| 摘要 |
Cryogenic process to produce a gaseous product at a required pressure uses a main heat exchanger (24) to vaporise a lower volatility component obtained from a gaseous mixture, e.g. oxygen from air. Purified feed is divided into two streams (40) (42), one of which (40) is compressed (18) and passed (26) into heat exchanger (24) to a location at which countercurrent streams should, in theory, have approximately the same temperature. The stream is then withdrawn (30) from this location, from which it is passed (26b) to the rectification plant. A second stream is also withdrawn (32), expanded (38), and passed to the plant without further use of the heat exchanger. Separated liquid product, e.g. liquid oxygen, is pressurised (96) and passed (28) through heat exchanger (24) to provide the required gaseous product at ambient temperature. Also claimed is associated apparatus as required to produce gaseous oxygen at elevated pressure by air separation and operation of heat exchanger (24) in the claimed manner. |
