Method for returning vapor phase of liquefied natural gas into liquid gas tank of liquefied petroleum gas carrier during discharge of liquefied petroleum gas carrier, involves utilizing jet pump for redirecting boil-off gas

摘要

The method involves utilizing a jet pump (8) for redirecting boil-off gas. Liquid gas i.e. liquefied natural gas, in a pump (5) is compressed of about 5-50 bars, so that an evaporator (7) converts condensed liquid into gas phase in a center opening. Difference in pressure between a storage tank (2) and a ship tank is used for returning vapor phase to a liquid gas tanker (1), which again-reflects the temperature difference between the storage tank and ship tank in an adverse condition. An independent claim is also included for a device for returning a vapor phase into a liquid gas tank of a liquefied petroleum gas carrier.