Carbon dioxide separation device

Abstract

The application discloses a carbon dioxide separation device for separating carbon dioxide in a gas to be treated, which comprises a first compression-condensation mechanism, a separator, a first rectifying tower, a second rectifying tower, a second compression-condensation mechanism, a first heat exchanger, a first pressure-reducing valve and a first containing device, a discharge port of the first compression-condensation mechanism is communicated with a feed port of the separator, a liquid-phase discharge port of the separator is communicated with a feed port of the first pressure-reducing valve, a discharge port of the first pressure-reducing valve is communicated with a feed port of the first rectifying tower through the first heat exchanger, a gas-phase discharge port of the first rectifying tower is communicated with a feed port of the second compression-condensation mechanism, a discharge port of the second compression-condensation mechanism is communicated with the feed port of the first rectifying tower through a first branch, and a liquid-phase discharge port of the second rectifying tower is communicated with the first containing device. The above scheme can solve the problem of resource waste caused by directly discharging the gas with a high carbon dioxide concentration in the related art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon dioxide separation, and particularly relates to a carbon dioxide separation device. BACKGROUND

[0002] In a coal chemical process, a steam reforming process is an important link in the coal chemical process, and the purpose is to adjust the CO / H2 ratio, increase the H2 content, etc., to provide suitable raw material ratio for subsequent synthesis devices (such as synthesis of ammonia, synthesis of methanol, etc.). However, the steam reforming process will also produce a large amount of CO2 gas.

[0003] In the related art, the tail gas generated by the steam reforming process is generally directly discharged to the atmosphere after decarburization by pressure swing adsorption. Since the concentration of CO2 in the gas after decarburization by pressure swing adsorption can reach more than 90%, directly discharging this part of gas to the atmosphere will cause great waste of resources. Of course, not only in the steam reforming process, but also in other processes, there is a problem of directly discharging gas containing a high concentration of CO2, thereby causing great waste of resources. SUMMARY

[0004] The present application discloses a carbon dioxide separation device to solve the problem of resource waste caused by directly discharging gas with a high concentration of carbon dioxide in the related art.

[0005] To solve the above technical problems, the present application is implemented as follows:

[0006] The present application discloses a carbon dioxide separation device for separating carbon dioxide in a gas to be treated, which comprises a first compression-condensation mechanism, a separator, a first rectifying column, a second rectifying column, a second compression-condensation mechanism, a first heat exchanger, a first pressure-reducing valve, and a first containing device, wherein,

[0007] The outlet of the first compression condensing mechanism is communicated with the inlet of the separator, the liquid phase outlet of the separator is communicated with the inlet of the first pressure reducing valve, the outlet of the first pressure reducing valve is communicated with the inlet of the first rectifying tower through the first heat exchanger, the gas phase outlet of the first rectifying tower is communicated with the inlet of the second compression condensing mechanism, the outlet of the second compression condensing mechanism is communicated with the inlet of the first rectifying tower through a first branch, the outlet of the second compression condensing mechanism is communicated with the inlet of the second rectifying tower through a second branch, the liquid phase outlet of the second rectifying tower is communicated with the first containing device, and the gas phase outlet of the second rectifying tower is communicated with the inlet of the second rectifying tower through the first heat exchanger, and the first heat exchanger is used for heat exchange between the gas phase outlet of the second rectifying tower and the outlet of the first pressure reducing valve, so that the temperature of the gas phase outlet of the second rectifying tower is reduced after passing through the heat exchanger.

