PROCESS FOR THE SEPARATION OF AIR BY CRYOGENIC DISTILLATION

摘要

A process for the separation of air by cryogenic distillation operates either with a product ratio greater than 2.5 in which case nitrogen enriched liquid is sent from a storage tank (27) to the column system and feed air or nitrogen enriched gas (29) from the column system is compressed in a first compressor (33) having an inlet temperature of less than -50°C and then sent to the heat exchanger, or with a product ratio less than 2.5 in which case a second nitrogen rich gas removed from the column system is expanded in a turbine (73) having an inlet temperature lower than the ambient temperature or liquefied in a liquefier and nitrogen enriched liquid (57) is sent to the storage tank from the outlet of the turbine and/or from the column system and/or from the liquefier.