Carbon dioxide hydrate compression device and storage method based on LNG ship cold energy utilization

Abstract

The invention discloses a carbon dioxide hydrate compression device based on LNG ship cold energy utilization and a storage method, and belongs to the technical field of ship transportation and environmental protection. The device comprises a carbon dioxide hydrate generation unit, a carbon dioxide hydrate compression unit, a transportation unit, an LNG cold energy supply and refrigeration unit and a safety and detection unit. Carbon dioxide generated in ship smoke achieves carbon capture through a hydrate method, then the carbon dioxide is compressed into blocks through a compressor, the blocks are loaded into a storage container and transferred to a refrigerating chamber, and the refrigerating capacity of the refrigerating chamber is provided by LNG. According to the invention, by efficiently utilizing the cold energy of the LNG ship and adopting a solid carbon dioxide hydrate storage mode, stable and high-density storage is realized, the carbon capture efficiency of the ship is improved, and particularly, transportation resources can be more effectively utilized in long-distance transportation or marine transportation.

Description

Technical Field

[0001] The invention involves multiple fields such as energy utilization, environmental protection technology, shipping industry and climate change mitigation. It is a new type of carbon dioxide hydrate storage device and method. Background Art

[0002] As the international community's regulations on carbon emissions become increasingly stringent, the development of LNG ships and the rise of hydrate technology have become key focuses. The background of this invention stems from concerns about carbon emissions in the maritime transport industry and the demand for comprehensive energy utilization and environmental protection technologies. Maritime transport carries over 80% of global trade, but its carbon emissions account for 2.5%-3% of the global total. If the current situation remains, this proportion is expected to rise to 10% by 2050. The heavy fuel oil (HFO) used by ships contains high sulfur content, and combustion releases large amounts of CO2, which will exacerbate climate warming. Summary of the Invention

[0003] In order to solve the existing carbon dioxide emission problem, the present invention provides a carbon dioxide hydrate compression device and storage method based on the utilization of LNG ship cold energy; this invention integrates LNG cold energy, hydrate capture technology and a new solid hydrate storage method, aiming to improve energy utilization efficiency and reduce carbon emissions, providing an environmentally friendly and sustainable solution for the shipping industry, which is in line with the global trend of sustainable development.

[0004] The technical solution adopted by the present invention is: a carbon dioxide hydrate compression device based on the utilization of cold energy of LNG ships, which includes a carbon dioxide hydrate generation unit, a carbon dioxide hydrate compression unit, a transportation unit, an LNG cold energy supply and refrigeration unit, and a safety and detection unit;

[0005] The reactor in the carbon dioxide hydrate generation unit is connected to a filter and a hydrate solution recovery tank respectively;

[0006] The filter is connected to the tank compressor in the carbon dioxide hydrate compression unit through a discharge pipe provided with a valve;

[0007] The hydrate compression unit incorporates a flexible compression material (such as a high-strength elastomer or composite material) to replace the traditional rigid compression structure. The flexible material can evenly distribute pressure during compression, adapting to the shape changes of the hydrate and preventing damage or performance degradation of the hydrate due to excessive local pressure.

[0008] The outlet of the tank-shaped compressor is connected to the inlet of the storage device through a spiral conveyor belt in the transport unit, and the spiral conveyor belt transports the hydrate mold cavity;

[0009] The LNG cold energy supply and refrigeration unit includes a refrigeration chamber and a heat exchanger, wherein a first heat exchanger and a second heat exchanger are arranged in the refrigeration chamber, and a first LNG storage tank and a second LNG storage tank are arranged outside the refrigeration chamber, wherein the first LNG storage tank is connected to the first heat exchanger, and the second heat exchanger is connected to the second LNG storage tank;

[0010] The safety and monitoring unit includes a temperature monitoring system and a pressure monitoring system; the temperature monitoring system installed in the cold storage room is used to ensure that the temperature inside the cold storage room is maintained within the stable temperature range of the hydrate; the pressure monitoring system installed on the tank-shaped compressor is used to adjust the pressure during the compression process according to the morphology of the hydrate.

