阅读说明：本技术 一种甲酰胺制备过程中精馏釜液回收系统及回收方法 (Rectifying still liquid recovery system and method in formamide preparation process ) 是由 崔德文 万建龙 吕晓梅 于 2020-05-08 设计创作，主要内容包括：本发明提供一种甲酰胺制备过程中精馏釜液回收系统及回收方法。本发明的甲酰胺制备过程中精馏釜液回收系统,包括与甲酰胺精馏系统连接的釜液槽,釜液槽通过输送泵连接过滤器,过滤器通过过滤后釜液管道连接釜液反应器,釜液反应器的下部设置有气氨分布器,气氨分布器连接气氨管道；釜液反应器的上部设置有文丘里喷射泵,文丘里喷射泵的进液端连接所述的过滤后釜液管道,文丘里喷射泵的出液口位于釜液反应器的长控液位的下方。本发明在处理甲酰胺聚合物分解操作过程中回收氨从而降低氨的消耗,过滤出釜液中的积碳等机械杂质,釜液反应器处理完毕后进行再次精馏操作,再次釜液回收,进而达到产品收料的最大化,甲酰胺生产的得率在97%以上。(The invention provides a rectifying still liquid recovery system and a rectifying still liquid recovery method in a formamide preparation process. The rectifying still liquid recovery system in the formamide preparation process comprises a still liquid tank connected with a formamide rectifying system, wherein the still liquid tank is connected with a filter through a delivery pump, the filter is connected with a still liquid reactor through a filtered still liquid pipeline, and a gas ammonia distributor is arranged at the lower part of the still liquid reactor and is connected with a gas ammonia pipeline; the upper portion of cauldron liquid reactor is provided with the venturi jet pump, and the feed liquor end of venturi jet pump is connected filtration back cauldron liquid pipeline, the liquid outlet of venturi jet pump is located the below of the long accuse liquid level of cauldron liquid reactor. According to the invention, ammonia is recovered in the decomposition operation process of formamide polymer treatment, so that the consumption of ammonia is reduced, mechanical impurities such as carbon deposition in the kettle liquid are filtered out, rectification operation is performed again after the kettle liquid reactor is finished, the kettle liquid is recovered again, so that the maximum product collection is achieved, and the yield of formamide production is over 97%.)

1. The utility model provides a rectifying still liquid recovery system in formamide preparation process, includes the cauldron liquid groove of being connected with formamide rectification system, characterized by: the device comprises a kettle liquid tank, a filter, a kettle liquid reactor, a gas ammonia distributor and a gas ammonia pipeline, wherein the kettle liquid tank is connected with the filter through a delivery pump, the filter is connected with the kettle liquid reactor through a filtered kettle liquid pipeline, and the lower part of the kettle liquid reactor is provided with the gas ammonia distributor which is connected with the gas ammonia pipeline; the upper portion of cauldron liquid reactor is provided with the venturi jet pump, the feed liquor end of venturi jet pump is connected filtration back cauldron liquid pipeline, the liquid outlet of venturi jet pump is located the below of the long accuse liquid level of cauldron liquid reactor.

2. The system for recovering the rectifying still liquid in the formamide preparation process according to claim 1, which is characterized in that: the formamide rectification system comprises a formamide rectification tower, a condenser is connected to the top of the formamide rectification tower, a product tank is connected to the outlet end of the condenser, a reboiler is connected to the bottom of the formamide rectification tower, and the outlet end of the reboiler is connected to the kettle liquid tank.

3. The system for recovering the rectifying still liquid in the formamide preparation process according to claim 1, which is characterized in that: the filter pore size of the filter is 1 μm.

4. The system for recovering the rectifying still liquid in the formamide preparation process according to claim 1, which is characterized in that: the gas ammonia distributor is provided with 4-10 mushroom head-shaped distribution heads, and small holes of 300x1mm are uniformly distributed on each distribution head.

