Patent ID: 8484992

Claim:
A method of producing a krypton-xenon-rich stream comprising: removing a pipeline oxygen stream, containing oxygen vapor, from an oxygen pipeline at ambient temperature; and introducing the pipeline oxygen stream into a cryogenic rectification process to produce the krypton-xenon-rich stream, said cryogenic rectification process comprising: cooling the pipeline oxygen stream to a temperature at or near a dew point temperature of the oxygen vapor contained in the pipeline oxygen stream; rectifying at least part of the pipeline oxygen stream, after having been cooled, in a distillation column to produce a krypton-xenon-rich liquid column bottoms; discharging the krypton-xenon-rich stream from the distillation column, the krypton-xenon-rich stream composed of the krypton-xenon-rich liquid column bottoms; imparting refrigeration into the cryogenic rectification process; the pipeline oxygen stream is cooled in a main heat exchanger; the rectification of the pipeline oxygen stream produces an oxygen-rich vapor column overhead; an oxygen-rich vapor stream composed of the oxygen-rich vapor column overhead is removed from the distillation column and divided into a first oxygen-rich vapor stream and a second oxygen-rich vapor stream; the first oxygen-rich vapor stream is condensed in a condenser to produce a reflux stream; at least part of the reflux stream is introduced into the distillation column as reflux: the second oxygen-rich vapor stream is passed in indirect heat exchange with the pipeline oxygen stream from the oxygen pipeline in the main heat exchanger to assist in the cooling of the pipeline oxygen stream; the second oxygen-rich vapor stream is recycled back to the oxygen pipeline; a heat exchange stream is compressed and then cooled within the main heat exchanger; the heat exchange stream is condensed in a reboiler operatively associated with the distillation column to produce boil-up within the distillation column; the heat exchange stream, after having been condensed, is reduced in pressure and vaporized in the condenser in indirect heat exchange with the first oxygen-rich vapor stream, thereby to condense the first oxygen-rich vapor stream; the heat exchange stream after having been vaporized is partially warmed within the main heat exchanger and then expanded in a turboexpander to produce an exhaust stream; the turboexpander is coupled to a compressor used in compressing the heat exchange stream; and the exhaust stream is fully warmed within the main heat exchanger to impart the refrigeration to the cryogenic rectification process and is recycled back to the compressor.