Gas supply and carbon capture system

Abstract

A gas supply and carbon capture system, comprising an LNG tank, a BOG compressor set, a dual-fuel engine, a CO2 capture unit, a CO2 compressor, a heat exchanger, and a CO2 storage tank, wherein the LNG tank is used for storing liquid LNG, BOG formed at the inner top of the LNG tank is fed to a cold side of the heat exchanger; the heat exchanger is used for heat exchange between pressurized CO2 and the BOG, cold energy of the BOG is utilized to liquefy the CO2, the obtained liquid CO2 is stored in the CO2 storage tank, and the BOG having a higher temperature after the heat exchange is sent to the BOG compressor set; and the BOG compressor set is used for pressurizing the BOG having a higher temperature and then delivering the BOG to the dual-fuel engine for combustion, and the BOG compressor set employs normal-temperature compressors. By means of the system, the cold energy of the BOG from the LNG tank is fully utilized, and the temperatures of the BOG entering the BOG compressors are caused to meet an inlet temperature requirement of the normal-temperature compressors.

Description

A gas supply and carbon capture system Technical Field

[0001] This invention relates to the field of shipbuilding technology, and in particular to a gas supply and carbon capture system. Background Technology

[0002] Faced with the severe challenges of global climate change, the international community is increasingly focusing on carbon emissions. The shipping industry accounts for approximately 2.89% of global human-caused carbon emissions, making it one of the most proactive sectors in reducing emissions. Ship propulsion companies and shipbuilding enterprises are actively promoting the development of decarbonization technologies such as green fuels and carbon capture. Summary of the Invention

[0003] In view of this, the present invention provides a gas supply and carbon capture system.

[0004] A gas supply and carbon capture system includes an LNG tank, a BOG compressor unit, a dual-fuel engine, a CO2 capture unit, a CO2 compressor, a heat exchanger, and a CO2 storage tank.

[0005] The CO2 capture unit is used to desorb CO2 from the exhaust gas of the dual-fuel engine using a chemical absorption method and deliver it to the CO2 compressor.

[0006] The CO2 compressor is used to pressurize the desorbed CO2 and send the pressurized CO2 into the first hot side of the heat exchanger;

[0007] The LNG compartment is used to store liquid LNG and the BOG gas formed at the top of the compartment is sent to the cold side of the heat exchanger.

[0008] The heat exchanger is used to exchange heat between the pressurized CO2 and BOG gas, using the cold energy of the BOG gas to liquefy CO2, and storing the resulting liquid CO2 in the CO2 storage chamber, while the BOG gas with a higher temperature is sent to the BOG compressor unit.

[0009] The BOG compressor unit is used to pressurize BOG gas at a higher temperature and then deliver it to the dual-fuel engine for combustion. The BOG compressor unit is a normal temperature compressor.

[0010] Preferably, the CO2 capture unit includes an absorption tower, a desorption tower, a heat exchanger, a rich liquor pump, and a lean liquor pump.

[0011] The exhaust port of the dual-fuel engine is connected to the exhaust gas inlet at the bottom of the absorption tower via a pipeline. The exhaust gas of the dual-fuel engine reacts with the absorbent sprayed from the top of the tower and is absorbed in the absorption tower. The remaining gas after decarbonization is discharged from the top of the absorption tower, and the low-temperature rich liquid formed by the reaction is pumped from the bottom of the tower by the rich liquid pump and sent to the cold side inlet of the heat exchanger.

[0012] The rich liquid flowing out from the cold side outlet of the heat exchanger enters the desorption tower through the rich liquid inlet at the top of the desorption tower. Inside the desorption tower, it is heated to the set temperature and desorbs CO2, while the rich liquid is regenerated into a high-temperature lean liquid. The high-temperature lean liquid is pumped from the bottom of the tower by the lean liquid pump and sent to the hot side inlet of the heat exchanger. Inside the heat exchanger, it exchanges heat with the low-temperature rich liquid. The desorbed CO2 is discharged from the top of the tower and, after drying and dehydration, is sent to the CO2 compressor.