5. A method for recovering rectifying still liquid in the formamide preparation process by using the rectifying still liquid recovery system in the formamide preparation process is characterized by comprising the following steps: the method comprises the following steps:

(1) after the kettle liquid in the formamide rectification system is discharged to a rectification kettle liquid tank, the kettle liquid in the rectification kettle liquid tank is conveyed to a filter by a conveying pump for filtering;

(2) the kettle liquid filtered by the filter enters a Venturi jet pump at the upper part of the kettle liquid reactor;

(3) introducing gas ammonia into the lower part of the kettle liquid reactor through a gas ammonia distributor to react;

(4) after the reaction is finished, sending the material in the kettle liquid reactor to a rectifying tower for rectifying and recovering operation;

(5) and the kettle liquid discharged after the recovery of the rectifying tower is sent to the kettle liquid reactor again for ammonia introduction reaction, so that the kettle liquid discharge is reduced, and the product yield is improved.

6. The process for recovering the rectifying still liquid in the formamide preparation process according to claim 5, characterized in that: the inlet pressure of the filter is 0.3-0.4 Mpa, and the outlet pressure of the filter is 0.2-0.3 Mpa.

7. The process for recovering the rectifying still liquid in the formamide preparation process according to claim 5, characterized in that: and (3) the ammonia gas is subjected to pressure reduction treatment, and the pressure of the ammonia gas is 0.1-0.2 MPa.

8. The method for recovering the rectifying still liquid in the formamide preparation process according to claim 5, wherein in the step (3), the reaction temperature is 40-50 ℃, the ammonia is introduced for reaction for 2-3 h, and the reaction is continuously circulated for 4h to ensure that unreacted ammonia is fully utilized, and the reaction is finished when the polymer is sampled and analyzed to be reduced to below 1500 PPm.

9. The process for recovering the rectifying still liquid in the formamide preparation process according to claim 5, characterized in that: the temperature of the kettle of the rectifying tower is 125-130 ℃, and the temperature of the top of the rectifying tower is 100-110 ℃.

The technical field is as follows:

the invention relates to a rectifying still liquid recovery system and a rectifying still liquid recovery method in a formamide preparation process, and belongs to the technical field of formamide production processes.

Background art:

formamide is a compound, is colorless transparent liquid, has slight ammonia smell, is a raw material for synthesizing medicines, spices, dyes and the like, can also be used as a solvent for spinning of synthetic fibers, plastic processing, production of lignocelluloses ink and the like, and is produced into a product with the purity of more than 99.5 percent by taking ammonia and methyl formate as raw materials through the processes of synthesis, rough distillation, dehydration, rectification and the like.

The detailed reaction formula is as follows: NH (NH)₃+ CH₃COOH = HCONH₂+CH₃OH+Q。

The formamide prepared by the reaction is a crude formamide which needs to be refined in the actual production process, so that a product with higher purity can be obtained. The refining process needs a certain temperature, the formamide can generate polymerization reaction at about 100 ℃, the polymerization is more serious at higher temperature, and decomposition and carbonization can occur at more than 130 ℃;

the reaction formula of the polymerization reaction is as follows: HCONH₂+HCONH₂=HCONH₂·HCONH₂(i.e., DiFA).

The polymer produced during the refining operation has a serious influence on the product quality and yield, and only the frequency of discharging the kettle liquid can be increased to ensure the product purity. Therefore, a process route for treating formamide kettle liquid can be found in the production process, qualified formamide products can be obtained, hazardous waste discharge can be reduced, and great economic benefits can be obtained.

The invention content is as follows:

the invention aims to provide a rectifying still liquid recovery system and a rectifying still liquid recovery method in a formamide preparation process, which are simple to operate and accurate to control, can treat mechanical impurities such as polymers and carbon residue in a still liquid generated in the formamide rectifying process, secondarily utilize unreacted gas ammonia so as to reduce the consumption of the gas ammonia, and recover the still liquid to obtain a qualified formamide product.

