
More preferably, the first micro-interface generator is a hydraulic micro-interface generator, ammonia gas coming from the gas guide tube is sucked by taking reaction liquid as power circulation to form turbulence so as to increase the contact area of the phase interface of the first micro-interface generator and the second micro-interface generator, the reaction liquid enters from the middle of the top of the first micro-interface generator, the ammonia gas is sucked by the channels on the two sides of the first micro-interface generator, the gas phase and the liquid phase are fully contacted in the micro-interface generator, and the mass transfer effect is increased.
The second micro-interface generator is a pneumatic micro-interface generator, and the mass transfer effect is improved by introducing ammonia gas into the micro-interface generator, contacting with the reaction liquid in the reaction kettle, and then crushing to form micro bubbles.
In order to further improve the sufficient contact of the reaction feed liquid, the outlet of the first micro-interface generator is preferably arranged opposite to the outlet of the second micro-interface generator.
More preferably, the outlet of the first micro-interface generator faces downwards vertically, the outlet of the second micro-interface generator faces upwards vertically, and the two outlets are opposite to each other, so that the micro-bubbles coming out from the outlets realize opposite impact, and the degree of turbulent stirring is further improved.
The micro-interface generator and the micro-interface intensifier can break a gas phase and/or a liquid phase in the multi-phase reaction medium into micro-bubbles and/or micro-droplets with the diameter of micron level in a preset action mode before the multi-phase reaction medium enters the reactor, so that the mass transfer area of a phase boundary between the gas phase and/or the liquid phase and/or a solid phase in the reaction process is increased, the mass transfer efficiency between the reaction phases is improved, and the multi-phase reaction is intensified within a preset temperature and/or preset pressure range.
The micro-interface generator and the micro-interface intensifier can be used for the reaction of gas-liquid, liquid-solid, gas-liquid, gas-liquid-solid, liquid-solid and other multi-phase reaction media, the specific structure of the micro-interface generator and the micro-interface intensifier can be freely selected according to the difference of flowing media, and the specific structure and the specific functional action of the micro-interface generator and the micro-interface intensifier are correspondingly recorded in the prior patents and documents, and are not described in detail herein.
Preferably, the hydrogenation reaction kettle for performing the hydrogenation reaction is one of a fixed bed reaction kettle, an emulsion bed reaction kettle and a boiling bed reaction kettle, more preferably a fixed bed reaction kettle, the catalyst in the fixed bed reaction kettle is fixed on the bed layer, the catalyst for the hydrogenation reaction is generally a nickel-based catalyst, preferably the catalyst can be a supported nickel-based catalyst, or more preferably a nickel-based catalyst modified by alkaline earth metal oxide or rare earth metal oxide.
Preferably, the hydrogenation reaction kettle is provided with a first material inlet and a first material outlet, when the fixed bed reaction kettle is used, hydrogen and adiponitrile enter from the first material inlet and pass through a catalyst bed layer to perform hydrogenation reaction, and the obtained hexamethylene diamine exits from the first material outlet.
Preferably, the position of the first material outlet is higher than that of the first material inlet, the first material inlet is arranged on one side wall of the hydrogenation reaction kettle, the first material outlet is arranged on the other side wall of the hydrogenation reaction kettle, and the materials flow from bottom to top in the reaction kettle to perform hydrogenation reaction.
Preferably, the synthesis system further comprises a hydrogen separation tank, after gas-liquid separation is performed in the hydrogen separation tank, the separated hydrogen is discharged from the top of the hydrogen separation tank and returned to the hydrogenation reaction kettle, and the unreacted material and the generated material enter the rectifying tower from the hydrogen separation tank for rectification.
Preferably, the rectifying tower comprises a deep purification section and a product purification section, a second material inlet is formed in a tower section between the deep purification section and the product purification section, and the second material inlet is connected with the first material outlet in the hydrogenation reaction kettle.
Materials from the second material inlet mainly comprise hexamethylene diamine, a small amount of hydrogen, adiponitrile, water and the like, after the rectification separation of the product purification section, the materials at the tower bottom mainly comprise adiponitrile, a small amount of hexamethylene diamine, water and the like, and the hexamethylene diamine, a small amount of hydrogen and the water are gradually rectified towards the direction of the tower top.
