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.

An apparatus for separation of air by cryogenic distillation comprising: a system of columns; a first turbine; a warm compressor coupled to the first turbine; a second turbine; a cold compressor coupled to the second turbine; a heat exchanger; means for sending air cooled in the heat exchanger at an intermediate temperature of the heat exchanger to the cold compressor; means for sending expanded air from the second turbine to the system of columns; means for sending air compressed in the cold compressor to an intermediate point of the heat exchanger and then at least in part to the system of columns via a first valve; means for sending air compressed in the cold compressor to the inlet of the first turbine via a second valve without passing through the heat exchanger, wherein the means for sending air compressed in the cold compressor to the inlet of the first turbine via the second valve without passing through the heat exchanger is also connected to the inlet of the first turbine; means for sending a fraction of air cooled in the heat exchanger to an intermediate temperature of the latter to the first turbine; means for sending expanded air from the first turbine to the system of columns; and a bypass line provided with an expansion valve configured to send air from the cold compressor to the system of columns without passing through the heat exchanger.

Method for separating air by cryogenic distillation in an air separation device comprising a system of columns, a first turbine and a second turbine, wherein, in de-icing operation, a common duct bringing air from the two turbines to a column is closed by means of an isolation valve, a purge gas is sent to the turbines at a temperature above 0 C. in order to de-ice them, but purge gas is not sent to the system of columns.

Method for separating air by cryogenic distillation, wherein at least part of the air to be distilled is boosted in an air booster, compressed air is allowed to expand in at least one expansion turbine and, if the pressure drop between two points of the booster passes under a threshold and/or a flow of the booster passes under a minimum flow of the booster, part of the air boosted in the booster is allowed to expand without having been cooled between the booster and the expansion turbine and the boosted expanded air is sent upstream or downstream of the at least one turbine, without having been cooled in the heat exchanger, after having been boosted.

Method for separating air by cryogenic distillation, wherein air is compressed in a compressor and is subsequently sent to a heat exchanger, with the air cooled in the exchanger being sent to a check valve downstream of the heat exchanger and subsequently to a turbine, the valve being positioned so that air from a short-circuiting duct cannot return to the exchanger from the compressor.

The invention proposes a process and an air separation plant comprising a rectification column system comprising a high-pressure column, a low-pressure column, a main heat exchanger, and a main air compressor. The total air supplied to the rectification column system is compressed in the main air compressor to a first pressure level. The high-pressure column is operated at a second pressure level, at least 3 bar below the first pressure level. A gaseous, nitrogen-rich fluid is removed from the high-pressure column and warmed up in the gaseous state without prior liquefaction. A first partial quantity of the gaseous, nitrogen-rich fluid is warmed to a first temperature level of 150 to 100 C., supplied at this first temperature level to a booster and compressed further to a third pressure level. The first partial quantity is then warmed to a second temperature level and discharged from the air separation plant.

An apparatus for the production of low pressure gaseous oxygen includes a heat exchanger and a system of columns comprised of an auxiliary column, a higher pressure column and a lower pressure column. The LP column and the HP column are thermally integrated via a top reboiler/condenser disposed on top of the HP column. The system of columns is configured to separate a cooled air stream into oxygen and nitrogen. The auxiliary column comprises a distillation section and a first and second reboiler. One of the reboilers is driven by the cooled air stream and the other reboiler is driven by a pressurized nitrogen stream. The first and second reboilers boil their fluids at the same pressure as the auxiliary column.

A method for the production of low pressure gaseous oxygen includes providing a system of distillation columns and a heat exchanger, wherein the system of columns comprises a lower pressure column, a higher pressure column, an auxiliary column, the auxiliary column having a distillation section, a first reboiler, and a second reboiler, wherein the LP column and the HP column are thermally integrated via a top reboiler/condenser disposed on top of the HP column. A cooled air stream is rectified within the system of columns such that the auxiliary column produces a cold oxygen fluid that is then warmed in the heat exchanger to produce a low pressure oxygen product. The cooled air stream provides reboiling duty for the first reboiler prior to rectification within the system of columns, and a compressed nitrogen stream received from a cold end of the heat exchanger provides reboiling duty for the second reboiler.