[0013] Preferably, the CO2 capture unit further includes a reheater for reheating the undesorbed rich liquid in the desorption tower.

[0014] Preferably, the absorbent used in the absorption tower is an organic amine solution.

[0015] Preferably, the BOG compressor unit includes a first-stage BOG compressor and a second-stage BOG compressor. The inlet of the first-stage BOG compressor is connected to the cold-side outlet of the heat exchanger, the outlet of the first-stage BOG compressor is connected to the second hot-side inlet of the heat exchanger, the second hot-side outlet of the heat exchanger is connected to the inlet of the second-stage BOG compressor, the outlet of the second-stage BOG compressor is connected to the third hot-side inlet of the heat exchanger, and the third hot-side outlet of the heat exchanger is connected to the inlet of the dual-fuel engine.

[0016] Preferably, a first three-way control valve is provided on the pipeline connecting the outlet of the first-stage BOG compressor to the inlet of the second heat side of the heat exchanger, and one of the outlets of the first three-way control valve is connected to the inlet of the second-stage BOG compressor through a pipeline.

[0017] A second three-way control valve is installed on the pipeline connecting the outlet of the two-stage BOG compressor to the inlet of the third heat side of the heat exchanger. One of the outlets of the second three-way control valve is connected to the intake port of the dual-fuel engine through a pipeline.

[0018] Preferably, a vent pipe is also connected to the pipeline connecting the first hot-side outlet of the heat exchanger to the liquid inlet of the CO2 storage chamber.

[0019] Preferably, the heat exchanger is a gas / gas heat exchanger.

[0020] The beneficial effects of this invention are:

[0021] The gas supply and carbon capture system of this invention covers the entire process flow, including gas supply, CO2 capture, CO2 compression, CO2 liquefaction, and CO2 storage. It fully utilizes the cold energy of BOG from the LNG tank to cool the BOG after compression by the BOG compressor, thus eliminating the need for an additional intercooler, aftercooler, or freshwater cooling system. It also fully utilizes the heat energy of the compressed BOG and compressed CO2 to heat the BOG from the LNG tank, ensuring that the temperature entering the BOG compressor reaches the inlet temperature requirement of a normal temperature compressor, thus allowing the BOG compressor to be a normal temperature compressor. Furthermore, it fully utilizes the heat energy of the exhaust gas from the dual-fuel engine to heat the rich liquid, thus eliminating the need for an additional heating medium and heat source. Finally, it fully utilizes the cold energy of the BOG from the LNG tank to liquefy CO2, thus eliminating the need for an additional cooling medium and cold source. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 is a schematic diagram of the structure of the present invention.

[0024] The labels in the diagram represent the following: 1 is a dual-fuel engine, 2 is a CO2 capture unit, 3 is a CO2 compressor, 4 is a heat exchanger, 5 is an LNG compartment, 6 is a CO2 storage compartment, 7 is a BOG compressor unit, 8 is an absorption tower, 9 is a desorption tower, 10 is a heat exchanger, 11 is a rich liquid pump, 12 is a lean liquid pump, 13 is the first pipeline, 14 is the second pipeline, 15 is the third pipeline, 16 is the fourth pipeline, 17 is the fifth pipeline, 18 is the sixth pipeline, 19 is the seventh pipeline, 20 is the sixteenth pipeline, 21 is the ninth pipeline, 22 is the tenth pipeline, 23 is the eleventh pipeline, 24 is the twelfth pipeline, 25 is the thirteenth pipeline, 26 is the fourteenth pipeline, 27 is the fifteenth pipeline, 28 is a reheater, 29 is the first-stage BOG compressor, and 30 is the second-stage BOG compressor. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0026] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0027] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms and should not be construed as indicating or implying relative importance. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information.

[0028] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0030] To better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings.

[0031] This invention provides a gas supply and carbon capture system, including an LNG tank 5, a BOG compressor unit 7, a dual-fuel engine 1, a CO2 capture unit 2, a CO2 compressor 3, a heat exchanger 4, and a CO2 storage tank 6.

