Abstract: A system for producing xenon concentrate suitable for further refining wherein a xenon concentrator column processes liquid from the sump of a lower pressure column and additionally produces oxygen gas for recovery or recycle to the lower pressure column.

Abstract: A cryogenic rectification system comprising an upstream krypton/xenon knockout column and a downstream oxygen upgrader column wherein the knockout column processes a crude feed for removal of heavy components including hydrocarbons and the upgrader column produces ultra high purity oxygen.

Abstract: A cryogenic rectification system comprising a rare gas concentrator column for producing a liquid having an enhanced concentration of krypton and xenon, and which processes atmospheric fluids and also produces gaseous oxygen and liquid nitrogen.

Abstract: A system for re-starting an air separation plant after an interruption in operation wherein descending liquid is collected in a non-operating distillation column and passed back to the separation section of that column before or upon re-start. The invention may employ a collection device situated in the column above the sump. Upon interruption in operation, the collection device accumulates descending liquid. From the collection device, liquid may be passed outside of the column and transferred to a holding vessel to re-inventory internal material of the column upon resumption in operation.

Abstract: A method is provided for separation of air by cryogenic rectification comprising compressing feed air, passing the compressed feed air through a prepurifier wherein the air is substantially cleaned of impurities, thereafter cooling the cleaned air in a cooled regenerator and then introducing it into a cryogenic air separation facility wherein it is separated into nitrogen-rich and oxygen-rich components.