The above purpose is realized by the following technical scheme:

a rectifying still liquid recovery system in a formamide preparation process comprises a still liquid tank connected with a formamide rectifying system, wherein the still liquid tank is connected with a filter through a conveying pump, the filter is connected with a still liquid reactor through a filtered still liquid pipeline, a gas ammonia distributor is arranged at the lower part of the still liquid reactor, and the gas ammonia distributor is connected with a gas ammonia pipeline; the upper portion of cauldron liquid reactor is provided with the venturi jet pump, the feed liquor end of venturi jet pump is connected filtration back cauldron liquid pipeline, the liquid outlet of venturi jet pump is located the below of the long accuse liquid level of cauldron liquid reactor.

Formamide preparation in-process rectifying still liquid recovery system, formamide rectifying system includes formamide rectifying column, the condenser is connected at the top of formamide rectifying column, the product groove is connected to the exit end of condenser, the reboiler is connected to the bottom of formamide rectifying column, the exit end of reboiler is connected the cauldron cistern.

In the rectifying still liquid recovery system in the formamide preparation process, the filtering aperture of the filter is 1 micrometer.

In the formamide preparation process, the rectifying still liquid recovery system is characterized in that the gas ammonia distributor is provided with 4-10 mushroom head-shaped distribution heads, and small holes of 300x1mm are uniformly distributed on each distribution head.

The method for recovering the rectifying still liquid in the formamide preparation process by using the rectifying still liquid recovery system in the formamide preparation process comprises the following steps:

(1) after the kettle liquid in the formamide rectification system is discharged to a rectification kettle liquid tank, the kettle liquid in the rectification kettle liquid tank is conveyed to a filter by a conveying pump for filtering;

(2) the kettle liquid filtered by the filter enters a Venturi jet pump at the upper part of the kettle liquid reactor;

(3) introducing gas ammonia into the lower part of the kettle liquid reactor through a gas ammonia distributor to react;

(4) after the reaction is finished, sending the material in the kettle liquid reactor to a rectifying tower for rectifying and recovering operation;

(5) and the kettle liquid discharged after the recovery of the rectifying tower is sent to the kettle liquid reactor again for ammonia introduction reaction, so that the kettle liquid discharge is reduced, and the product yield is improved.

According to the method for recovering the rectifying still liquid in the formamide preparation process, the inlet pressure of the filter is 0.3-0.4 MPa, and the outlet pressure of the filter is 0.2-0.3 MPa.

In the method for recovering the rectifying still liquid in the formamide preparation process, the ammonia gas in the step (3) is subjected to pressure reduction treatment, and the pressure of the ammonia gas is 0.1-0.2 Mpa.

In the method for recovering the rectifying still liquid in the formamide preparation process, in the step (3), the reaction temperature is 40-50 ℃, the ammonia is introduced for reaction for 2-3 h, and the reaction is continuously circulated for 4h to ensure that the unreacted ammonia is fully utilized, and the reaction is finished when the polymer is sampled and analyzed to be reduced to below 1500 PPm.

In the method for recovering the rectifying kettle liquid in the formamide preparation process, the kettle temperature of the rectifying tower is 125-130 ℃, and the tower top temperature is 100-110 ℃.

Has the advantages that:

according to the invention, the un-reacted ammonia on the upper part of the liquid surface of the reactor can be recovered by using the Venturi jet pump, so that the ammonia consumption is reduced; the filter arranged on the reaction liquid circulating pipeline can filter out mechanical impurities such as carbon residue with the diameter of more than 1 mu m in the kettle liquid; after entering the lower part of the reactor, gas ammonia is uniformly distributed through a plurality of small holes with the diameter of 1mm on the distributor, the temperature is kept at 40-50 ℃, the decomposition of polymers in the kettle liquid is facilitated, the maximum material receiving of products is further achieved, and the yield of formamide production is more than 97%.

Description of the drawings:

FIG. 1 is a schematic diagram of the system of the present invention.

In the figure: 1. a kettle liquid reactor; 2. a formamide rectification column; 3. a condenser; 4. a product tank; 5. a reboiler; 6. a kettle liquid tank; 7. a delivery pump; 8. a gas ammonia pipeline; 9. a venturi jet pump; 10. a gas ammonia distributor; 11. and (3) a filter.

