阅读说明：本技术 回收塔塔釜液处理系统 (Recovery tower kettle liquid treatment system ) 是由 陆玲 李大伟 杨淼 王涛 毛爽 张懿 邹明英 杨忠祥 于 2019-09-05 设计创作，主要内容包括：本发明涉及一种回收塔塔釜液处理系统,包括：缓冲罐,与回收塔塔釜连接,用于盛放由回收塔塔釜排出的塔釜液；脱氢氰酸塔；脱氢氰酸塔再沸器,连接缓冲罐和脱氢氰酸塔；成品塔；成品塔再沸器,连接缓冲罐和成品塔；成品塔和成品塔再沸器位于所述脱氢氰酸塔和所述脱氢氰酸塔再沸器的下游；脱氢氰酸塔再沸器和成品塔再沸器串联在缓冲罐的输出管路上；贫水泵,设置在输出管路上,将缓冲罐中的塔釜液泵送至脱氢氰酸塔再沸器和成品塔再沸器。本发明的处理系统可以利用温差,使得回收塔塔釜贫水的热能得到循环利用,从而节约能源。(The invention relates to a tower bottom liquid treatment system of a recovery tower, which comprises: the buffer tank is connected with the tower kettle of the recovery tower and is used for containing tower kettle liquid discharged from the tower kettle of the recovery tower; a dehydrocyanation tower; a dehydrocyanation tower reboiler which is connected with the buffer tank and the dehydrocyanation tower; a finished product tower; the finished product tower reboiler is connected with the buffer tank and the finished product tower; a finishing column and a finishing column reboiler are located downstream of the dehydrocyanation column and the dehydrocyanation column reboiler; a dehydrocyanation tower reboiler and a finished product tower reboiler are connected in series on an output pipeline of the buffer tank; and the lean water pump is arranged on the output pipeline and used for pumping tower bottom liquid in the buffer tank to the hydrocyanic acid removal tower reboiler and the finished product tower reboiler. The treatment system can utilize the temperature difference to recycle the heat energy of the lean water at the tower bottom of the recovery tower, thereby saving energy.)

1. A recovery tower bottoms processing system, comprising:

the buffer tank (1) is connected with the tower kettle of the recovery tower and is used for collecting tower kettle liquid discharged from the tower kettle of the recovery tower;

a dehydrocyanation tower (2);

a dehydrocyanation tower reboiler (3) connecting the buffer tank (1) and the dehydrocyanation tower (2);

a finished product tower (4);

a finished product tower reboiler (5) which is connected with the buffer tank (1) and the finished product tower (4);

the finishing column (4) and the finishing column reboiler (5) are located downstream of the dehydrocyanation column (2) and the dehydrocyanation column reboiler (3);

the dehydrocyanation tower reboiler (3) and the finished product tower reboiler (5) are connected in series on an output pipeline (101) of the buffer tank (1);

and the lean water pump (b) is arranged on the output pipeline (101) and is used for pumping the tower bottoms in the buffer tank (1) to the dehydrocyanation tower reboiler (3) and the finished product tower reboiler (5).

2. The recovery column bottoms processing system according to claim 1, wherein a first flow meter (9) for measuring a column bottoms flow rate to the dehydrocyanation column reboiler (3) and a first flow rate regulating valve (6) for regulating the column bottoms flow rate through the dehydrocyanation column reboiler (3) are provided on the output line (101) of the buffer tank (1).

3. The tower bottoms treatment system of the recovery tower of claim 2, wherein the dehydrocyanation tower (2) is provided with a dehydrocyanation tower temperature controller (8) for monitoring the temperature in the dehydrocyanation tower (2), comparing the measured temperature with a threshold value, and outputting the temperature to the first flow regulating valve (6).

4. The reclaimer tower bottoms processing system of claim 3, wherein the first flow regulating valve (6), the first flow meter (9) and the dehydrocyanation tower temperature controller (8) together constitute a cascade closed loop capable of achieving cascade regulation.

5. A reclaimer column bottoms processing system according to claim 1, characterized in that the outlet line (101) of the buffer tank (1) is further provided with a second flow meter (10) for metering the column bottoms flow delivered to the finishing column reboiler (5), and a second flow regulating valve (7) for regulating the column bottoms flow through the finishing column reboiler (5).