The deep purification section and the product purification section can be formed by randomly combining a plurality of tower plates and fillers.
Preferably, the top of the rectifying tower is provided with an overhead condenser, and the tower kettle is provided with a tower kettle reboiler, wherein the tower kettle reboiler is of a falling film reboiler type.
In addition, the adiponitrile preparation device mainly comprises an ammoniation reactor and a reaction rectifying tower, wherein the reaction in the ammoniation reactor mainly comprises the steps of carrying out ammoniation reaction on adipic acid and ammonia gas to generate adipamide, and then dehydrating the adipamide in the reaction rectifying tower to generate adiponitrile.
Preferably, the raw material inlet further comprises an adipic acid inlet, a tower kettle of the reaction rectifying tower is provided with a discharge port, and the discharge port is communicated with the adipic acid inlet.
The inlets of the raw materials adipic acid and ammonia gas are preferably arranged on the side surface of the ammoniation reactor in a parallel mode, so that the parallel and uniform feeding can be realized, unreacted raw materials, catalysts and other substances generally exist in a tower kettle of the reactive distillation tower, and therefore, after the reactive distillation tower is communicated with the adipic acid inlet, the effect of fully utilizing the raw materials is achieved, the conversion rate of the raw materials can be improved, the communication mode is generally realized through a pipeline, and a pump body can be arranged on the pipeline as required.
Because the first micro-interface generator and the second micro-interface generator are both positioned below the liquid level, in order to avoid instability caused by impact of liquid flow on the first micro-interface generator and the second micro-interface generator, connecting rods for mutual fixation are preferably arranged between the first micro-interface generator and the second micro-interface generator, and the specific materials, shapes and numbers of the connecting rods are not limited as long as the fixing effect can be achieved, and the connecting rods are preferably long rod-shaped.
More preferably, the number of the connecting rods is three, and the three connecting rods are uniformly arranged along the edge of the bottom of the first micro-interface generator and then fixedly connected with the second micro-interface generator at the bottom.
For better stability, the first micro-interface generator and the second micro-interface generator may be fixed inside the ammoniation reactor by using a fixing bracket, and preferably, the first micro-interface generator is fixed by using a grid plate, the grid plate is stable and has a plurality of grid holes, so that the normal flow of the reaction material liquid is not influenced.
By adopting the micro-interface generator, the temperature of the ammoniation reaction can be maintained at 200-230 ℃, the pressure is micro-positive pressure, and compared with the existing process, the operation temperature and the pressure are both reduced, so that the energy consumption is fully reduced, the energy is saved, and the safety is improved.
Compared with the traditional rectifying tower which is specially used for rectifying and separating, the reactive rectifying tower integrates the reaction and the rectification, so that the probability of generating by-products is reduced by quickly separating after the reaction, and the selectivity and the yield of the reaction are improved.
Preferably, the rectification section comprises a light component separation section for separating ammonia and water, a product separation section for purification and separation of adiponitrile;
preferably, the light component separation section and the product separation section are arranged at the upper part of the deep dehydration reaction section from top to bottom;
a feed inlet is arranged on a tower section between the product separation section and the deep dehydration reaction section and is used for introducing a product of an ammoniation reactor into the reaction rectifying tower, materials coming in from the feed inlet mainly comprise adipamide, a catalyst, unreacted raw materials and the like, the adipamide is subjected to dehydration reaction through the deep dehydration reaction section positioned below the feed inlet, heavy components such as adipic acid, the catalyst and the like are gradually rectified and separated to the tower bottom, products such as adiponitrile, ammonia gas, water and the like are rectified and separated towards the direction of the tower top, after the rectification separation of the product separation section, the product is extracted from the side line, a part of water is contained in the product extracted from the side line except the adiponitrile, and the rest ammonia gas and water are separated to the tower top through the light component separation section.
Furthermore, a product side line extraction unit arranged between the light component separation section and the product separation section is composed of a tower plate with a plurality of liquid collecting grooves, and the liquid collecting grooves have the function of collecting products in a liquid phase state, so that the collection and extraction of the products are facilitated.
