CN106905176B - Continuous hydrolysis prepares the method and self-oscillation reactor of imido oxalic acid - Google Patents

Abstract

The invention discloses a method for preparing iminodiacetic acid by continuous hydrolysis. It includes the following steps: mixing the reaction material imino diacetonitrile and water in proportion; providing a total mixing reactor, transporting the reaction material into the total mixing reactor, and performing a hydrolysis reaction; providing a tubular reactor, the whole mixing reactor The reaction liquid in the mixed reactor is transported into the tubular reactor under the action of the liquid level difference pressure; a product storage tank is provided, and the reaction material is periodically freed between the tubular reactor and the product storage tank. Oscillating flow, and the product is discharged into the product storage tank after the reaction is completed. The method for preparing iminodiacetic acid by continuous hydrolysis provided by the invention improves the reaction yield. The present invention also provides a self-oscillating reactor.

Description

Method for preparing iminodiacetic acid by continuous hydrolysis and self-oscillating reactor

technical field

The invention relates to the technical field of chemical equipment, in particular to a method for preparing iminodiacetic acid by continuous hydrolysis and a self-oscillating reactor.

Background technique

In chemical reactions, the liquid-solid reaction is mostly carried out in a tank reactor. The interphase mass transfer, mixing and heat transfer are important technical indicators that determine the performance of the reactor, which directly affect the reaction intensity, conversion rate and product quality. According to the operation mode, tank reactors include batch tank reactors and continuous tank reactors. Among them, batch tank reactors are suitable for the production of products with small batches, multiple varieties and long reaction time, but they have unstable product quality. The continuous tank reactor can avoid the shortcomings of the batch tank reactor, but the stirring effect will cause back-mixing of the fluid in the tank, and the agitation is violent, the liquid viscosity is low or the average residence time is long. In the case of , the flow pattern in the kettle can be regarded as a total mixed flow. Under the conditions of high conversion and high yield, the back-mixing phenomenon in the tank reactor is an unfavorable factor. Generally, multi-stage reactors are connected in series to reduce the adverse effects of back mixing. However, the multi-stage tank reactors are connected in series, so that the residence time of the material is long, the reaction efficiency is low, and the conversion rate can only be improved to a certain extent.

Therefore, it is necessary to provide a new process to solve the above-mentioned technical problems.

SUMMARY OF THE INVENTION

The object of the present invention is to overcome the above-mentioned technical problems and provide a method for preparing iminodiacetic acid by continuous hydrolysis with good mass transfer and heat transfer effect and high yield.

The technical scheme of the present invention is:

A method for preparing iminodiacetic acid by continuous hydrolysis, comprising the steps:

Step S1: mixing the reaction material imino diacetonitrile and water in proportion;

Step S2: provide a fully mixed reactor, and transport the reaction material into the fully mixed reactor to carry out a hydrolysis reaction;

Step S3: a tubular reactor is provided, and the reaction solution in the complete mixing reactor is transported into the tubular reactor under the action of liquid level difference pressure;

Step S4: a product storage tank is provided, the reaction material flows in a periodic self-oscillating flow between the tubular reactor and the product storage tank, and the product is discharged into the product storage tank after the reaction is completed.

Preferably, the flow path of the reaction material between the tubular reactor and the product storage tank is an inverted U shape, and the outlet of the tubular reactor is located higher than the inlet of the tubular reactor. The position of the feed port is lower than the maximum liquid level of the tubular reactor.

Preferably, the height difference between the outlet of the tubular reactor and the inlet of the tubular reaction is 1/3-1/2 of the highest liquid level value of the tubular reactor.

Preferably, the position of the discharge port of the total mixing reactor is higher than the uppermost end of the tubular reactor.

Preferably, in step S1, a feeding system is used to mix and transport the reaction materials into the fully mixed reaction kettle, and the feeding system includes a metering screw, a solid-liquid mixing device connected to the output end of the metering screw, and A transfer pump for transferring the mixed material to the fully mixed reactor.