[0008] The technical scheme adopted by the present application can achieve the following technical effects:

[0009] The carbon dioxide separation device disclosed by the embodiment of the present application can make the liquid phase outlet of the second rectifying tower be packaged as carbon dioxide with a purity meeting the requirements after the to-be-processed gas sequentially passes through the first compression condensing mechanism, the separator, the first rectifying tower, the second compression condensing mechanism and the second rectifying tower, so that the carbon dioxide in the to-be-processed gas can be reused, thereby reducing the waste of resources. Moreover, the carbon dioxide separation device disclosed by the embodiment of the present application makes the gas phase outlet of the second rectifying tower be communicated with the inlet of the second rectifying tower through the first heat exchanger, and the outlet of the first pressure reducing valve be communicated with the inlet of the first rectifying tower through the first heat exchanger, so that the gas phase outlet of the second rectifying tower is heat-exchanged with the outlet of the first pressure reducing valve in the first heat exchanger, so that the temperature of the gas phase outlet of the second rectifying tower is reduced after passing through the heat exchanger, and thus the part of the gas phase outlet of the second rectifying tower condensed into liquid after passing through the heat exchanger can be taken as the reflux feed of the second rectifying tower and enter the second rectifying tower, and the temperature of the outlet of the first pressure reducing valve after pressure reduction is low, so that the cold energy of the outlet of the first pressure reducing valve is fully utilized, thereby making the structure of the carbon dioxide separation device more optimized. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 The structure of the carbon dioxide separation device disclosed by the embodiment of the present application is shown in the figure.

[0011] The reference signs are explained as follows:

[0012] 110 - First compression and condensation mechanism; 111 - First compressor; 112 - First condenser; 120 - Separator; 130 - First distillation column; 131 - First reboiler; 140 - Second distillation column; 141 - Second reboiler; 150 - Second compression and condensation mechanism; 151 - Second compressor; 152 - Second condenser; 153 - Buffer device.

[0013] 160 - First heat exchanger, 170 - First pressure reducing valve, 180 - First receiving device, 190 - Reflux device

[0014] 210-Second heat exchanger, 220-Second pressure reducing valve, 230-Third pressure reducing valve, 240-Third heat exchanger, 250-Fourth heat exchanger, 260-Fourth pressure reducing valve, 270-Fifth heat exchanger, 280-Second containment device, 290-Fifth pressure reducing valve. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0016] The technical solutions disclosed in the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0017] Please refer to Figure 1 This invention discloses a carbon dioxide separation device for separating carbon dioxide from a gas to be treated. The gas to be treated can be the decarbonized gas produced in the ammonia synthesis process in coal chemical industry. Of course, the carbon dioxide separation device disclosed in this application is not limited to treating the gas to be treated produced in coal chemical industry, but can also be used to treat the gas produced in other chemical processes.

[0018] The disclosed carbon dioxide separation device includes a first compression and condensation mechanism 110, a separator 120, a first distillation column 130, a second distillation column 140, a second compression and condensation mechanism 150, a first heat exchanger 160, a first pressure reducing valve 170, and a first containment device 180.

[0019] The gas to be treated can enter the first compression and condensation mechanism 100 through its inlet. The first compression and condensation mechanism 100 can compress and condense the gas to be treated, converting carbon dioxide gas in the gas into a liquid phase. The outlet of the first compression and condensation mechanism 100 is connected to the inlet of the separator 120. The liquid phase and gas phase output from the outlet of the first compression and condensation mechanism 100 enter the separator 120 through its inlet.

[0020] Separator 120 can perform gas-liquid separation on the liquid and gaseous outputs from the outlet of the first compression and condensation unit 100. The gas in separator 120 can be discharged to the atmosphere or the plant end. Although the liquid entering separator 120 is mostly carbon dioxide, other liquids are still present, and the purity of the carbon dioxide liquid in separator 120 is relatively low. The liquid in separator 120 requires further treatment.

[0021] The liquid outlet of separator 120 is connected to the inlet of first pressure reducing valve 170. The outlet of first pressure reducing valve 170 is connected to the inlet of first distillation column 130 through first heat exchanger 160. The liquid in separator 120 is cooled down again after being depressurized by first pressure reducing valve 170, and then enters first distillation column 130 as feed.

