14 results on '"LNG leakage"'
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2. Quantitative Analysis of Leakage Consequences of LNG Ship-to-Ship Bunkering Based on CFD.
- Author
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Kong, Xiangyu, Jiao, Wenling, Xiang, Weidong, Wang, Qiang, Cao, Jiaolong, and Han, Lianfu
- Subjects
- *
LIQUEFIED natural gas , *LEAKAGE , *QUANTITATIVE research , *REFERENCE values , *FREIGHT & freightage - Abstract
Leakage incidents on LNG bunker vessels will result in a serious degree of hazard. This paper investigates typical high-risk scenarios such as hose ruptures and valve joint leakages. The consequences of an LNG leakage accident during the simultaneous operation of a bunker vessel and a container carrier are simulated using the FLACS software, and the dispersion range of the combustible vapor cloud is quantitatively analyzed under both ballast and laden conditions. Under the ballast condition, the diffusion range of the combustible vapor cloud on the side of the bunker vessel is 58 × 15.5 m from the front wall of the cargo equipment room to the bow of the vessel, and 35 × 9.5 m between the cargo equipment room and the transom of the vessel. Under the laden condition, the diffusion range on the side of the bunker vessel is 58 × 15.5 m from the front wall of the cargo equipment room to the bow of the vessel, and 15 × 4 m between the rear end wall of the cargo equipment room and the front wall of the stern of the vessel. These results provide important technical guidance and reference values for the safe operation of LNG bunker vessels. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
- Full Text
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3. Computational fluid dynamics simulation of cryogenic safety analysis in an liquefied natural gas powered ship during liquefied natural gas leakage
- Author
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Zhaowen Wang, Qipeng Zhang, Yi Wang, Xin Li, and Jiong Zhou
- Subjects
LNG powered ship ,LNG leakage ,cryogenic safety analysis ,CFD simulation ,fuel gas preparation room ,SST modeling ,General Works - Abstract
LNG is considered a promising alternative fuel for the marine industry with the increasingly strict environmental requirements while the safety problems caused by LNG leakage accidents need to be concerned and analyzed. In this article, the cryogenic safety analysis of the fuel gas preparation room in an LNG-powered ship during LNG leakage accidents was performed by CFD simulations. The simulation results showed as follows: the range of cryogenic region in the fuel gas preparation room was related to flow field direction during LNG leakage; The surface temperature of equipment dropped to some extent during LNG leakage accidents. The temperature drop was less than 15°C, which was confirmed to be a safe temperature range in engineering; In addition, for safety operation analysis, the NG distribution situation of dangerous regions with explosive limit was also obtained. more...
- Published
- 2023
- Full Text
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4. Layout optimization for safety evaluation on LNG-fueled ship under an accidental fuel release using mixed-integer nonlinear programming
- Author
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Haris Nubli, Jung Min Sohn, and Aditya Rio Prabowo
- Subjects
LNG-Fueled ship ,LNG leakage ,Process layout optimization ,Mixed-integer nonlinear programming ,Gas dispersion analysis ,Computational fluid dynamics ,Ocean engineering ,TC1501-1800 ,Naval architecture. Shipbuilding. Marine engineering ,VM1-989 - Abstract
The Liquefied Natural Gas (LNG)-fueled ship is an alternative solution to deal with the Emission Control Area (ECA) issued by the International Maritime Organization (IMO). LNG fuel has eco-green characteristics since sulfur oxide and particulate matter are eliminated. The equipment sitting on the Fuel Gas Supply System (FGSS) layout needs a good arrangement to prevent the domino effect. This study’s scopes are to establish the feasible FGSS layout based on the equipment position and conduct an accidental LNG release that adopts the Computational Fluid Dynamics (CFD). Mixed-Integer Nonlinear Programming (MINLP) is provided as an optimization tool. The MINLP framework is written in the Python programming language. The minimum separation distance, deck size, and non-overlapping functions of equipment are included as the MINLP constraint. The separation distances are provided based on the Center of Chemical Process Safety (CCPS) recommendation. Also, several options of the separation distance are added that consist of 5.0, 6.0, and 7.0 m to observe the congestion effect. The total pipe length is considered as the MINLP objective that can be used to estimate the pipe cost. The proposed MINLP framework is designated to generate a feasible layout that has an adequate separation distance and minimum cost of the pipe. CFD results show that the increase of separation distance can reduce the gas accumulation effectively which eventually reduces the severity of other consequences. Finally, the feasible layout is proposed based on a series of several consequences under an accidental LNG release, such as gas dispersion, fire, and vapor cloud explosion. more...