Preferably, in step S2, the step of preheating the reaction material is further included, and the preheated reaction material is transported to the full mixing reactor for reaction.

Preferably, the mixed molar ratio of iminodiacetonitrile and water in the reaction raw material is 1:5-20.

Preferably, the reaction temperature of the materials in the fully mixed reaction kettle is 190-200° C., and the reaction pressure is 9-11 MPa.

Preferably, the reaction temperature of the materials in the tubular reactor is 190-220°C.

The present invention also provides a self-oscillating reactor, comprising a total mixing reactor, a tubular reactor, a communication pipe and a product storage tank arranged in sequence according to the material flow direction, and the two ends of the communication pipe are respectively connected to the tubular reactor With the product storage tank, the flow path of the material between the tubular reactor and the product storage tank is an inverted U shape, and the discharge port of the full mixing reactor is located higher than the tubular reactor. The uppermost end of the reactor, the terminal of the communication pipe is set as the outlet of the tubular reactor, and the outlet of the tubular reactor is located higher than the inlet of the tubular reactor. and lower than the maximum liquid level of the tubular reactor.

Compared with the prior art, the method for preparing iminodiacetic acid by continuous hydrolysis provided by the present invention has the following beneficial effects:

1. The method for preparing iminodiacetic acid by continuous hydrolysis provided by the present invention uses iminodiacetonitrile and water as reaction raw materials, and performs hydrolysis reaction in the self-oscillating reactor, wherein the self-oscillating reactor is composed of all A combination of a mixed reaction kettle and a tubular reactor, wherein the discharge port of the fully mixed reaction kettle is higher than the uppermost end of the tubular reactor, so that a certain degree of reaction material in the fully mixed reaction kettle can be affected by the pressure difference. flow down into the tubular reactor; the tubular reactor and the product storage tank are connected by a communication pipe that makes the material flow path in an inverted U shape, and the terminal of the communication pipe is used as the pipe The outlet of the tubular reactor, and the outlet of the tubular reactor is located higher than the inlet of the tubular reactor and lower than the highest liquid level of the tubular reactor, so After the liquid level in the tubular reactor reaches a certain height, the material flows into the product storage tank from the outlet of the tubular reactor against the resistance of the tubular reactor; during the material flow, the The higher the liquid level of the material in the tubular reactor, the faster the flow rate. When the flow rate increases to a certain flow rate, the liquid level of the material in the tubular reactor decreases, and as the liquid level decreases to a certain extent, The flow rate of the material in the tubular reactor is reduced, and the liquid level of the material in the tubular reactor is lower than the highest liquid level but higher than the liquid level of the outlet due to the siphon phenomenon. When the liquid level cannot overcome the resistance of the tubular reactor, the outlet of the tubular reactor has no liquid outflow or the flow rate is very small; then the liquid level of the material in the tubular reactor increases again, so as to A fast-slow cycle is formed.

Therefore, the reaction material flows in a periodic self-oscillating flow in the tubular reactor, which strengthens the mass transfer and heat transfer effects of the tubular reactor, and also has better reaction and temperature at a lower flow rate. The control effect is improved, and the yield of the material reaction is improved.

The reaction yield of the method for continuous hydrolysis of iminodiacetic acid provided by the present invention is more than 95%.

2. The method for preparing iminodiacetic acid by continuous hydrolysis provided by the present invention is carried out in the self-oscillating reactor. The self-oscillating reactor is a continuous reactor, and the reaction rate is improved by controlling the reaction temperature and reaction pressure , thereby reducing the amount of water required in the reaction and reducing energy consumption.

Description of drawings

FIG. 1 is a schematic structural diagram of a self-oscillating reactor provided by the present invention.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and embodiments.

Please refer to FIG. 1 , which is a schematic structural diagram of the self-oscillating reactor provided by the present invention. The self-oscillating reactor 100 includes a feeding system 1, a heat exchanger 2, a fully mixed reactor 3, a tubular reactor 4, a communication pipe 5 and a product storage tank 6, and the feeding system 1, the heat exchanger 2. The total mixing reactor 3, the tubular reactor 4, the communication pipe 5 and the product storage tank 6 are connected in sequence.