[0032] The CO2 capture unit 2 is used to desorb CO2 from the exhaust gas of the dual-fuel engine 1 using a chemical absorption method and deliver it to the CO2 compressor;

[0033] The CO2 compressor 3 is used to pressurize the desorbed CO2 and send the pressurized CO2 into the first hot side of the heat exchanger 4;

[0034] The LNG compartment 5 is used to store liquid LNG and the BOG gas formed at the top of the compartment is sent to the cold side of the heat exchanger 4.

[0035] The heat exchanger 4 is used to exchange heat between the pressurized CO2 and BOG gas, using the cold energy of BOG gas to liquefy CO2, and storing the resulting liquid CO2 in the CO2 storage chamber 6. The resulting BOG gas with a higher temperature is sent to the BOG compressor unit 7.

[0036] The BOG compressor unit 7 is used to pressurize BOG gas at a higher temperature and then deliver it to the dual-fuel engine 1 for combustion. The BOG compressor unit 7 is a normal temperature compressor.

[0037] Specifically, in this embodiment, the CO2 capture unit 2 includes an absorption tower 8, a desorption tower 9, a heat exchanger 10, a rich liquid pump 11, and a lean liquid pump 12.

[0038] The exhaust port of the dual-fuel engine 1 is connected to the exhaust gas inlet at the bottom of the absorption tower 8 via a pipeline.

[0039] The absorption tower 8 is provided with a waste gas outlet at the top and a rich liquid outlet at the bottom, and a lean liquid inlet at the top. The desorption tower 9 is provided with a rich liquid inlet at the top, a gas outlet at the top, and a lean liquid outlet at the bottom.

[0040] The rich liquid outlet at the bottom of the absorption tower 8 is connected to the inlet of the rich liquid pump 11 via the first pipeline 13. The outlet of the rich liquid pump 11 is connected to the cold side inlet of the heat exchanger 10 via the second pipeline 14. The cold side outlet of the heat exchanger 10 is connected to the rich liquid inlet of the desorption tower 9 via the third pipeline 15. The gas outlet of the desorption tower 9 is connected to the gas inlet of the CO2 compressor 3 via the fourth pipeline 16. The lean liquid outlet of the desorption tower 9 is connected to the inlet of the lean liquid pump 12 via the fifth pipeline 17. The outlet of the lean liquid pump 12 is connected to the hot side inlet of the heat exchanger 10 via the sixth pipeline 18. The hot side outlet of the heat exchanger 10 is connected to the lean liquid inlet of the absorption tower 8 via the seventh pipeline 19.

[0041] The exhaust gas from the dual-fuel engine 1 enters the absorption tower 8 after dust removal treatment. Inside the absorption tower 8, the exhaust gas flows from bottom to top, while the absorbent sprayed from the top of the tower flows from top to bottom. The exhaust gas and the absorbent in the tower come into full contact in the opposite direction and react. The CO2 in the exhaust gas is absorbed by the absorbent. The remaining gas after decarbonization is discharged from the top of the absorption tower 8. The low-temperature rich liquid formed by the reaction is pumped from the bottom of the tower by the rich liquid pump 11 and sent to the cold side inlet of the heat exchanger 10. After heat exchange with the high-temperature lean liquid with a higher temperature in the heat exchanger 10, it flows out from the cold side outlet of the heat exchanger 10.

[0042] The rich liquid flowing out from the cold side outlet of heat exchanger 10 flows into desorption tower 9 from the rich liquid inlet at the top of desorption tower 9, desorbs CO2, and regenerates the rich liquid into a high-temperature lean liquid. The high-temperature lean liquid is pumped from the bottom of the tower by lean liquid pump 12 and sent to the hot side inlet of heat exchanger 10. In heat exchanger 10, it exchanges heat with the low-temperature rich liquid drawn from absorption tower 8. The heat of the high-temperature lean liquid is used to heat the low-temperature rich liquid drawn from the bottom of absorption tower 8. After heat exchange, the temperature of the high-temperature lean liquid decreases and becomes low-temperature lean liquid. It is sent back to the top of absorption tower 8 through the seventh pipeline 19 for CO2 recycling and absorption. The desorbed CO2 is discharged from the top of desorption tower 9 and sent to the CO2 compressor after drying and dehydration treatment.

