Device for continuously preparing adiponitrile from hypergravity adipic acid and method for preparing adiponitrile

Abstract

The invention discloses a device for continuously preparing adiponitrile from adipic acid by supergravity, which is characterized in that a specially designed gas-in-liquid mixed feeding mode is firstly adopted, so that liquid of a falling film assembly is uniformly dispersed as far as possible, and meanwhile, by accurately controlling the reaction temperature in the falling film assembly, side reactions are reduced; secondly, the contact mode of gas and liquid of the falling film assembly is changed, the gas-liquid countercurrent contact mode is changed into gas-liquid parallel flow, and the liquid is prevented from being stopped in a pipeline through the gas-liquid parallel flow; and finally, mixing and mass and heat transfer effects of adipic acid and ammonia molecules in the reaction process are enhanced by using a supergravity assembly, so that adipic acid decomposition and coking in a bubbling section of a traditional reactor are effectively slowed down, the reaction efficiency and the product yield are improved, and side reactions are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, and particularly to a device for continuously preparing adiponitrile from adipic acid by using high gravity and a method for preparing adiponitrile. Background Art

[0002] The raw materials used in the continuous preparation of adiponitrile by ammoniation of adipic acid are mainly ammonia, adipic acid and phosphoric acid. In the traditional production process of adiponitrile, a "bubbling + falling film" reactor is adopted. Due to the limitation of the gas-liquid mixing mass transfer process in the bubbling section, problems such as easy decomposition and coking of substances such as adipic acid and difficulty in continuous operation will occur. In the reaction process, the local temperature overheats, and adipic acid will decompose (starting to decompose at > 220°C) to generate cyclopentanone, and the generated cyclopentanone will undergo self-condensation at high temperature; at the same time, the high local temperature will also cause the polymerization of adiponitrile to generate adiponitrile dimer. At the same time, a large amount of water and adiponitrile are generated in the tubes of the falling film reactor, so that the gas and liquid phases show an upward flow and a downward flow in the tubes, resulting in obvious interfacial impact, causing the liquid phase in the tubes to stagnate, resulting in the problem of liquid holdup, which will cause coking and corrosion.

[0003] Therefore, the key is how to improve the mass transfer in the gas-liquid mixing process, achieve rapid and uniform heat supply in the reaction process, and improve the problem of liquid stagnation in the falling film tubes. Summary of the Invention

[0004] The purpose of the present invention is to provide a device for continuously preparing adiponitrile from adipic acid by using high gravity and a method for preparing adiponitrile, which can strengthen the mass transfer effect between adipic acid and ammonia, delay the corrosion and coking of the reactor, and extend the operation cycle of the device.

[0005] To achieve the above purpose, the present invention provides a device for continuously preparing adiponitrile from adipic acid by using high gravity, and the device includes: a falling film component 1, a high gravity component 2, a separation component 3, a mixing component 4, and a heater 6;

[0006] Among them, the bottom of the falling film component 1 is connected to the top of the high gravity component 2; the separation component 3 is arranged at the lower end of the high gravity component 2 and is connected to the high gravity component 2; the heater 6 and the mixing component 4 are respectively connected to the inlet 10 of the falling film component, and the heater 6 is used to heat the ammonia gas that sends the reaction materials in the mixing component 4 into the falling film component 1 for reaction; the reaction materials are formed by mixing molten adipic acid and a catalyst.

[0007] The present invention also provides a method for preparing adiponitrile, and the method includes:

[0008] Introduce molten adipic acid and a catalyst into the mixing component 4 to mix and form reaction materials;

[0009] Introduce the reaction materials and the ammonia gas adjusted by the heater 6 into the falling film component 1 for reaction to obtain a gas-liquid mixture;

[0010] Introduce the gas-liquid mixture into the high-gravity component 2 for reaction to obtain a reaction product;

[0011] Perform gas-liquid separation on the reaction product through the separation component 3 to obtain adiponitrile.

[0012] Technical effects and advantages of the present invention:

[0013] The continuous adiponitrile preparation device from adipic acid using high gravity provided by the present invention adopts a combination of a high-gravity reactor and a falling-film tube reactor. This device first uses a specially designed gas-carrying liquid mixed feeding mode to make the liquid in the falling-film component as evenly dispersed as possible, and at the same time precisely control the reaction temperature in the falling-film component to reduce the occurrence of side reactions; secondly, change the contact mode between the gas and the liquid in the falling-film component, change the countercurrent contact mode of gas and liquid to a co-current contact mode, and avoid the stagnation of the liquid in the pipeline through the co-current of gas and liquid; finally, use the high-gravity component to strengthen the mixing and mass and heat transfer effects of adipic acid and ammonia molecules during the reaction process, thereby effectively slowing down the decomposition and coking of adipic acid in the bubbling section of the traditional reactor, improving the reaction efficiency and product yield, and reducing side reactions.

