Recovery system for capturing carbon dioxide

Abstract

The utility model discloses a recovery system for capturing carbon dioxide. The recovery system comprises a carbon capturing unit, a cooling unit, a drying unit, a liquefying unit and a storage unit which are sequentially connected through pipelines, after the carbon capture unit captures carbon dioxide, the carbon dioxide is cooled by the cooling unit and dried by the drying unit, then enters the liquefaction unit to be compressed and liquefied to form liquid carbon dioxide, and then the liquid carbon dioxide is conveyed to the storage unit to be stored. According to the utility model, CO2 after carbon capture can be stored after being cooled, pressurized and liquefied. The system integrates unloading and reliquefaction functions, liquid CO2 in the storage tank can be lighted to a CO2 receiver, and gaseous CO2 in the storage tank is returned to the storage tank for storage after being cooled, pressurized and liquefied. And the system is provided with a plurality of instruments and meters, so that the whole system is more automatic and safer to operate.

Description

Technical Field

[0001] This utility model relates to the field of ship carbon capture technology, specifically to a carbon dioxide capture and recovery system. Background Technology

[0002] Existing carbon capture and carbon dioxide treatment systems are mainly used in large-scale land-based thermal power plants, while marine carbon capture is still in its early stages. Land-based equipment is unsuitable for ships due to its size and weight, while marine systems require simplicity, portability, and high efficiency, with higher demands for automation and safety. Furthermore, given the limited space on ships, minimizing space occupation while ensuring the safety of personnel on board remains a key challenge in current research and development. Utility Model Content

[0003] The present invention aims to overcome at least one of the defects of the prior art and provide a carbon dioxide capture and recovery system to achieve a high degree of automation and to realize the storage, unloading and reliquefaction of captured carbon dioxide.

[0004] This utility model provides a carbon dioxide capture and recovery system, including a carbon capture unit, a cooling unit, a drying unit, a liquefaction unit, and a storage unit connected in sequence by pipelines; after capturing carbon dioxide in the carbon capture unit, it is cooled down by the cooling unit, then dried by the drying unit, and then enters the liquefaction unit for compression and liquefaction to form liquid carbon dioxide, and then transported to the storage unit for storage.

[0005] The carbon capture unit can be any existing carbon capture device capable of capturing carbon dioxide. The cooling unit primarily utilizes circulating cooling water for heat exchange, providing initial cooling of the captured carbon dioxide. The cooled carbon dioxide then passes through a drying unit to reduce moisture, and a liquefaction unit converts the gaseous carbon dioxide into liquid carbon dioxide, which is finally stored in a storage unit. Therefore, the recovery system of this invention achieves the functions of carbon capture, cooling, drying, liquefaction, and storage.

[0006] Furthermore, the recycling system of this utility model also includes an unloading unit connected to the storage unit via a pipeline, the unloading unit being used to transfer the liquid carbon dioxide in the storage unit to the carbon dioxide receiving party.

[0007] To achieve carbon recovery and reuse, this invention also includes an unloading unit, comprising a receiving tank, an unloading pipeline, and a recovery pipeline. One end of the unloading pipeline is connected to the bottom of the storage unit, and the other end is connected to a first nozzle located at the top of the receiving tank. A first control valve is provided at the connection between the unloading pipeline and the storage unit; a second control valve is provided at the connection between the unloading pipeline and the receiving tank. One end of the recovery pipeline connects to the top of the storage unit, and the other end connects to the top of the receiving tank. A third control valve is provided at the connection between the recovery pipeline and the storage unit, and a fourth control valve is provided at the connection between the recovery pipeline and the receiving tank. Furthermore, a first delivery pump, a first unloading interface, and a first receiving interface are sequentially provided between the first and second control valves; a second receiving interface and a second unloading interface are sequentially provided between the fourth and third control valves.

[0008] The temperature and pressure inside the receiving tank are pre-adjusted to match the storage tank of the storage unit. Liquid CO2 in the storage tank is stored in the receiving tank via the first control valve, the first delivery pump, the first unloading port, the first receiving port, the second control valve, and the first nozzle. Gas in the receiving tank returns to the storage tank via the fourth control valve, pipeline, the second receiving port, the hose, the second unloading port, and the third control valve. The gas pipe and the liquid pipe form a loop to prevent the storage tank from losing pressure and the liquid carbon dioxide from solidifying.