- Published
- 2022
- Full Text
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5. Experimental and Numerical Study of Orifice Coefficient of Cargo Tank Design of LNG Vessels.
- Author
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Hwang, Se-Yun, Kim, Kwang-Sik, Jang, Ho-Sang, and Lee, Jang-Hyun
- Subjects
LIQUEFIED natural gas ,STORAGE tanks ,LIQUEFIED natural gas storage ,COMPUTATIONAL fluid dynamics ,PRESSURE vessels ,TANKS - Abstract
Liquid cargo storage tanks of liquefied natural gas (LNG) carriers are designed by strict standards to maintain the cryogenic state (−163 °C). For most LNG cargo storage tanks, it is mandatory to install a system that can safely store leaked fluid for 15 days in the case of leakage of liquid cargo due to crack of the insulation system. To ensure safety, it is necessary to predict the amount of LNG spilling from the cracks in the insulation panels. Although international regulations are provided, they rely on a conservative and consistent coefficient. In this study, experimental and numerical methods were applied to examine the design factor used to predict the flow rate in the tank design process. To check the amount of leakage that occurs under pressure conditions of LNG tanks, an experiment was conducted using crack specimens and pressure containers filled with water. In order to simulate the leakage of LNG, the amount of leakage was predicted using the Computational Fluid Dynamics (CFD) method. The distribution of leakage quantity was investigated according to the shape of the crack through the pressure vessel experiment and the analysis. Through CFD analysis, the leakage rate of LNG was calculated for each operating pressure condition through the crack. Finally, the results of this study examined the need to identify and reconsider the coefficients due to international guidelines and other factors in calculating orifice coefficients applied to the design of LNG tanks. [ABSTRACT FROM AUTHOR] more...
- Published
- 2020
- Full Text
- View/download PDF
6. Experimental and Numerical Study of Orifice Coefficient of Cargo Tank Design of LNG Vessels
- Author
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Se-Yun Hwang, Kwang-Sik Kim, Ho-Sang Jang, and Jang-Hyun Lee
- Subjects
orifice coefficient ,LNG leakage ,LNG cargo containment system ,leakage test ,computational fluid dynamics ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Liquid cargo storage tanks of liquefied natural gas (LNG) carriers are designed by strict standards to maintain the cryogenic state (−163 °C). For most LNG cargo storage tanks, it is mandatory to install a system that can safely store leaked fluid for 15 days in the case of leakage of liquid cargo due to crack of the insulation system. To ensure safety, it is necessary to predict the amount of LNG spilling from the cracks in the insulation panels. Although international regulations are provided, they rely on a conservative and consistent coefficient. In this study, experimental and numerical methods were applied to examine the design factor used to predict the flow rate in the tank design process. To check the amount of leakage that occurs under pressure conditions of LNG tanks, an experiment was conducted using crack specimens and pressure containers filled with water. In order to simulate the leakage of LNG, the amount of leakage was predicted using the Computational Fluid Dynamics (CFD) method. The distribution of leakage quantity was investigated according to the shape of the crack through the pressure vessel experiment and the analysis. Through CFD analysis, the leakage rate of LNG was calculated for each operating pressure condition through the crack. Finally, the results of this study examined the need to identify and reconsider the coefficients due to international guidelines and other factors in calculating orifice coefficients applied to the design of LNG tanks. more...