[0011] A method for storing carbon dioxide hydrate based on cold energy utilization of LNG ships, the method comprising the following steps:

[0012] S1. Carbon dioxide in the flue gas is reacted in a reactor under high pressure and low temperature to form a carbon dioxide hydrate slurry. The remaining reaction solution is recycled to a hydrate solution recovery tank. The hydrate slurry is filtered to remove impurities and then enters a carbon dioxide hydrate compression unit.

[0013] S2. The hydrate slurry is introduced into a tank-type compressor through a discharge port by gravity, where it is compressed into cake-shaped or block-shaped hydrates under high pressure. The hydrates are cooled during the compression process. A flexible compression material (such as a high-strength elastomer or composite material) is introduced into the hydrate compression unit to replace the traditional rigid compression structure. The flexible material can evenly distribute pressure during the compression process, adapting to the shape changes of the hydrates and preventing damage or performance degradation of the hydrates due to excessive local pressure.

[0014] The compressed CO2 hydrate cakes in S3 are transported from the compression unit to the entrance of the storage device via a conveying system. The bottom of the storage device is equipped with a mobile pulley and an automatic docking device to ensure alignment between the device and the conveying system. The hydrate cakes are then sequentially introduced into separate storage compartments. The sliding doors of the storage compartments are automatically opened and closed by an intelligent control system. Once the hydrate cakes are loaded, the compartments are automatically sealed to maintain a low temperature environment. The unit utilizes LNG cold energy to provide a continuous low-temperature environment, ensuring the long-term and stable storage of hydrates. When unloading or transportation is required, the storage device unlocks the pulleys and moves to the target area, implementing automated operations to ensure efficient and safe storage and transfer processes.

[0015] S4. The compression, transportation, and storage of carbon dioxide hydrate are all carried out in a cold room, and the LNG storage tank transfers cold energy to the cold room through a heat exchanger.

[0016] Furthermore, a temperature monitoring system installed in the cold storage room is used to ensure that the temperature inside the cold storage room is maintained within the stable temperature range of the hydrate; a pressure monitoring system installed on the tank-shaped compressor is used to adjust the pressure during the compression process according to the form of the hydrate.

[0017] The carbon dioxide generated from ship flue gas is captured through the hydrate method. After hydrate formation, the hydrate products are separated, and impurities in the hydrate slurry are removed through a filtration system to obtain a pure hydrate slurry. During the hydrate compression stage, the hydrate slurry is introduced into a block compressor, where it is compressed into blocks to improve storage and transportation efficiency. The compressed hydrate blocks are loaded into specially designed storage containers, which are then transferred from the hydrate generation unit to a cold storage room using a conveying system. The cold storage room is provided with cooling capacity by LNG. Through this device and storage method, carbon dioxide hydrate is stored in a solid form. Compared with gaseous and liquid forms, its storage density is higher and it occupies a relatively small volume. This helps reduce the space required for storage facilities and lowers transportation costs, especially in long-distance or maritime transportation, which can more efficiently utilize transportation resources. Carbon dioxide hydrate exists stably at relatively low temperatures and high pressures, providing a reliable storage method and reducing the risk of carbon dioxide leakage. The high-density storage form of carbon dioxide hydrate. This invention achieves stable and high-density storage by efficiently utilizing the cold energy of LNG ships and adopting the storage method of solid carbon dioxide hydrates, thereby improving the carbon capture efficiency of ships and providing a solution for the maritime transportation industry to achieve more environmentally friendly and sustainable development.

[0018] The beneficial effects of this invention are as follows: the system utilizes waste heat or cold energy generated by LNG ships to form hydrates through a carbon dioxide hydrate generation unit. This hydrate is then compressed into blocks by a hydrate compression unit and transported to a cold storage room. The cold storage room utilizes the cold energy of LNG to maintain a suitable temperature, enabling stable storage of the hydrates. The entire system ensures safe and stable operation through automatic control and monitoring systems, while also considering waste disposal and energy efficiency, providing an environmentally friendly and efficient technical solution for LNG ship transportation.

