• Journal of Ocean Engineering and Technology
• /
• v.38 no.5
• /
• pp.245-256
• /
• 2024

As the importance of carbon capture and storage (CCS) technology increases for greenhouse gas reduction, CO2 transportation technology is also becoming crucial. Efficiently handling boil-off gas (BOG) generated during voyages is particularly important. This paper proposes a process incorporating two-stage separation and mixed refrigerants to reliquefy CO2 BOG containing nitrogen efficiently. This process was optimized based on specific power consumption (SPC) criteria and compared with the conventional single-stage separation using an ammonia refrigerant. The two-stage separation allows the removal of non-condensable gases, such as nitrogen, before expansion, and the use of mixed refrigerants enables more efficient heat exchange than ammonia refrigerants, improving the reliquefaction rate. As a result, the proposed process reduced SPC by up to 8.8 % with a nitrogen content of 5 mol% and up to 74.7 % with a nitrogen content of 15 mol%. In addition, the proposed process achieved a reliquefaction rate of over 74.2 % across all nitrogen content ranges of 5-15 mol%.

• Clean Technology
• /
• v.20 no.1
• /
• pp.1-6
• /
• 2014

$CO_2$ is generated by the combustion reaction, when getting the energy from fossil fuel. If the carbon dioxide emissions increases more, the global warming problem will become more serious. CCS (carbon capture storage) needs to be developed for the prevention of this. When liquefied $CO_2$ is transported, BOG (boil-off gas) is generated because of several problems. In the study, by injecting liquefied $CO_2$ in two tanks which contains $40m^3$each, the amount of BOG and its composition were measured during 30 days when generating pressure changes and external heat, loading, unloading. In result, 16,040 kg of BOG was generated and the composition has been found out to be 99.95% $CO_2$ and 0.05 % $N_2$. Also, we conducted simulation process for reliquefaction of generated BOG with vapor compression cycle using the PRO/II with PROVISION version 9.2. As a result, the refrigeration cycle of the total circulation flow rate was 42.07 kg/h and the condenser utility consumption was 48.85 kg/h.

• Journal of the Korean Society of Industry Convergence
• /
• v.27 no.5
• /
• pp.1027-1040
• /
• 2024

The development of liquid CO₂ storage tanks and liquid CO₂ handling technology are key for liquid CO₂ carriers, and it is necessary to extract core patents of competitors that may lead to patent disputes in the future, establish response strategies, and strengthen the IP portfolio by creating new IPs. As a result of patent analysis for this purpose, patent applications and technology development are being led by the three large domestic shipbuilding companies(Hyundai, Samsung, and Hanwha) and the large Japanese shipbuilding company(MHI), and the handling of liquid CO₂ storage tanks and liquid CO₂ (prevention of dry ice formation) Technology-related patent applications and technology development are actively taking place, so there may be concerns about patent infringement. Currently, It has been confirmed that there are no core patents that are likely to cause patent disputes in the future. However, the technology concept in question lacks patentability as it is a combination of known technologies, so the creation of new IP is necessary to establish exclusive rights. Accordingly, through this project, four new IP creations and patent applications based on competitors' patents were completed. ① Technology to prevent the release of dry ice during unloading using filters, ② Technology to prevent the creation of dry ice in the unloading piping during unloading, ③ BOG reliquefaction technology to respond to CO₂ emission ban regulations, and ④ Technology that can utilize BOG within ships.