Patent ID: 8959930
Filing Date: 2015-02-24
Classification: F17C

Abstract:
1. A method for treating boil-off gas generated in an LNG storage tank of an LNG carrier for transporting LNG in a cryogenic liquid state, comprising the steps of discharging boil-off gas from the LNG storage tank at a pressure greater than 0.25 bar to 2 bar, and reliquefying said boil-off gas in a reliquefaction plant, wherein a uniform temperature distribution is maintained in the LNG storage tank by spraying the LNG from a lower portion of the LNG storage tank toward boil-off gas at an upper portion of the LNG storage tank and injecting the boil off gas into the LNG at the lower portion of the LNG storage tank, and wherein the amount of boil-off gas that is discharged is regulated as a function of the level of LNG in the LNG storage tank, wherein the level of LNG in the LNG storage tank is calculated by measuring the flow rate of fuel gas supplied from the LNG storage tank to a fuel gas supply line to a fuel gas propulsion means, and wherein the flow rate of fuel gas is measured by a flow rate measurer within the fuel gas supply line.