GAS PURIFIER

PROBLEM TO BE SOLVED: To provide a gas purifier that removes moisture and oxygen from inert gases and reducing gases, for example, at sub-atmospheric pressures.SOLUTION: The bed of a purifier comprises: a first bed of material comprising micropore mass transfer limited molecular sieves that remove moisture from an inert gas and a reducing gas, the molecular sieves having a largest dimension of less than 0.7 mm±20%; and a second bed of material comprising a metal catalyst on a support that removes oxygen from the inert gas and the reducing gas, the metal catalyst being at least partially regenerated to a reduced form by the reducing gas at room temperature. 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.