Method for recycling cold energy of isolation void cabin of LNG (Liquefied Natural Gas) ship
By designing ethylene glycol circulation pipelines and redundant paths, the problem of unutilized cold energy in the isolated empty compartments of LNG ships was solved, realizing the reuse of cold energy and energy saving and consumption reduction of the system, which is suitable for carbon capture systems of LNG ships.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUDONG ZHONGHUA SHIPBUILDINGGROUP
- Filing Date
- 2026-01-30
- Publication Date
- 2026-05-08
AI Technical Summary
The cold energy in the isolation compartments of LNG ships is not effectively utilized, resulting in energy waste. At the same time, the carbon capture system requires a large amount of fresh water and electricity to cool carbon dioxide, which increases the ship's energy consumption and operating costs.
The design incorporates a glycol circulation pipeline, utilizing the operation of first and second heat exchangers and shut-off valves to achieve cold energy reuse. Marine steam is used for heating in redundant paths to ensure normal system operation.
It enables the reuse of cold energy, reduces the energy consumption of LNG ships, and reduces the consumption of fresh water and electricity, making it economical and environmentally friendly.
Smart Images
Figure CN121990104A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of shipbuilding technology, and in particular to a method for reusing cold energy in the isolated empty compartments of LNG ships. Background Technology
[0002] LNG (liquefied natural gas) ships use an ethylene glycol system to heat the isolation compartments between cargo holds to maintain their temperature. Specifically, an ethylene glycol solution flows from the isolation compartment into a heater, which heats the solution with steam. The heated ethylene glycol solution is then cooled within the isolation compartment. In this cycle, a significant amount of cooling energy gained by the ethylene glycol solution from the isolation compartment is not effectively utilized and is directly dissipated through the heating process, resulting in significant energy waste and failing to meet the development requirements for ship energy conservation. On the other hand, carbon capture technology is increasingly being applied to LNG ships. Before the carbon dioxide in the carbon capture system enters the compressor, it needs to be cooled. Currently, ships typically use a freshwater system for cooling carbon dioxide. This method not only consumes a large amount of cooling freshwater but also requires a significant amount of electrical energy to drive the cooling pumps, further increasing the ship's energy consumption and operating costs. Summary of the Invention
[0003] To address the shortcomings of existing technologies, this invention provides a method for reusing cold energy in the isolated empty compartments of LNG ships.
[0004] The present invention achieves the above-mentioned technical objectives through the following technical means.
[0005] A method for reusing cold energy in the isolation compartments of an LNG carrier is based on the following structure: the structure includes a first isolation compartment, a second isolation compartment, a machinery room, and a carbon capture compartment; ethylene glycol coils are installed in the upper regions of both the first and second isolation compartments; the machinery room is equipped with a first shut-off valve, a second shut-off valve, a third shut-off valve, a fourth shut-off valve, an ethylene glycol pump, and a second heat exchanger; the carbon capture compartment is equipped with a desorption tower and a first heat exchanger; the method involves using an ethylene glycol circulation pipeline to circulate the ethylene glycol solution between the components, thereby achieving cold energy reuse.
[0006] Furthermore, the first isolation compartment is located between the engine room and the LNG cargo tank, and the second isolation compartment is located between the two LNG cargo tanks.
[0007] Furthermore, the ethylene glycol coils in the upper region of the first isolation chamber and the ethylene glycol coils in the upper region of the second isolation chamber are connected in parallel.
[0008] Furthermore, the machinery room is located on the starboard side of the LNG carrier.
[0009] Furthermore, the structure also includes a superstructure and a cabin canopy, and the locations for installing the ethylene glycol circulation pipeline are, in sequence, a first isolation chamber, a machinery room, the starboard side of the superstructure, the starboard side of the cabin canopy, a carbon capture chamber, the starboard side of the cabin canopy, the starboard side of the superstructure, the machinery room, and the first isolation chamber.
[0010] Furthermore, electric heating tapes and insulation layers are tied to the pipes on the starboard side of the superstructure and the starboard side of the engine room hangar.
[0011] Furthermore, based on the installation of the ethylene glycol circulation pipeline, the ethylene glycol solution circulation path is as follows: the low-temperature ethylene glycol solution flows out from port B of the ethylene glycol coil, and enters the first heat exchanger from port C by closing the first shut-off valve and opening the third shut-off valve; the high-temperature CO2 in the stripping tower enters the first heat exchanger from port E; the low-temperature ethylene glycol solution and the high-temperature CO2 exchange heat in the first heat exchanger; then the low-temperature CO2 after heat exchange is discharged from port F of the first heat exchanger, and the high-temperature ethylene glycol solution after heat exchange flows out from port D of the first heat exchanger. By closing the second shut-off valve and opening the fourth shut-off valve, the high-temperature ethylene glycol solution flows into port A of the ethylene glycol coil via the ethylene glycol pump.
[0012] Furthermore, when the ethylene glycol solution circulation path fails, a redundant ethylene glycol circulation path is established by closing the third and fourth stop valves and opening the first and second stop valves.