[0022] The vapor outlet of the first distillation column 130 is connected to the inlet of the second compression and condensation mechanism 150. The vapor outlet of the first distillation column 130 enters the second compression and condensation mechanism 150 through the inlet of the second compression and condensation mechanism 150. The second compression and condensation mechanism 150 is used to compress and condense the feed entering it to form a liquid output.

[0023] The outlet of the second compression and condensation mechanism 150 is connected to the inlet of the first distillation column 130 via a first branch, and the outlet of the second compression and condensation mechanism 150 is connected to the inlet of the second distillation column 140 via a second branch. The discharge of the second compression and condensation mechanism 150 can be used as reflux feed for the first distillation column 130 and the second distillation column 140.

[0024] The liquid outlet of the second distillation column 140 is connected to the first container 180. The purity of the carbon dioxide discharged from the liquid outlet of the second distillation column 140 meets the process requirements, and can therefore be sealed by the first container 180.

[0025] The vapor outlet of the second distillation column 140 is connected to the feed inlet of the second distillation column 140 through the first heat exchanger 160. The first heat exchanger 160 is used for heat exchange between the vapor outlet of the second distillation column 140 and the outlet of the first pressure reducing valve 170, so that the temperature of the vapor outlet of the second distillation column 140 decreases after passing through the heat exchanger 160. The portion of the vapor outlet of the second distillation column 140 that condenses into liquid after passing through the heat exchanger 160 can be used as reflux feed into the second distillation column 140.

[0026] It should be noted that the first heat exchanger 160 may have two different heat exchange chambers. The vapor discharge from the vapor outlet of the second distillation column 140 can pass through one heat exchange chamber of the first heat exchanger 160 and then enter the second distillation column 140 through its inlet. The discharge from the outlet of the first pressure-reducing valve 170 can pass through the other heat exchange chamber of the first heat exchanger 160 and then enter the first distillation column 130 through its inlet. Specifically, the vapor outlet of the second distillation column 140 and the outlet of the first pressure-reducing valve 170 can be connected to the heat exchange chambers via pipelines. Of course, the pipeline connecting the vapor outlet and the inlet of the second distillation column 140 can also pass through the heat exchange chambers, and the pipeline connecting the outlet of the first pressure-reducing valve 170 and the inlet of the first distillation column 130 can also pass through the heat exchange chambers. The connection to the first heat exchanger 160 mentioned in this application may refer to the connection to a heat exchange chamber in the first heat exchanger 160, or the corresponding pipeline passing through a heat exchange chamber in the first heat exchanger 160.

[0027] The carbon dioxide separation device disclosed in this application sequentially passes the gas to be treated through a first compression and condensation mechanism 110, a separator 120, a first distillation column 130, a second compression and condensation mechanism 150, and a second distillation column 140. The liquid phase output from the second distillation column 140 can be packaged as carbon dioxide with the required purity, thereby enabling the reuse of carbon dioxide in the gas to be treated and reducing resource waste. Furthermore, the carbon dioxide separation device disclosed in this application connects the vapor outlet of the second distillation column 140 to the inlet of the second distillation column 140 via a first heat exchanger 160, and the outlet of the first pressure reducing valve 170 is connected to the inlet of the first distillation column 130 via the first heat exchanger 160. This allows the vapor outlet of the second distillation column 140 and the outlet of the first pressure reducing valve 170 to exchange heat within the first heat exchanger 160. This reduces the temperature of the vapor outlet of the second distillation column 140 after passing through the heat exchanger 160, allowing the portion of the vapor outlet of the second distillation column 140 that condenses into liquid after passing through the heat exchanger 160 to be used as reflux feed into the second distillation column 140. Since the outlet temperature after pressure reduction by the first pressure reducing valve 170 is low, the cooling capacity of the outlet from the first pressure reducing valve 170 is fully utilized, thus optimizing the structure of the carbon dioxide separation device.

