Patent ID: 6295837
Filing Date: 2001-10-02
Classification: F25J,Y10S

Abstract:
An apparatus for air separation comprising:a cryogenic separation unit for receiving pre-purified feed air and separating the same into nitrogen gas and oxygen gas;a first heat exchanger for receiving liquefied natural gas as a cold source and for cooling and liquefying a refrigerant by indirect heat exchange with said liquefied natural gas;a second heat exchanger;a refrigerant supply line for supplying said refrigerant liquefied in the first heat exchanger to the second heat exchanger;a refrigerant return line for returning said refrigerant vaporised in the second heat exchanger to the first heat exchanger;a first nitrogen gas line for sending at least part of the nitrogen gas separated in said cryogenic separation unit to the second heat exchanger;a second nitrogen gas line for supplying said nitrogen gas cooled within the second heat exchanger to the outside; anda low-temperature nitrogen compressor provided on the second nitrogen line for compressing said nitrogen gas and supplying the compressed nitrogen gas as high-pressure product gas to the outside.