Patent ID: 11933541
Assignee: PRAXAIR TECHNOLOGY, INC.
Field: Chemical engineering (Chemistry)
Classification: CPC F | IPC F

Claim 0:
1. An argon and nitrogen producing air separation unit configured to receive an incoming feed air stream and produce a nitrogen product stream and an argon stream, the argon and nitrogen producing air separation unit having a main air compression and purification system, a main heat exchanger, a distillation column system having a higher pressure column and a lower pressure column linked in a heat transfer arrangement via a main condenser-reboiler, and an argon column arrangement comprising an argon column configured for receiving an argon-oxygen containing stream from the lower pressure column and an argon condenser configured for condensing an argon-rich vapor stream from the argon column against an oxygen containing condensing medium from the higher pressure column, the argon and nitrogen producing air separation unit characterized by:
a first portion of a boil-off stream from the argon condenser configured to be combined with an oxygen stream from the lower pressure column and expanded in a waste expansion turbine; and
a second portion of the boil-off stream from the argon condenser is configured to be recycled and mixed with the incoming feed air stream.