A method and system for cryogenic air separation that employs both a primary refrigeration circuit and an auxiliary refrigeration circuit is provided. The auxiliary refrigeration circuit is configured in a manner that it can be easily tied-in or modified to an existing air separation plant.

A method and apparatus for argon rejection and recovery in which argon is separated from air within a cryogenic air separation plant having a divided wall argon rejection column and condensed using an argon condenser disposed internally within the lower pressure column. The resulting argon stream is subsequently rejected or recovered and optionally purified within an integrated adsorbent based argon refining and purification subsystem to produce product grade argon.

A method and apparatus for argon recovery in which an impure argon stream is separated from air within a cryogenic air separation unit having a divided wall argon rejection/rectification column. The resulting argon stream is subsequently recovered and purified within an integrated pressure swing adsorption system to produce product grade argon.

A method and apparatus for increasing argon recovery in which an impure argon stream is separated from air within a cryogenic air separation unit and purified within an integrated, multi-stage pressure swing adsorption system to produce product grade argon with high argon recovery levels.

A method and apparatus for argon recovery in which an impure argon stream is separated from air within a cryogenic air separation unit having an argon rejection column and a reflux type argon condenser disposed internally within the lower pressure column. An impure argon stream is subsequently recovered from the argon rejection column and purified within an integrated adsorbent based argon refining and purification subsystem to produce product grade argon. The waste stream from the adsorbent based argon refining and purification subsystem is recycled back to the argon rejection column so as to improve the argon recovery.

A method and apparatus for argon recovery in which an impure argon stream is separated from air within a cryogenic air separation unit having a divided wall argon rejection/rectification column. The resulting argon stream is subsequently recovered and purified within an integrated pressure swing adsorption system to produce product grade argon.

The invention relates to a column for separating air by means of cryogenic distillation, said column comprising a shell and at least four distillation segments, including at least a first intermediate distillation segment of the low-pressure column, which is surrounded by an auxiliary shell around which a space is defined that is divided into a lower section and an upper section along the radius of the column, the intermediate segment(s) being located in an intermediate part of the low-pressure column, the capacity of the first intermediate segment being greater than that of at least one adjacent segment, and an opening being disposed in the shell between two adjacent segments, which opening can be sealed if the column is to form part of an argon production device.

An apparatus and process for argon recovery can be configured so that an argon-enriched stream including oxygen therein can be recycled to a column for air separation and subsequent argon separation to provide improved argon recovery with reduced power. The recycling of this argon-enriched stream can be provided such that there is sufficient nitrogen within the column to facilitate separation of argon from oxygen within the column so additional argon that can be provided via the recycling can be separated and purified instead of being output as a waste stream or otherwise lost.