Patent ID: 9435583
Filing Date: 2016-09-06
CPC Classification: F25J

Claim Text:
1. A method of liquefying a hydrocarbon stream from a feed stream, the method at least comprising the steps of: (a) providing a feed stream; (b) passing the feed stream through at least two cooling stages to provide a liquefied hydrocarbon stream, each cooling stage involving one or more heat exchangers, one of said heat exchangers involving a first refrigerant circuit having a first refrigerant stream of a first mixed refrigerant, and a second of said heat exchangers involving a second refrigerant circuit having a second refrigerant stream of a second mixed refrigerant; (c) separating the first refrigerant stream into a first light refrigerant stream and a first heavy refrigerant stream, and separating the second refrigerant into a second light refrigerant stream and a second heavy refrigerant stream; (d) expanding the liquefied hydrocarbon stream and separating flashed vapour from the liquefied hydrocarbon stream to provide a liquefied hydrocarbon product stream and a gaseous stream; and (e) passing the gaseous stream, the first light refrigerant stream and the second light refrigerant stream through an end heat exchanger, for the gaseous stream to provide cooling to the first and second light refrigerant streams.