RELIQUEFACTION OF BOIL-OFF FROM LIQUEFIED NATURAL GAS

摘要

The present invention relates to an improved process for the reliquefaction of boil-off gas (1) containing up to 10% nitrogen resulting from the evaporation of liquefied natural gas (LNG) contained in a storage vessel. In the process, a closed-loop nitrogen refrigeration cycle is utilized wherein the nitrogen is isenthalpically expanded (108) under conditions for generating a liquid and vapor with the liquid (15) being pressurized by pumping and warmed against an initially cooled boil-off stream (3). The boil-off LNG stream (2) is initially cooled by indirect heat exchange with an isentropically expanded refrigerant stream (33).