[0014] Other features and advantages of the present invention will be described in the subsequent specification, and part of them will be obvious from the specification or understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures pointed out in the specification and the drawings. Description of the Drawings

[0015] Figure 1 It is a structural diagram of the continuous adiponitrile preparation device from adipic acid using high gravity;

[0016] Figure 2 It is a partial view of the falling-film component and the high-gravity component in the continuous adiponitrile preparation device from adipic acid using high gravity;

[0017] Figure 3 It is a structural diagram of the high-gravity component;

[0018] Description of the Drawings: 1. Falling-film component; 2. High-gravity component; 3. Separation component; 4. Mixing component; 5. Motor; 6. Heater; 7. Condenser; 8. Pickling tank; 9. Sleeve; 10. Falling-film component inlet; 11. Fluid distributor; 12. Rotating drum; 13. Cutting unit; 14. Rotating shaft. Detailed Embodiments

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those who are familiar with this technology to understand and read, and are not used to limit the limited conditions under which the present invention can be implemented. Therefore, they do not have a substantial technical meaning. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", and "one" cited in this specification are only for the convenience of clear narration and are not used to limit the scope of implementation of the present invention. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope that the present invention can implement.

[0021] To solve the deficiencies of the prior art, the present invention discloses a device for continuously preparing adiponitrile from adipic acid by high gravity. The following is a detailed introduction to this device in combination with Figure 1 to introduce this device in detail.

[0022] A device for continuously preparing adiponitrile from adipic acid by high gravity, the device includes: a falling film component 1, a high gravity component 2, a separation component 3, a mixing component 4, and a heater 6.

[0023] Among them, the mixing component 4 is connected to the inlet 10 of the falling film component. Specifically, the mixing component 4 can introduce the molten adipic acid solution and the catalyst to form reaction materials.

[0024] Among them, the bottom of the falling film component 1 is connected to the top of the high gravity component 2; the falling film component 1 includes: one or more falling film tubes 9 and a temperature control unit connected to the falling film tubes 9; the falling film tubes 9 are of a double-tube structure, the inside of the falling film tubes contains reaction materials and ammonia gas, and the inside of the outer tube contains a heat exchange liquid; the temperature control unit controls the reaction temperature of the reaction materials and ammonia gas by adjusting the temperature of the heat exchange liquid.

[0025] Specifically, the falling film component 1 is mainly used to implement the neutralization reaction and dehydration reaction of adipic acid and ammonia gas (i.e., the reaction for preparing adiponitrile). In the falling film tube, the traditional gas-liquid countercurrent contact method is changed to gas-liquid cocurrent. That is, ammonia gas is used to bring molten adipic acid and catalyst phosphoric acid from the top of the falling film component 1 into the falling film component 1, so as to realize the cocurrent contact of ammonia gas and the molten mixture in the falling film component 1, thereby slowing down the stagnation of the liquid in the falling film tube 9, and finally slowing down the coking and corrosion of the reaction raw materials and products in the pipeline. Moreover, heated ammonia gas is introduced into the falling film tube at the inlet 10 of the falling film component, so that the liquid phase is evenly dispersed, which can enhance the full mixing reaction of gas and liquid in the falling film tube. As Figure 2 shown.

[0026] It should also be noted that the falling film component 1 further includes: a pressure sensor and a closing door provided at the inlet 10 of the falling film component, and a driver provided on the falling film component 1; wherein, the driver is connected to the pressure sensor, and drives the closing door to open and close the inlet 10 of the falling film component through the pressure signal of the pressure sensor. Preferably, the pressure sensor can be attached to the closing door. In the initial state, the closing door is closed. When the reaction material presses on the closing door, a downward pressure will be generated, which is captured by the pressure sensor and an electrical signal is sent to the driver. The driver can set this electrical signal as a control signal and start to open the closing door after receiving the electrical signal, so as to realize continuous production.