The feeding system 1 includes a metering screw 11 , a solid-liquid mixing device 12 and a material conveying pump 13 , and the output end of the metering screw 11 is connected to the solid-liquid mixing device 12 . The metering screw 11 is used for conveying solid materials, and is precisely metered according to the material ratio, so that the materials sent to the solid-liquid mixing device 12 meet the ratio requirements. The fixed mixing device 12 is connected to a liquid material supply device (not shown), and the fixed material and the liquid material are mixed in the solid-liquid mixing device 12 and are transported to the heat exchanger 2 by the material conveying pump 13 for reaction. Material preheating. The solid-liquid mixing device 12 may be a solid-liquid mixing pump, and its structure may refer to the solid-liquid mixing pump in the prior art.

The heat exchanger 2 is used for heating the reaction material, and includes a first body 21 , a first feed port 22 and a first discharge port 23 , and the first feed port 22 is provided on the first body 21 . At the bottom, the first outlet 23 is provided on the top of the second body 21 .

In the present invention, the heat exchanger 2 is a non-essential component, because in addition to using the heat exchanger to heat the reaction material, it can also be realized by arranging a jacket outside the full mixing reactor 3 .

The fully-mixed reaction kettle 3 includes a second body 31, a second feed port 32, a second discharge port 33, a discharge port 34, and a stirrer 35 located on the kettle body 31 for detecting materials in the kettle. The first temperature measurement and control instrument 36 for the reaction temperature and the pressure measurement and control instrument 37 for detecting the reaction pressure in the kettle.

The second body 31 is a hollow structure, and a accommodating space for accommodating materials is formed therein. The agitator 35 is installed and fixed on the top of the second body 31, and the stirring blade is arranged in the accommodating space. The second inlet port 32 is set at the top of the second body 31, the second discharge port 33 is set at the bottom of the second body 31, and the discharge port 34 is also set at the first The bottom of the second body 31, and its setting position is lower than the position of the second discharge port 33, which is used to drain the material in the kettle when cleaning.

Of course, in addition to the above-mentioned embodiment, the position of the second feed port 32 may also be located at the bottom of the second body 31 , and its position is lower than the position of the second discharge port 33 .

The first temperature measurement and control instrument 36 is used to detect the reaction temperature of the material in the full mixing reactor 3, and can send the measurement data to the material delivery pump 13 for controlling the output of the material delivery pump 13. . The pressure measurement and control instrument 37 is used to detect the reaction pressure in the full mixing reactor 3, and adjust the reaction pressure according to the detection result, so that the pressure in the kettle meets the requirements.

The tubular reactor 4 includes a third body 41 , a third inlet 42 , a third outlet 43 and a second temperature monitoring and control instrument 44 .

Wherein, the terminal end of the communication pipe 5 is set as the third discharge port 43 , and the terminal end of the communication pipe 5 refers to the end connected with the product storage tank 6 .

The position of the second outlet 33 is higher than the position of the third inlet 42 and the third outlet 43; preferably, the second outlet 33 is higher than the pipe The position of the uppermost end of the tubular reactor 4 , that is, the second outlet 33 is higher than the highest liquid level of the tubular reactor 4 . The highest liquid level of the tubular reactor 4 refers to the liquid level when the maximum limit material is contained therein. As shown in FIG. 1 , the highest liquid level is the top of the tubular reactor.

The position of the third outlet 43 is higher than the position of the third inlet 42, and is lower than the highest liquid level of the tubular reactor 4, so that the material flows from the tubular reactor 4 into the reactor. The circulation path of the product storage tank 6 is an inverted U shape. Preferably, the height difference between the third outlet 43 and the third inlet 42 is 1/3-1/2 of the highest liquid level value of the tubular reactor.