6. The reclaimer tower bottoms processing system of claim 2, wherein the ratio of the flow of the first flow meter (9) to the flow of the first flow regulating valve (6) is between 97.5:2.5-35: 65.

7. The reclaimer tower bottoms processing system of claim 6, wherein the ratio of the flow of the first flow meter (9) to the flow of the first flow regulating valve (6) is between 92:8 and 40: 60.

8. The reclaimer tower bottoms processing system of claim 7, wherein the ratio of the flow of the first flow meter (9) to the flow of the first flow regulating valve (6) is 43.3: 56.7.

9. The reclaimer tower bottoms processing system of claim 5, wherein the ratio of the flow of the second flow meter (10) to the flow of the second flow regulating valve (7) is between 97.5:2.5-35: 65.

10. The reclaimer tower bottoms processing system of claim 9, wherein the ratio of the flow of the second flow meter (10) to the flow of the second flow regulating valve (7) is between 92:8 and 40: 60.

11. The reclaimer tower bottoms processing system of claim 10, wherein the ratio of the flow of the second flow meter (10) to the flow of the second flow regulating valve (7) is 43.3: 56.7.

12. The reclaimer column bottoms processing system of claim 1, wherein the dehydrocyanogen column (2) has a first column bottoms outlet (201) and a first feed inlet (202);

the dehydrocyanation tower reboiler (3) is communicated with the first tower bottom material outlet (201) and the first material inlet (202).

13. The reclaimer tower bottoms processing system of claim 1, wherein the finishing tower (4) has a second tower bottoms outlet (401) and a second material inlet (402);

the finished product tower reboiler (5) is communicated with the second tower kettle material outlet (401) and the second material inlet (402).

Technical Field

The invention relates to the field of acrylonitrile production, in particular to a tower bottom liquid treatment system of a recovery tower.

Background

The production technology of acrylonitrile in the world mainly adopts propylene and ammoxidation methods. In recent decades, with the continuous updating of catalysts and the continuous improvement of process flows, the process technology route for preparing acrylonitrile by propylene and ammoxidation still keeps the leading position.

The process flow of the acrylonitrile main device comprises the following steps: a reaction part, a recovery part, a refining part and a four-effect evaporation part. The absorption tower of the recovery part adopts water as an absorbent, the absorbed water becomes lean water, and the water saturated with acrylonitrile and other organic matters is called rich water. The recovery tower is an extractive distillation tower using water as a solvent, and acrylonitrile, hydrocyanic acid and acetonitrile are recovered and desorbed from rich water. In the prior art, the lean water is usually extracted from the first tray of the recovery tower and is recycled as the absorption water of the absorption tower and the solvent water of the recovery tower. But a large amount of heat energy in the lean water is not reasonably utilized, so that the energy is wasted.

Disclosure of Invention

The invention aims to solve the problems and provides a tower bottom liquid treatment system of a recovery tower.

In order to achieve the above object, the present invention provides a system for treating tower bottom liquid of a recovery tower, comprising:

the buffer tank is connected with the tower kettle of the recovery tower and is used for containing tower kettle liquid discharged from the tower kettle of the recovery tower;

a dehydrocyanation tower;

a dehydrocyanation tower reboiler connecting the buffer tank and the dehydrocyanation tower;

a finished product tower;

the finished product tower reboiler is connected with the buffer tank and the finished product tower;

the finishing column and the finishing column reboiler are located downstream of the dehydrocyanation column and the dehydrocyanation column reboiler;

the dehydrocyanation tower reboiler and the finished product tower reboiler are connected in series on an output pipeline of the buffer tank;

and the lean water pump is arranged on the output pipeline and used for pumping the tower bottoms in the buffer tank to the dehydrocyanation tower reboiler and the finished product tower reboiler.

According to one aspect of the present invention, a first flow meter for measuring a column bottom liquid flow rate delivered to the dehydrocyanation column reboiler and a first flow regulating valve for regulating the column bottom liquid flow rate passing through the dehydrocyanation column reboiler are provided on an output line of the buffer tank.

According to one aspect of the invention, the dehydrocyanation tower is provided with a dehydrocyanation tower temperature controller for monitoring the temperature in the dehydrocyanation tower, comparing the measured temperature with a threshold value and outputting the temperature to the first flow regulating valve.

