Article
Green & Sustainable Science & Technology
R. Morales-Ospino, A. Celzard, V. Fierro
Summary: Liquid hydrogen (LH2) has the highest storage density with no chemical reaction required, but it needs to be cooled to 20 K using energy-intensive refrigeration. LH2 storage results in the evaporation of LH2, known as boil-off, leading to process inefficiency and energy losses. This review discusses the definition, challenges, state-of-the-art, and recovery strategies to minimize hydrogen evaporation, including zero boil-off (ZBO), hydrogen reliquefaction, and compression solutions. The expertise gained in cryogenic storage for spacecraft has potential applications beyond the industry. Proper integration of reliquefaction systems with LH2 tanks and non-mechanical compressors for boil-off hydrogen offer attractive options for advancing LH2 logistics.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2023)
Article
Green & Sustainable Science & Technology
Shilin Li, Zhongchao Zhao, Zhengchao Chen, Weiqin Zeng, Huizhi Gong
Summary: This paper investigated an improved BOG reliquefaction system for LNG transportation and storage, exploring the most suitable scheme for different refrigerants. Through simulation and optimization, it was found that using mixed refrigerants in both high-temperature and low-temperature refrigeration subsystems could achieve the best performance. The results showed improvements in performance after optimization in all three cases, with optimized Case 3 achieving the best overall performance.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2021)
Article
Thermodynamics
Haneul Mun, Hyeonchul Kim, Jinwoo Park, Inkyu Lee
Summary: This paper investigates the challenge of boil-off gas (BOG) reliquefaction in the intercontinental transport of liquefied natural gas (LNG) and proposes a novel system using liquid air. Two different process designs, low-pressure liquid air (LPLA) and high-pressure liquid air (HPLA), are introduced. The results show that using liquid air can significantly reduce the energy consumption for reliquefaction, and the proposed HPLA process is more economical than commercial processes.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Thermodynamics
Jiubing Shen, Siyuan Yan, Zhichao Li, Yanping Xiao, Niugao Tan
Summary: This research proposes a more efficient and compact BOG reliquefaction process for LNG-fueled ships by replacing external precooling cycle with BOG self-expansion precooling cycle. Among the three proposed processes, case 1 performs the best with all BOG entering the expander for self-expansion precooling.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Mingyue Yan, Zhen Pan, Liyan Shang, Li Zhou, Jingxian Yu
Summary: In this study, improvements were made to three BOG reliquefaction systems for small LNG ships, aiming to address the problem of boil-off gas affecting transportation safety. The systems were simulated using Aspen Plus and optimized using a mathematical model in Matlab. The results showed that the improved single mixed refrigerant reliquefaction system had advantages in thermodynamic performance and economic analysis under a BOG mass flowrate of 350 kg/h.
JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS
(2022)
Article
Energy & Fuels
Chulmin Hwang, Sungkyun Oh, Donghoi Kim, Truls Gundersen, Youngsub Lim
Summary: This paper comparatively analyzes the re-liquefaction system for a low-pressure gas injection engine according to the refrigerant, with a focus on energy, economic, and environmental aspects. The results show that the process without external refrigerant performs better in terms of economy, while the single mixed refrigerant process is more suitable in terms of energy efficiency and environmental impact.
Article
Energy & Fuels
Sarun Kumar Kochunni, Kanchan Chowdhury
Summary: This study investigates the impact of precooling on the performance of reliquefiers in LNG carrier ships, comparing different precooling systems for efficiency. The reverse Brayton and Claude systems show improved exergy efficiency after precooling with transcritical CO2 cycle, with increases of 7.5% and 7.0% respectively.
JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING
(2021)
Article
Energy & Fuels
Linda Barelli, Gianni Bidini, Michele Perla, Francesco Pilo, Lorenzo Trombetti
Summary: This paper evaluates the phenomenon of pressure build-up and discharge in small LNG tanks by applying a model and conducting flow and pressure measurements. The aim is to improve safety awareness and design ventilation systems to reduce flammable gas concentration.
Article
Thermodynamics
Saif Z. S. Al Ghafri, Fernando Perez, Ki Heum Park, Liam Gallagher, Liam Warr, Aaron Stroda, Arman Siahvashi, Yonghee Ryu, Sungwoo Kim, Sung Gyu Kim, Yutaek Seo, Michael L. Johns, Eric F. May
Summary: This study conducted experiments to measure BOG production and pressure change under various industrial conditions for LNG-like binary mixtures of methane and ethane. Three distinct stages of BOG evolution were identified and a new non-equilibrium model using the GERG-2008 equation of state showed good agreement with experimental data in the self-pressurisation and homogeneous stages but had limitations in the transient stage.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Zhongdi Duan, Hongxiang Xue, Xueru Gong, Wenyong Tang
Summary: This study presents a non-equilibrium model to predict LNG boil-off in storage tanks, which is significant for tank design, BOG management and thermoeconomic assessment. The model shows that vapor superheating leads to additional loss during initial boil-off, while liquid natural convection enhances LNG evaporation and helps reduce total boil-off loss. The findings provide insights relevant to reducing BOG rate and total boil-off loss.