The second temperature measurement and control instrument 44 is used to detect the temperature of the material in the tubular reactor 4, so that the material can complete the reaction under a certain temperature condition.

The self-oscillating reactor provided by the present invention works as follows:

The position of the discharge port of the fully mixed reaction kettle 3 is higher than the uppermost end of the tubular reactor 4, so that the reaction material that reaches a certain level in the fully mixed reaction kettle 3 flows into the tubular reactor under the action of the pressure difference. In the reactor 4; the tubular reactor 4 and the product storage tank 6 are connected by a communication pipe 5 that makes the material flow path in an inverted U shape, and the terminal of the communication pipe 5 is used as the tubular type. The outlet of the reactor 4, and the position of the outlet of the tubular reactor 4 is higher than the position of the inlet of the tubular reactor 4 and lower than the highest liquid of the tubular reactor 4. When the liquid level in the tubular reactor 4 reaches a certain height, the material overcomes the resistance of the tubular reactor 4 and flows into the product storage tank 6 from the outlet of the tubular reactor 4; During the material flow process, the higher the material liquid level in the tubular reactor 4, the faster the flow rate, when the flow rate increases to a certain flow rate, the material liquid level in the tubular reactor 4 decreases, As the liquid level decreases to a certain extent, the flow rate of the material in the tubular reactor 4 decreases. Due to the siphon phenomenon, the liquid level of the material in the tubular reactor 4 is lower than its highest liquid level but higher than its maximum liquid level. Liquid level at the outlet. When the liquid level cannot overcome the resistance of the tubular reactor 4, there is no liquid outflow from the outlet of the tubular reactor 4 or the flow rate is very small; then the liquid level of the material in the tubular reactor 4 increases again , thus forming a fast-slow cycle.

Therefore, the material flows in a periodic self-oscillating flow in the tubular reactor 4, which strengthens the mass transfer and heat transfer effects of the tubular reactor 4, and also has better reaction and heat transfer at a lower flow rate. The temperature control effect improves the yield of the material reaction.

The following describes in detail the process of applying the self-oscillating reactor to continuous hydrolysis to prepare iminodiacetic acid through specific embodiments.

Example 1

A method for preparing iminodiacetic acid by continuous hydrolysis, comprising the steps:

Step S1: mixing the reaction material imino diacetonitrile and water according to a molar ratio of 1:5;

Specifically, the raw material imino diacetonitrile is sent to the solid-liquid mixing device 12 through the metering screw 11; the raw material water is also sent to the solid-liquid mixing device 12, so that the two are mixed in proportion;

Step S2: the mixed material is transported to the fully mixed reactor 3 for hydrolysis reaction;

Specifically, the material transport pump 13 transports the mixed material into the heat exchanger 2 to heat the reaction material, and after the heating, the reaction material enters the full mixing reactor 3 through the second feed port 32; And control the reaction temperature in the complete mixing reactor 3 to be 190°C, and the reaction pressure to be 9MPa;

Step S3: the reaction liquid in the fully mixed reaction kettle 3 flows into the tubular reactor 4 under the action of the liquid level difference pressure;

Specifically, when the material in the complete mixing reactor 3 reacts to a certain extent, the material flows out from the second discharge port 33 under the action of the pressure difference, and enters the In the tubular reactor 4; and the reaction temperature in the tubular reactor is controlled to be 220°C.

Step S4: the reaction material is periodically self-oscillating flow between the tubular reactor 4 and the product storage tank 6, and the product is discharged into the product storage tank 6 after the reaction is completed;

Specifically, when the liquid level in the tubular reactor 4 reaches a certain height, the material overcomes the resistance of the tubular reactor 4 and flows into the product storage tank from the third discharge port 43; during the material flow process , the higher the liquid level of the material in the tubular reactor, the faster the flow rate, when the flow rate increases to a certain flow rate, the liquid level of the material in the tubular reactor 4 decreases, and as the liquid level decreases To a certain extent, the flow rate of the material in the tubular reactor is reduced, and the liquid level of the material in the tubular reactor is lower than its highest liquid level but higher than the liquid level of its outlet due to the siphon phenomenon;

When the liquid level cannot overcome the resistance of the tubular reactor 4, the third outlet 43 has no liquid flowing out or the flow rate is very small; then the liquid level of the material in the tubular reactor 4 increases again, so that A fast-slow flow rate cycle is formed, so that the reaction material flows in the tubular reactor 4 in a periodic self-oscillating flow.

