Parametric Investigation of BOG Generation for Ship-to-Ship LNG Bunkering

Shao, Yude; Lee, Yoon-Hyeok; Kim, You-Taek; Kang, Hokeun

doi:10.7837/kosomes.2018.24.3.352

Cited by 8 publications

(8 citation statements)

References 3 publications

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“…8⋅4%). One plausible explanation is that, during the ballast legs, the temperature in the cargo tanks must be the correct one to receive LNG to minimise thermal stresses while minimising BOG generation (Lu et al., 2016; Shao et al., 2018). This cooling procedure adds time to the ballast leg, as seen in Figure 3, for the berthing time.…”

Section: Resultsmentioning

confidence: 99%

An empirical analysis on the operational profile of liquefied natural gas carriers with steam propulsion plants

et al. 2020

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Liquefied natural gas (LNG) offers negligible NOx and SOx emissions as well as reductions in CO2 compared with other liquid hydrocarbons. LNG is a significant player in the global energy mix, with a projection of 40% increase in demand for the next two decades. It is anticipated that the expected rise in demand will cause the fleet of LNG carriers (LNGC) to expand. This work concentrates on steam-powered LNGC, which accounted for 47% of the LNGC fleet in 2018. It performs an empirical analysis of continuous monitoring data that provide high levels of accuracy and transparency. The analysis is done on data collected from 40 LNGCs for over a year to estimate the fleet's operational profile, fuel mix and energy performance. The findings of this work are relevant for bottom-up analysis and simulation models that depend on technical assumptions, but also for emission studies such as the upcoming Fourth International Maritime Organization Greenhouse Gases study.

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Section: Resultsmentioning

confidence: 99%

An empirical analysis on the operational profile of liquefied natural gas carriers with steam propulsion plants

et al. 2020

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“…With regard to the initial design considerations, the minimum filling ratio of 10% can be assumed as a rule of thumb. The amount of LNG remaining in the tank directly affects the tank's pressure and temperature and the bunkering process [26]. When the amount of LNG is insufficient to maintain the tank at a critical temperature, bunkering thermal shock can occur in the LNG fuel tank because of the significant temperature difference between the tank atmosphere and charged LNG [27].…”

Section: Sph Methodsmentioning

confidence: 99%

Numerical Study on the Tank Heel Determination Using Smoothed Particle Hydrodynamics

Park

Luong

Choung

2021

JMSE

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Tank heel minimization is a significant issue in the design of LNG fuel tanks because it is associated with stable suction pump operation and thermal shock requirements during LNG bunkering. This study examined how the LNG tank heel is minimized, maintaining a suction pump fully submerged in LNG during dynamic vessel motion. The study assumed two LNG fuel tanks mounted on the forward deck of a 50,000 deadweight class oil product carrier. Information on the dimensions and shape of the LNG fuel tank was determined from Wartsila’s brochure, and the specifications of Vanzetti’s suction pump were referred to. The LNG fuel tank and LNG heel were modeled as rigid elements and hydrodynamically smoothed-particles, respectively. The number of particles could be determined by performing even keel analyzes by adding or subtracting particles until the target head was satisfied under the gravity load. To simulate the motion of the LNG fuel tank, the pitch and roll periods and amplitudes of the ship were calculated using the DNV classification rules. Visual observations of the dynamic flow during the pitch and roll motions with respect to the ship’s center of mass showed that the roll motion was more critical from the viewpoint of the LNG heel than the pitch motion. After performing the simulations for three cycles of roll and pitch motions, the suction pump submergence was reviewed in the last cycle. Under the conditions assumed in this study, a filling ratio of 15% was determined as the minimum LNG tank heel. Although the LNG heel has customarily been determined, the LNG heel needs to be determined through hydrodynamic analyses of each vessel because it depends on the shape of the fuel tank and the vessel motion characteristics.

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“…A few ships may require a shorter bunkering time when compared to others based on their operating profile. Based on the frequency of bunkering and the size of the fuel tanks, the owners may wish to maximize the bunkering rate [32].…”

Section: Lng Flow Rate and Total Lng Bunkering Amountmentioning

confidence: 99%

Dynamic Optimization of Boil-Off Gas Generation for Different Time Limits in Liquid Natural Gas Bunkering

2019

Self Cite

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This study focus on the optimal time limit of ship-to-ship (STS) liquid natural gas (LNG) bunkering by dynamic simulation. Based on this, a mathematical model for calculating the boil-off gas (BOG) amount was developed. With respect to the modeling of the study, the diameter of the bunkering line is set as 8 inch while that of the BOG return pipeline is set as 4 inch to satisfy the pressure of the receiving ship and BOG generation. The capacities of the cargo tank and fuel tank for bunkering and receiving ships are set as 4538 m3 and 700 m3, respectively. The results indicated that the BOG amount with different LNG bunkering time limit is variable. The BOG flow rate varies inversely with respect to the bunkering time limit after 20 min. Additionally, it is necessary to control the bunkering time within 120 min since additional BOG is generated when the capacity of the pump exceeds 100,000 kg/h, and thus the tank pressure difference between bunkering and receiving ship may be reduced. It is believed that the results of the research could provide feasible assistance for STS LNG bunkering for the ports, and could give a specific guideline for the amount of the BOG generation.

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Parametric Investigation of BOG Generation for Ship-to-Ship LNG Bunkering

Cited by 8 publications

References 3 publications

An empirical analysis on the operational profile of liquefied natural gas carriers with steam propulsion plants

An empirical analysis on the operational profile of liquefied natural gas carriers with steam propulsion plants

Numerical Study on the Tank Heel Determination Using Smoothed Particle Hydrodynamics

Dynamic Optimization of Boil-Off Gas Generation for Different Time Limits in Liquid Natural Gas Bunkering

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