| 摘要 |
Process to produce gaseous oxygen at a required delivery pressure from air uses a double rectification column (30,32) equipped with a condenser-reboiler (40) having a sump (42). Liquid oxygen produced in low pressure section (32) descends to this sump, where heavy impurities are concentrated by reboiling, and from which a stream (84) is withdrawn. This stream is compressed to a pressure at which the impurities and oxygen will vaporise concurrently, and is then vaporised by passage through the main process heat exchanger. A stream (80) of descending liquid oxygen is withdrawn from a position upstream of sump (42), and is compressed to the required delivery pressure, after which it is vaporised in the main heat exchanger to provide the gaseous oxygen product. Also claimed is the associated apparatus, which includes a pump (86) capable of compressing the impurity-laden stream (84) to a pressure at which the concurrent vaporisation takes place in the main heat exchanger. |