Example 2

A method for preparing iminodiacetic acid by continuous hydrolysis, comprising the steps:

Step S1: mixing the reaction material imino diacetonitrile and water according to a molar ratio of 1:10;

Step S2: the mixed material is transported to the fully mixed reactor 3 for hydrolysis reaction;

Specifically, the material transport pump 13 transports the mixed material into the heat exchanger 2 to heat the reaction material, and after the heating, the reaction material enters the full mixing reactor 3 through the second feed port 32; The control reaction temperature was 195°C, and the reaction pressure was 10MPa;

Step S3: the reaction liquid in the fully mixed reaction kettle 3 flows into the tubular reactor 4 under the action of the liquid level difference pressure;

Specifically, when the material in the complete mixing reactor 3 reacts to a certain extent, the material flows out from the second discharge port 33 under the action of the pressure difference, and enters the In the tubular reactor 4; and the reaction temperature in the tubular reactor 4 is controlled to be 200°C.

Step S4: Step S4: The reaction material flows in a periodic self-oscillating flow between the tubular reactor 4 and the product storage tank 6, and the product is discharged into the product storage tank 6 after the reaction is completed;

Refer to Example 1 for the principle that the material in the tubular reactor 4 is self-oscillating and periodically flowing.

Example 3

A method for preparing iminodiacetic acid by continuous hydrolysis, comprising the steps:

Step S1: mixing the reaction raw material imino diacetonitrile and water according to a molar ratio of 1:20;

Step S2: the mixed material is transported to the fully mixed reactor 3 for hydrolysis reaction;

Specifically, the material transport pump 13 transports the mixed material into the heat exchanger 2 to heat the reaction material, and after the heating, the reaction material enters the full mixing reactor 3 through the second feed port 32; The control reaction temperature was 200°C, and the reaction pressure was 11MPa;

Step S3: the reaction liquid in the fully mixed reaction kettle 3 flows into the tubular reactor 4 under the action of the liquid level difference pressure;

Specifically, when the material in the complete mixing reactor 3 reacts to a certain extent, the material flows out from the second discharge port 33 under the action of the pressure difference, and enters the In the tubular reactor 4; and the reaction temperature in the tubular reactor 4 is controlled to be 190°C.

Step S4: the reaction material is periodically self-oscillating flow between the tubular reactor 4 and the product storage tank 6, and the product is discharged into the product storage tank 6 after the reaction is completed;

Refer to Example 1 for the principle that the material in the tubular reactor 4 is self-oscillating and periodically flowing.

According to the method for preparing iminodiacetic acid by continuous hydrolysis described in Examples 1-3, the self-oscillating reactor 100 was continuously operated for 1 month, and the yield statistics were carried out, and the yield statistics results were as follows:

Example 1 Example 2 Example 3 Yield (%) 95.4 96.7 95.9

It can be seen from the above data that the reaction yield of the method for preparing iminodiacetic acid by continuous hydrolysis using the self-oscillating reactor 100 provided by the present invention is greater than 95%.

Compared with the prior art, the method for preparing iminodiacetic acid by continuous hydrolysis provided by the present invention has the following beneficial effects:

1. The method for preparing iminodiacetic acid by continuous hydrolysis provided by the present invention uses iminodiacetonitrile and water as reaction raw materials, and conducts a hydrolysis reaction in the self-oscillating reactor, which is composed of a fully mixed self-oscillating reactor. The reaction kettle and the tubular reactor are combined, and the material flows in the tubular reactor in a periodic self-oscillating flow, which strengthens the mass transfer and heat transfer effects of the tubular reactor, and also has a lower flow rate. Better reaction and temperature control effects improve the yield of material reaction.

