Patent ID: 11933539
Assignee: PRAXAIR TECHNOLOGY, INC.
Field: Chemical engineering (Chemistry)
Classification: CPC F | IPC F

Claim 0:
1. An oxygen, argon and nitrogen producing air separation unit configured to receive an incoming feed air stream and produce one or more oxygen product streams one or more nitrogen product streams, and an argon stream, the air separation unit having a main air compression and purification system, a main heat exchanger, and 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, an argon column configured for receiving an argon-oxygen containing stream from the lower pressure column, and an argon condensing arrangement configured for condensing an argon-rich vapor stream from the argon column against an oxygen containing condensing medium, the air separation unit characterized by:
a first portion of a boil-off vapor stream exiting the argon condenser is configured to be returned to the lower pressure column; and
a second portion of the boil-off vapor stream exiting the argon condenser is configured to be recycled and mixed with the incoming feed air stream.