[0009] Furthermore, the storage unit includes a storage tank, which is equipped with, from top to bottom, an over-high alarm position, a high alarm position, and a low alarm position. A first temperature sensor is located at the top of the storage tank, and a second temperature sensor is located at the bottom. The storage tank also includes, from top to bottom, a pressure sensor, a level gauge, and a hydraulic sensor. Gaseous CO2 in the storage tank is liquefied into liquid form via a ninth control valve and pipeline, then via a liquefaction unit, and returns to the storage tank via pipeline, a tenth control valve, and a second nozzle.

[0010] The storage tank of this invention has multiple instruments. A second temperature sensor is located at the bottom of the tank, and a first temperature sensor is located near the top of the tank, below the maximum permissible liquid level, for monitoring the CO2 temperature inside the tank. It includes a level gauge and a hydraulic sensor, enabling low-level, high-level, and ultra-high-level alarms for remote monitoring and local display of the liquid level inside the tank. A pressure sensor monitors the tank pressure. When the pressure is abnormal, it automatically closes all control valves connected to the tank, stops all compressors and pumps, and issues an audible and visual alarm. When the pressure switch pressure exceeds the set value, it automatically opens the ninth control valve, liquefying gaseous CO2 through the liquefaction unit and returning it to the tank for cooling and depressurization.

[0011] Furthermore, the liquefaction unit includes a buffer tank, a first compressor, a heat exchanger assembly, and a pressure reducing valve connected in sequence via pipelines; the buffer tank is connected to the drying unit via pipelines, and the pressure reducing valve is connected to the storage unit via pipelines.

[0012] Furthermore, the heat exchanger assembly includes a first heat exchanger, a second heat exchanger, a second compressor, an expansion valve, and a cooling system; one end of the first heat exchanger is connected to one end of the second compressor and one end of the second heat exchanger in sequence via a first cooling pipe, and the other end of the heat exchanger is connected to the expansion valve and one end of the second heat exchanger in sequence via a second cooling pipe; the cooling pipe contains circulating refrigerant; one end of the first heat exchanger is connected to the first compressor, and the other end is connected to the pressure reducing valve; both ends of the second heat exchanger are connected to the cooling system.

[0013] Furthermore, the cooling system includes a first cooling pipe, a second cooling pipe, and a fifth control valve and a sixth control valve respectively installed on the first and second cooling pipes; circulating cooling water flows through the first and second cooling pipes. Further, the cooling unit includes a seventh control valve, a third heat exchanger, an eighth control valve, and a condenser connected sequentially via pipelines; one end of the condenser is connected to the drying unit; a drain pipe is connected to the bottom; and a fourth heat exchanger is also included. One end of the third heat exchanger is connected sequentially to a third delivery pump and one end of the fourth heat exchanger via a third cooling pipe, and the other end of the third heat exchanger is connected to the other end of the fourth heat exchanger via a fourth cooling pipe; cooling circulating water pipelines are connected to both ends of the fourth heat exchanger. CO2 captured by the carbon capture system is cooled and condensed by the cooling unit through pipelines, and the condensate is discharged through the drain pipe. CO2 further absorbs moisture from the gas in the dryer 102 to lower the dew point, and is compressed and liquefied into liquid CO2 by the liquefaction unit. This liquid CO2 is then sprayed out through a second nozzle at the top of the storage tank and stored in the tank under low temperature and medium pressure. The liquefaction unit liquefies gaseous CO2. The input gaseous CO2 is buffered in a buffer tank, compressed by a first compressor, and cooled by a first heat exchanger, converting it into liquid CO2. The liquid CO2 is then depressurized by a pressure reducing valve to match the pressure in the storage tank and transported there for storage. The refrigerant cycle consists of a first heat exchanger, a second compressor, an expansion valve, and necessary connecting pipelines. The refrigerant is compressed by the second compressor, increasing its temperature and pressure. It then passes through the second heat exchanger, exchanging heat with the cooling water pipeline to lower its temperature to ambient temperature. The pressure decreases further through the expansion valve, and the temperature further decreases to T1. The refrigerant exchanges heat with carbon dioxide in the first heat exchanger, increasing its temperature. It is then compressed by the second compressor to begin the next cycle. The temperature range is -56℃ ≤ T1 ≤ -20℃.

