NATURAL GAS LIQUEFACTION PROCESS

摘要

A natural gas liquefaction process according to the present invention uses a single closed-loop refrigeration cycle employing a mixed refrigerant, thereby having a simple structure for the liquefaction process and allowing the liquefaction process to be easily operated. Furthermore, the present invention cools natural gas after one stream is separated into two streams, thereby having an excellent efficiency of the liquefaction process.

主权项

1. A natural gas liquefaction process in which natural gas is primarily cooled in a first heat exchange part and secondarily cooled in a second heat exchange part distinguished from the first heat exchange part by using a single closed-loop refrigeration cycle using a mixed refrigerant, the closed-loop refrigeration cycle comprising:
a condensation step of partially condensing the mixed refrigerant; a first separation step of separating the mixed refrigerant into a first stream having a liquid phase and a second stream having a gas phase after the condensation step; a first introduction step of introducing the first stream into the first heat exchange part after the first separation step; a first expansion step of expanding the first stream discharged from the first heat exchange part after the first introduction step; a first cooling step of introducing the first stream again into the first heat exchange part to cool the natural gas in the first heat exchange part through the first stream after the first expansion step; a first recovery step of recovering the first stream from the first heat exchange part after the first cooling step; a second introduction step of introducing the second stream into the first heat exchange part after the first separation step; a third introduction step of introducing the second stream discharged from the first heat exchange part into the second heat exchange part after the second introduction step; a second expansion step of expanding the second stream discharged from the second heat exchange part after the third introduction step; a second cooling step of introducing the second stream again into the second heat exchange part to cool the natural gas in the second heat exchange part through the second stream after the second expansion step; and a second recovery step of recovering the second stream from the second heat exchange part after the second cooling step; wherein the first stream is transferred for the condensation step after the first recovery step, and the second stream is transferred for the condensation step after the second recovery step.