To facilitate adaptation of variation in demand for nitrogen and oxygen or the like and further expand an amount of utilization of cold heat of LNG.
Cooling of raw material air under an operation of an air/ nitrogen heat exchanger 24 and a refining tower 25 is carried out by nitrogen gas forming a Brayton cycle. Nitrogen gas is cooled with an LNG/nitrogen heat exchanger 26, its pressure is increased by a low pressure compressor 28 of a circulating nitrogen compressor 27 and cooled again by the LNG/nitrogen heat exchanger 26, its pressure is increased by a high pressure compressor 29 of the circulating nitrogen compressor 27, it is cooled by the LNG/nitrogen heat exchanger 26, liquefied, thereafter fed into a refining tower 25 and used for separating raw material air. A first power generator 31 rotates a nitrogen expansion turbine 35 and drives it. A second power generator 32 is driven by a gas turbine 39. As natural gas becoming fuel, a part of the natural gas fed out of the device is used. A third power generator 33 is driven by a natural gas expansion turbine 40.
OHAMA TAKASHI
YAMAZAKI YOSHIHIRO
SUGIYAMA OSAMU
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