Scheme for sharing one set of liquid cargo system by multiple liquid CO2 storage tanks

Abstract

A scheme that a plurality of liquid CO2 storage tanks share one set of liquid cargo system comprises a plurality of liquid CO2 storage tanks, and the plurality of liquid CO2 storage tanks are communicated with one another through connecting pipelines and share one set of liquid cargo system. A plurality of loading branch pipelines extend out of the loading main pipeline and respectively extend into the liquid CO2 storage tanks, the other end of the loading main pipeline is connected with a loading system or an unloading system, a liquid cargo unloading pump is arranged in one of the liquid CO2 storage tanks, and the liquid cargo unloading pump is connected with the loading main pipeline through an unloading pipeline. A plurality of liquid CO2 singing devices share one set of sweeping system, the top of each liquid CO2 storage tank is provided with a boil-off gas branch pipeline, the boil-off gas branch pipelines are gathered to a boil-off gas main pipeline to enter the CO2 low-temperature and low-pressure liquefaction skid, and the boil-off gas branch pipelines are treated by the CO2 low-temperature and low-pressure liquefaction skid and then return to each liquid CO2 storage tank. The system configuration is reduced through system sharing, especially the number of liquid cargo pumps is greatly reduced, and the purchase cost of ship related systems is reduced.

Description

Technical Field

[0001] This invention belongs to the field of marine vessel design and construction, specifically relating to a scheme for multiple liquid CO2 storage tanks to share a single liquid cargo system. Background Technology

[0002] To mitigate and address the global climate change problem, countries around the world are researching how to solve the carbon dioxide emissions from production and daily life. In recent years, with the deepening of research, carbon capture, utilization, and storage (CCUS) has emerged as a new industry.

[0003] Carbon capture, utilization and storage refers to the industrial process of separating carbon dioxide (CO2) from industrial emission sources and then utilizing or storing it to achieve CO2 emission reduction.

[0004] Carbon capture, utilization and storage (CCDS) is an emerging technology with the potential for large-scale carbon dioxide emission reduction. It is expected to achieve low-carbon utilization of fossil energy and is widely regarded as one of the important technologies for addressing global climate change and controlling greenhouse gas emissions.

[0005] Given the crucial role of carbon capture, utilization, and storage (CFS) technologies in addressing climate change and reducing carbon emissions, developed countries in Europe and America are exploring ways to provide CFS technologies with the same level of policy support as other clean energy sources in order to accelerate the industrialization of CFS technologies.

[0006] From the perspective of my country's emission reduction needs to achieve its carbon neutrality goals, based on current technological development forecasts, the emission reductions required through carbon capture, utilization, and storage (CCS) technologies will be 600-1.4 billion tons and 1 billion-1.8 billion tons of carbon dioxide by 2050 and 2060, respectively. As the ocean is the most ideal location for carbon dioxide sequestration, strengthening the research and development of marine carbon sequestration equipment has become a key focus for domestic and international carbon processing companies in recent years.

[0007] However, current carbon capture, utilization and storage technologies still face prominent issues such as high costs. Among these, the construction cost of carbon dioxide transport ships and carbon dioxide storage ships is the core issue affecting the initial investment of related industries. The construction cost of these two types of ships directly affects whether the entire industrial chain can proceed normally. How to reduce the construction cost of carbon transport ships and carbon dioxide storage ships has become a matter of great concern to the industry and even relevant national departments.

[0008] However, due to the high investment cost of this type of vessel, it is still only in small-scale experimental development and cannot be widely implemented. The core cost of carbon dioxide transport ships and carbon dioxide storage and sealing ships mainly lies in the liquid CO2 storage tanks and the associated liquid cargo systems they are equipped with.

[0009] To reduce the cost of CO2 tank cargo systems, ultra-large volume liquid CO2 storage tanks are generally used in the development of this type of vessel to reduce the number of liquid CO2 storage tanks, thereby reducing the total cost of the vessel's liquid CO2 tank cargo system.

[0010] However, the increased tank volume results in a significant increase in both the size and weight of individual tanks, with each tank weighing over a thousand tons. Such massive tanks, due to their enormous size and weight, are difficult to construct and install due to the limited number of shipyards available, thus drastically increasing construction and installation costs. Furthermore, the increase in volume may outweigh the cost reduction of the liquid cargo system. Therefore, the effect of increasing tank volume and reducing the number of liquid cargo systems to lower the overall cost of the vessel is not significant.