[0014] Furthermore, the drying unit includes one or more sets of dryers connected in parallel; each of the dryers is provided with a control valve at both ends; a one-way valve is provided on the pipeline connecting the drying unit to the liquefaction unit; the recovery system also includes multiple drip trays located at the bottom of the storage unit.

[0015] It has multiple drip trays, which are placed at locations where liquid carbon dioxide may leak, to prevent low-temperature damage to the lower deck caused by liquid carbon dioxide leaks, and is equipped with leak monitoring and alarm.

[0016] This utility model is designed with multiple safety valves. When the pressure in the storage tank exceeds the set value of the safety valve, the safety valve opens to release the pressure inside the tank. Safety valves are installed in pipelines that may contain residual liquid carbon dioxide and are isolated. When the liquid carbon dioxide vaporizes, the safety valves open to prevent pipeline damage.

[0017] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0018] This invention allows for the cooling, pressurization, and liquefaction of CO2 after carbon capture for storage. Furthermore, the system integrates unloading and reliquefaction functions, enabling the transfer of liquid CO2 from the storage tank to a CO2 receiving facility and the cooling, pressurization, and liquefaction of gaseous CO2 back to the storage tank. The system also incorporates multiple instruments, enhancing automation and safety. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the carbon dioxide capture and recovery system of this utility model.

[0020] Figure 2 This is a schematic diagram of the liquefaction unit of this utility model.

[0021] Figure 3 This is a schematic diagram of the storage tank of this utility model. Detailed Implementation

[0022] The accompanying drawings illustrate the technical solutions of this utility model in more detail. Throughout the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The described embodiments are only some, not all, embodiments of this utility model. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0023] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0024] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0025] Example 1

[0026] This embodiment describes the storage process of the carbon dioxide capture and recovery system of this invention.

[0027] like Figure 1 As shown, the left frame represents the ship, and the right frame represents the receiver. The CO2 captured by the carbon capture system 100 is cooled and condensed by the cooling unit 101 through pipes 121-123. The dryer 102 further absorbs moisture from the gas to lower the dew point to -40°C. The liquefaction unit 103 compresses and liquefies the CO2 into liquid CO2. The tenth control valve 111 is opened, and the CO2 is then stored in the storage tank 104 through the second nozzle 310 at a low temperature (t = -35°C) and a medium pressure (P = 1.5 MPa). The cooling unit 101 includes a seventh control valve 501, a third heat exchanger 502, an eighth control valve 503, and a condenser 504 connected sequentially via pipelines. One end of the condenser 504 is connected to the drying unit; a vent pipe 505 is connected to its bottom. It also includes a fourth heat exchanger 506. One end of the third heat exchanger 502 is connected sequentially to a third transfer pump 508 and one end of the fourth heat exchanger 506 via a third cooling pipe 507. The other end of the third heat exchanger 502 is connected to the other end of the fourth heat exchanger 506 via a fourth cooling pipe 509. Cooling circulating water pipes 510 are connected to both ends of the fourth heat exchanger 506. Pipe drip trays 108-109 are installed at locations where liquid carbon dioxide leaks may occur to prevent low-temperature damage to the lower deck caused by liquid carbon dioxide leaks, and are equipped with leak monitoring and alarm functions. A one-way valve 116 is installed on the pipeline connecting the drying unit to the liquefaction unit.

[0028] Example 2

[0029] This embodiment describes the unloading process of the carbon dioxide capture and recovery system of this invention.

[0030] The temperature and pressure inside the receiving tank 201 are adjusted in advance to match those of the storage tank 104. The liquid CO2 in the storage tank 104 is stored in the receiving tank 201 via the first control valve 113, the first transfer pump 105, the first unloading port 106, the hose 207, the first receiving port 202, the unloading pipeline 209, the second control valve 205, and the first nozzle 206. The gas in the receiving tank 201 is returned to the storage tank 104 via the fourth control valve 204, the recovery pipeline 210, the second receiving port 203, the hose 208, the second unloading port 107, and the third control valve 114. The gas pipe and the liquid pipe form a loop to prevent the storage tank 104 from losing pressure and the liquid carbon dioxide from solidifying.