The rectifying section and the deep dehydration reaction section in the reactive rectifying tower can be formed by randomly combining a plurality of tower plates and fillers, preferably, the tower plate structure is adopted at the position close to the tower kettle, and the filler structure is adopted at the position close to the tower top, because the pressure drop of the tower plates is larger and the pressure drop of the fillers is smaller.
Preferably, the synthesis system further comprises an overhead condenser and a kettle reboiler. And a part of light components reflows to the reaction rectifying tower through the overhead condenser, and the other part of light components flows out of the overhead condenser and is recycled in the form of ammonia water, and the light components can also be further post-treated to form ammonia gas which returns to the ammonification reactor for recycling.
Preferably, the reboiler of the tower kettle is preferably selected to be a falling film reboiler, compared with the reboiler of the common type, the reboiler of the type has the advantages of high heat exchange efficiency, short residence time and difficult coking due to the fact that the film is formed on the tube wall, and the generation of byproducts due to the polymerization of substances in the tower kettle is avoided.
The synthesis system of the invention can be provided with the pump body on the corresponding connecting pipeline according to the actual requirement.
The invention also provides a method for synthesizing hexamethylene diamine, which comprises the following steps:
(A) after the adiponitrile and the hydrogen are dispersed and crushed in the micro interface intensifier, the adiponitrile and the hydrogen enter the hydrogenation reaction kettle to carry out hydrogenation reaction to generate hexamethylenediamine;
(B) and (3) putting the hexamethylene diamine into a rectifying tower, and rectifying to obtain the product.
The hexamethylenediamine product prepared by the method has good quality, high yield and improved selectivity, the conversion rate of the raw materials is improved by 10-20 percent compared with the conventional method, and the yield and the selectivity can also be improved by about 10 percent.
Compared with the prior art, the invention has the beneficial effects that:
(1) the hexamethylenediamine synthesis system optimizes the reaction route, improves the reaction separation efficiency, and further improves the quality and yield of the product;
(2) the hexamethylene diamine synthesis system has the advantages of simple structure, less three wastes, realization of full recycling of raw materials and small occupied area;
(3) the synthesis system improves the mass transfer effect of the reaction phase interface by arranging the micro-interface intensifier, reduces the energy consumption and the production cost, and obviously improves the reaction efficiency in the reaction process;
(4) the micro-interface intensifier is fully utilized, so that the temperature and the pressure of the hydrogenation reaction can be greatly reduced, the energy consumption is fully reduced, and the safety is improved;
(5) the method for synthesizing the hexamethylene diamine finally realizes that the conversion rate of the raw materials is improved by 10-20 percent compared with the prior art, and the yield and the selectivity of the hexamethylene diamine can be improved by about 10 percent.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
fig. 1 is a schematic structural diagram of a synthesis system for preparing hexamethylenediamine by hydrogenation of adiponitrile according to an embodiment of the present invention.
Description of the drawings:
100-an ammoniation reactor; 110-a first micro-interface generator;
1101-airway tube; 120-a second micro-interface generator;
130-a connecting rod; 140-ammonia gas inlet;
150-adipic acid inlet; 160-reaction feed liquid inlet;
170-reaction feed liquid outlet;
200-a reactive distillation column; 210-a rectification section;
211-a light fraction separation section; 212-product separation section;
220-deep dehydration reaction section; 230-a feed inlet;
240-discharge hole; 250-a product sidedraw unit;
300-micro interface enhancer; 400-a hydrogenation reaction kettle;
410-a first material inlet; 420-a first material outlet;
500-a rectification column; 510-deep purification section;
520-product purification section; 530-second material inlet;
550-column kettle reboiler; 560-overhead condenser;
700-hydrogen knockout drum.
Detailed Description
The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and the detailed description, but those skilled in the art will understand that the following described embodiments are some, not all, of the embodiments of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In order to more clearly illustrate the technical solution of the present invention, the following description is made in the form of specific embodiments.
