Process for Krypton and Xenon Recovery in Pumped-LOX ASU Cycles
Publication Date: 2003-Sep-12
The IP.com Prior Art Database
Xenon is recovered from the high pressure column by withdrawing a small stream of heavies-rich crude LOX. When combined with traditional techniques for xenon removal from the LP column, the overall xenon recovery from pumped LOX cycles can be improved substantially. Xenon is typically recovered from a double column air separation plant (producing oxygen) by removing a small liquid stream from the LP column sump that is further purified in a separate distillation column. This scheme produces very high xenon recoveries when the oxygen product is removed from the LP column as a low-pressure vapor. When the oxygen product is withdrawn from the LP column as a liquid, as in pumped LOX cycles, the liquid product flow is typically removed a stage or two above the sump to allow the heavier xenon (and also krypton) to accumulate in the sump liquid. Unfortunately, the xenon and krypton that exit the column with the oxygen product are not recovered and the xenon recovery is reduced to approximately 72%.