[0028] In an optional embodiment, the carbon dioxide separation device may further include a reflux device 190, a second heat exchanger 210, and a second pressure reducing valve 220. The reflux device 190 may include a first inlet, a first liquid phase outlet, and a first gas phase outlet. The gas phase outlet of the second distillation column 140 can be connected to the first inlet via the first heat exchanger 160. The gas phase output of the second distillation column 140 can enter the reflux device 190 after heat exchange in the first heat exchanger 160, and the reflux device 190 can separate the incoming gas and liquid. The first liquid phase outlet can be connected to the feed inlet of the second distillation column 140, and the liquid output from the reflux device 190 can enter the second distillation column 140 from the feed inlet via the first liquid phase outlet. The first gas phase outlet is sequentially connected to the second pressure reducing valve 220 and the second heat exchanger 210. The gas output from the reflux device 190 can be cooled by the pressure reduction of the second pressure reducing valve 220, allowing it to enter the second heat exchanger 210 for heat exchange, and then discharged to the atmosphere or the plant end after heat exchange. The outlet of the first compression condensation mechanism 100 can be connected to the inlet of the separator 120 through the second heat exchanger 210, allowing the output from the first compression condensation mechanism 100 to enter the separator 120 after passing through the second heat exchanger 210. The second heat exchanger 210 can be used for heat exchange between the output from the first gas phase outlet and the output from the first compression condensation mechanism 100, so that the output from the first compression condensation mechanism 100 can be cooled after passing through the second heat exchanger 210.

[0029] It should be noted that the second heat exchanger 210 may have two different heat exchange chambers. The discharge from the first gas phase outlet can pass through one of the heat exchange chambers in the second heat exchanger 210, and the discharge from the first compression and condensation mechanism 100 can pass through the other heat exchange chamber in the second heat exchanger 210, thereby enabling heat exchange between the discharge from the first gas phase outlet and the discharge from the first compression and condensation mechanism 100. Specifically, the pipeline connected to the first gas phase outlet can be connected to one of the heat exchange chambers in the second heat exchanger 210, or the pipeline connected to the first gas phase outlet can pass through one heat exchange chamber; the pipeline connecting the discharge port of the first compression and condensation mechanism 100 and the inlet of the separator 120 can be connected to another heat exchange chamber, or pass through another heat exchange chamber. The term "connected to the second heat exchanger 210" in this application can refer to being connected to one of the heat exchange chambers in the second heat exchanger 210, or the corresponding pipeline passing through one of the heat exchange chambers in the second heat exchanger 210.

[0030] The carbon dioxide separation device disclosed in this application embodiment, by setting up a reflux device 190, a second heat exchanger 210, and a second pressure reducing valve 220, allows the gaseous discharge from the second distillation column 140 to enter the reflux device 190 after heat exchange in the first heat exchanger 160. The reflux device 190 can separate the incoming gas and liquid, allowing the liquid discharge in the reflux device 190 to enter the second distillation column 140 through the first liquid phase outlet from the feed inlet. The gaseous discharge in the reflux device 190 can be depressurized by the second pressure reducing valve 220, and its temperature will decrease before it can enter the second heat exchanger 210 for heat exchange. This allows the discharge from the first gas phase outlet to exchange heat with the discharge from the first compression and condensation mechanism 100, so that the discharge from the first compression and condensation mechanism 100 can be depressurized by the second heat exchanger 210. This allows for full utilization of the cooling capacity of the discharge after pressure reduction by the second pressure reducing valve 220, which is beneficial for the recovery of cooling capacity in the carbon dioxide separation device.

[0031] Optionally, the outlet of the second compression and condensation mechanism 150 can be connected sequentially to the first reboiler 131 and the feed inlet of the first distillation column 130 via a first branch. The outlet of the second compression and condensation mechanism 150 can be connected sequentially to the second reboiler 141 and the feed inlet of the second distillation column 140 via a second branch. It should be noted that the connection between the first branch and the first reboiler 131 of the first distillation column 130 means that the discharge from the first branch can exchange heat with the first reboiler 131, so that the condensed discharge from the first branch enters the first distillation column 130 through the feed inlet. Similarly, the connection between the second branch and the second reboiler 141 of the second distillation column 140 means that the discharge from the second branch can exchange heat with the second reboiler 141, so that the condensed discharge from the second branch enters the first distillation column 130 through the feed inlet.