[0011] In summary, reducing the construction costs of vessels used for transporting and storing captured carbon dioxide, and thus lowering investor investment, has become a key challenge for the industrialization of CO2 marine storage technology. Summary of the Invention

[0012] To address the above problems, this invention provides a solution for multiple liquid CO2 storage tanks to share a single liquid cargo system. The technical solution adopted is as follows:

[0013] Multiple liquid CO2 storage tanks share a single liquid cargo system. There are multiple liquid CO2 storage tanks, each with an overflow well at its bottom. Adjacent overflow wells are interconnected via connecting pipelines. Multiple connecting pipeline isolation valves are installed on the connecting pipelines at the overflow well openings to control the different flow directions of the liquid. Multiple loading branch pipelines extend from the main loading pipeline and extend into each liquid CO2 storage tank. The other end of the main loading pipeline is connected to the loading system or unloading system. One of the liquid CO2 storage tanks is equipped with a liquid cargo unloading pump, which is connected to the main loading pipeline via an unloading pipeline.

[0014] The main CO2 scavenging pipeline extends into multiple scavenging branch pipelines, which respectively extend into each liquid CO2 storage tank and connect to the scavenging pump in each liquid CO2 storage tank.

[0015] Each liquid CO2 storage tank is equipped with an evaporation gas branch pipeline at the top. The evaporation gas branch pipelines converge into the evaporation gas main pipeline, and then enter the CO2 cryogenic and low-pressure liquefaction skid through the evaporation gas main pipeline. After being processed by the CO2 cryogenic and low-pressure liquefaction skid, it returns to each liquid CO2 storage tank through the loading branch pipeline.

[0016] The main CO2 scavenging pipeline is equipped with multiple scavenging system isolation valves. By opening and closing these valves, the flow of liquid CO2 in each storage tank during the scavenging process is controlled.

[0017] The above-mentioned scheme of multiple liquid CO2 storage tanks sharing a single liquid cargo system is further elaborated. The CO2 cryogenic and low-pressure liquefaction skid includes a compressor, a CO2 storage tank, and a cooler. The main evaporation gas pipeline is connected to the compressor via a pipeline. The compressor is connected to the CO2 storage tank and the cooler via pipelines. The cooler is connected to the loading main pipeline. The CO2 storage tank is connected to the CO2 fire extinguishing system.

[0018] In the above-mentioned scheme where multiple liquid CO2 storage tanks share a single liquid cargo system, the liquid cargo pump and the tank sweeping pump are further located at the overflow well.

[0019] The above-mentioned scheme of multiple liquid CO2 storage tanks sharing a single liquid cargo system further includes a main sweeping pipeline connected to an impurity receiving vessel at the other end, through which impurities in the CO2 storage tanks are transported to the impurity receiving vessel.

[0020] The above-mentioned scheme of multiple liquid CO2 storage tanks sharing a single liquid cargo system can be further improved by having only one loading or unloading system.

[0021] Furthermore, in the above-mentioned scheme where multiple liquid CO2 storage tanks share a single liquid cargo system, the connecting pipelines and the isolation valves on the connecting pipelines are all wrapped with an insulating layer.

[0022] This invention provides a shared liquid cargo system design for a highly economical CO2 storage tank. By sharing the system, the system configuration is reduced, especially the number of liquid cargo pumps is greatly reduced, thereby lowering the procurement costs of ship-related systems.

[0023] By sharing the system, the system configuration is reduced, and the size design and selection of liquid CO2 storage tanks are more flexible. This avoids making individual storage tanks too large due to system cost considerations, which would increase installation difficulty and cost. With the adoption of this patented invention, the size of the storage tank can be reduced, the lifting and installation weight can be reduced, thereby reducing installation costs.

[0024] By connecting the shared pipeline of the evaporated gas in the CO2 storage tank to the liquefaction system, which employs a low-temperature, low-pressure process to reliquefy the evaporated gas, the liquefied CO2 is then returned to the storage tank. This reduces the amount of liquid CO2 lost through evaporation from the storage tank, thereby improving the ship's economic efficiency.

[0025] By adding a CO2 storage tank, a portion of CO2 gas can be stored to address the problem of unstable operation of the reliquefied air compressor when the evaporation gas is unstable.

[0026] The method of low-temperature and low-pressure reliquefaction is adopted to deal with the liquefaction problem of vaporized gas from liquid CO2 storage tanks. It makes full use of the low-temperature cold energy of liquid CO2, reduces the capacity of the compressor, reduces the energy consumption of the ship, and thus reduces the operating cost of the ship.