[0043] The CO2 discharged from the top of the desorption tower 9 is compressed and pressurized by the CO2 compressor and sent to the first hot side of the heat exchanger 4 through the ninth pipeline 21. Meanwhile, the BOG gas formed in the LNG compartment 5 is also sent to the cold side of the heat exchanger 4 through the tenth pipeline 22. Since the temperature of the BOG gas is low and the temperature of the CO2 is high, the BOG gas and CO2 exchange heat inside the heat exchanger 4. The cold energy of the BOG gas is used to liquefy the CO2 and the liquid CO2 is stored in the CO2 storage compartment 6 through the eleventh pipeline 23. The BOG gas that has absorbed the cold energy and become a higher temperature is sent to the BOG compressor unit through the twelfth pipeline 24.

[0044] Preferably, the eleventh pipe 23 is also connected to a vent pipe.

[0045] The BOG compressor unit includes a first-stage BOG compressor 29 and a second-stage BOG compressor 30. The inlet of the first-stage BOG compressor 29 is connected to the cold-side outlet of the heat exchanger 4 via the twelfth pipe 24. The outlet of the first-stage BOG compressor 29 is connected to the second hot-side inlet of the heat exchanger 4 via the thirteenth pipe 25. The second hot-side outlet of the heat exchanger 4 is connected to the inlet of the second-stage BOG compressor 30 via the fourteenth pipe 26. The fifteenth pipe 27 of the outlet of the second-stage BOG compressor 30 is connected to the third hot-side inlet of the heat exchanger 4. The sixteenth pipe 20 of the third hot-side outlet of the heat exchanger 4 is connected to the inlet of the dual-fuel engine 1.

[0046] Preferably, a first three-way control valve A is provided on the thirteenth pipeline 25, and one of the outlets of the first three-way control valve A is connected to the air inlet of the second-stage BOG compressor 30 through a pipeline.

[0047] The fifteenth pipeline 27 is equipped with a second three-way control valve B, one of the outlets of which is connected to the air intake of the dual-fuel engine 1 via a pipeline.

[0048] In this embodiment, the heat exchanger is a gas / gas heat exchanger, and the absorbent used in the absorption tower is an organic amine solution.

[0049] Preferably, the CO2 capture unit further includes a reheater 28 for reheating the undesorbed rich liquid in the desorption tower 9 (it exchanges heat with the high-temperature lean liquid in the heat exchanger 10, and the high-temperature rich liquid that absorbs heat from the high-temperature lean liquid enters the desorption tower 9 to desorb CO2, but there is still some high-temperature rich liquid that is not desorbed, so this part of the high-temperature rich liquid needs to enter the reheater 28 for reheating). The reheated rich liquid is returned to the desorption tower to fully release CO2, so as to improve the desorption rate of the rich liquid. It can also heat the exhaust gas of the dual-fuel engine 1, and the heated exhaust gas is then sent to the exhaust gas inlet at the bottom of the absorption tower 8.

[0050] The gas supply and carbon capture system of this invention fully utilizes the cold energy of BOG from the LNG tank to cool the BOG compressed by the BOG compressor, thus eliminating the need for an additional intercooler, aftercooler, or freshwater cooling system; it also fully utilizes the heat energy of the compressed BOG and compressed CO2 to heat the BOG from the LNG tank, ensuring that the temperature entering the BOG compressor reaches the inlet temperature requirement of a normal temperature compressor, thus allowing the BOG compressor to be a normal temperature compressor; it fully utilizes the heat energy of the dual-fuel engine exhaust gas to heat the rich liquid, thus eliminating the need for an additional heating medium and heat source; and it fully utilizes the cold energy of the BOG from the LNG tank to liquefy CO2, thus eliminating the need for an additional cooling medium and cold source.