[0032] The carbon dioxide separation device disclosed in this application connects the outlet of the second compression and condensation mechanism 150 to the first reboiler 131 and the inlet of the first distillation column 130 via a first branch, and the outlet of the second compression and condensation mechanism 150 is connected to the second reboiler 141 and the inlet of the second distillation column 140 via a second branch. This allows the discharge from the second compression and condensation mechanism 150 to be cooled by the corresponding first reboiler 131 and second reboiler 141 before entering the first distillation column 130 from the inlet and the second distillation column 140 from the inlet.

[0033] Furthermore, the carbon dioxide separation unit also includes two third pressure reducing valves 230. One of the two third pressure reducing valves 230 can be located in the first branch, between the feed inlet of the first reboiler 131 and the feed inlet of the first distillation column 130. The other is located in the second branch, between the feed inlet of the second reboiler 141 and the feed inlet of the second distillation column 140.

[0034] The carbon dioxide separation apparatus disclosed in this application has one of two third pressure-reducing valves 230 located in the first branch, between the inlet of the first reboiler 131 and the feed inlet of the first distillation column 130. The other valve is located in the second branch, between the inlet of the second reboiler 141 and the feed inlet of the second distillation column 140. This allows the feed entering the first distillation column 130 through the first branch from the feed inlet to be further cooled by pressure reduction, and the feed entering the second distillation column 140 through the second branch to be further cooled.

[0035] In one optional embodiment, the second compression and condensation mechanism 150 may include a second compressor 151, a second condenser 152, and a buffer device 153. The vapor outlet of the first distillation column 130 may be connected to the inlet of the second compressor 151, the outlet of the second compressor 151 may be connected to the inlet of the second condenser 152, the outlet of the second condenser 152 may be connected to the inlet of the buffer device 153, the outlet of the buffer device 153 may be connected to the inlet of the first distillation column 130 via a first branch, and the outlet of the buffer device 153 may be connected to the inlet of the second distillation column 140 via a second branch.

[0036] The carbon dioxide separation device disclosed in this application configures the second compression and condensation mechanism 150 to include a second compressor 151, a second condenser 152, and a buffer device 153. This allows the material to be compressed and condensed by the second compressor 151 and the second condenser 152, then buffered in the buffer device 153 before entering the first distillation column 130 and the second distillation column 140 through the first branch and the second branch, respectively. This makes the material delivery in the first branch and the second branch more stable.

[0037] Furthermore, the carbon dioxide separation device may also include a third heat exchanger 240. The vapor outlet of the first distillation column 130 can be connected to the inlet of the second compressor 151 through the third heat exchanger 240. The outlet of the buffer device 153 can be connected to the third heat exchanger 240 and the inlet of the first distillation column 130 in sequence through a first branch. The outlet of the buffer device 153 can be connected to the inlet of the third heat exchanger 240 and the inlet of the second distillation column 140 in sequence through a second branch. The vapor outlet of the first distillation column 130 can exchange heat with the outlet of the buffer device 153 to reduce the temperature of the feed entering the first distillation column 130 and the feed entering the second distillation column 140.

[0038] It should be noted that the connecting pipe between the vapor outlet of the first distillation column 130 and the inlet of the second compressor 151 can connect to one heat exchange chamber of the third heat exchanger 240, or it can pass through one heat exchange chamber of the third heat exchanger 240. The first branch can connect to the other heat exchange chamber of the third heat exchanger 240, or it can pass through the other heat exchange chamber of the third heat exchanger 240.

