초록 ▼

This invention relates to a process for liquefying a pressurized gas stream rich in methane in which the liquefication of the gas stream occurs in a heat exchanger being cooled by a cascade refrigeration system to produce a methane-rich liquid product having a temperature above about -112.degree. C.

This invention relates to a process for liquefying a pressurized gas stream rich in methane in which the liquefication of the gas stream occurs in a heat exchanger being cooled by a cascade refrigeration system to produce a methane-rich liquid product having a temperature above about -112.degree. C. (-170.degree. F.). In this process, a pressurized gas stream is introduced into heat exchange contact with a first refrigerant cycle comprising at least one refrigeration stage whereby the temperature of the gas stream is reduced by heat exchange with a first portion of a first refrigerant to produce a cooled gas stream. The cooled gas stream is then introduced into heat exchange contact with a second refrigerant cycle comprising at least one refrigeration stage whereby the temperature of the cooled gas stream is further reduced by heat exchange with a second refrigerant to produce a liquefied methane-rich stream having a temperature above about -112.degree. C. (-170.degree. F.) and a pressure sufficient for the liquefied stream to be at or below its bubble point.

대표청구항 ▼

[ What is claimed is:] [1.] A process for liquefying a pressurized methane-rich gas stream comprising the steps of:(a) introducing the gas stream into heat exchange contact with a first refrigerant cycle comprising at least one refrigeration stage whereby the temperature of the gas stream is reduced

[ What is claimed is:] [1.] A process for liquefying a pressurized methane-rich gas stream comprising the steps of:(a) introducing the gas stream into heat exchange contact with a first refrigerant cycle comprising at least one refrigeration stage whereby the temperature of the gas stream is reduced by heat exchange with a first portion of a first refrigerant to produce a cooled gas stream;(b) introducing the cooled gas stream into heat exchange contact with a second refrigerant cycle comprising at least one refrigeration stage whereby the temperature of the cooled gas stream is further reduced by heat exchange with a second refrigerant to produce a liquefied methane-rich stream having a temperature above about -112.degree. C. (-170.degree. F.), said second refrigerant having a boiling point lower than the boiling point of the first refrigerant and the second refrigerant being partially cooled and condensed by heat exchange with a second portion of the first refrigerant; and(c) introducing the liquefied stream to a storage means at a temperature above about -112.degree. C. (-170.degree. F.) and a pressure sufficient for the liquefied stream to be at or below its bubble point.