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 method is provided for refining an argon gas, in which oxygen is added to the argon gas containing hydrogen, carbon monoxide (CO), and oxygen as impurities so that the hydrogen and the CO are converted into water and carbon dioxide in a catalyst tower, or hydrogen is added to the argon gas so that the oxygen is converted into the water; the method including: monitoring the hydrogen, the CO, and the oxygen on an outlet side of the catalyst tower; and at least one of adding the oxygen to the argon gas when any one of the hydrogen and the CO is detected on the outlet side of the catalyst tower, and adding the hydrogen when the oxygen is detected, wherein the oxygen or the hydrogen to be added is intermittently added to the catalyst tower relative to continuous supply of the argon gas to the catalyst tower.

The invention provides a process of purifying a fluid useful in a manufacturing process, particularly in the manufacture of silicon wafers, by removing one or more impurities; and apparatus for use in the process.

A process comprising: subjecting a process gas containing NOx to a stage for absorption of NOx in a suitable absorption means, obtaining nitric acid and a tail gas containing nitrogen, argon and residual NOx; subjecting said tail gas to a treatment which comprises at least one NOx removal stage, obtaining a conditioned tail gas; subjecting at least a portion of said conditioned tail gas to a separation treatment, obtaining a product stream containing argon and a product stream containing nitrogen.

In a method for separating argon by cryogenic distillation, in which a flow containing argon, oxygen and nitrogen and being more rich in argon than the air is sent to a distillation column, and an argon-rich gas flow is withdrawn at the top of the column, a portion of the argon-rich gas flow is mixed with beads to form a gas mixture containing beads, the beads being capable of adsorbing oxygen in the presence of argon at the column operating temperatures; the portion of the argon-rich gas flow mixed with the beads is condensed and then sent to the top of the column; and a bottom liquid containing beads is withdrawn from the column and treated to remove the beads, the beads removed being regenerated to remove the adsorbed oxygen and being again mixed with the argon-rich gas flow.

A process comprising: subjecting a process gas containing NOx to a stage for absorption of NOx in a suitable absorption means, obtaining nitric acid and a tail gas containing nitrogen, argon and residual NOx; subjecting said tail gas to a treatment which comprises at least one NOx removal stage, obtaining a conditioned tail gas; subjecting at least a portion of said conditioned tail gas to a separation treatment, obtaining a product stream containing argon and a product stream containing nitrogen.

In a method for separating argon by cryogenic distillation, in which a flow containing argon, oxygen and nitrogen and being more rich in argon than the air is sent to a distillation column, and an argon-rich gas flow is withdrawn at the top of the column, a portion of the argon-rich gas flow is mixed with beads to form a gas mixture containing beads, the beads being capable of adsorbing oxygen in the presence of argon at the column operating temperatures; the portion of the argon-rich gas flow mixed with the beads is condensed and then sent to the top of the column; and a bottom liquid containing beads is withdrawn from the column and treated to remove the beads, the beads removed being regenerated to remove the adsorbed oxygen and being again mixed with the argon-rich gas flow.

Disclosed herein are new processes for adsorbing oxygen using adsorbent compositions comprising RHO zeolites kinetically selective for oxygen. The RHO zeolites can be used in pressure swing adsorption processes for separating oxygen from oxygen containing streams, such as for, but not limited to, purifying a crude argon feed stream or separating oxygen from an air feed stream.

The invention relates to a gas purifier that removes moisture and oxygen from inert gases and reducing gases, for example, at sub-atmospheric pressures. The purifier can remove part per million levels of moisture in a gas stream to less than 100 parts per trillion by volume, and has a low pressure drop and a sharp breakthrough curve.

Disclosed herein are novel RHO zeolites useful as kinetically selective adsorbents for oxygen and/or nitrogen. The adsorbents can be used in pressure swing adsorption processes for selectively adsorbing oxygen and/or nitrogen from feed streams such as an air stream or crude argon stream. Also disclosed are novel methods of preparing RHO zeolites, including in particular mixed-cation RHO zeolites.