US 11,933,541 B2
Cryogenic air separation unit with argon condenser vapor recycle
Zhengrong Xu, East Amherst, NY (US)
Assigned to Praxair Technology, Inc., Danbury, CT (US)
Filed by Zhengrong Xu, East Amherst, NY (US)
Filed on Aug. 11, 2021, as Appl. No. 17/399,713.
Prior Publication US 2023/0050296 A1, Feb. 16, 2023
Int. Cl. F25J 3/04 (2006.01)
CPC F25J 3/04678 (2013.01) [F25J 3/04412 (2013.01); F25J 2200/06 (2013.01); F25J 2200/72 (2013.01); F25J 2215/42 (2013.01); F25J 2215/50 (2013.01); F25J 2215/58 (2013.01); F25J 2245/58 (2013.01)] 18 Claims
OG exemplary drawing
 
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.