Examples
Referring to fig. 1, a synthesis system for preparing hexanediamine by adiponitrile hydrogenation according to an embodiment of the present invention includes an adiponitrile preparation apparatus, a micro interface enhancer 300, a hydrogenation reactor 400, and a rectifying tower 500, which are connected in sequence, wherein the adiponitrile preparation apparatus includes two main apparatus bodies, namely, an ammoniation reactor 100 and a reactive rectifying tower 200.
The type of the hydrogenation reactor 400 is selected from a fixed bed reactor, a first material inlet 410 is arranged on one side wall of the fixed bed reactor, hydrogen and adiponitrile from the micro interface intensifier 300 enter the fixed bed reactor from the first material inlet 410, the hydrogenation reaction temperature is 50 ℃ and the reaction pressure is 1MPa after the hydrogen and the adiponitrile pass through a bed layer filled with a nickel-based catalyst, reaction products are collected after the reaction, the reaction products are extracted from a first material outlet 420 on the other side wall and enter a hydrogen separation tank 700 for gas-liquid separation, the separated hydrogen goes out from the top of the hydrogen separation tank 700 and returns to the hydrogenation reactor 400, and unreacted materials and generated materials enter a rectifying tower 500 for rectification and purification from a second material inlet 530.
The rectifying column 500 comprises a deep purification section 510 and a product purification section 520, wherein a tower top condenser 560 is arranged at the tower top, a tower bottom reboiler 550 is arranged at the tower bottom, the components at the tower top are mainly hexamethylene diamine, one part of the hexamethylene diamine returns to the rectifying column through the tower top condenser 560, and the other part of the hexamethylene diamine flows out from the tower top condenser 560.
The tower kettle reboiler 550 is a falling film reboiler, the reboiler of the type is efficient, the generation of byproducts is avoided, in order to provide certain transportation power, a transportation pump is arranged on a connecting pipeline between the tower kettle reboiler 550 and the rectifying tower 500, the materials of the tower kettle mainly comprise adiponitrile, a small amount of hexamethylenediamine, water and the like, and the hexamethylenediamine, a small amount of hydrogen and the water are gradually rectified towards the direction of the top of the tower.
In the adiponitrile production apparatus of this embodiment, the ammoniation reactor 100 is provided with a raw material inlet and a reaction feed liquid outlet 170, and the raw material inlet includes an ammonia gas inlet 140 and an adipic acid inlet 150.
The ammoniation reactor 100 is provided with a first micro-interface generator 110 and a second micro-interface generator 120 arranged in an up-down manner.
The first micro-interface generator 110 and the second micro-interface generator 120 are fixed inside the ammonification reactor 100, and the first micro-interface generator 110 is fixed by a grid plate.
First micro-interface generator 110 is located the upper portion, its inside lets in the reaction feed liquid that returns from reaction feed liquid export 170 circulation, in order to play the effect of the reaction feed liquid in the dispersion ammoniation reactor 100, first micro-interface generator 110 still is connected with air duct 1101, the top of air duct 1101 stretches out ammoniation reactor 100 liquid level, there is some ammonia to run on the liquid level in the reaction process, the usable mode that sets up air duct 1101, through the mode that surges with this part ammonia entrainment to first micro-interface generator, thereby realize recycle, improve mass transfer efficiency. The entrainment mode can cause the gas-liquid phase to generate more violent turbulence in the micro-interface generator, so that the bubbles are broken, more micron bubbles with smaller diameter are generated, and the generated micron bubbles are discharged from the outlet of the micro-interface generator.
Specifically, a reaction material liquid inlet 160 is disposed at the top of the first micro-interface generator 110, the reaction material liquid inlet 160 is connected to the reaction material liquid outlet 170 through a circulation pipeline, and a circulation pump for providing power is disposed on the circulation pipeline, so that the reaction material liquid can circulate through the circulation pipeline.
The second micro-interface generator 120 is located at the lower part, the tail end of the ammonia gas inlet 140 extends into the second micro-interface generator 120 to play a role in dispersing ammonia gas coming from the ammonia gas inlet 140, a plurality of pore channels are distributed on the pipeline, reaction liquid in the pipeline is extruded and crushed through pressure, micron bubbles are formed, and the effect of crushing and dispersing is achieved.
