Decarburization system additionally arranged on CO2 capture system of electric propulsion LNG ship and LNG ship

Abstract

The invention provides a decarburization system added to a CO2 capture system of an electric propulsion LNG ship. A steam supply unit comprises at least two boilers arranged side by side, and a pressure reduction regulation and control unit is connected to the output end of the steam supply unit through a main steam pipeline; the desorption regeneration unit is connected to the output end of the pressure reduction regulation and control unit through a desorption steam inlet pipeline and comprises a plurality of steam distribution branch pipes distributed in a solid adsorption bed of the carbon capture system, and a steam outlet of each branch pipe is adjacent to or embedded into a solid adsorbate; the cooling and condensing unit is connected to a gas outlet of the desorption and regeneration unit through a mixed gas pipeline and comprises at least two coolers which are arranged in parallel; the gas-liquid separation and condensate recovery unit is connected to the downstream of the cooling condensation unit and comprises an automatic release valve and a hot well. According to the technical scheme, an existing low-pressure steam system of a ship can be integrated, efficient and stable heating regeneration of the solid adsorbent is achieved through the optimized process and layout design, and efficient separation and recovery of CO2 and steam are completed.

Description

Technical Field

[0001] This invention belongs to the field of green and intelligent ship design and construction technology, and specifically relates to a decarbonization system installed on the CO2 capture system of an electrically propelled LNG ship and the LNG ship itself. Background Technology

[0002] As the International Maritime Organization (IMO) continues to advance its strategy for reducing greenhouse gas emissions from ships, particularly aiming to achieve net-zero emissions from the shipping industry, carbon emission controls on ships are becoming increasingly stringent. Currently, electrically propelled LNG carriers rely on main generators to burn methane or heavy oil fuel. The process generates electricity, which is then used to power the ship's propulsion motors, and finally, the propulsion system. Throughout this process, the main generator consumes a significant amount of fuel. Based on carbon emission calculations, this is no longer sufficient to meet emission requirements. Existing electric-propelled LNG ships urgently need to be equipped with carbon capture systems to meet these requirements. However, carbon capture systems that absorb CO2 using solid materials require heat to decompose the CO2. How to achieve this is a pressing issue that needs to be addressed. Summary of the Invention

[0003] This invention provides a decarbonization system and LNG ship that can be installed in the CO2 capture system of an electrically propelled LNG ship. It can integrate the ship's existing low-pressure steam system and achieve efficient and stable heating and regeneration of solid adsorbents through optimized process and layout design, and complete the efficient separation and recovery of CO2 and steam.

[0004] In one embodiment of the present invention, a decarbonization system is provided for the CO2 capture system of an electrically propelled LNG ship, comprising: a steam supply unit, a pressure reduction and control unit, a desorption and regeneration unit, and a cooling and condensation unit; The steam supply unit includes at least two boilers arranged side by side for generating low-pressure saturated steam; The pressure reduction control unit is connected to the output end of the steam supply unit through the main steam pipeline, and is used to reduce the pressure of steam from the boiler to a predetermined pressure suitable for CO2 desorption. The analytical regeneration unit is connected to the output end of the pressure reducing and regulating unit through an analytical steam inlet pipeline. It includes multiple steam distribution branches distributed in the solid adsorption bed of the carbon capture system. The steam outlet of each branch is located adjacent to or embedded in the solid adsorbent, and is used to provide heating steam to the solid adsorbent that adsorbs CO2, so that the CO2 in it is desorbed and forms a mixture of steam and CO2. The cooling and condensing unit is connected to the gas outlet of the analytical regeneration unit via a mixed gas pipeline, and includes at least two coolers arranged in parallel to cool the mixed gas and condense the water vapor therein. The gas-liquid separation and condensate recovery unit is connected downstream of the cooling and condensation unit and includes an automatic relief valve and a hot well. The automatic relief valve is used to receive and temporarily store the condensate generated after cooling and automatically discharge it to the hot well according to the liquid level, while the separated pure CO2 gas is discharged from the exhaust port.