- Published
- 2020
- Full Text
- View/download PDF
7. Risk management framework of LNG offshore transfer and delivery system.
- Author
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Kang, Zhuang, Li, Zonglin, and Kang, Jichuan
- Subjects
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FAILURE mode & effects analysis , *LIQUEFIED natural gas , *COLLISIONS at sea , *COMPUTATIONAL fluid dynamics , *SYSTEM failures , *WORKFLOW - Abstract
The leakage of Liquefied Natural Gas (LNG) is susceptible to chain accidents such as fire and explosion, threating the safety of LNG vessels. This paper proposes a risk management framework for LNG offshore transfer and delivery system, which is a critical assembly of LNG offshore operation. The components and the workflow of the system are addressed. Failure mode and effects analysis (FMEA) is implemented to identify potential failure modes, failure causes and final effects of the system in the accident of leakage. According to the risk identification results, typical failure scenarios are established to explore the impact of different factors, including environmental parameters and the layout of ships. Computational Fluid Dynamics (CFD) method is introduced to solve the model, achieving the characteristics of the LNG vapor leakage risk. Based on the leakage risk assessment, the optimized risk control options (RCOs) are determined. The results indicate that the proposed framework can be applied to analyze different risk scenarios and propose controls to improve the security of the system. • A risk management framework is proposed for leakage risk analysis of LNG offshore transfer and delivery system. • Based on the FMEA method, the potential failure modes and failure causes of the system are identified and analyzed. • CFD simulation is performed to investigate the impact of different operating environment conditions on risk of LNG leakage. • The risk control opinions (RCOs) of the system and related equipment are provided. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
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8. CFD and EnKF coupling estimation of LNG leakage and dispersion
- Author
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Wu, Jiansong (author), Cai, Jitao (author), Yuan, S. (author), Zhang, Xiaole (author), Reniers, G.L.L.M.E. (author), Wu, Jiansong (author), Cai, Jitao (author), Yuan, S. (author), Zhang, Xiaole (author), and Reniers, G.L.L.M.E. (author) more...
- Abstract
As a kind of clean fuel, increasing quantities of natural gas have been transported as liquefied natural gas (LNG) worldwide. The safety of LNG storage has gained the concerns from the public due to the potential severe consequences that may arise from LNG leakage. In this paper, a three-dimensional model with the combination of computational fluid dynamics (CFD) and the ensemble Kalman filter (EnKF) is proposed to predict LNG vapor dispersion and estimate the strength of the LNG leakage source. The LNG vapor dispersion CFD model is validated by the experimental data with good feasibility, and is further demonstrated with the reasonable modeling of the characteristics of the LNG vapor dispersion in a typical receiving terminal. The effectiveness of the proposed CFD and EnKF coupling model is evaluated and validated by a twin experiment. The results of the twin experiment indicate that the proposed CFD and EnKF coupling model allows the integration of observation data into the CFD simulations to enhance the prediction accuracy of the LNG vapor spatial-temporal distribution and thereby realizing a reasonable estimation of the LNG leakage velocity under complex environments. This study can provide technical supports for safety control, loss prevention and emergency response in case of LNG leakage accidents., Safety and Security Science more...
- Published
- 2021
- Full Text
- View/download PDF
9. Computational study of LNG evaporation and heat diffusion through a LNG cargo tank membrane.
- Author
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Lee, Jang Hyun, Kim, Yoon Jo, and Hwang, Seyun
- Subjects
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LIQUEFIED natural gas , *THERMAL analysis , *COMBUSTION , *DIFFUSION , *THERMODYNAMICS - Abstract
The seepage of the cryogenic LNG through the cracks in membrane insulation may result in cold spots within the hull structures of LNG vessels. At the cold spot, the hull structure will be crystalized and brittle. Also, the loss of LNG containments may lead to a potentially significant hazard. The estimation of the temperature distribution along the insulation panel and the heat diffusion speed through the insulation materials are crucial to assess the safety of LNG vessels. The prediction of the flow and thermal behaviors of the leaked LNG requires complex multiphase flow numerical simulation. The CFD (computational fluid dynamics) model is proposed to simulate the diffusion behavior and the heat transfer characteristics of leaked LNG including the liquid-to-gas phase change through porous structure. The CFD model considers phase change, gas–liquid reactions in the porous media and the accompanied rates of heat transfer. It also considers the geometry of NO96 membrane storage facilities with glass wool and plywood. In the numerical simulation, the LNG pool spreading, heat diffusion, and the evaporation are investigated. The simulation indicates that the predicted speed of seepage is too high to evaporate the LNG after the leakage. [ABSTRACT FROM AUTHOR] more...
- Published
- 2015
- Full Text
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10. Hazard assessment and hazard mitigation of fuel leak inside a ship elevator for LNG-fueled vessel.
