METHOD AND APPARATUS FOR LIQUEFYING A HYDROCARBON STREAM

摘要

Method of liquefying a hydrocarbon stream such as natural gas from a feed stream (10), the method at least comprising the steps of: (a) circulating a first refrigerant stream (70) in a first refrigerant circuit (110); (b) cooling the first refrigerant stream (70) in one or more heat exchangers (14) of a first cooling stage (100) to provide a cooled first refrigerant stream (20); (c) passing at least part of the cooled first refrigerant stream (20) through one or more expanders to provide one or more expanded cooled first refrigerant streams (30); (d) passing the or at least one of the expanded cooled first refrigerant streams (30) and the feed stream (10) through the first one or more heat exchangers (14) to provide a cooled hydrocarbon stream (40); (e) passing the cooled hydrocarbon stream (40) through a second cooling stage (200) against a second refrigerant stream (50) to provide a liquefied hydrocarbon stream (60); wherein at least one expander is an expansion turbine (12) whose work energy created in step (c) is used in the first refrigerant circuit (110).