[0005] Furthermore, at least two boilers in the steam supply unit are fixedly installed on bases on the left and right sides of the second deck of the ship's engine room, and the pressure reduction and control unit is located on the second deck of the ship's engine room and is connected to the steam outlet of each boiler through the main steam pipeline.

[0006] Furthermore, the pressure reduction control unit includes a pressure reduction valve assembly for reducing the pressure of steam generated by the boiler at 0.6 bar-0.8 bar to saturated steam at 0.25 bar-0.35 bar.

[0007] Furthermore, the multiple steam distribution branches in the analytical regeneration unit include at least four parallel branches, labeled as the first branch, the second branch, the third branch, and the fourth branch, which are inserted into or arranged around the solid adsorption bed at predetermined intervals and in a predetermined manner to ensure heating uniformity.

[0008] Furthermore, at least two coolers in the cooling and condensing unit are shell-and-tube or plate coolers, and their cooling freshwater inlet pipes and cooling freshwater outlet pipes are respectively connected in parallel to a branch loop of the ship's central cooling water system.

[0009] Furthermore, the first of the at least two coolers is fixedly installed on the third deck of the engine room and located directly above or diagonally above the hot well, and its bottom condensate outlet is directly connected to the hot well via a gravity flow pipe.

[0010] Furthermore, the automatic discharge valve in the gas-liquid separation and condensate recovery unit is a float type or an electronic liquid level control type, which is equipped with a high liquid level trigger switch. When the condensate liquid level reaches the set value, the discharge valve is automatically opened to discharge the condensate into the hot well, and then automatically closed.

[0011] Furthermore, a second shut-off valve is provided on the mixed gas output pipeline of the analytical regeneration unit or on the gas inlet pipeline of the cooling and condensing unit to control the delivery of the mixed gas to the cooling and condensing unit.

[0012] Furthermore, a first shut-off valve is provided on the steam inlet pipeline between the pressure reducing control unit and the desorption regeneration unit. This first shut-off valve is located near the pressure reducing control unit and is used to manually or automatically cut off the steam supply to the desorption regeneration unit.

[0013] Furthermore, the solid adsorbent in the analysis and regeneration unit is at least one of synthetic zeolite, activated alumina, or metal-organic framework materials.

[0014] Furthermore, the decarbonization system also includes a control subsystem, which is connected to the liquid level signals of the first shut-off valve, the second shut-off valve, and the automatic relief valve. The control subsystem is used to automatically start and stop the steam supply, mixed gas cooling, and condensate discharge processes according to the ship's operating conditions, the adsorption saturation of the carbon capture system, or manual commands.

[0015] In another embodiment of the present invention, an LNG carrier is provided, the LNG carrier including a decarbonization system as described in any of the above claims, which is installed in the CO2 capture system of an electrically propelled LNG carrier.

