Patent ID: 9625208
Date: 2017-04-18
CPC Classifications: F25J

Claim:
1. A method of liquefying a gaseous hydrocarbon stream, the method at least comprising the steps of: (a) providing a feed stream comprising the gaseous hydrocarbon stream at an elevated pressure; (b) dividing the feed stream of step (a) to provide at least a first stream and a second stream; (c) expanding the first stream or compressing the second stream, or both; (d) cooling and liquefying the first stream downstream of step (c) by heat exchanging exclusively against a liquid nitrogen stream that is at a pressure of less than 10 bara, to provide a first liquefied hydrocarbon stream and an at least partly evaporated nitrogen stream; and (e) cooling and liquefying the second stream downstream of step (c) by heat exchanging against the at least partly evaporated nitrogen stream of step (d) without invoking a significant change in pressure of the evaporated nitrogen stream other than a de minemus operational pressure loss caused by the present heat exchanging of step (e) and passing the evaporated nitrogen stream from the heat exchanging of step (d) to the present heat exchanging of step (e), wherein the cooling of the first stream and second stream is carried out at different pressures.