Patent ID: 7552598
Filing Date: 2009-06-30
Classification: F25J

Abstract:
1. A process for sub-cooling an LNG stream obtained by cooling using a first refrigeration cycle, the process comprising the following steps: (a) introducing the LNG stream at a temperature of less than −90° C. into a first heat exchanger; (b) sub-cooling the LNG stream in the first heat exchanger by heat exchange with a refrigerating fluid comprising a mixture of nitrogen and methane; (c) subjecting the refrigerating fluid to a closed second refrigeration cycle which is independent of said first cycle, the closed second refrigeration cycle comprising the following successive phases: wherein the sub-cooling stream issuing from step (iii1) is placed in the heat exchange relationship with the stream of refrigerating mixture in the third heat exchanger, without placing the stream of refrigerating mixture issuing from step (iii1) in a heat exchange relationship with the LNG stream.