Patent ID: 9476640
Filing Date: 2016-10-25
CPC Classification: F25J

Claim Text:
1. A method for producing nitrogen by cryogenic distillation of air, the method comprising the steps of: analyzing a carbon monoxide content of an air stream; sending the air stream to a cryogenic distillation column; taking a flow D of nitrogen from the top of the distillation column, the flow D of nitrogen having a CO content less than a fixed value S1; and sending a flow of nitrogen-rich cryogenic liquid coming from an external source to the top of the cryogenic distillation column, the flow rate of the nitrogen-rich cryogenic liquid sent to the cryogenic distillation column being less than a value V if the CO content in the air stream does not exceed a previously defined threshold, wherein the flow rate of the nitrogen-rich cryogenic liquid sent to the cryogenic distillation column is greater than a value V if the carbon monoxide content of the air stream exceeds this previously defined threshold.