To provide a nitrogen producing method and an apparatus, which cope with increase/decrease of a wide-range product nitrogen gas use amount in a unit consumption of power nearly equal to before, and supply products different in purity or pressure if necessary.
By liquefying and separating material air at a low temperature in a first intermediate-pressure rectifying tower 22, a first product nitrogen gas N1 is collected. Pseudo air led out of a low-pressure rectifying tower 23 accompanying the first rectifying tower 22 is compressed at normal temperatures and is led into a second intermediate-pressure rectifying tower 25, and a second product nitrogen gas N2 is collected from the second rectifying tower 25. In reduced amount operation, the product nitrogen gas N1 is collected and supplied from only the first rectifying tower 22 by stopping a pseudo air compressor. The product nitrogen gasses N1, N2 different in the purity or the pressure are collected from the first rectifying tower 25 and the second rectifying tower 25.
COPYRIGHT: (C)2004,JPO
Toshiyuki Nojima
Takashi Tatsumi
| JP56044577A |
| US6397631 |