Process for the production of a subcooled liquefied natural gas stream from a natural gas feed stream, and associated installation

摘要

A process for the production of a subcooled liquefied natural gas stream from a natural gas feed stream. Passing a first natural gas feed stream through a first heat exchanger for precooling by heat exchange with a first stream of gaseous refrigerant produced in a first refrigeration cycle comprising a first dynamic expansion turbine. Passing the precooled feed stream through a second heat exchanger for liquefying by heat exchange with a second stream of gaseous refrigerant produced in a second refrigeration cycle comprising a second dynamic expansion turbine. Passing the liquefied natural gas stream through a third heat exchanger for subcooling the liquefied gas by heat exchange with a third refrigerant stream produced in a third refrigeration cycle comprising a third dynamic expansion turbine separate from the first turbine and the second turbine. An installation includes devices for conveying the natural gas stream, the heat exchangers and the turbines and compression devices cooling the refrigerants for the heat exchangers.