[0013] Furthermore, the redundant ethylene glycol circulation path is as follows: the low-temperature ethylene glycol solution flows out from port B of the ethylene glycol coil, flows into the second heat exchanger through the first shut-off valve, and after heat exchange with marine steam in the second heat exchanger, the high-temperature ethylene glycol solution flows out from the second heat exchanger, flows into port A of the ethylene glycol coil through the second shut-off valve and the ethylene glycol pump.
[0014] The beneficial effects of this invention are: This invention addresses the characteristics of carbon capture tanks and ethylene glycol-heated isolation compartment systems in LNG carriers. It fully utilizes the energy between systems and designs an ethylene glycol circulation pipeline, which not only meets the normal operation requirements of LNG carriers and reduces ship energy consumption, but also achieves the goal of reusing cold energy within the isolation compartment. This method is both energy-saving and economical and environmentally friendly.
[0015] This invention designs a redundant ethylene glycol circulation path by operating a shut-off valve, ensuring the normal operation of the system. Attached Figure Description
[0016] Figure 1 This is a front view of the LNG ship isolated empty compartment cold energy reuse structure described in this invention.
[0017] Figure 2This is a top view of the LNG ship isolated empty compartment cold energy reuse structure described in this invention.
[0018] Figure 3 This is a schematic diagram of the isolated cabin structure described in this invention.
[0019] Figure 4 This is a schematic diagram of the mechanical chamber structure described in this invention.
[0020] Figure 5 This is a schematic diagram of the carbon capture chamber structure described in this invention.
[0021] In the diagram: 1. First isolation chamber, 2. Second isolation chamber, 3. Machinery room, 4. Carbon capture chamber, 5. Desorption tower, 6. First heat exchanger, 7. Ethylene glycol coil, 8. First shut-off valve, 9. Second shut-off valve, 10. Third shut-off valve, 11. Fourth shut-off valve, 12. Ethylene glycol pump, 13. Second heat exchanger, 14. Superstructure, 15. Cabin. Detailed Implementation
[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.
[0023] A method for reusing cold energy in the isolated empty compartments of LNG carriers, such as Figures 1-5 As shown, it includes: a first isolation chamber 1, a second isolation chamber 2, a machine room 3, a carbon capture chamber 4, a desorption tower 5, a first heat exchanger 6, an ethylene glycol coil 7, a first shut-off valve 8, a second shut-off valve 9, a third shut-off valve 10, a fourth shut-off valve 11, an ethylene glycol pump 12, a second heat exchanger 13, a superstructure 14, and a nacelle hangar 15.
[0024] The first isolation compartment 1 is located between the engine room and the LNG cargo tank, and the second isolation compartment 2 is located between the two LNG cargo tanks. The upper area of the first isolation compartment 1 and the upper area of the second isolation compartment 2 are both equipped with ethylene glycol coils 7, and the ethylene glycol coils 7 in the two upper areas are connected in parallel. The machine room 3 is located on the starboard side of the LNG ship. The first shut-off valve 8, the second shut-off valve 9, the third shut-off valve 10, the fourth shut-off valve 11, the ethylene glycol pump 12, and the second heat exchanger 13 are all located in the machine room 3. The desorption tower 5 and the first heat exchanger 6 are both located in the carbon capture compartment 4. The superstructure 14 and the engine room shed 15 are located on the deck.
[0025] To achieve the purpose of reusing the cold energy of the isolated empty compartments of LNG ships, an ethylene glycol circulation pipeline is installed. The locations of the ethylene glycol circulation pipeline installation are, in order, the first isolated empty compartment 1, the engine room 3, the starboard side of the superstructure 14, the starboard side of the engine room canopy 15, the carbon capture compartment 4, the starboard side of the engine room canopy 15, the starboard side of the superstructure 14, the engine room 3, and the first isolated empty compartment 1.
[0026] Based on the installation of the ethylene glycol circulation pipeline, the ethylene glycol solution circulation path is as follows: the low-temperature ethylene glycol solution flows out from port B of the ethylene glycol coil 7, and enters the first heat exchanger 6 from port C by closing the first shut-off valve 8 and opening the third shut-off valve 10; the high-temperature CO2 in the desorption tower 5 enters the first heat exchanger 6 from port E; the low-temperature ethylene glycol solution and the high-temperature CO2 exchange heat in the first heat exchanger 6; then the low-temperature CO2 after heat exchange is discharged from port F of the first heat exchanger 6, and the high-temperature ethylene glycol solution after heat exchange flows out from port D of the first heat exchanger 6. By closing the second shut-off valve 9 and opening the fourth shut-off valve 11, the high-temperature ethylene glycol solution flows into port A of the ethylene glycol coil 7 via the ethylene glycol pump 12, thereby heating the first isolation chamber 1 and the second isolation chamber 2.
[0027] To prevent the temperature of the ethylene glycol solution in the long pipes passing through the starboard side of the superstructure 14 and the starboard side of the engine room 15 from dropping, electric heating tape and insulation layers are tied to this section of the pipe to maintain the temperature of the ethylene glycol solution in the pipe.