The outlets of the first micro-interface generator 110 and the second micro-interface generator 120 are opposite, the outlet of the first micro-interface generator 110 faces downwards vertically, and the outlet of the second micro-interface generator 120 faces upwards vertically, so that micro-bubbles discharged from the outlets generate opposite impact, and the turbulence degree is improved.
A connecting rod 130 is disposed between the first micro-interface generator 110 and the second micro-interface generator 120 for fixing the two to each other, and the connecting rod 130 may preferably be in the shape of a long rod.
The number of the connecting rods 130 is three, and the three connecting rods are uniformly arranged along the bottom edge of the first micro-interface generator 110 and then fixedly connected with the second micro-interface generator 120 at the bottom.
The reaction rectifying tower 200 in the adiponitrile preparation device comprises a rectifying section 210 and a deep dehydration reaction section 220, a tower kettle of the reaction rectifying tower 200 is provided with a discharge port 240, the discharge port 240 is communicated with an adipic acid inlet 150 on the ammoniation reactor 100 through a pipeline, a catalyst, adipic acid and the like in the tower kettle can be recycled to the ammoniation reactor 100, the raw materials and the catalyst are recycled, and a conveying pump is arranged on the pipeline.
The rectifying section 210 includes a light component separating section 211 for separating ammonia and water, and a product separating section 212 for purification and separation of adiponitrile. Wherein, the light component separation section 211 and the product separation section 212 are arranged at the upper part of the deep dehydration reaction section 220 from top to bottom.
A feed inlet 230 is arranged on the tower section between the product separation section 212 and the deep dehydration reaction section 220, the product of the ammoniation reactor 100 is introduced into the reaction rectifying tower 200 from the feed inlet 230, and the material from the feed inlet 230 mainly comprises adipamide, a catalyst, unreacted raw materials and the like.
A product side draw unit 250 is disposed between the light component separation section 211 and the product separation section 212, and the product side draw unit 250 is mainly composed of a tray with a plurality of liquid collecting grooves, because the product is mainly in a liquid phase form, in order to facilitate the gas phase condensation in the tower to be drawn, the liquid collecting grooves can achieve the function of collecting liquid phase products.
The light component separation section 211 and the product separation section 212 are mainly composed of trays and packing materials, and the packing materials can be Raschig rings, pall rings, ladder rings and the like.
The deep dehydration reaction section 220 is mainly composed of trays, and may not be added with a filler.
In the above embodiment, the micro-interface generator is not limited to two micro-interface generators, and in order to increase the dispersion and mass transfer effects, additional micro-interface generators may be additionally provided, especially, the second micro-interface generator is not limited to be installed at any position, and may be installed externally or internally, and when the second micro-interface generator is installed internally, the micro-bubbles emitted from the outlet of the micro-interface generator may be installed on the side wall inside the kettle in a manner of being arranged oppositely, so as to generate counter-flushing.
The installation position of the micro-interface enhancer 300 is not limited, and the micro-interface enhancer may be built in or out.
In the above embodiment, the type of the hydrogenation reactor 400 may also be a fluidized bed reactor, etc., and the feeding and discharging manner is not limited, and the feeding and discharging manner may be from below, and the discharging manner may also be from above, or from above, but it is preferable that the feeding and discharging manner is from below and from above.
In the above embodiment, the number of the pump bodies is not specifically required, and the pump bodies may be arranged at corresponding positions as required.
In the above embodiment, the light component separation section 211, the product separation section 212, and the deep dehydration reaction section 220 of the reactive distillation column 200 are only a preferable configuration, and may be increased or decreased according to the actual distillation effect, for example, it is also feasible not to provide the light component separation section 211.
In addition, the height, diameter, number of plates, and division of the column section of the reactive distillation column 200 can be adjusted according to actual needs.
The working process and principle of the synthesis system for preparing hexamethylene diamine by hydrogenation of adiponitrile according to the invention are briefly described as follows:
nitrogen gas purges the inside of the adiponitrile preparation device, the micro interface intensifier 300, the hydrogenation reaction kettle 400, the pipelines of the rectifying tower 500 and the reactor.
