Options and Evaluations on Propulsion Systems of LNG Carriers

Huan, Tu; Fan, Hongjun; Lei, Wei; Guo-qiang, Zhou

doi:10.5772/intechopen.82154

Cited by 25 publications

(22 citation statements)

References 4 publications

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“…The difference in speeds between steam-powered LNGCs and the whole liquefied gas tanker fleet has important implications for the quantification of emissions and fuel consumption on bottom-up approaches since they tend to aggregate the whole fleet per ship class 1 under an average speed and ship/propulsion efficiency. With STPS, higher operational speeds coupled with lower propulsive efficiency (Tu et al., 2019) will tend to higher estimated CO 2 emissions per ship than for LNGCs with an alternative propulsion system (e.g. dual-fuel four-stroke diesel engine).…”

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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“…Currently, there are two types of dual fuel engines for large ships, namely, the highpressure engines operating on the Diesel cycle and the low-pressure engines operating on the lean-burn Otto cycle. The low-pressure engines allow the gas to be injected at low pressure, ranging from 5 to 16 bar [49,50]. This results in low levels of NOx emissions and can meet the IMO Tier III requirements.…”

Section: 22mentioning

confidence: 99%

Comparison of the Economic Performances of Three Sulphur Oxides Emissions Abatement Solutions for a Very Large Crude Carrier (VLCC)

Fan

Huan

Enshaei

et al. 2021

JMSE

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Ship-source air pollutants, especially sulphur oxides (SOx), have a major impact on human health, the marine environment and the natural resources. Therefore, control of SOx emissions has become a main concern in the maritime industry. The International Maritime Organization (IMO) has set a global limit on sulphur content of 0.50% m/m (mass by mass) in marine fuels which has entered into effect on 1 January 2020.To comply with the sulphur limits, ship owners are facing the need to select suitable abatement solutions. The choice of a suitable solution is a compromise among many issues, but the economic performance offers the basis for which ones are attractive to ship owners. Currently, there are three technologically feasible SOx abatement solutions that could be used by ships, namely, liquified natural gas (LNG) as a fuel (Solution A), scrubbers (Solution B) and low-sulphur fuel oil (LSFO) (Solution C). To compare the economic performances of the mentioned three solutions for a newbuilding very large crude carrier (VLCC), this paper proposes a voyage expenses-based method (VEM). It was found that, within the initial target payback period of 6 years, Solution A and C are more expensive than Solution B, while Solution C is more competitive than Solution A. Five scenarios of target payback years were assumed to compare the trends of the three proposed solutions. The results show that Solution B maintains its comparative advantage. As the assumed target payback years becomes longer, the economy of Solution A gradually improves and the economics of Solution B and C gradually decline. A comparison between Solution A and C shows 6.5 years is a turning point. The advantage of Solution A is prominent after this payback period. In addition, the performance of a certain solution in terms of adaptability to the IMO greenhouse gas (GHG) emissions regulations is also a factor that ship owner need to consider when making decisions. In conclusion, when the IMO air pollutant regulations and GHG regulations are considered simultaneously, the advantages of using LNG are obvious.

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“…The number of cylinders installed for a large generator is seven, and a small generator has five; one of these cylinders can generate 460 kW. The distribution system for each ship is symmetrical, and the number of generators ranges mostly from 3 to 5 [8][9][10], but the types and sizes of many other devices that depend on them vary from ship to ship. A generator contains an engine that is assembled with several units of cylinders for power generation.…”

Section: Introductionmentioning

confidence: 99%

A Study of the Method for Calculating the Optimal Generator Capacity of a Ship Based on LNG Carrier Operation Data

2021

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Currently, the total generator capacity installed in most ships is greater than the required capacity. In addition, due to new environmental regulations, various auxiliary gears are required to avoid breaking the law. Therefore, the internal environments of ships, such as their machine rooms, have become narrower, making creating space more important than ever before. This paper provides a method for optimizing generator capacity through an analysis of total load data in order to avoid overestimating the generator capacity. In addition, an actual situation in which the generator capacity is determined by the number of cylinders is considered. Three practical case studies with different possible combinations of generators and varying capacities are presented. Therefore, this method can secure space and reduce weight, which can be beneficial in many ways. Additionally, since it does not require various types of data, this information can be used for already built ships or those that will be made in the future.

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Options and Evaluations on Propulsion Systems of LNG Carriers

Cited by 25 publications

References 4 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

Comparison of the Economic Performances of Three Sulphur Oxides Emissions Abatement Solutions for a Very Large Crude Carrier (VLCC)

A Study of the Method for Calculating the Optimal Generator Capacity of a Ship Based on LNG Carrier Operation Data

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