[0019] The present invention makes full use of the waste heat or cold energy generated by LNG ships, captures carbon dioxide to form hydrates, and compresses them into blocks for storage and transportation. This innovative technical solution not only achieves efficient utilization and storage of carbon dioxide, but also the storage method of this block hydrate has the characteristics of high density and stability. Combined with the transportation characteristics of ships, centralized collection of carbon dioxide can be achieved by docking, and greenhouse gas emissions are reduced through environmentally friendly hydrate transportation methods. At the same time, the use of LNG's cold energy to refrigerate hydrate blocks not only improves the comprehensive utilization efficiency of energy, but also provides a sustainable and environmentally friendly solution for the LNG ship transportation industry. Overall, the invention has multiple beneficial effects such as reducing carbon emissions, improving energy utilization efficiency, complying with environmental protection regulations, and promoting sustainable development.

[0020] The carbon dioxide hydrate generated during the ship carbon capture process can be compressed, stored at low temperatures and safely transported efficiently and stably, while preventing the hydrate from adhering to, agglomerating or deteriorating on the inner wall of the equipment, improving storage efficiency and system reliability, and making full use of the cold energy resources generated during the operation of LNG ships to achieve the synergistic benefits of energy recovery and carbon emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the structure of a carbon dioxide hydrate compression device based on the utilization of cold energy from LNG ships.

[0022] Figure 2 is a side view of the storage device.

[0023] Figure 3 is a front view of the storage device.

[0024] In the figure: 1. Reactor, 2. Hydrate solution recovery tank, 3. First valve, 4. Solid-liquid separator, 5. Second valve, 6. First discharge port valve, 7. Second discharge port valve, 8. Pressure detection system, 9. Tank compressor, 10. Hydrate mold cavity, 11. Spiral conveyor, 12. Storage device, 13. Temperature detector, 14. First heat exchanger, 15. Second heat exchanger, 16. First LNG storage tank, 17. Second LNG storage tank, 18. Refrigeration room, 19. Flexible pressure plate, 20. Cooling pipe, 21. Pulley, 22. Visual interface, 23. Manual pull handle, 24. Electric door, 25. Temperature sensor, 26. Pressure sensor. DETAILED DESCRIPTION

[0025] A carbon dioxide hydrate compression device based on the utilization of cold energy of LNG ships comprises a carbon dioxide hydrate generation unit, a carbon dioxide hydrate compression unit, a transportation unit, an LNG cold energy supply and refrigeration unit, and a safety and detection unit.

[0026] The reactor 1 in the carbon dioxide hydrate formation unit is connected to the solid-liquid separator 4 and the hydrate solution recovery tank 2. The solid-liquid separator 4 is connected to the tank compressor 9 in the carbon dioxide hydrate compression unit through a discharge pipe with a valve.

[0027] Flexible compression materials are introduced into the hydrate compression unit, replacing the traditional rigid compression structure. The flexible material can evenly distribute pressure during the compression process, adapting to the shape changes of the hydrate and preventing hydrate damage or performance degradation caused by excessive local pressure.

[0028] The outlet of the tank compressor 9 is connected to the inlet of the storage device 12 via a spiral conveyor belt 11 in the transport unit. The spiral conveyor belt 11 transports the hydrate mold cavity 10. Each module in the storage device 12 is a separate box-like unit, internally divided into multiple storage compartments, each for storing a single hydrate block. This modular design facilitates loading, unloading, and transportation. A flexible pressure plate 19 is placed behind each row of storage compartments to stabilize the hydrate cake within the storage compartment and prevent movement or breakage.

[0029] A cooling pipe 20 is embedded in each storage module and connected to the LNG cold energy system. The appropriate temperature is maintained by circulating the low-temperature coolant ethylene glycol aqueous solution, which efficiently utilizes the cold energy of the LNG ship and ensures the long-term stability of the hydrate.