Then, adipic acid and phosphoric acid as a catalyst are proportionally introduced into the ammoniation reactor 100, while ammonia gas is proportionally introduced into the ammonia gas inlet 140, and the adipic acid fills the whole ammoniation reactor 100.
The ammoniation reactor 100 has a reaction temperature of 200-230 ℃ and a reaction pressure of 1atm or more.
The rising ammonia and the descending adipic acid are subjected to neutralization reaction in the ammonification reactor 100 to generate adipamide, in the reaction process, the reaction liquid in the ammonification reactor 100 is circulated through the first micro-interface generator 110, the excessive ammonia enters the space above the liquid level of the ammonification reactor 100, and the part of ammonia is collected and sucked into the first micro-interface generator 110 through the arranged gas guide pipe 1101 and is stirred with the reaction liquid in the first micro-interface generator 110 in a turbulent mode.
The ammonia gas from the ammonia gas inlet is dispersed and crushed by the second micro-interface generator 120, so that the mass transfer effect of the reaction phase interface is improved, and components such as a gas distributor and the like do not need to be additionally arranged in the ammonification reactor 100.
The first micro-interface generator 110 is opposite to the second micro-interface generator 120 in outlet, the discharged micro-bubbles just generate opposite impact to realize more favorable stirring turbulence, the micro-bubbles can flow along the flowing direction of the reaction liquid after opposite impact, thus the micro-bubbles can keep continuous contact with the reaction liquid, the mass transfer effect is improved, and the diameter of the micro-bubbles is kept at the micron level.
The generated adipamide, the catalyst and the unreacted raw material adipic acid enter the deep dehydration reaction section 220 from the middle section of the reactive rectification column 200 through a pipeline to perform dehydration reaction. The operation pressure of the reactive distillation column 200 is negative pressure, and the bottom temperature is 230 ℃ or higher, preferably 240 ℃ or 250 ℃.
After the dehydration reaction, the generated adiponitrile and water are extracted from the side line of the product separation section 212, ammonia and water are separated to the top of the tower through the light component separation section 211, one part of the ammonia and the water flow through the top of the tower to reflux through a top condenser, the other part of the ammonia and the water flow through the top condenser to be discharged, and the ammonia and the water flow separated by the gas-liquid separation tank are reused as raw materials for the reaction.
In addition, unreacted raw materials, catalyst and a small amount of adiponitrile products are separated to the tower bottom after the dehydration reaction, part of the unreacted raw materials, the catalyst and the adiponitrile products pass through a tower bottom reboiler of the tower bottom to realize circulating rectification in the tower bottom, and the other part of the unreacted raw materials returns to the ammoniation reactor 100 from a discharge hole 240 in the tower bottom to be combined with the raw materials.
The type of the tower kettle reboiler is a falling film reboiler, the material is evaporated by the tower kettle reboiler, and then returns to the reactive distillation tower 200 after passing through the liquid distributor for liquid distribution from the bottom of the tower kettle reboiler, and the liquid distributor is arranged for improving the distillation efficiency.
Adiponitrile and water extracted from the side line of the reactive rectifying tower 200 enter a micro interface intensifier 300 after being rectified, hydrogen is simultaneously introduced into the micro interface intensifier 300, the hydrogen and the adiponitrile from the micro interface intensifier 300 enter a hydrogenation reaction kettle 400, the hydrogenation reaction temperature is 50 ℃ and the reaction pressure is 1MPa after passing through a bed layer filled with a nickel-based catalyst, reaction products are collected after reaction, the reaction products are extracted from a first material outlet 420 on the other side wall and enter a hydrogen separation tank 700 for gas-liquid separation, the separated hydrogen is discharged from the top of the hydrogen separation tank 700 and returns to the hydrogenation reaction kettle 400, unreacted materials and generated materials enter a rectifying tower 500 from a second material inlet 530 for rectification, one part of the rectified product hexamethylenediamine returns to the rectifying tower 500 through an overhead condenser 560, the other part of the rectified product flows out of the overhead condenser 560, part of the raw material, water and a small amount of hexamethylenediamine at the bottom of the column are returned to the rectifying column 500 through the column reboiler 550, and the other part flows out from the column reboiler 550.