[0039] The carbon dioxide separation device disclosed in this application embodiment provides a third heat exchanger 240, which allows the vapor phase output of the first distillation column 130 to exchange heat with the output of the buffer device 153 within the third heat exchanger 240. This reduces the temperature of the feed entering the first distillation column 130 and the feed entering the second distillation column 140, thereby effectively reducing the temperature of the reflux feed entering the first distillation column 130 and the second distillation column 140.

[0040] In an optional embodiment, the carbon dioxide separation device may further include a fourth heat exchanger 250 and a fourth pressure reducing valve 260. The outlet of the buffer device 153 may be connected to the inlet of the fourth pressure reducing valve 260 via a third branch. The outlet of the fourth pressure reducing valve 260 may be connected to the gas phase outlet of the first distillation column 130 via the fourth heat exchanger 250. The outlet of the first compression and condensation mechanism 100 may be connected to the inlet of the separator 120 via the fourth heat exchanger 250. The fourth heat exchanger 250 may be used to exchange heat between the outlet of the fourth pressure reducing valve 260 and the outlet of the first compression and condensation mechanism 100, so as to reduce the temperature of the outlet of the first compression and condensation mechanism 100.

[0041] It should be noted that the connecting pipe between the outlet of the fourth pressure reducing valve 260 and the vapor outlet of the first distillation column 130 can be connected to one heat exchange chamber of the fourth heat exchanger 250, or pass through one heat exchange chamber. Similarly, the connecting pipe between the outlet of the first compression and condensation mechanism 100 and the inlet of the separator 120 can be connected to another heat exchange chamber of the fourth heat exchanger 250, or pass through another heat exchange chamber.

[0042] The carbon dioxide separation device disclosed in this application embodiment is equipped with a fourth heat exchanger 250 and a fourth pressure reducing valve 260, which reduces the outlet temperature after pressure reduction by the fourth pressure reducing valve 260. This allows the outlet of the fourth pressure reducing valve 260 to exchange heat with the outlet of the first compression and condensation mechanism 100, thereby reducing the outlet temperature of the first compression and condensation mechanism 100. This allows full utilization of the cooling capacity after pressure reduction by the fourth pressure reducing valve 260.

[0043] In an optional embodiment, the carbon dioxide separation device may further include a fifth heat exchanger 270. The liquid phase outlet of the first distillation column 130 may be connected to the fifth heat exchanger 270, and the liquid phase outlet of the second distillation column 140 may also be connected to the fifth heat exchanger 270. The fifth heat exchanger 270 can be used for heat exchange between the liquid phase outlets of the first distillation column 130 and the liquid phase outlets of the second distillation column 140, so that the temperature of the liquid phase outlet of the second distillation column 140 decreases after passing through the fifth heat exchanger 270. After heat exchange in the fifth heat exchanger, the liquid phase outlet temperature of the first distillation column 130 increases before being discharged to the atmosphere or the plant end.

[0044] It should be noted that the liquid outlet of the first distillation column 130 can be connected to one heat exchange chamber of the fifth heat exchanger 270 via a pipeline, or pass through one heat exchange chamber; the liquid outlet of the second distillation column 140 can be connected to another heat exchange chamber of the fifth heat exchanger 270, or pass through another heat exchange chamber.

[0045] The carbon dioxide separation device disclosed in this application embodiment, by setting a fifth heat exchanger 270, allows the liquid phase outlet of the first distillation column 130 to exchange heat with the liquid phase outlet of the second distillation column 140. This causes the temperature of the liquid phase outlet of the second distillation column 140 to decrease after passing through the fifth heat exchanger 270, thereby making full use of the cooling capacity of the liquid phase outlet of the first distillation column 130 to further cool the carbon dioxide entering the first containment device 180.