According to one aspect of the invention, the output pipeline of the buffer tank is further provided with a second flow meter for metering the amount of the tower bottom liquid conveyed to the finished product tower reboiler, and a second flow regulating valve for regulating the tower bottom liquid flow passing through the finished product tower reboiler.

According to one aspect of the invention, the first flow regulating valve, the first flow meter and the dehydrocyanation tower temperature controller together form a cascade closed loop capable of realizing cascade regulation.

According to one aspect of the invention, the ratio of the flow rate of the first flow meter to the flow rate of the first flow regulating valve is between 97.5:2.5 and 35: 65.

According to one aspect of the invention, the ratio of the flow rate of the first flow meter to the flow rate of the first flow regulating valve is between 92:8 and 40: 60.

According to one aspect of the invention, the ratio of the flow rates of the first flow meter and the first flow regulating valve is 43.3: 56.7.

According to one aspect of the invention, the ratio of the flow rate of the second flow meter to the flow rate of the second flow regulating valve is between 97.5:2.5 and 35: 65.

According to one aspect of the invention, the ratio of the flow rate of the second flow meter to the flow rate of the second flow regulating valve is between 92:8 and 40: 60.

According to one aspect of the invention, the ratio of the flow rates of the second flow meter and the second flow regulating valve is 43.3: 56.7.

According to one aspect of the invention, the dehydrocyanation column has a first column bottoms outlet and a first material inlet;

the dehydrocyanation tower reboiler is communicated with the first tower kettle material outlet and the first material inlet.

According to one aspect of the invention, the finishing column has a second column bottoms outlet and a second material inlet;

the finished product tower reboiler is communicated with the second tower kettle material outlet and the second material inlet.

According to one scheme of the invention, the buffer tank collects the high-temperature tower bottom liquid of the recovery tower and then sequentially pumps the high-temperature tower bottom liquid into the dehydrocyanation tower reboiler and the finished product tower reboiler, and heat sources are respectively provided for the dehydrocyanation tower and the finished product tower by utilizing temperature difference, so that the heat energy of the tower bottom liquid of the recovery tower is recycled, and the energy is saved.

According to one scheme of the invention, the first flow regulating valve, the first flow meter and the dehydrocyanation tower temperature controller jointly form a cascade closed loop capable of realizing cascade regulation, so that the amount of tower bottom liquid conveyed to a dehydrocyanation tower reboiler can be more accurately controlled.

Drawings

Fig. 1 is a block diagram schematically showing a bottom treatment system of a recovery tower according to an embodiment of the present invention.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

In describing embodiments of the present invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship that is based on the orientation or positional relationship shown in the associated drawings, which is for convenience and simplicity of description only, and does not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, the above-described terms should not be construed as limiting the present invention.

The present invention is described in detail below with reference to the drawings and the specific embodiments, which are not repeated herein, but the embodiments of the present invention are not limited to the following embodiments.

Fig. 1 is a block diagram schematically showing a bottom treatment system of a recovery tower according to an embodiment of the present invention. As shown in fig. 1, the recovery tower bottom liquid treatment system of the present invention comprises: a buffer tank 1, a dehydrocyanation tower 2, a dehydrocyanation tower reboiler 3, a finished product tower 4, a finished product tower reboiler 5 and a water-poor pump b. The buffer tank 1 is connected with the tower kettle A of the recovery tower in the figure 1 and is used for containing tower kettle liquid discharged from the tower kettle A of the recovery tower. The dehydrocyanation tower reboiler 3 and the finished product tower reboiler 5 are arranged in series on the output pipeline 101 of the buffer tank 1. The dehydrocyanation tower reboiler 3 is connected with the buffer tank 1 and the dehydrocyanation tower 2, the finished product tower reboiler 5 is connected with the output end of the dehydrocyanation tower reboiler 3 and the finished product tower 4, and the finished product tower 4 and the finished product tower reboiler 5 are positioned at the downstream of the dehydrocyanation tower 2 and the dehydrocyanation tower reboiler 3. The lean water pump b is arranged on the output pipeline 101, connected with the outlet of the buffer tank 1 and used for pumping the tower bottoms in the buffer tank 1 to the dehydrocyanation tower reboiler 3 and the finished product tower reboiler 5.