[0027] By making full use of liquid CO2 vapor, the ship's CO2 fire extinguishing system can be refilled by its own cylinders, reducing the ship's reliance on external sources and improving the ship's economy and safety. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the system scheme of the present invention;

[0029] Figure 2 This is a schematic diagram of the loading system scheme of the present invention;

[0030] Figure 3 This is a schematic diagram of the uninstallation system scheme of the present invention;

[0031] Figure 4 This is a schematic diagram of the cabin sweeping system of the present invention;

[0032] Figure 5 This is a schematic diagram of the evaporation gas reliquefaction system of the present invention;

[0033] Figure 6 This is a schematic diagram of the CO2 gas storage system for evaporation gas according to the present invention.

[0034] Figure 7 This is a schematic diagram of the CO2 gas filling system for a ship CO2 fire extinguishing system based on the present invention.

[0035] Among them, 1-Liquid CO2 storage tank, 2-Connecting pipeline, 3-Sweeping branch pipeline, 4-Evaporated gas branch pipeline, 5-CO2 low-temperature and low-pressure liquefaction skid, 6-Unloading pipeline, 7-Loading branch pipeline, 8~8a~8k-Loading branch pipeline isolation valve, 9-Unloading system isolation valve, 10~10a~10j-Sweeping system isolation valve, 11~11a~11s-Evaporated gas pipeline isolation valve, 12-Liquid cargo unloading pump, 13-Compressor, 14-CO2 storage tank, 15-CO2 fire extinguishing system, 16-Sweeping pump, 17~17a~17f-Connecting pipeline isolation valve, 18-Cooler, 19-Overflow well, 20-Loading main pipeline, 21-Sweeping main pipeline, 22-Evaporated gas main pipeline, 23-Insulation layer. Detailed Implementation

[0036] Multiple liquid CO2 storage tanks share a single liquid cargo system, such as Figure 1 As shown, it includes multiple liquid CO2 storage tanks and a liquid cargo system. The liquid cargo system includes a loading system, an unloading system, a tank cleaning system, a CO2 fire extinguishing system, and a cryogenic and low-pressure reliquefaction skid. All system pipelines installed inside and outside the liquid CO2 storage tanks are installed to the inside and outside of the liquid CO2 storage tanks in accordance with the prior design and relevant specifications and standards.

[0037] Install the liquid cargo unloading pump into the overflow well position inside tank No. 1 and connect it to the unloading pipeline 6. This embodiment uses tank No. 3 as an example.

[0038] Install the tank sweeping pump 16 inside the storage tank at the overflow well position of the liquid CO2 storage tank, and connect it to the tank sweeping branch pipeline 3 inside the liquid CO2 storage tank.

[0039] The completed liquid CO2 storage tank 1 will be installed on the corresponding ship according to the preliminary design plan and relevant specifications and standards.

[0040] Install the bottom connecting pipe 2 of the liquid CO2 storage tank and the isolation valves 17a~17f of the bottom connecting pipe of the liquid CO2 storage tank to the corresponding positions according to the previous design plan and relevant specifications and standards. The bottoms of multiple liquid CO2 storage tanks are connected together through the bottom connecting pipe 2 and the isolation valves of the connecting pipe, so that the bottoms of multiple liquid CO2 storage tanks are interconnected.

[0041] Install thermal insulation on the bottom connecting pipe 2 and the isolation valves 17a~17f of the connecting pipe of the liquid CO2 storage tank, and test the reliability of the installation to ensure that the thermal insulation installation will not cause low temperature leakage.

[0042] Install the pipelines, isolation valves, cryogenic and low-pressure reliquefaction skids 5, etc. of each system to the corresponding positions on the ship according to the previous design plan and relevant specifications and standards.

[0043] Connect the air compressor output pipeline and CO2 storage tank output pipeline of the low-temperature and low-pressure reliquefaction skid 5 to the ship's carbon dioxide fire extinguishing system pipeline.

[0044] After completing the above installation and connection work, the entire system needs to be debugged and tested according to the design and relevant specifications to ensure the safety and reliability of the system.

[0045] After completing the above inspection and testing, the target vessel can then begin loading cryogenic CO2.

[0046] like Figure 2As shown, the external cryogenic liquid CO2 transport vessel connects to the inlet of the loading main pipeline on the loaded vessel. There are two main operating modes for loading liquid CO2 into the three liquid CO2 storage tanks. In one mode, the liquid CO2 input from the outside is directly loaded into the three liquid CO2 storage tanks via the loading main pipeline and branch pipelines. During loading, the loading branch pipeline isolation valves 8, 8a, 8b, 8c, 8f, 8j, 8j, and 8i on the loading main pipeline and branch pipelines can be opened simultaneously as needed to achieve simultaneous loading of the three liquid storage tanks. Alternatively, each tank can be loaded individually; simply open the isolation valve on each tank separately. Another approach is to open the isolation valves 17, 17a, 17b, 17c, 17d, 17e, and 17f on the bottom connecting pipe 2 above the overflow well at the bottom of the liquid CO2 storage tank. This way, as long as liquid CO2 is loaded into any one of the liquid CO2 storage tanks 1, it will be transferred to the other liquid CO2 storage tanks through the bottom connecting pipe 2. This solution can still meet the needs of loading liquid CO2 into the tank even if there is a problem with the branch pipe or isolation valve on a certain liquid storage tank.