- Author
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Xie, Cheng, Huang, Liwen, Deng, Jian, Wang, Rui, and Hao, Guozhu
- Subjects
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HAZARD mitigation , *COLLISIONS at sea , *RISK assessment , *ELEVATORS , *HEAT transfer , *WATER leakage , *MARINE accidents - Abstract
The demands of passing through dams are on the raise with increasing in the number of LNG fueled-vessels recently. Ship elevators that is a convenient means to pass through high-dam navigable waters play an important role, however, when the LNG fueled-vessels pass through the ship elevator, there are high risks of combustion caused by LNG fuel leak, and even leading to explosion due to the semi-closed structure of ship elevators, which hazard people's lives, and structures. In this study, the largest ship elevator worldwide located at the Three Gorges is chosen as the research object. A quantitative method of assessing the combustion and explosion hazards to the people and structure from LNG fuel leak accidents inside ship elevator is proposed, and the numerical simulations of three typical LNG leak accidents are carried out based on the heat transmission mechanism of LNG liquid-phase leaks on water surfaces constructed in our paper, finally, corresponding hazard mitigation measures are proposed according to analysis results and their validity is proved. Our work discloses the hazard level of fuel leak accidents when an LNG fueled-vessel passes the ship elevator, and provides theoretical references to risk decision-making and risk management of LNG fueled-vessels passing ship elevators. • A quantitative method of assessing the hazards exposed on people and structure from LNG fuel leak accidents in the ship elevator is proposed. • Numerical simulations of leak accidents are carried out based on user-defined heat transmission mechanism of LNG liquid-phase leaks. • Two measures to mitigate the LNG leak hazards inside a ship elevator are proposed. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
- Full Text
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11. Engineering design of explosion protection in LNG receiving terminal.
- Author
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Yin Hong
- Subjects
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LIQUEFIED natural gas transportation , *LIQUEFIED natural gas shipping terminals , *EXPLOSIONS , *CHEMICAL engineering , *PREVENTION ,PETROLEUM shipping terminal accidents - Abstract
Explosion-proof security is the top priority of the enterprise in the gas industry, terminal corresponding measures must be taken in engineering design in the liquefied natural gas (LNG) receiving terminal. This paper discusses environment characteristics and harms of the LNG receiving terminal explosion, as well as the determination of release source, summarizes the risk zoning dividing method and expounds commonly used explosion-proof measures of the LNG receiving station, such as the explosion-proof design of the structure, ventilation design, the selection of explosion-proof electrical equipment, etc., then concludes the explosion-proof design characteristics of domestic LNG receiving terminal engineering, and proposes the reference suggestions to the subsequent project construction. [ABSTRACT FROM AUTHOR] more...
- Published
- 2013
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12. Research on quantitative risk assessment of fuel leak of LNG-fuelled ship during lock transition process.
- Author
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Xie, Cheng, Huang, Liwen, Wang, Rui, Deng, Jian, Shu, Yaqing, and Jiang, Dan
- Subjects
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RISK assessment , *QUANTITATIVE research , *HEAT radiation & absorption , *LIQUEFIED gases , *SHIPS , *COLLISIONS at sea , *EXPLOSIONS , *WATER leakage - Abstract
• An QRA model to assess fuel leak of LNG-fuelled ship during lockage is proposed. • HAZOP-LOPA methodology is used to obtain LNG leak probabilities. • The frequencies of initiating event are calculated based on Bayesian estimation. • LNG leak consequences are simulated using CFD model. • QRA results show the individual risk are within the acceptable range. As a clean and efficient new maritime fuel, the strict emission standards worldwide recently have been stimulating the use of Liquefied nature gas (LNG), leading a great increase in the number of LNG-fuelled ship. Due to the hazard characteristics of freezing and flammability after release inside a ship lock, it may cause fire and explosion consequence which may threaten the safety of people and lock structure, the research on quantitative risk assessment (QRA) of fuel leakage during lockage is urgently needed in the safety management of LNG-powered ship and ship lock. This paper proposes an integrated QRA model for analysing the fuel leakage risk during lockage of LNG-fuelled ship, and the QRA process based on the world's largest lock Three Gorges lock is performed including the risk identification, probability calculation and consequence modelling. The results show that the individual risks (IRs) of LNG-fuelled ship during lockage is within the negligible area, and the main threat of LNG leakage is heat radiation rather than overpressure. The research results of the study can provide theoretical support in policy-making process of LNG-fuelled ship and ship lock. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
- Full Text
- View/download PDF
13. Hazard analysis by leakage and diffusion in Liquefied Natural Gas ships during emergency transfer operations on coastal waters.