[0046] Optionally, the carbon dioxide separation device may further include a second containing device 280. The liquid phase outlet of the separator 120 can be connected to the inlet of the first pressure reducing valve 170 via a fourth branch, and the liquid phase outlet of the separator 120 can be connected to the second containing device 280 via a fifth branch. The second containing device 280 can encapsulate the discharge from the liquid phase outlet of the separator 120. The carbon dioxide encapsulated in the second containing device 280 has a relatively low purity, and can be used as an industrial material. The carbon dioxide encapsulated in the first containing device 180 has a relatively higher purity, and can therefore be used as a food additive. The fourth and fifth branches may each be equipped with a switching valve, which can control the switching of the corresponding passage. The fifth branch may also be equipped with a fifth pressure reducing valve 290 for pressure reduction treatment before the carbon dioxide is encapsulated in the second containing device 280.

[0047] The carbon dioxide separation device disclosed in this application connects the liquid phase outlet of the separator 120 to the inlet of the first pressure reducing valve 170 via a third branch.

[0048] Optionally, the first compression and condensation mechanism 110 may include a plurality of first compressors 111 and a plurality of first condensers 112, which may be arranged sequentially at intervals. By providing a plurality of first compressors 111 and a plurality of first condensers 112, the gas to be processed can be sufficiently compressed and condensed, while also providing redundancy for the first compression and condensation mechanism 110.

[0049] The above embodiments of the present invention focus on describing the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be described in detail here.

[0050] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A carbon dioxide separation device for separating carbon dioxide from a gas to be treated, characterized in that, It includes a first compression and condensation mechanism (110), a separator (120), a first distillation column (130), a second distillation column (140), a second compression and condensation mechanism (150), a first heat exchanger (160), a first pressure reducing valve (170), and a first containment device (180), wherein, The outlet of the first compression condensing mechanism (110) is connected to the inlet of the separator (120). The liquid outlet of the separator (120) is connected to the inlet of the first pressure reducing valve (170). The outlet of the first pressure reducing valve (170) is connected to the inlet of the first distillation column (130) through the first heat exchanger (160). The gas outlet of the first distillation column (130) is connected to the inlet of the second compression condensing mechanism (150). The outlet of the second compression condensing mechanism (150) is connected to the inlet of the first distillation column (130) through a first branch. The outlet of the condensation mechanism (150) is connected to the inlet of the second distillation column (140) through a second branch. The liquid outlet of the second distillation column (140) is connected to the first container (180). The gas outlet of the second distillation column (140) is connected to the inlet of the second distillation column (140) through the first heat exchanger (160). The first heat exchanger (160) is used to exchange heat between the gas outlet of the second distillation column (140) and the outlet of the first pressure reducing valve (170) so that the temperature of the gas outlet of the second distillation column (140) decreases after passing through the heat exchanger (160). The first compression and condensation mechanism (110) includes a first compressor (111) and a first condenser (112) located at the outlet of the first compressor (111), and the second compression and condensation mechanism (150) includes a second compressor (151) and a second condenser (152) located at the outlet of the second compressor (151).

2. The carbon dioxide separation device according to claim 1, characterized in that, The carbon dioxide separation device further includes a reflux device (190), a second heat exchanger (210), and a second pressure reducing valve (220). The reflux device (190) includes a first inlet, a first liquid phase outlet, and a first gas phase outlet. The gas phase outlet of the second distillation column (140) is connected to the first inlet through the first heat exchanger (160). The first liquid phase outlet is connected to the feed inlet of the second distillation column (140). The first gas phase outlet is connected to the second pressure reducing valve (220) and the second heat exchanger (210) in sequence. The outlet of the first compression condensation mechanism (110) is connected to the feed inlet of the separator (120) through the second heat exchanger (210). The second heat exchanger (210) is used for heat exchange between the discharge from the first gas phase outlet and the discharge from the first compression condensation mechanism (110) so that the temperature of the discharge from the first compression condensation mechanism (110) decreases after passing through the second heat exchanger (210).

