METHOD FOR SUBCOOLING A LNG STREAM OBTAINED BY COOLING BY MEANS OF A FIRST REFRIGERATING CYCLE, AND RELATED INSTALLATION

摘要

The invention concerns a method which consists in subcooling a LNG stream (11) with a coolant (41) in a first heat exchanger (19). Said coolant (41) is subjected to a closed refrigerating cycle (21). The closed cycle (21) comprises a phase for heating the coolant (42) in a second heat exchanger (23), and a phase for compressing the coolant (43) in a compression apparatus (25) up to a pressure higher than its critical pressure. It further includes a phase for cooling the coolant (45) from the compression apparatus (25) in the second heat exchanger (23) and a phase of dynamic expansion of part (47) of the refrigerating fluid derived from the second heat exchanger (23) in a turbine (31). The coolant (41) comprises a mixture of nitrogen and methane.