The supplier of the plant is Italian company SIAD MI. The air compressed by a centrifugal compressor and is pre-cooled within a duct contact after cooler, the moisture is separated by condensation and the air gets into the molecular sieves adsorbing unit for CO2 removal and drying. Two vessels compress the unit; one is on stream while the other one is being regenerated. Then the air goes through a filter to remove possible dust and enters the cold box where is cooled and separated.
The air coming from the preliminary treatment enters the main exchanger where it cools in counter current with outlet gases and partially enters the medium pressure column and partially enters the expander. After expansion, the air enters the low-pressure column.
The liquid Nitrogen, at the top of MP column, is sent to LP column in order to from the main reflux. Also the kettle is sent to an intermediate part of the LP column and this forms the minor reflux. At the bottom of LP column (i.e in the main condenser) the liquid oxygen is collected and evaporating, condenses the gaseous Nitrogen that enters the MP column.