[0047] like Figure 3 As shown, when the target vessel needs to unload liquid CO2 from its hydraulic CO2 storage tank to other vessels or inject it into a storage location, the unloading method may be a single tank or multiple tanks simultaneously, depending on the operating mode. When using a single tank for unloading, the No. 1 liquid CO2 storage tank is the main unloading tank. First, all connecting pipe isolation valves 17, 17a, 17b, 17c, 17d, 17e, and 17f on the bottom connecting pipe 2 are closed. Simultaneously, isolation valves 8, 8a, and 8c on the loading main pipe are also closed. The unloading system isolation valve 9 and the loading system isolation valve 8b on the unloading pipe 6 are opened. The liquid cargo unloading pump 12 is then started. The liquid cargo unloading pump 12 then pumps the liquid CO2 from the No. 1 liquid CO2 storage tank through the unloading pipe 6 and the unloading system isolation valve... 9 and loading main pipeline 7 and loading system isolation valve 8b are unloaded to other ships or injected into the storage site; if the liquid CO2 in the No. 2 liquid CO2 storage tank also needs to be exported at the same time, simply open the connection pipeline isolation valves 17, 17a, and 17b on the bottom connection pipeline 2, and the liquid CO2 in the No. 2 liquid CO2 storage tank will automatically flow through the bottom connection pipeline to the No. 1 liquid CO2 storage tank, and be discharged through the liquid cargo unloading pump 12 to be unloaded to other ships or injected into the storage site; the unloading of the No. 3 liquid CO2 storage tank can also adopt the above scheme.

[0048] like Figure 4As shown, when the liquid CO2 storage tank 1 is cleaned and the sludge needs to be discharged, the sludge at the bottom of each tank needs to be discharged from the tanks 1, 2, and 3 through the cleaning branch pipe 3 and the cleaning system isolation valves 10, 10a, 10b, 10c, 10d, 10e, 10h, 10g installed on the pipe, and the cleaning system isolation valves 10j, 10f installed on the pipe. Alternatively, the isolation valves 17, 17a, 17b, 17c, 17d, 17e, 17f on the bottom connecting pipe 6 of the three tanks can be opened individually or all of them. In this way, the sludge in the liquid CO2 storage tanks 2 and 3 will flow into the overflow well at the bottom of the liquid CO2 storage tank 1 through the bottom connecting pipe 2. Thus, the cleaning operation of the three tanks can be achieved by only opening the cleaning pump 16 in the liquid CO2 storage tank 1.

[0049] like Figure 5 As shown, when the liquid CO2 stored in the liquid CO2 storage tank 1 evaporates to produce gaseous CO2, if the gas pressure in the storage tank is too high, the evaporated gas will be collected from the branch pipe of the evaporation gas path 4 connected to the storage tank 1 to the main pipe, and then reach the gas inlet boundary between the air compressor 13 of the low-temperature low-pressure reliquefaction skid 5 and the gas discharge column through the main pipe. If the pressure and flow rate of the collected gas do not exceed the standard, the evaporation gas pipeline isolation valve 11i on the pipeline connected to the gas discharge column will be closed, and the evaporation gas pipeline isolation valve 11j on the pipeline connected to the air compressor 13 on the low-temperature low-pressure reliquefaction skid 5 will be opened. This part of the collected gas enters the compressor 13 for compression, and the compressed gas is then... The vaporized gas enters the cooler 18 through the isolation valve 11o of the evaporation gas pipeline. To fully utilize its own cooling energy and reduce the high compression demand on the compressor 13, the scavenging pump 16a in the liquid CO2 storage tank 1 is started. The scavenging pump 16a uses the scavenging pump 16a to draw the liquid CO2 in the storage tank 2 through the scavenging pipeline 3 and the opened scavenging system isolation valves 10h, 10c, and 10j into the cooler 18, where it becomes a coolant for cooling the gas compressed from the compressor 13. In the cooler, the vaporized gas is liquefied from a gaseous state to a liquid state for the first time through a low-temperature and low-pressure process. After exiting the cooler, the liquid CO2 is refilled into the storage tank through the loading pipeline 7 and the opened loading branch pipeline isolation valves 8d, 8f, and 8j. This completes the operation process of vaporized gas reliquefaction.