[0051] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A gas supply and carbon capture system, characterized in that, Includes an LNG compartment, BOG compressor unit, dual-fuel engine, CO2 capture unit, CO2 compressor, heat exchanger, and CO2 storage compartment. The CO2 capture unit is used to desorb CO2 from the exhaust gas of the dual-fuel engine using a chemical absorption method and deliver it to the CO2 compressor. The CO2 compressor is used to pressurize the desorbed CO2 and send the pressurized CO2 into the first hot side of the heat exchanger; The LNG compartment is used to store liquid LNG and the BOG gas formed at the top of the compartment is sent to the cold side of the heat exchanger. The heat exchanger is used to exchange heat between the pressurized CO2 and BOG gas, using the cold energy of the BOG gas to liquefy CO2, and storing the resulting liquid CO2 in the CO2 storage chamber, while the BOG gas with a higher temperature is sent to the BOG compressor unit. The BOG compressor unit is used to pressurize BOG gas at a higher temperature and then deliver it to the dual-fuel engine for combustion. The BOG compressor unit is a normal temperature compressor.

2. The gas supply and carbon capture system according to claim 1, characterized in that, The CO2 capture unit includes an absorption tower, a desorption tower, a heat exchanger, a rich solution pump, and a lean solution pump. The exhaust port of the dual-fuel engine is connected to the exhaust gas inlet at the bottom of the absorption tower via a pipeline. The exhaust gas of the dual-fuel engine reacts with the absorbent sprayed from the top of the tower and is absorbed in the absorption tower. The remaining gas after decarbonization is discharged from the top of the absorption tower, and the low-temperature rich liquid formed by the reaction is pumped from the bottom of the tower by the rich liquid pump and sent to the cold side inlet of the heat exchanger. The rich liquid flowing out from the cold side outlet of the heat exchanger enters the desorption tower through the rich liquid inlet at the top of the desorption tower. Inside the desorption tower, it is heated to the set temperature and desorbs CO2, while the rich liquid is regenerated into a high-temperature lean liquid. The high-temperature lean liquid is pumped from the bottom of the tower by the lean liquid pump and sent to the hot side inlet of the heat exchanger. Inside the heat exchanger, it exchanges heat with the low-temperature rich liquid. The desorbed CO2 is discharged from the top of the tower and, after drying and dehydration, is sent to the CO2 compressor.

3. The gas supply and carbon capture system according to claim 2, characterized in that, The CO2 capture unit also includes a reheater for reheating the undesorbed rich liquid in the desorption tower.

4. The gas supply and carbon capture system according to claim 2, characterized in that, The absorbent used in the absorption tower is an organic amine solution.

5. The gas supply and carbon capture system according to claim 1, characterized in that, The BOG compressor unit includes a primary BOG compressor and a secondary BOG compressor. The inlet of the primary BOG compressor is connected to the cold-side outlet of the heat exchanger, the outlet of the primary BOG compressor is connected to the second hot-side inlet of the heat exchanger, the second hot-side outlet of the heat exchanger is connected to the inlet of the secondary BOG compressor, the outlet of the secondary BOG compressor is connected to the third hot-side inlet of the heat exchanger, and the third hot-side outlet of the heat exchanger is connected to the inlet of the dual-fuel engine.

6. The gas supply and carbon capture system according to claim 5, characterized in that, A first three-way control valve is installed on the pipeline connecting the outlet of the first-stage BOG compressor to the inlet of the second heat side of the heat exchanger. One of the outlets of the first three-way control valve is connected to the inlet of the second-stage BOG compressor through a pipeline. A second three-way control valve is installed on the pipeline connecting the outlet of the two-stage BOG compressor to the inlet of the third heat side of the heat exchanger. One of the outlets of the second three-way control valve is connected to the intake port of the dual-fuel engine through a pipeline.

7. The gas supply and carbon capture system according to claim 1, characterized in that, A vent pipe is also connected to the pipeline connecting the first hot-side outlet of the heat exchanger to the inlet of the CO2 storage chamber.

8. The gas supply and carbon capture system according to claim 1, characterized in that, The heat exchanger is a gas / gas heat exchanger.

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