[0016] The beneficial effects of this invention are as follows: As can be seen from the above scheme, the embodiments of the present invention provide a decarbonization system installed in the CO2 capture system of an electrically propelled LNG ship. The steam supply unit includes at least two boilers arranged side by side for generating low-pressure saturated steam. The pressure reduction and control unit is connected to the output end of the steam supply unit through the main steam pipeline for reducing the pressure of the steam from the boiler to a predetermined pressure suitable for CO2 desorption. The desorption and regeneration unit is connected to the output end of the pressure reduction and control unit through the desorption steam inlet pipeline and includes multiple steam distribution branches distributed in the solid adsorption bed of the carbon capture system. The steam outlet of each branch is located adjacent to or embedded in the solid adsorbent for providing heating steam to the solid adsorbent that has adsorbed CO2. The cooling and condensation unit is connected to the gas outlet of the desorption and regeneration unit through the mixed gas pipeline and includes at least two coolers arranged in parallel. The gas-liquid separation and condensate recovery unit is connected downstream of the cooling and condensation unit and includes an automatic relief valve and a hot well. The automatic relief valve is used to receive and temporarily store the condensate generated after cooling and automatically discharge it to the hot well according to the liquid level, while the separated pure CO2 gas is discharged from the exhaust port. The technical solution of this invention can integrate the existing low-pressure steam system of ships, and through optimized process and layout design, achieve efficient and stable heating and regeneration of solid adsorbents, and complete the efficient separation and recovery of CO2 and steam. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a decarbonization system installed in the CO2 capture system of an electrically propelled LNG ship according to the present invention; Figure 2 This is a schematic diagram of the three decks of a decarbonization system installed in the CO2 capture system of an electrically propelled LNG ship according to the present invention; In the diagram, 1 is the first boiler, 2 is the second boiler, 3 is the pressure reducing valve group, 4 is the first shut-off valve, 401 is the first branch pipe, 402 is the second branch pipe, 403 is the third branch pipe, 404 is the fourth branch pipe, 5 is the second shut-off valve, 6 is the solid adsorbent, 7 is the first cooler, 8 is the second cooler, 9 is the automatic relief valve, and 10 is the hot well. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. 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.

[0019] like Figure 1 and Figure 2 As shown, Figure 1 This is a schematic diagram of a decarbonization system installed in the CO2 capture system of an electrically propelled LNG ship according to the present invention; Figure 2 This is a schematic diagram of a three-deck decarbonization system installed in the CO2 capture system of an electrically propelled LNG ship according to the present invention.

[0020] Figure 1 A decarbonization system installed in the CO2 capture system of an electrically propelled LNG ship includes: a steam supply unit, a pressure reduction and control unit, a desorption and regeneration unit, and a cooling and condensation unit; The steam supply unit includes at least two boilers arranged side by side for generating low-pressure saturated steam; The pressure reduction control unit is connected to the output end of the steam supply unit through the main steam pipeline, and is used to reduce the pressure of steam from the boiler to a predetermined pressure suitable for CO2 desorption. The analytical regeneration unit is connected to the output end of the pressure reducing and regulating unit through an analytical steam inlet pipeline. It includes multiple steam distribution branches distributed in the solid adsorption bed of the carbon capture system. The steam outlet of each branch is located adjacent to or embedded in the solid adsorbent, and is used to provide heating steam to the solid adsorbent that adsorbs CO2, so that the CO2 in it is desorbed and forms a mixture of steam and CO2. The cooling and condensing unit is connected to the gas outlet of the analytical regeneration unit via a mixed gas pipeline, and includes at least two coolers arranged in parallel to cool the mixed gas and condense the water vapor therein. The gas-liquid separation and condensate recovery unit is connected downstream of the cooling and condensation unit and includes an automatic relief valve and a hot well. The automatic relief valve is used to receive and temporarily store the condensate generated after cooling and automatically discharge it to the hot well according to the liquid level, while the separated pure CO2 gas is discharged from the exhaust port.

[0021] In this embodiment of the invention, a decarbonization system installed on the CO2 capture system of an electrically propelled LNG ship eliminates the need for an external heat source. It creatively combines the ship's auxiliary boiler system with carbon capture and analysis requirements, enabling cascaded energy utilization: boiler steam production → pressure reduction to a suitable grade → direct contact heating. In this embodiment, the system exhibits a high degree of modularity, with clearly defined functions and interfaces for each unit, greatly facilitating installation on existing ships and solving the core challenge of complex heat source integration and retrofitting.

[0022] In another embodiment of the present invention, at least two boilers in the steam supply unit are respectively fixedly installed on bases on the left and right sides of the second deck of the ship's engine room, and the pressure reduction and control unit is located on the second deck of the ship's engine room and is connected to the steam outlet of each boiler through the main steam pipeline.

