Boil Off Gas (BOG)
Boil off is a term used in LNG projects. However well insulated LNG storage tanks may be, the LNG is always at its boiling point, and small quantities will continue to boil off. In liquefaction plants a small volume of boil off gas is required to ensure that the plant flare is operational. Boil off not needed for this purpose will normally be used in the plant’s own low pressure fuel system. On LNG tankers driven by steam turbines the gas is normally used as a fuel to drive the ships.