TITLE:
An Analysis of the Greenhouse Gas Emissions by the Re-Liquefaction of Boil-Off Gas of LNG Storage Tank
AUTHORS:
Gang Sun, Shengchun Liu, Xueqiang Li
KEYWORDS:
LNG, Boil-Off Gas, Re-Liquiefication, Greenhouse Gas Emissions
JOURNAL NAME:
Energy and Power Engineering,
Vol.7 No.8,
August
13,
2015
ABSTRACT: The pressure in liquefied natural gas (LNG) storage tank continues to increase due to the heat
transfer from ambient air to low temperature LNG, which raises safety concerns. Accordingly,
there is increasing interest to explore the technical approaches capable of recovering Boil-Off Gas
(BOG) and even eliminating the ventilation of LNG storage tank. This research numerically analyzed
the greenhouse gas emissions of the re-liquefaction of BOG using the following four approaches:
1) a Claude cycle driven by electrical motor with the electricity produced by burning
coal; 2) a Claude cycle driven by a gas turbine fuelled by BOG released; 3) a Claude cycle driven by
a SI engine fuelled by gasoline; 4) burning nature gas directly released by BOG. The impact of heat
transfer coefficient, LNG tank configuration, size, and percentage of LNG stored in tank on the rate
of BOG and energy needed for the re-liquefaction of methane vapor were investigated. The greenhouse
gas emissions (GGE) was examined and compared. The data presented in this paper provide
guideline for the management of pressure development in LNG storage tank.