[0023] In this embodiment of the invention, the relatively spacious and structurally robust second deck of the ship's engine room is fully utilized, enabling a balanced arrangement of equipment and contributing to ship stability. Simultaneously, this location facilitates pipeline design, shortens steam transport distances, reduces heat loss, and demonstrates optimized utilization of the ship's unique spatial structure.

[0024] In another embodiment of the present invention, the pressure reduction control unit includes a pressure reduction valve group for reducing the pressure of steam generated by the boiler at a pressure of 0.6 bar to 0.8 bar to saturated steam at a pressure of 0.25 bar to 0.35 bar.

[0025] Preferably, the boiler generates steam at a pressure of 0.7 bar. When the pressure is reduced to 0.3 bar, the corresponding saturation temperature is approximately 144°C. This temperature range is highly effective for CO2 desorption processes using common solid adsorbents such as zeolites, ensuring sufficient desorption efficiency while avoiding potential damage to the adsorbent structure or energy waste due to excessively high temperatures. This pressure parameter is the optimal result after matching the adsorbent characteristics with the operating conditions of the ship's boiler, ensuring the economic efficiency and reliability of the system operation.

[0026] In another embodiment of the present invention, the plurality of steam distribution branches in the analytical regeneration unit include at least four branches connected in parallel, respectively labeled as the first branch, the second branch, the third branch and the fourth branch, which are inserted into or arranged around the solid adsorption bed at a predetermined spacing and arrangement to ensure heating uniformity.

[0027] The parallel distribution of multiple branches ensures that the heating steam can uniformly and fully contact the entire cross-section of the solid adsorption bed, avoiding local overheating or heating dead zones. This improves the overall regeneration efficiency of the adsorbent and the rate of CO2 desorption, ensuring the stability and consistency of the carbon capture system's cyclic operation.

[0028] In another embodiment of the present invention, at least two coolers in the cooling and condensing unit are shell-and-tube or plate coolers, and their cooling freshwater inlet pipes and cooling freshwater outlet pipes are respectively connected in parallel to a branch loop of the ship's central cooling water system.

[0029] The parallel design enhances the reliability and flexibility of the cooling system, allowing one cooler to continue operating while another fails or requires maintenance. Connecting to the ship's central cooling water system fully utilizes the ship's existing, well-capacity cooling infrastructure, eliminating the need for additional large cooling water pumps and piping, simplifying the system, and reducing retrofit costs and operating energy consumption.

[0030] In another embodiment of the present invention, the first of the at least two coolers is fixedly installed on the third deck of the engine room and located directly above or diagonally above the hot well, and its bottom condensate outlet is directly connected to the hot well through a gravity flow pipeline.

[0031] The vertical layout of the cooler within the heat well enables gravity-fed condensate recovery. Eliminating the need for a condensate pump not only saves on equipment costs and installation space but also improves the reliability of the condensate recovery system (no risk of rotating part failure) and reduces maintenance requirements.

[0032] In another embodiment of the present invention, the automatic discharge valve in the gas-liquid separation and condensate recovery unit is a float type or an electronic liquid level control type, which is equipped with a high liquid level trigger switch. When the condensate liquid level reaches the set value, the discharge valve is automatically opened to discharge the condensate into the hot well, and then automatically closed.

[0033] The automatic discharge valve control system enables fully automated condensate discharge, eliminating the need for frequent crew intervention. Both float-type and electronic level control are mature and reliable, ensuring timely and quantitative discharge of condensate into the heat well for recycling. This prevents condensate accumulation in the system from affecting CO2 gas separation purity or causing water hammer in pipelines, thus improving the system's automation level and stability.

[0034] In another embodiment of the present invention, a second shut-off valve is provided on the mixed gas output pipeline of the analytical regeneration unit or on the gas inlet pipeline of the cooling and condensing unit for controlling the delivery of the mixed gas to the cooling and condensing unit.

[0035] The second shut-off valve provides an additional process control point, which can be used when the cooling separation unit needs to be isolated (such as for maintenance), enhancing the convenience of system segmented control and maintenance, and improving the overall system operation flexibility.

