• Journal of Navigation and Port Research
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• v.44 no.4
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• pp.283-290
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• 2020

BOG (Boil Off Gas) generation is unavoidable in the liquefied hydrogen carrier, and proper measures are necessary to prevent pressure problems inside the cargo tank. The BOG can be used as propulsion fuel for ships, and the remaining parts used for propulsion must be effectively managed, such as in the form of reliquefying or burning. This study proposes an BOG reliquefaction system optimized for a 160,000 m3 liquefied hydrogen carrier with a hydrogen propulsion system. The system comprises a hydrogen compression and helium refrigerant section, and increases the efficiency by effectively using the cold energy of the BOG discharged from the cargo tank. In this study, the system was evaluated through the exergy efficiency and SEC (Specific Energy Consumption) analysis according to the rate of the reliquefaction of the BOG while the hydrogen BOG with a supply temperature of -220℃ entered the reliquefaction system. As a result, it showed SEC of 4.11 kWh/kgLH2 and exergy efficiency of 60.1% at the rate of reliquefaction of 20%. And the parametric study of the effects of varying the hydrogen compression pressure, inlet temperature of the hydrogen expander, and the feed hydrogen temperature was conducted.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.361-369
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• 2022

Countries worldwide are shifting to a hydrogen economy to respond to stringent environmental regulations, and the transport of hydrogen between countries is expected to increase in the mid- to long-term. Hydrogen is traded between countries in different forms, such as ammonia, liquid hydrogen, and LOHC (Liquid Organic Hydrogen Carrier), on account of the renewable energy resources in exporting countries, the type of hydrogen use in importing countries, and the technological maturity; however, it is not traded only in a singular form. As marine transportation of ammonia and LOHC is a relatively mature technology compared to that of liquid hydrogen, in this article, we analyzed the technical feasibility of liquid hydrogen carriers while identifying detailed technologies required for their future development and securing possible designs through various technical alternatives.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.6
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• pp.827-837
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• 2022

If the hydrogen industry is activated, the introduction of C-type and pressurized liquefied hydrogen (LH2) tank suitable for small and medium-sized transp- ortation and storage will be given priority in the future. Therefore in this paper, the behavior for the LH2 property changes and boil-off gas (BOG) treatment of the C-type cargo tank through voyage of the LH2 carrier and pressurized tank of the LH2 receiving terminal were analyzed through computational simulations by making assumptions about the carrier operation and unloading conditions.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.2
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• pp.119-127
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• 2019

Reliable $H_2$ supply is necessary for entering a $H_2$ society. Among the various $H_2$ storage and transportation methods, liquid organic $H_2$ carrier (LOHC) is in the spotlight because of a lot of advantages compared to conventional one such as compressed $H_2$ and liquefied $H_2$. Therefore, we performed preliminary economic analysis of $H_2$ supply cost using LOHC for a $H_2$ production capacity of $300Nm^3\;h^{-1}$ employing itemized cost estimation and sensitivity analysis to evaluate economic viability of this technology in Korea.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.3
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• pp.499-507
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• 2023

The core of the liquefied natural gas (LNG) carrier cargo containment system (CCS) is to store and transport LNG safely under temperatures below -163 degrees Celsius. The secondary barrier of the LNG CCS is adopted to prevent LNG leakage from CCS to the ship's hull structure. Recently, as the size of the LNG CCS increases, various studies have been conducted on the applied temperature and load ranges. The present study investigates the working condition-dependent bonding strength of the PU15 adhesives of the secondary barrier. In addition, the mechanical performance is analyzed at a cryogenic temperature of -170 degrees Celsius, and the failure surface and failure mode are investigated depending on the working condition of the bonded process. Even though the RSB and FSB-based fracture mode was confirmed, the results showed that all the tested scenarios satisfied the minimum requirement of the regulation.