[0030] The storage module uses an intelligent temperature and pressure control system to monitor and adjust the temperature of each module in real time.

[0031] Each storage compartment in the storage module is equipped with an independent electric door 24, which uses a sliding or flip-up structure and is opened and closed by an actuator motor. The storage module also provides a real-time visual interface 22, indicating the status of each storage compartment, such as free, full, or loading, and allows the use of manual handles 23 or automatic switching of storage compartments.

[0032] The storage device 12 is equipped with a pulley 21, which can be easily moved between the cold storage room, compression unit and transportation area, reducing the limitations brought by fixed storage; the LNG cold energy supply and refrigeration unit includes a cold storage room 18 and a heat exchanger. The first heat exchanger 14 is mainly used to exchange heat for the cold storage room 18. The second heat exchanger 15 is connected to the cooling pipe built into the storage device 12, and is mainly used to provide cold energy to the storage device. The first LNG storage tank 16 is connected to the first heat exchanger 14, and the second heat exchanger 15 is connected to the second LNG storage tank 17.

[0033] The interior walls of all containers involved in hydrate storage and transportation are sprayed with a specialized anti-stick coating. This hydroxyl-containing super-hydrophobic coating inhibits hydrate nucleation and prevents hydrate adhesion, significantly reducing the adhesion of hydrates to the container surface. This prevents hydrates from adhering to the interior walls of equipment during compression, storage, and transportation, reducing energy consumption and maintenance costs, and improving system operational efficiency.

[0034] The safety and monitoring unit includes a temperature monitoring system 13 and a pressure monitoring system 8; the temperature monitoring system 13 provided in the cold storage room 18 is used to ensure that the internal temperature of the cold storage room 18 is maintained within the stable temperature range of the hydrate; the pressure monitoring system 8 provided on the tank compressor 9 is used to adjust the pressure during the compression process according to the form of the hydrate.

[0035] Example 1

[0036] Figure 1 This is a carbon dioxide hydrate compression device based on the utilization of cold energy of LNG ships, including a carbon dioxide hydrate generation unit, a carbon dioxide hydrate compression unit, a transportation unit, an LNG cold energy supply and refrigeration unit, and a safety and detection unit. Specifically, it includes the following steps:

[0037] S1. The carbon dioxide in the flue gas generates carbon dioxide hydrate slurry in reactor 1 under high pressure and low temperature. The remaining reaction solution is recycled to hydrate solution recovery tank 2. The hydrate slurry passes through solid-liquid separator 4 and enters the carbon dioxide hydrate compression unit.

[0038] S2. The hydrate slurry is introduced into the tank compressor 9 through the discharge ports 6 and 7 by gravity and compressed into a cake or block of hydrate. During the compression process, the temperature is always kept within the hydrate stable range;

[0039] S3. The conveying system then uses a spiral conveyor belt 11 to transfer the mold cavity 10 containing the cake or block hydrate to the storage device 12;

[0040] S4. The compressed carbon dioxide hydrate cake is transported from the compression unit to the entrance of the storage device 12 via a conveying system. The storage device is equipped with a movable pulley 21 and an automatic docking device at the bottom. The hydrate cake is sequentially introduced into independent storage compartments. Each compartment is equipped with a flexible compression plate 19. The sliding door 24 of the storage compartment is automatically opened and closed by an intelligent control system. After the hydrate cake is loaded, the compartment is automatically sealed to maintain a low temperature environment.

[0041] S5. When unloading or transportation is required, the storage device unlocks the pulleys and moves to the target area, achieving automated operation and ensuring efficient and safe storage and transfer processes.

[0042] S6. The compression, transportation, and storage of carbon dioxide hydrate are all carried out in the cold storage room 18. The LNG storage tank transfers cold energy to the cold storage room 18 through a heat exchanger.