[0036] In another embodiment of the present invention, a first shut-off valve is provided on the steam inlet pipeline between the pressure reducing control unit and the desorption regeneration unit. The first shut-off valve is located near the pressure reducing control unit and is used to manually or automatically cut off the steam supply to the desorption regeneration unit.

[0037] In another embodiment of the present invention, the solid adsorbent in the desorption and regeneration unit is at least one of synthetic zeolite, activated alumina, or metal-organic framework materials.

[0038] The solid adsorbent clarifies the core working medium applicable to this system, particularly zeolite materials, which exhibit good thermal compatibility and chemical stability with saturated steam at approximately 144°C, resulting in high desorption efficiency. This limitation clarifies the scope of protection of this invention and closely aligns with the preferred embodiments.

[0039] In another embodiment of the present invention, the decarbonization system further includes a control subsystem, which is connected to the liquid level signals of the first shut-off valve, the second shut-off valve and the automatic relief valve, and is used to automatically start and stop the steam supply, mixed gas cooling and condensate discharge processes according to the ship's operating conditions, the adsorption saturation of the carbon capture system or manual commands.

[0040] The control subsystem elevates the system from manual / semi-automatic operation to intelligent control. Based on signals from the adsorption saturation sensor or preset programs, the control subsystem can automatically start and stop the entire desorption and regeneration process, achieving intelligent linkage with the carbon capture system's adsorption cycle. This significantly reduces the operational burden on the crew, ensures the decarbonization process operates under optimal conditions, represents the development direction of intelligent emission reduction in ships, and significantly enhances the invention's creativity and practicality.

[0041] In another embodiment of the present invention, an LNG carrier is provided, the LNG carrier including a decarbonization system as described in any of the above claims, which is installed in the CO2 capture system of an electrically propelled LNG carrier.

[0042] In one embodiment of the present invention, a decarbonization system installed in the CO2 capture system of an electrically propelled LNG ship is implemented as follows: First, the steam supply unit utilizes the two existing auxiliary boilers (Boiler 1 and Boiler 2) on the second deck of the ship's engine room, which are typically used to supply steam for the ship's domestic and working needs. This system combines the outlet steam from the two boilers through a newly added main steam pipeline.

[0043] Next, the steam enters the pressure reducing valve assembly 3 of the pressure reducing control unit. According to the CO2 desorption process requirements, pressure reducing valve assembly 3 stably reduces the steam from the boiler at approximately 0.7 bar (gauge pressure) to approximately 0.3 bar saturated steam. On the desorption steam inlet pipeline after pressure reducing valve assembly 3, near pressure reducing valve assembly 3, a first shut-off valve 4 is installed for system start-up and shutdown control.

[0044] Saturated steam (approximately 144°C) after depressurization at 0.3 bar is transported via pipeline to the desorption and regeneration unit located in the desorption zone of the carbon capture system. This unit contains four parallel steam distribution branches (branch 401 to branch 404), evenly distributed within an adsorption bed filled with zeolite (solid adsorbent 6). Steam flows out from openings or nozzles at the ends of each branch, directly contacting the adsorbed saturated zeolite and providing the heat required for desorption. Upon heating, CO2 desorbs from the zeolite and mixes with the steam to form a mixed gas.

[0045] The mixed gas collects at the top of the separation zone and is led out through a mixed gas pipeline. A second shut-off valve 5 can be installed on the pipeline for control before it enters the cooling system. The mixed gas is then led to the cooling and condensing unit located on the third deck of the engine room. This unit consists of a first cooler 7 and a second cooler 8 connected in parallel, their cooling water inlets and outlets connected in parallel to the ship's central cooling freshwater system. The mixed gas is cooled within the coolers, where the water vapor condenses into liquid water.

