A system and method for recovery of rare gases such as neon, helium, xenon, and krypton in an air separation unit is provided. The rare gas recovery system comprises a non-condensable stripping column linked in a heat transfer relationship with a xenon-krypton column via an auxiliary condenser-reboiler. The non-condensable stripping column produces a rare gas containing overhead that is directed to the auxiliary condenser-reboiler where most of the neon is captured in a non-condensable vent stream that is further processed to produce a crude neon vapor stream that contains greater than about 50% mole fraction of neon with the overall neon recovery exceeding 95%. The xenon-krypton column further receives two streams of liquid oxygen from the lower pressure column and the rare gas containing overhead from the non-condensable stripping column and produces a crude xenon and krypton liquid stream and an oxygen-rich overhead.

A system and method for recovery of rare gases such as neon, helium, xenon, and krypton in an air separation unit is provided. The rare gas recovery system comprises a non-condensable stripping column linked in a heat transfer relationship with a xenon-krypton column via an auxiliary condenser-reboiler. The non-condensable stripping column produces a rare gas containing overhead that is directed to the auxiliary condenser-reboiler where most of the neon is captured in a non-condensable vent stream that is further processed to produce a crude neon vapor stream that contains greater than about 50% mole fraction of neon with the overall neon recovery exceeding 95%. The xenon-krypton column further receives two streams of liquid oxygen from the lower pressure column and the rare gas containing overhead from the non-condensable stripping column and produces a crude xenon and krypton liquid stream and an oxygen-rich overhead.

A system and method for neon recovery in a double column or triple column air separation unit is provided. The neon recovery system comprises a non-condensable stripping column configured to produce a liquid nitrogen-rich liquid column bottoms and a non-condensable gas containing overhead and one or more condensing units arranged to produce a crude neon vapor stream that contains greater than about 50% mole fraction of neon with the overall neon recovery exceeding 95%. In addition, there is minimal liquid nitrogen consumption and since much of the liquid nitrogen is recycled back to the lower pressure column of the air separation unit, there is minimal impact on the recovery of other products from the air separation unit.

A system and method serve generate oxygen by low-temperature air separation in a distillation column system having a high-pressure column and a low-pressure column, a main condenser which is constructed as a condenser-evaporator, and an auxiliary column. A gaseous oxygen-containing fraction is introduced into the auxiliary column. A nitrogen-containing liquid stream from the high-pressure column, the main condenser or the low-pressure column is applied as reflux to the top of the auxiliary column. An argon-rich stream from an intermediate site of the low-pressure column is introduced into an argon removal column that has an argon removal column top condenser. The low-pressure column is arranged beside the high-pressure column, the main condenser is arranged over the high-pressure column, the auxiliary column is arranged over the main condenser, the argon removal column is arranged over the auxiliary column and the argon removal column top condenser is arranged over the argon removal column.

A method for the low-temperature separation of air using an air separation plant which comprises a rectification column arrangement (10) having a pressure column, a low-pressure column and an argon column, wherein: the low-pressure column comprises a first and a second rectification region (A, B); the argon column comprises a first and a second rectification region (C, D, D1, D2); argon-enriched fluid is removed from the low-pressure column between the first and second rectification region (A, B) thereof and is fed into the first rectification region (C) of the argon column; and argon-depleted fluid is removed from the first rectification region (C) of the argon column (13a, 13b) and is fed into the low-pressure column between the first and second rectification region (A, B) thereof.

The invention relates to a plant for low-temperature air separation, having a rectification column system comprising a high-pressure column, a divided low-pressure column and a divided argon column, and a cold box system comprising a first cold box and a second cold box. The high-pressure column is arranged beneath the lower section of the low-pressure column. The high-pressure column together with the lower section of the low-pressure column is located in the first cold box, and the top section of the low-pressure column in the second cold box. It is proposed to arrange the base section of the argon column in the first cold box and the top section of the argon column in the second cold box, or vice versa. The present invention likewise provides a corresponding method.

The invention relates to a plant for low-temperature fractionation of air, having a rectification column system comprising a high-pressure column, a divided low-pressure column and an argon column, and a coldbox system comprising a first coldbox, a second coldbox and a third coldbox. The high-pressure column is disposed beneath the lower section of the low-pressure column. The high-pressure column together with the lower portion of the low-pressure column is disposed in the first coldbox, and the top portion of the low-pressure column in the second coldbox. It is proposed that the argon column or one or more sections of the argon column be disposed in the third coldbox. The pure oxygen column is disposed in the second coldbox. The present invention likewise provides a corresponding process.

The plant is used for producing oxygen by cryogenic air separation. The plant has a high-pressure column, a low-pressure column and a main condenser. An argon-elimination column is in fluid connection with an intermediate point of the low-pressure column and is connected to an argon-elimination column head condenser. An auxiliary column has a sump region, into which gas is introduced from the argon-elimination column head condenser. The head of the auxiliary column is connected to a return flow liquid line, in order to introduce a liquid stream from the high-pressure column or the head condenser. The liquid stream has an oxygen content which is at least equal to that of air. At least one part of the crude liquid oxygen from the sump of the high-pressure column is fed to the auxiliary column at a first intermediate point.

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.