The reaction yield of the method for continuous hydrolysis of iminodiacetic acid provided by the present invention is more than 95%.

2. The method for preparing iminodiacetic acid by continuous hydrolysis provided by the present invention is carried out in the self-oscillating reactor. The self-oscillating reactor is a continuous reactor, and the reaction rate is improved by controlling the reaction temperature and reaction pressure , thereby reducing the amount of water required in the reaction and reducing energy consumption.

The above descriptions are only the embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied to other related technologies Fields are similarly included in the scope of patent protection of the present invention.

Claims (8)

1. a kind of method that continuous hydrolysis prepares imido oxalic acid, which comprises the steps of:

Step S1: reaction mass imido grpup diacetonitrile and water are mixed in proportion；

Step S2: perfectly mixed reactor is provided, reaction mass is delivered in the perfectly mixed reactor, reaction is hydrolyzed；

Step S3: providing tubular reactor, and the reaction solution in the perfectly mixed reactor is delivered to institute under the effect of liquid level differential pressure It states in tubular reactor；

Step S4: product storage tank is provided, reaction mass is between the tubular reactor and the product storage tank in periodically certainly Oscillation Flows, product drains into the product storage tank after reaction；

Wherein the discharge port position of the complete mixed reaction kettle is higher than the tubular reactor topmost, and reaction mass is described Circulation path between tubular reactor and the product storage tank is inverted u-shaped, the discharge port position of the tubular reactor Feed inlet position higher than the tubular reactor and the highest liquid level lower than the tubular reactor.

2. the method that continuous hydrolysis according to claim 1 prepares imido oxalic acid, which is characterized in that the tubular type is anti- Answering the difference in height between the discharge port of device and the feed inlet of the tubular reactor is the tubular reactor highest level value 1/3-1/2。

3. the method that continuous hydrolysis according to claim 1 prepares imido oxalic acid, which is characterized in that in step S1, Reaction mass is mixed and is delivered to using feed system and is mixed in reaction kettle entirely, the feed system includes metering spiral shell Rotation, the solid-liquid mixer that connect with the output end of the metering screw and for mixed material to be delivered to described mix entirely instead Answer the delivery pump of device.

4. the method that continuous hydrolysis according to claim 1 prepares imido oxalic acid, which is characterized in that in step S2, Further include the steps that preheating reaction mass, the reaction mass after preheating is delivered in the entirely mixed reaction kettle and carries out instead It answers.

5. the method that continuous hydrolysis according to any one of claim 1 to 4 prepares imido oxalic acid, feature exist In the mixing molar ratio 1:5-20 of imido grpup diacetonitrile and water in reaction raw materials.

6. the method that continuous hydrolysis described in any one of -4 prepares imido oxalic acid according to claim 1, which is characterized in that The entirely mixed material in reactor reaction temperature is 190-200 DEG C, reaction pressure 9-11MPa.

7. the method that continuous hydrolysis described in any one of -4 prepares imido oxalic acid according to claim 1, which is characterized in that Material reaction temperature is 190-220 DEG C in the tubular reactor.

8. a kind of self-oscillation reactor, which is characterized in that including the complete mixed reaction kettle, tubular type set gradually by Flow of Goods and Materials direction Reactor, communicating pipe and product storage tank, the communicating pipe both ends, which are separately connected the tubular reactor and the product storage tank, to be made Circulation path of the material between the tubular reactor and the product storage tank is inverted u-shaped, the discharging of the complete mixed reaction kettle Mouth position is higher than the tubular reactor topmost, sets the terminal of the communicating pipe as the discharging of the tubular reactor Mouthful, the discharge port position of the tubular reactor is higher than the feed inlet position of the tubular reactor and lower than described The highest liquid level of tubular reactor, and between the discharge port of the tubular reactor and the feed inlet of the tubular reactor Difference in height is the 1/3-1/2 of the tubular reactor highest level value.