[0046] The condensed gas-liquid mixture enters the gas-liquid separation and condensate recovery unit. The liquid water (condensate) first enters the automatic relief valve 9 for temporary storage. The automatic relief valve 9 has a built-in level sensor; when the condensate level reaches a set high value, the valve automatically opens, and the condensate flows by gravity through a short pipe into the lower hot well 10 for recovery. The hot well 10 is an existing device on the ship for collecting clean condensate, which can be pumped to the boiler feedwater system for recycling. Simultaneously, the pure CO2 gas separated from the condensate is discharged from the gas outlet at the top of the automatic relief valve 9, and can be connected to the subsequent CO2 compression, liquefaction, and storage modules.

[0047] In a preferred automated embodiment, all valves (first shut-off valve 4, second shut-off valve 5) can be solenoid valves or pneumatic valves and are connected to a central controller (not shown in the figure). The controller receives an "adsorption saturation" signal from the carbon capture system or a time-programmed instruction and automatically opens the first shut-off valve 4 and the second shut-off valve 5 to initiate the analysis process. Simultaneously, it monitors the liquid level of the automatic relief valve 9 and the status of the cooling water system, achieving fully automated control of the entire process.

[0048] In this embodiment of the invention, the existing boilers, cooling water and condensate recovery systems of the ship are fully utilized. By adding a relatively simple set of depressurization, distribution, cooling and separation pipelines and equipment, the carbon capture system is successfully and efficiently enhanced. The amount of retrofitting work is small, the impact on the original ship operation is minimal, and it has extremely high engineering practical value and promotion prospects.

[0049] This invention provides a decarbonization system for an LNG carrier's CO2 capture system. The steam supply unit includes at least two boilers arranged side-by-side to generate low-pressure saturated steam. A pressure-reducing control unit is connected to the output of the steam supply unit via a main steam pipeline to reduce the pressure of the steam from the boilers to a predetermined pressure suitable for CO2 desorption. The desorption and regeneration unit is connected to the output of the pressure-reducing control unit via a desorption steam inlet pipeline and includes multiple steam distribution branches distributed within the solid adsorption bed of the carbon capture system. The steam outlet of each branch is adjacent to or embedded in the solid adsorbent, providing heating steam to the CO2-adsorbed solid adsorbent. The cooling and condensation unit is connected to the gas outlet of the desorption and regeneration unit via a mixed gas pipeline and includes at least two coolers arranged in parallel. A gas-liquid separation and condensate recovery unit is connected downstream of the cooling and condensation unit and includes an automatic discharge valve and a hot well. The automatic discharge valve receives and temporarily stores the condensate generated after cooling and automatically discharges it to the hot well according to the liquid level, while the separated pure CO2 gas is discharged from the exhaust port.

[0050] The technical solution of this invention can integrate the existing low-pressure steam system of ships, and through optimized process and layout design, achieve efficient and stable heating and regeneration of solid adsorbents, and complete the efficient separation and recovery of CO2 and steam.

[0051] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A decarbonization system installed in the CO2 capture system of an electrically propelled LNG ship, characterized in that, The decarbonization system includes: a steam supply unit, a pressure reduction and control unit, a desorption and regeneration unit, and a cooling and condensation unit; The steam supply unit includes at least two boilers arranged side by side for generating low-pressure saturated steam; The pressure reduction control unit is connected to the output end of the steam supply unit through the main steam pipeline, and is used to reduce the pressure of steam from the boiler to a predetermined pressure suitable for CO2 desorption. The analytical regeneration unit is connected to the output end of the pressure reducing and regulating unit through an analytical steam inlet pipeline. It includes multiple steam distribution branches distributed in the solid adsorption bed of the carbon capture system. The steam outlet of each branch is located adjacent to or embedded in the solid adsorbent, and is used to provide heating steam to the solid adsorbent that adsorbs CO2, so that the CO2 in it is desorbed and forms a mixture of steam and CO2. The cooling and condensing unit is connected to the gas outlet of the analytical regeneration unit via a mixed gas pipeline, and includes at least two coolers arranged in parallel to cool the mixed gas and condense the water vapor therein. The gas-liquid separation and condensate recovery unit is connected downstream of the cooling and condensation unit and includes an automatic relief valve and a hot well. The automatic relief valve is used to receive and temporarily store the condensate generated after cooling and automatically discharge it to the hot well according to the liquid level, while the separated pure CO2 gas is discharged from the exhaust port.