3. The carbon dioxide separation device according to claim 1, characterized in that, The outlet of the second compression condensation mechanism (150) is connected in sequence to the first reboiler (131) of the first distillation column (130) and the inlet of the first distillation column (130) through the first branch; the outlet of the second compression condensation mechanism (150) is connected in sequence to the second reboiler (141) of the second distillation column (140) and the inlet of the second distillation column through the second branch.

4. The carbon dioxide separation device according to claim 3, characterized in that, The carbon dioxide separation device includes two third pressure reducing valves (230), one of which is located in the first branch and between the inlet of the first reboiler (131) and the inlet of the first distillation column (130), and the other is located in the second branch and between the inlet of the second reboiler (141) and the inlet of the second distillation column (140).

5. The carbon dioxide separation device according to claim 1, characterized in that, The second compression and condensation mechanism (150) further includes a buffer device (153). The gas phase outlet of the first distillation column (130) is connected to the inlet of the second compressor (151). The outlet of the second compressor (151) is connected to the inlet of the second condenser (152). The outlet of the second condenser (152) is connected to the inlet of the buffer device (153). The outlet of the buffer device (153) is connected to the inlet of the first distillation column (130) through the first branch. The outlet of the buffer device (153) is connected to the inlet of the second distillation column (140) through the second branch.

6. The carbon dioxide separation device according to claim 5, characterized in that, The carbon dioxide separation device further includes a third heat exchanger (240). The vapor outlet of the first distillation column (130) is connected to the inlet of the second compressor (151) through the third heat exchanger (240). The outlet of the buffer device (153) is connected to the inlet of the third heat exchanger (240) and the first distillation column (130) in sequence through the first branch. The outlet of the buffer device (153) is connected to the inlet of the third heat exchanger (240) and the second distillation column (140) in sequence through the second branch. The vapor outlet of the first distillation column (130) exchanges heat with the outlet of the buffer device (153) to reduce the temperature of the feed entering the first distillation column (130) and the feed entering the second distillation column (140).

7. The carbon dioxide separation device according to claim 6, characterized in that, The carbon dioxide separation device further includes a fourth heat exchanger (250) and a fourth pressure reducing valve (260). The outlet of the buffer device (153) is connected to the inlet of the fourth pressure reducing valve (260) through a third branch. The outlet of the fourth pressure reducing valve (260) is connected to the gas phase outlet of the first distillation column (130) through the fourth heat exchanger (250). The outlet of the first compression condensation mechanism (110) is connected to the inlet of the separator (120) through the fourth heat exchanger (250). The fourth heat exchanger (250) is used for heat exchange between the outlet of the fourth pressure reducing valve (260) and the outlet of the first compression condensation mechanism (110) to reduce the temperature of the outlet of the first compression condensation mechanism (110).

8. The carbon dioxide separation device according to claim 1, characterized in that, The carbon dioxide separation device further includes a fifth heat exchanger (270). The liquid phase outlet of the first distillation column (130) is connected to the fifth heat exchanger (270), and the liquid phase outlet of the second distillation column (140) is also connected to the fifth heat exchanger (270). The fifth heat exchanger (270) is used to exchange heat between the liquid phase outlet of the first distillation column (130) and the liquid phase outlet of the second distillation column (140), so that the temperature of the liquid phase outlet of the second distillation column (140) decreases after passing through the fifth heat exchanger (270).

9. The carbon dioxide separation device according to claim 1, characterized in that, The carbon dioxide separation device further includes a second containment device (280). The liquid phase outlet of the separator (120) is connected to the inlet of the first pressure reducing valve (170) through a fourth branch. The liquid phase outlet of the separator (120) is connected to the second containment device (280) through a fifth branch.

10. The carbon dioxide separation device according to claim 1, characterized in that, The first compression and condensation mechanism (110) includes a plurality of first compressors (111) and a plurality of first condensers (112), wherein the plurality of first compressors (111) and the plurality of first condensers (112) are arranged sequentially at intervals.

Images