The above steps are repeated circularly to make the whole synthesis system run smoothly.
By adopting the synthesis process, the conversion rate of the raw materials is increased by 10-20% compared with the prior art, the product selectivity and yield are correspondingly improved compared with the prior art, and the effects of reducing energy consumption and improving the conversion rate of the raw materials, the product yield and the selectivity can be achieved.
In addition, by laying the micro-interface generator, the micro-interface intensifier and other devices, the pressure and the temperature of the hydrogenation reaction kettle are reduced, and the energy consumption is fully reduced.
In a word, compared with the synthesis system for preparing the hexamethylene diamine by the adiponitrile hydrogenation in the prior art, the synthesis system disclosed by the invention has the advantages of fewer equipment components, small occupied area, low energy consumption, low cost, high safety, controllable reaction and high raw material conversion rate, provides a synthesis system with stronger operability for the process for preparing the hexamethylene diamine by the adiponitrile hydrogenation, and is worthy of wide popularization and application.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A synthetic system for preparing hexamethylene diamine by hydrogenation of adiponitrile is characterized by comprising the following components: the system comprises an adiponitrile preparation device, a micro-interface intensifier, a hydrogenation reaction kettle and a rectifying tower which are sequentially connected, wherein hydrogen and adiponitrile prepared from the adiponitrile preparation device are introduced into the micro-interface intensifier;
adiponitrile preparation facilities includes ammoniation reactor and reaction rectifying column, be provided with raw materials import and reaction feed liquid export on the ammoniation reactor, the raw materials import includes the ammonia import, be provided with first micro-interface generator and the second micro-interface generator of arranging from top to bottom in the ammoniation reactor, let in the first micro-interface generator and follow the reaction feed liquid that the reaction feed liquid export circulated back, first micro-interface generator is connected with the air duct, stretch out the top of air duct ammoniation reactor liquid level is used for retrieving the ammonia, the end of ammonia import extends to in the second micro-interface generator.
2. The synthesis system according to claim 1, wherein the hydrogenation reaction kettle is one of a fixed bed reaction kettle, an emulsion bed reaction kettle and a boiling bed reaction kettle, preferably a fixed bed reaction kettle.
3. The synthesis system of claim 2, wherein the hydrogenation reaction kettle is provided with a first material inlet and a first material outlet.
4. The synthesis system of claim 3, wherein the rectifying tower comprises a deep purification section and a product purification section, a second material inlet is arranged on a tower section between the deep purification section and the product purification section, and the second material inlet is connected with the first material outlet on the hydrogenation reaction kettle.
5. The synthesis system of claim 3, further comprising a hydrogen knock-out tank connected to the first material outlet.
6. A synthesis system according to any of claims 1 to 5, characterized in that the top of the rectification column is provided with an overhead condenser and the bottom is provided with a bottom reboiler, of the type falling film reboiler.
7. A synthesis system according to claim 3, characterised in that the first material outlet is at a higher level than the first material inlet.
8. The synthesis system according to any one of claims 1 to 5, wherein a reaction liquid inlet is arranged at the top of the first micro-interface generator, and the reaction liquid inlet is connected with a reaction liquid outlet through a circulating pipeline;
preferably, a circulating pump is arranged on the circulating pipeline.
9. The synthesis system according to any one of claims 1-5, wherein the outlet of the first micro-interface generator is opposite the outlet of the second micro-interface generator;
preferably, the outlet of the first micro-interface generator faces vertically downwards, and the outlet of the second micro-interface generator faces vertically upwards.
10. A method for synthesizing hexamethylenediamine using the synthesis system according to any one of claims 1 to 9, comprising the steps of:
(A) after the adiponitrile and the hydrogen are dispersed and crushed in the micro interface intensifier, the adiponitrile and the hydrogen enter the hydrogenation reaction kettle to carry out hydrogenation reaction to generate hexamethylenediamine;
(B) and (3) putting the hexamethylene diamine into a rectifying tower, and rectifying to obtain the product.
CN201911163720.9A 2019-11-25 2019-11-25 Synthesis system and method for preparing hexamethylene diamine by hydrogenation of adiponitrile Pending CN112830878A (en)

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