Linde Aktiengesellschaft

Wolfgang Haag

Dietrich Rottmann

Horst Corduan

Christian Kunz

Juergen Voit

The process and the apparatus serve to produce pressurized nitrogen by low-temperature fractionation of air in a rectification system which has a pressure column (,) and a low-pressure column (,). Feed air (,) is passed into the pressure column (,). An oxygen-containing liquid fraction (,) is taken off from the pressure column (,) and fed into the low-pressure column (,). Gaseous nitrogen (,) from the low-pressure column (,) is at least partially condensed in a top condenser (,) by indirect heat exchange with an evaporating liquid (,). Nitrogen from the low-pressure column is produced as gaseous pressurized nitrogen product (,) at a pressure which is higher than the operating pressure of the low-pressure column (,). Liquid nitrogen (,) withdrawn from the low-pressure column is brought (,) in the liquid state to a pressure which exceeds the pressure of the low-pressure column (,). The pressurized liquid (,) is evaporated in a product evaporator (,) by indirect heat exchange with a heat-transfer medium (,) and is subsequently produced as gaseous pressurized nitrogen product (,). (FIG.,)

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Munich, Germany

Wolfgang Haag