According to one embodiment of the invention, the outlet line 101 of the buffer vessel 1 is provided with a first flow regulating valve 6 and a first flow meter 9. The first flow regulating valve 6 is connected in parallel with the dehydrocyanation tower reboiler 3, and adopts a bypass to regulate the tower kettle liquid flow passing through the dehydrocyanation tower reboiler 3. The dehydrocyanation tower 2 is provided with a dehydrocyanation tower temperature controller 8 for monitoring the temperature in the dehydrocyanation tower 2, comparing the measured temperature with a threshold value and outputting to the first flow regulating valve 6. The first flow regulating valve 6, the first flow meter 9 and the dehydrocyanation tower temperature controller 8 jointly form a cascade closed loop capable of realizing cascade regulation, so that the amount of tower bottoms conveyed to the dehydrocyanation tower reboiler 3 is controlled more accurately.

The output pipeline 101 of the buffer tank 1 is provided with a second flow regulating valve 7 and a second flow meter 10. The second flow regulating valve 7 is connected in parallel with the finished product tower reboiler 5, and the tower bottom liquid flow passing through the finished product tower reboiler 5 is regulated by a bypass.

According to one embodiment of the invention, the dehydrocyanation tower 2 has a first tower bottom material outlet 201 and a first material inlet 202, and the dehydrocyanation tower reboiler 3 communicates the first tower bottom material outlet 201 and the first material inlet 202. The material in the tower bottom of the dehydrocyanation tower 2 flows out from a first tower bottom material outlet 201 and enters a dehydrocyanation tower reboiler 3 to exchange heat with the kettle liquid in the output pipeline 101, and then flows into the dehydrocyanation tower 2 from a first material inlet 202 to finish heat transfer. The finished product tower 4 is provided with a second tower bottom material outlet 401 and a second material inlet 402, the finished product tower reboiler 5 is communicated with the second tower bottom material outlet 401 and the second material inlet 402, and the heat exchange process of the finished product tower reboiler is the same as that of the dehydrocyanic acid tower reboiler 3.

According to one embodiment of the invention, the ratio of the flow rates of the first flow meter 9 and the first flow regulating valve 6 and the ratio of the flow rates of the second flow meter 10 and the second flow regulating valve 7 are set between 97.5:2.5 and 35:65, preferably between 92:8 and 40: 60.

According to one embodiment of the present invention, the ratio of the flow rates of the first flow meter 9 and the first flow regulating valve 6, and the ratio of the flow rates of the second flow meter 10 and the second flow regulating valve 7 are 43.3: 56.7.

The operation of the present invention will be described below with reference to the present embodiment by taking as an example the design of a plant for producing 13 million tons of acrylonitrile annually. The temperature of the lean water (namely tower bottom liquid) discharged from the tower bottom of the recovery tower A is about 120 ℃, the lean water enters a buffer tank 1 for collection, the pressure of the lean water liquid in the buffer tank 1 is increased through a lean water pump b, the lean water liquid is pumped to a dehydrocyanation tower reboiler 3, and the flow rate is controlled in a cascade mode through a first flow regulating valve 6, a first flow meter 9 and a dehydrocyanation tower temperature controller 8. The temperature of the kettle liquid in the output pipeline 101 after passing through the dehydrocyanation tower reboiler 3 is about 111 ℃, and then the kettle liquid enters the finished product tower reboiler 5, and the temperature of the kettle liquid after heat exchange in the finished product tower reboiler 5 is about 93 ℃.

According to the embodiment of the invention, the buffer tank 1 collects the high-temperature tower bottoms of the recovery tower A and then sequentially pumps the high-temperature tower bottoms into the dehydrocyanation tower reboiler 3 and the finished product tower reboiler 5, heat sources are respectively provided for the dehydrocyanation tower 2 and the finished product tower 4 by utilizing temperature difference, and the high-temperature tower bottoms return to the absorption tower to serve as an absorbent, so that the heat energy of the tower bottoms of the recovery tower A is recycled, and the energy is saved. The first flow regulating valve 6, the first flow meter 9 and the dehydrocyanation tower temperature controller 8 jointly form a cascade closed loop capable of realizing cascade regulation, and the amount of tower bottom liquid conveyed to the dehydrocyanation tower reboiler 3 can be controlled more accurately.

The above description is only one embodiment of the present invention, and is not intended to limit the present invention, and it is apparent to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.