[0027] Among them, the high-gravity component 2 includes: a cutting unit 13 and a rotating unit provided in the shell of the high-gravity component 2; the cutting unit 13 is connected to the rotating unit and is used to shear the gas-liquid mixture introduced from the falling film component 1 into fluid micro-elements. The rotating unit includes: a rotating shaft 14 and a rotating drum 12; the rotating shaft 14 penetrates through the rotating drum 12, and the cutting unit 13 is fixed on the rotating drum 12. The rotating unit further includes: a fluid distributor 11 provided with a plurality of branch pipes; wherein, the fluid distributor 11 is connected to the outlet of the falling film component 1 to form a fluid channel, and the fluid distributor is arranged around the rotating shaft; the branch pipes face the cutting unit, and a plurality of openings are provided on the branch pipes. As Figure 3 shown.

[0028] Preferably, the cutting unit 13 and the rotating drum 12 are coaxially arranged and driven by the same motor.

[0029] Preferably, the opening direction of the branch pipes on the fluid distributor is radially facing the cutting unit 13 or tangentially facing the rotating direction of the cutting unit 13.

[0030] Preferably, the surface of the cutting unit 13 is coated with a hydrophobic coating. This can effectively prevent liquid adhesion, and at the same time endows the cutting unit 13 with a certain self-cleaning ability. Further, due to its hydrophobic effect during rotation, the hydrophobic surface can also reduce the kinetic energy loss when the liquid droplets impact the cutting unit 13, and will not cause a large amount of kinetic energy to be offset due to surface adsorption.

[0031] Specifically, the gas-liquid mixture resulting from the reaction in the falling film tube enters the high gravity component 2 for further reaction (i.e., this reaction is to increase the yield, similar to the reaction in the falling film component 1). In the high gravity component 2, the mixing process of adipic acid and ammonia molecules and the mass transfer and heat transfer effects can be further enhanced, thereby effectively slowing down the decomposition and coking of adipic acid in the bubbling section of the traditional reactor, thus improving the reaction efficiency and product yield and reducing side reactions.

[0032] Among them, the separation component 3 is arranged at the lower end of the high gravity component 2 and is connected to the high gravity component 2.

[0033] Specifically, the separation component 3 can perform gas-liquid separation on the reaction products to obtain adiponitrile.

[0034] Among them, the device further includes: a reaction material pipeline for transporting reaction materials and an ammonia pipeline for transporting ammonia.

[0035] Among them, the device further includes: a motor 5 connected to the high gravity component 2, which is used to drive the rotation unit in the high gravity component 2 to rotate, generate a stable and adjustable centrifugal force field, and simulate the high gravity environment generated by the gravitational field.

[0036] Among them, the device further includes: a condenser 7 and a pickling tank 8 connected to the separation component 3 in sequence; the condenser 7 is used to condense and recover the product adiponitrile; the pickling tank 8 is used to absorb ammonia in the tail gas after the reaction.

[0037] The present invention also provides a method for continuously preparing adiponitrile from adipic acid under high gravity, specifically including:

[0038] 1. Introduce the molten adipic acid and the catalyst into the mixing component 4 to mix and form reaction materials;

[0039] 2. Introduce the reaction materials and the ammonia gas adjusted by the heater 6 into the falling film component 1 for reaction to obtain a gas-liquid mixture;

[0040] 3. Introduce the gas-liquid mixture into the high gravity component 2 for reaction to obtain reaction products;

[0041] 4. Perform gas-liquid separation on the reaction products through the separation component 3 to obtain adiponitrile.

[0042] Among them, the temperature of the molten adipic acid and the phosphoric acid catalyst is 180 °C, and the temperature of the mixing component is 170 - 280 °C.

[0043] Among them, the ammonia gas flow rate is 0 - 30 L / min, and the temperature of the ammonia gas after being heated is 170 - 280 °C.

[0044] Among them, the parameters for the reaction in the falling film component (1) include: the molar ratio of ammonia gas to adipic acid is 5:1, the reaction temperature is 170 - 280 °C, and the concentration of the catalyst phosphoric acid is 0.2%.

[0045] Among them, the parameters for the reaction in the high gravity component (2) include: the rotation speed is 0 - 1500 rpm, the molar ratio of ammonia gas to adipic acid is 5:1, the concentration of the catalyst phosphoric acid is 0.2%, the reaction temperature is 170 - 280 °C, and the reaction time is 30 - 60 min.

[0046] Since the content protected by this method is similar to the content protected by the above device, it will not be introduced in detail here. For details, please refer to the discussion part of the above method.

