A method for capturing CO.sub.2 from a gas stream using a metal organic framework (MOF) based physisorbent CO.sub.2 concentrator is provided. In the method, MOF material is pretreated, a gas stream is then introduced into the CO.sub.2 concentrator which comprises the pretreated MOF material. CO.sub.2 from the gas stream is captured with the CO.sub.2 concentrator to generate a CO.sub.2-free stream, which is discharged the from the CO.sub.2 concentrator into the atmosphere. Introduction of the gas stream into the CO.sub.2 concentrator is stopped when the pretreated MOF material becomes saturated with CO.sub.2. The CO.sub.2 concentrator with the saturated MOF material is then regenerated by introducing hot air, hot nitrogen, vacuum, or a combination thereof into the CO.sub.2 concentrator thereby generating a CO.sub.2-rich stream. The CO.sub.2-rich stream is diverted for purification and the regenerated CO.sub.2 concentrator is recycled for future capture of CO.sub.2.

An adsorbate-selective metal organic framework includes a transition metal; and a plurality of organic molecules coordinated to the transition metal so as to preserve open coordination sites for selectively adsorbing molecules that have low-lying π* orbitals. The transition metal has a lowest energy spin state in the presence of the selectively adsorbed molecules that are strongly bonding to the transition metal through π-donating interactions which is different than the lowest energy spin state in the absence of these adsorbed molecules. The transition metal has also a lowest energy spin state in the presence of non-selected molecules that are weakly bonding to the transition metal through σ- and/or π-accepting and/or donating interactions.

Novel methods for pretreating a rare-gas-containing stream exiting an etch chamber followed by recovering the rare gas from the pre-treated, rare-gas containing stream are disclosed. More particularly, the invention relates to the pretreatment and recovery of a rare gas, such as xenon or krypton, from a nitrogen-based exhaust stream with specific gaseous impurities generated during an etch process that is performed as part of a semiconductor fabrication process.

Novel methods for pretreating a rare-gas-containing stream exiting an etch chamber followed by recovering the rare gas from the pre-treated, rare-gas containing stream are disclosed. More particularly, the invention relates to the pretreatment and recovery of a rare gas, such as xenon or krypton, from a nitrogen-based exhaust stream with specific gaseous impurities generated during an etch process that is performed as part of a semiconductor fabrication process.

Novel methods for pretreating a rare-gas-containing stream exiting an etch chamber followed by recovering the rare gas from the pre-treated, rare-gas containing stream are disclosed. More particularly, the invention relates to the pretreatment and recovery of a rare gas, such as xenon or krypton, from a nitrogen-based exhaust stream with specific gaseous impurities generated during an etch process that is performed as part of a semiconductor fabrication process.

The present invention relates to a device for the reversible adsorption of carbon dioxide from a gas mixture, comprising at least one adsorbent vessel comprising one or a plurality of gas permeable cartridge vessels of an inert and dimensionally stable material, and each cartridge comprising a suitable polymeric particular adsorbent having a primary amino functionality; to an arrangement including the device, and to a method for adand desorption of carbon dioxide.

The invention relates to a process for removing oxygen from liquid argon using a TSA (temperature swing adsorption) cyclical process that includes cooling an adsorbent bed to sustain argon in a liquid phase; supplying the adsorbent bed with a liquid argon feed that is contaminated with oxygen and purifying the liquid argon thereby producing an argon product with less oxygen contaminant than is in the initial liquid argon feed; draining the purified residual liquid argon product and sending purified argon out of the adsorbent bed. Regeneration of specially prepared adsorbent allows the adsorbent bed to warm up to temperatures that preclude the use of requiring either vacuum or evacuation of adsorbent from the bed.

A process and plant for producing a high purity CO.sub.2 product, comprising: providing a CO.sub.2-rich stream containing hydrocarbons, hydrogen and/or CO, combining it with a stream rich in methane (CH.sub.4), and mixing it with oxygen, thereby forming a CO.sub.2/O.sub.2- mixture; subjecting the CO.sub.2/O.sub.2- mixture to a catalytic oxidation step, thereby producing a purified stream having a higher CO.sub.2 and/or H.sub.2O concentration; removing H.sub.2O from said purified stream, for producing said high purity CO.sub.2 product stream. The CO.sub.2-rich stream is for instance derived from the CO.sub.2-removal section of a plant for producing hydrogen.

Recovering helium from a gaseous stream includes contacting an acid gas removal membrane with a gaseous stream to yield a permeate stream and a residual stream, removing a majority of the acid gas from the residual stream to yield a first acid gas stream and a helium depleted clean gas stream, removing a majority of the acid gas from the permeate stream to yield a second acid gas stream and a helium rich stream, and removing helium from the helium rich stream to yield a helium product stream and a helium depleted stream. A helium removal system for removing helium from a gaseous stream including hydrocarbon gas, acid gas, and helium includes a first processing zone including a first acid gas removal unit, a second processing zone including a second acid gas removal unit, a third processing zone, and a helium purification unit.

In a helium purification process, a stream containing at least 10% of helium, at least 10% of nitrogen in addition to hydrogen and methane is separated to form a helium-enriched stream containing hydrogen, a first stream enriched in nitrogen and in methane and a second stream enriched in nitrogen and in methane, the helium-enriched stream is treated to produce a helium-rich product and a residual gas containing water, the residual gas is treated by adsorption (TSA) to remove the water and the regeneration gas from the adsorption is sent to a combustion unit (O).