Patent ID: 8893515

Claim:
A method of Wobbe index control of LNG in an LNG storage tank, comprising: fluidly coupling an LNG storage tank to a regasification unit such that the tank provides LNG to the regasification unit; fluidly coupling a compression unit to the LNG storage tank such that the tank provides cold boil-off gas to the compression unit, wherein the compression unit forms a compressed boil-off gas; heat-exchanging a first stream of the compressed boil-off gas using the cold boil-off gas to form cooled compressed boil-off gas, and combining a first portion of the cooled compressed boil-off gas with the LNG that is fed to the regasification unit; reliquefying a second portion of the cooled compressed boil-off gas to form a reliquefied boil-off gas; separating nitrogen from the reliquefied boil-off gas to produce a lean reliquefied boil-off gas; and feeding the lean reliquefied boil-off gas into the LNG storage tank.