Claims

1. A carbon dioxide hydrate compression device based on the utilization of cold energy from LNG ships, characterized by: The device includes a carbon dioxide hydrate generation unit, a carbon dioxide hydrate compression unit, a transportation unit, an LNG cold energy supply and refrigeration unit, and a safety and detection unit; The reactor (1) in the carbon dioxide hydrate generation unit is connected to a solid-liquid separator (4) and a hydrate solution recovery tank (2) respectively; The solid-liquid separator (4) is connected to the tank compressor (9) in the carbon dioxide hydrate compression unit through a discharge pipe provided with a valve; The outlet of the tank compressor (9) is connected to the inlet of the storage device (12) via a spiral conveyor belt (11) in the transport unit, and the spiral conveyor belt (11) transports the hydrate mold cavity (10); Each module in the storage device (12) is an independent box-type unit, the interior of which is divided into a plurality of storage compartments, each compartment being used to store a single hydrate; a cooling pipe (20) is embedded in each storage module and connected to the LNG cold energy system; the storage module is monitored in real time using a temperature sensor (25) and a pressure sensor (26); The LNG cold energy supply and refrigeration unit includes a refrigeration chamber (18) and a heat exchanger, wherein the first heat exchanger (14) is mainly used for exchanging heat for the refrigeration chamber (18), the second heat exchanger (15) is connected to a cooling pipe built into the storage device (12), and is mainly used for providing cold energy to the storage device, the first LNG storage tank (16) is connected to the first heat exchanger (14), and the second heat exchanger (15) is connected to the second LNG storage tank (17).

2. The device according to claim 1, characterized in that: Each storage compartment of the storage module is equipped with an independent electric door (24) which adopts a sliding or flip structure, and the switch is driven by an actuator; The storage module provides a real-time visual interface (22) to display the status of each storage compartment; the storage compartment is provided with a manual handle (23).

3. The device according to claim 1, characterized in that: A pulley (21) is installed at the bottom of the storage device (12), and the storage device moves between the cold storage room, the compression unit and the transportation area.

4. The safety and monitoring unit includes a temperature monitoring system (13) and a pressure monitoring system (8); the temperature monitoring system (13) provided in the cold storage room (18) is used to ensure that the internal temperature of the cold storage room (18) is maintained within the stable temperature range of the hydrate; the pressure monitoring system (8) provided on the tank compressor (9) is used to adjust the pressure during the compression process according to the morphology of the hydrate.

5. A method for storing carbon dioxide hydrate based on the utilization of cold energy of LNG ships, characterized in that: The device used in the storage method is the device according to any one of claims 1 to 3; the storage method comprises the following steps: S1. Carbon dioxide in the flue gas generates carbon dioxide hydrate slurry in a reactor (1) under a high-pressure and low-temperature environment. The remaining reaction solution is recycled to a hydrate solution recovery tank (2). The hydrate slurry is filtered through a filter (4) to remove impurities and enters a carbon dioxide hydrate compression unit. S2. introducing the hydrate slurry into a tank-shaped compressor (9) through a discharge port by gravity, and compressing it into a cake-shaped or block-shaped hydrate. During the compression process, the temperature is always ensured to be controlled within the hydrate stable region; S3. Using a conveying system and then using a spiral conveyor belt (11), the mold cavity (10) containing the cake or block hydrate is transferred to a storage device (12); S4. The compressed carbon dioxide hydrate cake is transported from the compression unit to the entrance of the storage device (12) through a conveying system. The bottom of the storage device is equipped with a moving pulley (21) and an automatic docking device. The hydrate cake is sequentially introduced into independent storage grids. Each grid is equipped with a flexible compression plate (19). The electric door (24) of the storage grid is automatically opened and closed by an intelligent control system. After the hydrate cake is loaded, the storage grid is sealed to maintain a low temperature environment. S5. When unloading or transportation is required, the storage device unlocks the pulley (21) and moves to the target area to achieve automated operation; S6. The compression, transportation, and storage of carbon dioxide hydrate are all carried out in the cold storage room (18), and the LNG storage tank transfers cold energy to the cold storage room (18) through a heat exchanger.

Images