The specific implementation mode is as follows:

for a better understanding and appreciation of the invention, it is further described and illustrated below in connection with the accompanying drawings.

As shown in fig. 1: the rectifying still liquid recovery system in the formamide preparation process comprises a still liquid tank 6 connected with a formamide rectifying system, wherein the still liquid tank 6 is connected with a filter 11 through a delivery pump 7, the filter 11 is connected with a still liquid reactor 1 through a filtered still liquid pipeline, a gas ammonia distributor 10 is arranged at the lower part of the still liquid reactor 1, and the gas ammonia distributor 10 is connected with a gas ammonia pipeline 8; the upper portion of kettle liquid reactor 1 is provided with venturi jet pump 9, venturi jet pump 9's inlet end is connected filtration back kettle liquid pipeline, venturi jet pump's liquid outlet is located kettle liquid reactor's long below of controlling the liquid level, and venturi jet pump primary function is the gaseous ammonia of retrieving complete reaction not.

Rectifying still liquid recovery system in the formamide preparation process described in this embodiment, formamide rectifying system includes formamide rectifying column 2, condenser 3 is connected at the top of formamide rectifying column 2, product tank 4 is connected to the exit end of condenser 3, reboiler 5 is connected to the bottom of formamide rectifying column 2, the exit end of reboiler 5 is connected kettle liquid tank 6.

In the rectifying still liquid recovery system in the formamide preparation process described in this embodiment, the filter pore size of the filter 11 is 1 μm.

In the formamide preparation process rectifying still liquid recovery system in this embodiment, the gas ammonia distributor 10 is provided with 4-10 mushroom head-shaped distribution heads, and each distribution head is uniformly provided with small holes of 300x1mm, so that the gas ammonia is uniformly distributed.

The method for recovering the rectifying still liquid in the formamide preparation process by using the rectifying still liquid recovery system in the formamide preparation process comprises the following steps:

(1) after the kettle liquid in the formamide rectification system is discharged to a rectification kettle liquid tank, the kettle liquid in the rectification kettle liquid tank is conveyed to a filter by a conveying pump for filtering;

(2) the kettle liquid filtered by the filter enters a Venturi jet pump at the upper part of the kettle liquid reactor;

(3) introducing gas ammonia into the lower part of the kettle liquid reactor through a gas ammonia distributor to react so as to promote the decomposition of the polymer into formamide;

(4) after the reaction is finished, sending the material in the kettle liquid reactor to a rectifying tower for rectifying and recovering operation;

(5) and the kettle liquid discharged after the recovery of the rectifying tower is sent to the kettle liquid reactor again for ammonia introduction reaction, so that the kettle liquid discharge is reduced, and the product yield is improved. In this embodiment, the bottoms discharged from the other formamide rectifying towers are discharged into the tank and are collectively sent to the reactor for treatment.

In the method for recovering the rectifying still liquid in the formamide preparation process, the inlet pressure of the filter is 0.3-0.4 Mpa, and the outlet pressure of the filter is 0.2-0.3 Mpa.

In the method for recovering the rectifying still liquid in the formamide preparation process, the ammonia gas in the step (3) is ammonia gas subjected to pressure reduction treatment, and the pressure of the ammonia gas is 0.1-0.2 Mpa.

In the method for recovering the rectifying still liquid in the formamide preparation process, in the step (3), the reaction temperature is 40-50 ℃, the ammonia is introduced for reaction for 2-3 hours, and the reaction is continuously circulated for 4 hours, so that the unreacted ammonia is fully utilized, and the reaction is finished when the polymer is sampled and analyzed to be reduced to below 1500 PPm.

In the method for recovering the rectifying still liquid in the formamide preparation process, the temperature of the rectifying still is 125-130 ℃, and the temperature of the top of the rectifying still is 100-110 ℃.

The technical means disclosed by the scheme of the invention are not limited to the technical means disclosed by the technical means, and also comprise the technical scheme formed by equivalent replacement of the technical features. The present invention is not limited to the details given herein, but is within the ordinary knowledge of those skilled in the art.