Patent ID: 8820096
Filing Date: 2014-09-02
Classification: F17C

Abstract:
1. An LNG tank ship comprising: a heat insulated tank; LNG and boil-off gas of the LNG contained in the tank; a safety valve configured to release part of the boil-off gas of the LNG from the tank when a vapor pressure within the tank exceeds a cut-off pressure of the safety valve, wherein the safety valve is configured to adjust the cut-off pressure within a range between a first value and a second value, the first value being 0.25 bar (gauge pressure) or below, the second value being between about 0.25 bar (gauge pressure) and about 2 bar (gauge pressure); and a controller configured to monitor settings of the cut-off pressure of the safety valve based on a currently allowable cut-off pressure of the safety valve computed using a volume of the LNG contained in the tank.