[0050] like Figure 6As shown, because the evaporation rate of the vaporized gas in the liquid CO2 storage tank fluctuates, the flow rate and pressure of the vaporized gas discharged from the tank also change continuously. This fluctuation significantly affects the compression efficiency of the compressor 13. To reduce the impact of vaporized gas fluctuations on the operation of the compressor 13, a CO2 storage tank is installed on the low-temperature, low-pressure reliquefaction skid 5. This tank initially stores some CO2 gas. When the vaporized gas in the storage tank 1 becomes unstable, the CO2 storage tank 14 releases a portion of the CO2 gas as needed to regulate the vaporized gas entering the compressor 13. The gas in the storage tank is pre-stored after being compressed by the compressor 13 from the vaporized gas in the liquid storage tank. Specifically, the vaporized gas from the liquid storage tank is compressed inside the compressor 13 and then distributed into the CO2 storage tank 14 via the opened vaporized gas pipeline isolation valves 11n, 11m, and 11L. The evaporation gas isolation valves 11o, 11q, and 11k on the pipeline connected to this pipeline must all be in the closed state.

[0051] like Figure 7 As shown, according to regulations, ships are required to be equipped with a CO2 fire suppression system. This system includes CO2 cylinders 15, which store CO2 gas. In the event of a fire, the gas in the CO2 cylinders is released to the fire area through pipelines. Once the CO2 gas in cylinder 15 is emptied, it needs to be refilled by an external gas source. Since the product of the evaporation of liquid CO2 in liquid CO2 storage tank 1 is CO2 gas, when CO2 cylinder 15 needs refilling, the gas in CO2 storage tank 14 can be released. This gas then passes through the opened evaporation gas pipeline isolation valves 11L and 11k, merges with the gas evaporated from the liquid CO2 storage tank, and enters the compressor 13. After being compressed by the compressor, it is transported through the evaporation gas pipeline via the opened evaporation gas pipeline isolation valves 11n and 11q to the CO2 storage tank 15 of the ship's CO2 fire suppression system for refilling. This allows the ship to refill the CO2 storage tank of its own CO2 fire suppression system.

Claims

1. A system for sharing a single liquid CO2 storage tank system, characterized in that, There are multiple liquid CO2 storage tanks (1), and overflow wells (19) are provided at the bottom of the multiple liquid CO2 storage tanks. The adjacent overflow wells are connected to each other through connecting pipes (2). Multiple connecting pipe isolation valves are provided on the connecting pipes at the overflow well openings. The multiple connecting pipe isolation valves control the different flow directions of the liquid. Multiple loading branch pipes (7) extend from the loading main pipeline (20) and extend into each liquid CO2 storage tank respectively. The other end of the loading main pipeline is connected to the loading system or unloading system. A liquid cargo unloading pump (12) is provided in one of the liquid CO2 storage tanks. The liquid cargo unloading pump is connected to the loading main pipeline through the unloading pipe (6). The CO2 scavenging main pipeline (21) has multiple scavenging branch pipelines (3) extending into each liquid CO2 storage tank and connecting to the scavenging pump (16) in each liquid CO2 storage tank. Each liquid CO2 storage tank is equipped with an evaporation gas branch pipe (4) at the top. The evaporation gas branch pipes are connected to the evaporation gas main pipe (22). The gas enters the CO2 low temperature and low pressure liquefaction skid (5) through the evaporation gas main pipe. After being processed by the CO2 low temperature and low pressure liquefaction skid, the gas returns to each liquid CO2 storage tank through the loading branch pipe. Multiple scavenging system isolation valves are installed on the main CO2 scavenging pipeline. The flow of liquid CO2 in each storage tank during the scavenging process is controlled by opening and closing these valves. The CO2 low-temperature and low-pressure liquefaction skid includes a compressor (13), a CO2 storage tank (14), and a cooler (18). The main evaporation gas pipeline is connected to the compressor through a pipeline. The compressor is connected to the CO2 storage tank and the cooler through pipelines respectively. The cooler is connected to the loading main pipeline. The CO2 storage tank is connected to the CO2 fire extinguishing system (15). The cargo pump and the tank sweeping pump are located at the overflow well; The other end of the main sweeping pipeline is connected to the impurity receiving vessel, and the impurities in the CO2 storage tank are transported to the impurity receiving vessel through the main sweeping pipeline. Only one loading or unloading system is set up.

2. The liquid CO2 storage tank sharing a single liquid cargo system according to claim 1, characterized in that, The connecting pipelines and the isolation valves on the connecting pipelines are all wrapped with an insulating layer (23).

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