Article
Engineering, Marine
Dong-Ha Lee, Seung-Joo Cha, Jeong-Dae Kim, Jeong-Hyeon Kim, Seul-Kee Kim, Jae-Myung Lee
Summary: The demand for environmentally-friendly fuels has led to an increase in cryogenic fuel ships, where insulation systems are crucial in preventing the generation of boil-off gas. Finite element analysis can be used to predict thermal conductivity and boil-off rate in cryogenic fuel tanks, ensuring accurate and efficient design.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Proceedings Paper
Engineering, Industrial
Hongbo Tan, Na Wen, Xiping Kou, Jun Zha, Huizhuo Zhang, Boshi Shao
Summary: A BOG re-liquefaction process based on the single-stage mixed refrigerant cycle was designed and optimized using genetic algorithms. The optimization results showed a reduction in energy consumption and an increase in system exergy efficiency. Multi-objective optimization helped to determine optimal system parameters for low energy consumption and high heat transfer efficiency.
PROCEEDINGS OF THE 2021 IEEE 16TH CONFERENCE ON INDUSTRIAL ELECTRONICS AND APPLICATIONS (ICIEA 2021)
(2021)
Article
Thermodynamics
Taejong Yu, Donghoi Kim, Truls Gundersen, Youngsub Lim
Summary: This study investigates the feasibility of using HFO refrigerants in the re-liquefaction systems of LNG carriers. The simulations and optimizations show that using HFO refrigerants can reduce energy consumption and contribute to reducing explosion risk. However, the expected decrease in global warming impact is not significant, primarily due to the influence of energy consumption.
Article
Environmental Sciences
A. D. S. Borges, M. Oliveira, B. Varandas
Summary: Improving energy efficiency is crucial in the face of climate change. This research introduces a method for a compact liquefied natural gas station to operate independently from the public electric grid. By utilizing the boil-off gas generated during the vehicle supply process and combining it with a photovoltaic system, the station can achieve electricity self-sustainability. The trial operations showed promising results, with daily recovery of boil-off gas and an excess generation of electrical energy, making this method highly valuable.
INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY
(2023)
Article
Energy & Fuels
Saif Z. S. Al Ghafri, Adam Swanger, Vincent Jusko, Arman Siahvashi, Fernando Perez, Michael L. Johns, Eric F. May
Summary: A model has been developed to calculate self-pressurization and boil-off losses of liquid hydrogen in different tank geometries and thermal insulation systems. The model shows excellent agreement with experimental and industrial data across various simulated conditions.
Article
Engineering, Marine
Bongeun Goo, Joohee Lee, Suwon Seo, Daejun Chang, Hyun Chung
INTERNATIONAL JOURNAL OF NAVAL ARCHITECTURE AND OCEAN ENGINEERING
(2019)
Article
Engineering, Industrial
M. S. Kang, H. Chung
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY
(2018)
Article
Engineering, Industrial
Yangyang Zhao, Hyun Chung
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY
(2018)
Article
Engineering, Marine
Minjoo Choi, Stein Ove Erikstad, Hyun Chung
Article
Engineering, Marine
Hyeonkyeong Lee, Hyun Chung
INTERNATIONAL JOURNAL OF NAVAL ARCHITECTURE AND OCEAN ENGINEERING
(2019)
Article
Thermodynamics
Yangyang Zhao, Phill-Seung Lee, Hyun Chung
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2019)
Article
Computer Science, Interdisciplinary Applications
Bongeun Goo, Hyun Chung, Soonheung Han
SIMULATION MODELLING PRACTICE AND THEORY
(2019)
Article
Engineering, Industrial
Joohee Lee, Wan Chul Yoon, Hyun Chung
COGNITION TECHNOLOGY & WORK
(2020)
Article
Engineering, Marine
Jaemin Lee, Hyun Chung
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2020)
Article
Green & Sustainable Science & Technology
Jong Hun Woo, Haoyu Zhu, Dong Kun Lee, Hyun Chung, Yongkuk Jeong
Summary: The fourth industrial revolution has led to an increasing demand for smart technologies in manufacturing industries. Companies are striving to improve their maturity level to achieve smart manufacturing and construct smart factories. However, the wide range and variety of new technologies make it challenging to achieve productivity improvement goals and plans.
Article
Engineering, Marine
Byeong Cheol Lee, Youngsu Choi, Hyun Chung
Summary: The design of firefighting piping on offshore plants is limited by material and design restrictions, with this study proposing a modified iterative-deepening search and greedy algorithm for optimizing the arrangement of firefighting equipment, addressing issues in traditional research methods.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Article
Engineering, Marine
Jaemin Lee, Diego Perrera, Hyun Chung
Summary: In this article, a method based on a layered shell element and elastic finite element is developed to predict welding distortion in multi-pass welding. The prediction is achieved by extracting equivalent plastic strain and HAZ width for each pass, and comparing the results with experimental data shows good agreement.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Article
Computer Science, Interdisciplinary Applications
Adeel Ikram, Hyun Chung
Summary: A numerical model was developed to investigate the influence of pulse frequency on the metal transfer mode, dynamics, and thermal behavior in the pulsed wire-arc additive manufacturing process. The results show that only the current pulses with a medium frequency regime achieve the one-droplet-per-pulse mode of metal transfer. An increase in pulse frequency leads to a shorter necking length of the pendent droplet and a significantly lower average speed and temperature of the detached droplet.
JOURNAL OF COMPUTATIONAL DESIGN AND ENGINEERING
(2022)
Article
Engineering, Marine
Sang-Gab Lee, Jae-Seok Lee, Hyun Chung, Yangsup Na, Kyung-Hoon Park
INTERNATIONAL JOURNAL OF NAVAL ARCHITECTURE AND OCEAN ENGINEERING
(2020)
Article
Chemistry, Multidisciplinary
Jaemin Lee, Hyun Chung
APPLIED SCIENCES-BASEL
(2020)