[0047] Finally, it should be noted that: the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A device for continuously preparing adiponitrile by supergravity adipic acid, characterized in that, The device includes: a falling film component (1), a high gravity component (2), a separation component (3), a mixing component (4), and a heater (6); Among them, the bottom of the falling film component (1) is connected to the top of the high gravity component (2); the separation component (3) is arranged at the lower end of the high gravity component (2) and is connected to the high gravity component (2); the heater (6) and the mixing component (4) are respectively connected to the falling film component inlet (10), and the heater (6) is used to heat the ammonia gas that sends the reaction materials in the mixing component (4) into the falling film component (1) for reaction; the reaction materials are formed by mixing adipic acid molten liquid and a catalyst.

2. The device according to claim 1, characterized in that, The falling film component (1) includes: one or more falling film tubes (9) and a temperature control unit connected to the falling film tubes (9); Among them, the falling film tube (9) is of a double-tube structure. The falling film tube (9) contains reaction materials and ammonia gas, and the inner tube contains heat exchange liquid; the temperature control unit controls the reaction temperature of the reaction materials and ammonia gas by adjusting the temperature of the heat exchange liquid.

3. The device according to claim 2, characterized in that, The falling film component (1) further includes: a pressure sensor and a closing door arranged at the falling film component inlet (10), and a driver arranged on the falling film component (1); Among them, the driver is connected to the pressure sensor and drives the closing door to open and close the falling film component inlet (10) through the pressure signal of the pressure sensor.

4. The device according to claim 1, characterized in that, The high gravity component (2) includes: a cutting unit (13) and a rotating unit arranged inside the housing of the high gravity component (2); Among them, the cutting unit (13) is connected to the rotating unit and is used to shear the gas-liquid mixture introduced from the falling film component (1) into fluid micro-elements.

5. The device according to claim 4, characterized in that, The rotating unit includes: a rotating shaft (14) and a rotating drum (12); Among them, the rotating shaft (14) penetrates through the rotating drum (12), and the cutting unit (13) is fixed on the rotating drum (12).

6. The device according to claim 5, characterized in that, The rotating unit further includes: a fluid distributor (11) provided with a plurality of branch pipes; Among them, the fluid distributor (11) is connected to the outlet of the falling film component (1) to form a fluid channel, and the fluid distributor (11) is arranged around the rotating shaft (14); the branch pipes face the cutting unit, and a plurality of openings are provided on the branch pipes.

7. The device according to claim 6, characterized in that, The surface of the cutting unit is coated with a hydrophobic coating.

8. The device according to claim 1, characterized in that, The device further includes: a motor (5) connected to the high gravity component (2) for driving the rotation of the rotating unit in the high gravity component (2).

9. The device according to claim 1, wherein The device further includes: a condenser (7) and a pickling tank (8) connected to the separation component (3) in sequence; Among them, the condenser (7) is used to condense and recover the product adiponitrile; the pickling tank (8) is used to absorb ammonia gas in the tail gas after the reaction.

10. A method for preparing adiponitrile using any of the apparatuses according to claims 1-9, characterized in that, The method includes: Introducing adipic acid molten liquid and a catalyst into the mixing component (4) to mix and form reaction materials; Introducing the reaction materials and the ammonia gas adjusted by the heater (6) into the falling film component (1) for reaction to obtain a gas-liquid mixture; Introducing the gas-liquid mixture into the high gravity component (2) for reaction to obtain a reaction product; Performing gas-liquid separation on the reaction product through the separation component (3) to obtain adiponitrile.

11. The method according to claim 10, wherein The temperature inside the mixing component (4) is 170 - 280 °C.

12. The method according to claim 10, wherein The ammonia gas flow rate is 0 - 30 L / min; the temperature of the ammonia gas is 170 - 280 °C.

13. The method according to claim 10, wherein The parameters for the reaction in the introduced falling film component (1) include: the molar ratio of ammonia gas to adipic acid is 5:1; the reaction temperature is 170 - 280 °C; the concentration of the catalyst is 0.2%.

14. The method according to claim 10, characterized in that, The parameters for the reaction in the high gravity component (2) include: the rotational speed is 0 - 1500 rpm; the molar ratio of ammonia gas to adipic acid is 5:1; the concentration of the catalyst is 0.2%; the reaction temperature is 170 - 280 °C; the reaction time is 30 - 60 min.

Images