| 摘要 |
Nitrogen is produced by feeding cooled, compressed purified air to a distillation column (14) to produce O-rich liquid bottoms (26) and a N-rich overhead vapour (20). Liquid (28) with N2 content greater than that of the bottoms is extracted from the column, and this and the bottoms are expanded and used to cool and at least partly condense the overhead vapour. The expanded bottoms stream (38) is indirectly heat-exchanged with feed air, and the expanded second liquid stream (40) is compressed, cooled and returned to the column bottom. The appts. in which the above process is performed is also claimed. A main heat-exchanger (12) cools feed air, partially warms the vaporised bottoms stream and fully cools the vaporised second liquid stream. A condenser condenses the overhead, returns part as reflux and vaporises the liquid streams, and is connected to the main exchanger, via a compressor for the second vaporised stream. There are two expansion valves (32,34) between the condenser and column for the liquid streams. |