[0031] Example 3

[0032] This embodiment describes the reliquefaction process of the carbon dioxide capture and recovery system of this invention.

[0033] The CO2 stored in the liquefaction unit 103 is liquefied again and then returned to the storage tank 104 via pipeline 123, the ninth control valve 112, pipeline 124, the tenth control valve 111, and the second nozzle 310.

[0034] Example 4

[0035] This embodiment describes the implementation of liquefaction and reliquefaction of carbon dioxide by liquefaction unit 103:

[0036] Combination Figure 2 As shown, the input gaseous CO2 is buffered by buffer tank 401, compressed and pressurized to 20 bar by first compressor 402, liquefied by first heat exchanger 403 to -35°C, and then depressurized to 15 bar by pressure reducing valve 404 before being stored in storage tank 104. In refrigerant cycle 410, the refrigerant is a helium-oxygen mixture in a 1:1 ratio. It is compressed by second compressor 405, causing its temperature and pressure to rise, with temperature T2 reaching 50°C. It then exchanges heat with cooling system 411 through second heat exchanger 406, lowering the temperature of the helium-oxygen mixture to ambient temperature. After expansion by expansion valve 407, the temperature drops to T3, where T3 = -50°C. The helium-oxygen mixture absorbs heat from carbon dioxide in first heat exchanger 403, causing its temperature to rise. It is then compressed and pressurized by second compressor 405 for the next cycle. The cooling system 411 includes a first cooling pipe 412, a second cooling pipe 413, and a fifth control valve 408 and a sixth control valve 409 respectively disposed on the first cooling pipe 412 and the second cooling pipe 413; the first cooling pipe 412 and the second cooling pipe 413 contain circulating cooling water.

[0037] Example 5

[0038] This embodiment describes an automatic control method for storage tanks.

[0039] Combination Figure 3 As shown, the storage unit includes a storage tank 104, which contains, from top to bottom, a high-level alarm position 302, a high-level alarm position 303, and a low-level alarm position 309. A first temperature sensor 301 is located at the top of the storage tank 104, and a second temperature sensor 306 is located at the bottom. The storage tank 104 also contains, from top to bottom, a pressure sensor 304, a level gauge 307, and a hydraulic sensor 308. (Combined with...) Figure 1 As shown, gaseous CO2 in storage tank 104 is liquefied into liquid through the ninth control valve 112 and pipeline, and then through the liquefaction unit 103. It then returns to storage tank 104 through pipeline, tenth control valve 111, and second nozzle 310.

[0040] When the pressure in storage tank 104 exceeds the set value of safety valve 119 (SET: 1.65MPa), safety valve 119 opens to release the pressure inside the tank. Safety valves 117-119 are installed in pipelines that may contain residual liquid carbon dioxide and are isolated. When the liquid carbon dioxide vaporizes, safety valves 117-119 open (SET: 1.65MPa) to prevent pipeline damage.

[0041] Combination Figure 1 As shown, pressure sensor 304 monitors the pressure of storage tank 104. When the pressure is abnormal, it automatically closes all control valves in the tank and stops the operation of all compressors and pumps, and issues an audible and visual alarm. When the pressure switch 305 exceeds the set value, it automatically starts the reliquefaction operation according to embodiment 3 or embodiment 4.

[0042] The above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to the preferred embodiments above, those skilled in the art should understand that modifications or equivalent substitutions to the technical solution of this utility model should not depart from the spirit and scope of this utility model. Those skilled in the art can also make other changes within the spirit of this utility model for its design, as long as they do not deviate from the technical effect of this utility model. These changes made according to the spirit of this utility model should all be included within the scope of protection claimed by this utility model.

Claims

1. A recovery system for capturing carbon dioxide, characterized by, The carbon capture unit, the cooling unit (101), the drying unit, the liquefaction unit (103) and the storage unit are connected in sequence through pipelines. After the carbon dioxide is captured by the carbon capture unit, the carbon dioxide is cooled by the cooling unit (101), dried by the drying unit, compressed and liquefied into liquid carbon dioxide by the liquefaction unit (103), and then transported to the storage unit for storage.

