Abstract: Disclosed herein is a natural gas liquefaction process using a single refrigeration cycle adopting a mixed refrigerant, and therefore having a simple structure and thus a compact system which is easy to operate, and further, after the mixed refrigerant is separated into two refrigerant parts, the two refrigerant parts are not mixed with each other but go through condensing (cooling), expanding, heat-exchanging, and compressing stages individually, and thus, optimal temperature and pressure conditions are applied to each of the separated refrigerant parts to increase efficiency of the liquefaction process.

Abstract: 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.

Abstract: Provided is a re-liquefying method for a stored liquid which has a simple structure or operation and excellent process efficiency. Since the method does not use separate refrigerant, the structure or operation in the re-liquefying method is significantly simplified. In addition, since a portion of a main stream is separated to form a cycle similar to a refrigerant cycle which cools the mainstream, the process efficiency of the re-liquefying method is significantly improved. The above Abstract is a more accurate literal translation of the abstract from the original priority application than the PCT abstract.

Abstract: Disclosed herein is a natural gas liquefaction process of pre-cooling natural gas using a closed loop pre-cooling cycle and liquefying the pre-cooled natural gas using a closed loop liquefying cycle, wherein the closed loop pre-cooling cycle includes first and second pre-cooling cycles in parallel for pre-cooling supplied natural gases together in the same first heat exchange region through the respective pure refrigerants, and the closed loop liquefying cycle includes at least one liquefying cycle for liquefying the pre-cooled natural gas through a mixed refrigerant, the first and second pre-cooling cycles being a closed circuit cooling cycle.

Abstract: Disclosed herein is a natural gas liquefaction process using a single refrigeration cycle adopting a mixed refrigerant, and therefore having a simple structure and thus a compact system which is easy to operate, and further, after the mixed refrigerant is separated into two refrigerant parts, the two refrigerant parts are not mixed with each other but go through condensing (cooling), expanding, heat-exchanging, and compressing stages individually, and thus, optimal temperature and pressure conditions are applied to each of the separated refrigerant parts to increase efficiency of the liquefaction process.