- Author
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Zhu, Mingchang, Huang, Liwen, Huang, Zhiqiu, Shi, Feng, and Xie, Cheng
- Subjects
LIQUEFIED natural gas ,TERRITORIAL waters ,HAZARD mitigation ,RICE hulls ,MARITIME shipping ,COMPUTATIONAL fluid dynamics ,LEAKAGE ,DIFFUSION - Abstract
With global warming and 2050 carbon reduction targets, the demand for Liquefied Natural Gas (LNG) marine transportation continues to increase. LNG carriers that experience emergency unseaworthy accidents at sea have the need for emergency transfer rescue, which brings many safety management issues for ships and coastal waters due to high risk of LNG leakage. This paper investigates the impacts on the ship and marine safety caused by the LNG leakage and diffusion from ship-to-ship (STS) emergency transfer operations on coastal waters. Firstly, the computational fluid dynamics (CFD) method is used to establish an LNG STS transfer leakage diffusion model. Then, LNG dispersion characteristics and the range of the vapour cloud in transfer operating waters under accident conditions with different wind speeds and wind angles are calculated and simulated. The results show that the diffusion of LNG vapour cloud is significantly influenced by wind speed and hull restrictions, and the flammable volume fraction and 1% volume fraction of the LNG vapour cloud spread to different distances through transport effect, mixing and dilution effect of wind. In addition, an LNG cryogenic hazard zone exists in the vicinity of the leakage point. This study can provide the guidance to authorities to formulate disaster prevention, mitigation regulations, and emergency response measures, which can benefit marine safety management in coastal waters. • LNG leakages from STS emergency transfer on coastal waters are simulated and analysed. • Mechanism of LNG vapour diffusion effected by navigation environment in narrow waters are investigated. • Hazard migration measures for LNG STS transfer operations are proposed. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
- Full Text
- View/download PDF
14. CFD and EnKF coupling estimation of LNG leakage and dispersion.
- Author
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Wu, Jiansong, Cai, Jitao, Yuan, Shuaiqi, Zhang, Xiaole, and Reniers, Genserik
- Subjects
- *
LIQUEFIED natural gas , *COMPUTATIONAL fluid dynamics , *LIQUEFIED natural gas industry , *DISPERSION (Chemistry) , *LEAKAGE , *NATURAL gas - Abstract
• A 3D CFD and EnKF coupling model for estimating LNG leakage and predicting LNG vapor dispersion is proposed. • The CFD-EnKF-based model is validated by a twin experiment with good feasibility. • The characteristics of LNG vapor dispersion in a real receiving terminal at ports are presented. As a kind of clean fuel, increasing quantities of natural gas have been transported as liquefied natural gas (LNG) worldwide. The safety of LNG storage has gained the concerns from the public due to the potential severe consequences that may arise from LNG leakage. In this paper, a three-dimensional model with the combination of computational fluid dynamics (CFD) and the ensemble Kalman filter (EnKF) is proposed to predict LNG vapor dispersion and estimate the strength of the LNG leakage source. The LNG vapor dispersion CFD model is validated by the experimental data with good feasibility, and is further demonstrated with the reasonable modeling of the characteristics of the LNG vapor dispersion in a typical receiving terminal. The effectiveness of the proposed CFD and EnKF coupling model is evaluated and validated by a twin experiment. The results of the twin experiment indicate that the proposed CFD and EnKF coupling model allows the integration of observation data into the CFD simulations to enhance the prediction accuracy of the LNG vapor spatial-temporal distribution and thereby realizing a reasonable estimation of the LNG leakage velocity under complex environments. This study can provide technical supports for safety control, loss prevention and emergency response in case of LNG leakage accidents. [ABSTRACT FROM AUTHOR] more...
- Published
- 2021
- Full Text
- View/download PDF
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