2. The recycling system of claim 1, wherein, The unloading unit is further connected to the storage unit through a pipeline, and the unloading unit is used to transfer the liquid carbon dioxide in the storage unit to a carbon dioxide receiving party.

3. The recycling system of claim 2, wherein, The unloading unit includes a receiving tank (201), an unloading pipeline (209) and a recovery pipeline (210). One end of the unloading pipeline (209) is connected to the bottom of the storage unit, and the other end is connected with a first spray head (206), which is arranged on the top of the receiving tank (201). A first control valve (113) is arranged at the connection between the unloading pipeline (209) and the storage unit. A second control valve (205) is arranged at the connection between the unloading pipeline (209) and the receiving tank (201). One end of the recovery pipeline (210) is connected to the top of the storage unit, and the other end is connected to the top of the receiving tank (201). A third control valve (114) is arranged at the connection between the recovery pipeline (210) and the storage unit. A fourth control valve (204) is arranged at the connection between the recovery pipeline (210) and the receiving tank (201).

4. The recycling system of claim 3, wherein, A first delivery pump (105), a first unloading interface (106) and a first receiving interface (202) are arranged in sequence between the first control valve (113) and the second control valve (205). A second receiving interface (203) and a second unloading interface (107) are arranged in sequence between the fourth control valve (204) and the third control valve (114).

5. The recycling system of claim 1, wherein, The storage unit includes a storage tank (104), and the storage tank (104) is sequentially provided with an ultrahigh alarm position (303), a high alarm position (302) and a low alarm position (309) from top to bottom. A first temperature sensor (301) is arranged at the top of the storage tank (104), and a second temperature sensor (306) is arranged at the bottom of the storage tank (104). A pressure sensor (304), a liquid level meter (307) and a hydraulic sensor (308) are further arranged in the storage tank (104) from top to bottom.

6. The recycling system of claim 1, wherein, The liquefaction unit (103) includes a buffer tank (401), a first compressor (402), a heat exchanger group and a pressure reducing valve (404) connected in sequence through pipelines. The buffer tank (401) is connected to the drying unit through a pipeline, and the pressure reducing valve (404) is connected to the storage unit through a pipeline.

7. The recycling system of claim 6, wherein, The heat exchanger group includes a first heat exchanger (403), a second heat exchanger (406), a second compressor (405), an expansion valve (407) and a cooling system (411). One end of the first heat exchanger (403) is connected with one end of the second compressor (405) through the first cooling pipe (412), and the other end of the first heat exchanger (403) is connected with one end of the second heat exchanger (406) through the second cooling pipe (413); the cooling pipes are circulated with refrigerant; One end of the first heat exchanger (403) is connected with the first compressor (402), and the other end is connected with the pressure reducing valve (404); two ends of the second heat exchanger (406) are connected with the cooling system (411).

8. The recycling system of claim 7, wherein, The cooling system (411) comprises the first cooling pipe (412), the second cooling pipe (413), and the fifth control valve (408) and the sixth control valve (409) arranged on the first cooling pipe (412) and the second cooling pipe (413) respectively; the first cooling pipe (412) and the second cooling pipe (413) are circulated with cooling water.

9. The recycling system according to any one of claims 1 to 8, characterized in that The cooling unit (101) comprises the seventh control valve (501), the third heat exchanger (502), the eighth control valve (503), and the condenser (504) connected in sequence through pipes; one end of the condenser (504) is connected with the drying unit; the bottom is connected with the discharge pipe (505); the cooling unit (101) further comprises the fourth heat exchanger (506); one end of the third heat exchanger (502) is connected with one end of the fourth heat exchanger (506) through the third cooling pipe (507) and the third delivery pump (508) in sequence; the other end of the third heat exchanger (502) is connected with the other end of the fourth heat exchanger (506) through the fourth cooling pipe (509); two ends of the fourth heat exchanger (506) are connected with the cooling circulating water pipe (510).

10. The recycling system according to any one of claims 1 to 8, characterized in that The drying unit comprises one or more groups of parallel dryers (102); two ends of the dryer (102) are respectively provided with control valves; the pipe connecting the drying unit with the liquefaction unit (103) is provided with a one-way valve; the recovery system further comprises a plurality of drip trays arranged at the bottom of the storage unit.

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