| 摘要 |
A low temperature rectification process and apparatus in which a compressed gaseous mixture, for instance, air, is rectified to produce a lower volatility component in liquid form which is then pumped to a delivery pressure. After having been pumped, the lower volatility component is vaporized within a main heat exchanger. In order to effect the vaporization, a stream of the compressed gaseous mixture being cooled in the main heat exchanger is further compressed to form a further compressed stream. In order to minimize thermodynamic irreversibility within the main heat exchanger above a theoretical pinch point temperature thereof a portion of the further compressed stream is removed from the main heat exchanger at or near the theoretical pinch point temperature and then is still further compressed and introduced at a level of the main heat exchanger warmer temperature than the theoretical pinch point temperature. Either the balance of the further compressed stream or some other stream of the compressed gaseous mixture being cooled is removed from the main heat exchanger and is then cooled to a temperature suitable for its rectification without further use of the main heat exchanger. Such removal reduces thermodynamic irreversibility within the main heat exchanger below the theoretical pinch point temperature.
|