[0028] When the ethylene glycol solution circulation path fails, heating of the first isolation chamber 1 and the second isolation chamber 2 is achieved by closing the third shut-off valve 10 and the fourth shut-off valve 11, and opening the first shut-off valve 8 and the second shut-off valve 9, using a redundant ethylene glycol circulation path. The redundant ethylene glycol circulation path is as follows: the low-temperature ethylene glycol solution flows out from port B of the ethylene glycol coil 7, flows into the second heat exchanger 13 through the first shut-off valve 8, exchanges heat with marine steam in the second heat exchanger 13, and then the high-temperature ethylene glycol solution flows out from the second heat exchanger 13, flows into port A of the ethylene glycol coil 7 through the second shut-off valve 9 and the ethylene glycol pump 12.
[0029] This invention not only achieves the goal of reusing the cold energy of ethylene glycol solution in the isolated chamber, but also effectively reduces the temperature at which CO2 enters the compressor.
[0030] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.
Claims
1. A method for reusing cold energy in the isolated empty compartment of an LNG ship, characterized in that, The structure is based on the following structure, which includes a first isolation chamber (1), a second isolation chamber (2), a mechanical room (3), and a carbon capture chamber (4); the upper regions of the first isolation chamber (1) and the upper regions of the second isolation chamber (2) are both equipped with ethylene glycol coils (7); the mechanical room (3) is equipped with a first shut-off valve (8), a second shut-off valve (9), a third shut-off valve (10), a fourth shut-off valve (11), an ethylene glycol pump (12), and a second heat exchanger (13); the carbon capture chamber (4) is equipped with an analytical tower (5) and a first heat exchanger (6); the method is to set up an ethylene glycol circulation pipeline so that the ethylene glycol solution circulates between the components to achieve cold energy reuse.
2. The method for reusing cold energy in the isolated empty compartment of an LNG ship according to claim 1, characterized in that, The first isolation compartment (1) is located between the cabin and the LNG cargo tank, and the second isolation compartment (2) is located between the two LNG cargo tanks.
3. The method for reusing cold energy in the isolated empty compartment of an LNG ship according to claim 1, characterized in that, The ethylene glycol coil (7) in the upper region of the first isolation chamber (1) and the ethylene glycol coil (7) in the upper region of the second isolation chamber (2) are connected in parallel.
4. The method for reusing cold energy in the isolated empty compartment of an LNG ship according to claim 1, characterized in that, The machine room (3) is located on the starboard side of the LNG ship.
5. The method for reusing cold energy in the isolated empty compartment of an LNG ship according to claim 1, characterized in that, The structure also includes a superstructure (14) and a cabin (15). The locations for installing the ethylene glycol circulation pipeline are, in order, the first isolation chamber (1), the machine room (3), the starboard side of the superstructure (14), the starboard side of the cabin (15), the carbon capture chamber (4), the starboard side of the cabin (15), the starboard side of the superstructure (14), the machine room (3), and the first isolation chamber (1).
6. The method for reusing cold energy in the isolated empty compartment of an LNG ship according to claim 5, characterized in that, Electric heating tapes and insulation layers are tied to the pipes on the starboard side of the superstructure (14) and the starboard side of the engine room (15).
7. The method for reusing cold energy in the isolated empty compartment of an LNG ship according to claim 5, characterized in that, Based on the installation of the ethylene glycol circulation pipeline, the circulation path of the ethylene glycol solution is as follows: the low-temperature ethylene glycol solution flows out from port B of the ethylene glycol coil (7), and enters the first heat exchanger (6) from port C by closing the first stop valve (8) and opening the third stop valve (10); the high-temperature CO2 in the desorption tower (5) enters the first heat exchanger (6) from port E; the low-temperature ethylene glycol solution and the high-temperature CO2 exchange heat in the first heat exchanger (6); then the low-temperature CO2 after heat exchange is discharged from port F of the first heat exchanger (6), and the high-temperature ethylene glycol solution after heat exchange flows out from port D of the first heat exchanger (6), and flows into port A of the ethylene glycol coil (7) by closing the second stop valve (9) and opening the fourth stop valve (11).
8. The method for reusing cold energy in the isolated empty compartment of an LNG ship according to claim 7, characterized in that, When the ethylene glycol solution circulation path fails, the third shut-off valve (10) and the fourth shut-off valve (11) are closed, and the first shut-off valve (8) and the second shut-off valve (9) are opened, thus creating a redundant ethylene glycol circulation path.
9. The method for reusing cold energy in the isolated empty compartment of an LNG ship according to claim 8, characterized in that, The redundant ethylene glycol circulation path is as follows: the low-temperature ethylene glycol solution flows out from port B of the ethylene glycol coil (7), flows into the second heat exchanger (13) through the first shut-off valve (8), and after heat exchange with marine steam in the second heat exchanger (13), the high-temperature ethylene glycol solution flows out from the second heat exchanger (13), flows into port A of the ethylene glycol coil (7) through the second shut-off valve (9) and the ethylene glycol pump (12).