Estimation of Evaporation Losses of Bunker LNG

Analysis of efficiency of transport systems using liquefied natural gas (LNG) as fuel is impossible without a comprehensive understanding of the volumes of fuel LNG losses from evaporation during main technological operations: transportation (storage), bunkering, and cool-down of fuel tanks. Despite active development of water and land natural gas vehicles, practical approaches for obtaining appropriate estimates in a wide range of characteristics of cargo tanks have not been previously published.

The objective of this work is to analyze LNG losses in road, rail and ship tanks (with a capacity of up to 5600 m3), as well as in tank containers, provided that LNG is stored with an overpressure of about 5–7 atmospheres.

In the work, numerical modelling was used as a method. The evaporation process of LNG is described using models of heat exchange between the liquid phase of LNG, its vapours, as well as a cargo tank and the external environment. This makes it possible to simulate the behaviour and phase transformations of LNG during its storage in a tank, as well as during main technological operations. Numerical modelling of thermodynamic processes during storage of LNG is performed using a computer simulation model implemented in AnyLogic environment. Quantitative estimates of LNG losses during bunkering and cool-down of fuel tanks were obtained based on analytical calculations.

An analysis of sensitivity of the created models to various parameters, as well as massive numerical calculations, made it possible to construct regression relationships to determine LNG losses during operations under consideration. The obtained dependencies can be used to search for the most effective configurations of the system for low-tonnage LNG transportation, as well as to perform economic assessments of feasibility of using LNG as fuel for water and land transport.

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