2. The decarbonization system for an electric propulsion LNG ship CO2 capture system according to claim 1, characterized in that, At least two boilers in the steam supply unit are fixedly installed on bases on the left and right sides of the second deck of the ship's engine room. The pressure reduction and control unit is located on the second deck of the ship's engine room and is connected to the steam outlet of each boiler through the main steam pipeline.

3. A decarbonization system for an electric propulsion LNG ship CO2 capture system according to claim 1, characterized in that, The pressure reduction control unit includes a pressure reduction valve assembly for reducing the pressure of steam generated by the boiler from 0.6 bar to 0.8 bar to saturated steam from 0.25 bar to 0.35 bar.

4. A decarbonization system for an electric propulsion LNG ship CO2 capture system according to claim 1, characterized in that, The multiple steam distribution branches in the analytical regeneration unit include at least four parallel branches, labeled as the first branch, the second branch, the third branch, and the fourth branch, which are inserted into or arranged around the solid adsorption bed at predetermined intervals and in a predetermined manner to ensure heating uniformity.

5. A decarbonization system for an electric propulsion LNG ship CO2 capture system according to claim 1, characterized in that, At least two of the coolers in the cooling and condensing unit are shell-and-tube or plate coolers, and their cooling freshwater inlet pipes and cooling freshwater outlet pipes are respectively connected in parallel to a branch loop of the ship's central cooling water system.

6. A decarbonization system for an electric propulsion LNG ship CO2 capture system according to claim 1, characterized in that, The first of the at least two coolers is fixedly installed on the third deck of the engine room and located directly above or diagonally above the hot well. Its bottom condensate outlet is directly connected to the hot well via a gravity-fed pipeline.

7. A decarbonization system for an electric propulsion LNG ship CO2 capture system according to claim 1, characterized in that, The automatic discharge valve in the gas-liquid separation and condensate recovery unit is a float type or an electronic liquid level control type. It is equipped with a high liquid level trigger switch. When the condensate liquid level reaches the set value, the discharge valve will automatically open to discharge the condensate into the hot well, and then automatically close.

8. A decarbonization system for an electric propulsion LNG ship CO2 capture system according to claim 1, characterized in that, A second shut-off valve is also provided on the mixed gas output pipeline of the analytical regeneration unit or on the gas inlet pipeline of the cooling and condensing unit to control the delivery of the mixed gas to the cooling and condensing unit.

9. A decarbonization system for an electric propulsion LNG ship CO2 capture system according to claim 1, characterized in that, A first shut-off valve is provided on the steam inlet pipeline between the pressure reducing control unit and the desorption regeneration unit. The first shut-off valve is located near the pressure reducing control unit and is used to manually or automatically cut off the steam supply to the desorption regeneration unit.

10. A decarbonization system for an electric propulsion LNG ship CO2 capture system according to claim 1, characterized in that, The solid adsorbent in the desorption and regeneration unit is at least one of synthetic zeolite, activated alumina, or metal-organic framework materials.

11. A decarbonization system for an electric propulsion LNG ship CO2 capture system according to claim 1, characterized in that, The decarbonization system also includes a control subsystem, which is connected to the liquid level signals of the first shut-off valve, the second shut-off valve, and the automatic relief valve. The control subsystem is used to automatically start and stop the steam supply, mixed gas cooling, and condensate discharge processes according to the ship's operating conditions, the adsorption saturation of the carbon capture system, or manual commands.

12. An LNG carrier, characterized in that, The LNG carrier includes a decarbonization system as described in any one of claims 1 to 11, which is installed in the CO2 capture system of an electrically propelled LNG carrier.

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