Abstract: Hydrogen and carbon monoxide impurities are removed from a dry gas comprising the impurities, wherein the dry gas is at least substantially free of carbon dioxide, by passing the dry gas with sufficient residence time, e.g. at least 1.5 s, through a layer of catalyst comprising a mixture of manganese oxide and copper oxide. The use of expensive noble metal catalysts to remove hydrogen may thereby be avoided. In addition, regeneration of the catalyst using oxygen-containing regeneration gas does not reduce the effectiveness of the catalyst.

Abstract: Hydrogen and carbon monoxide impurities are removed from a dry gas comprising the impurities, wherein the dry gas is at least substantially free of carbon dioxide, by passing the dry gas with sufficient residence time, e.g. at least 1.5 s, through a layer of catalyst comprising a mixture of manganese oxide and copper oxide. The use of expensive noble metal catalysts to remove hydrogen may thereby be avoided. In addition, regeneration of the catalyst using oxygen-containing regeneration gas does not reduce the effectiveness of the catalyst.

Abstract: Reduction of water, CO2 and N2O in an air stream comprising: passing said air stream at a feed temperature through a first adsorbent, whose Henry's Law selectivity for CO2/N2O is at least 12.5, and a second adsorbent, whose Henry's Law constant for CO2 is less than 1020 mmol/g/atom and whose Henry's Law selectivity for CO2/N2O is at most 5; and passing a heated regenerating gas at a temperature which is between 20° C. and 80° C. to at least the second adsorbent, and passing a second regenerating gas at a temperature less than the temperature of the heated regenerating gas to the first and second adsorbents in a direction opposite to the feed direction; the second adsorbent occupying from 25% to 40% of the total volume of the adsorbents, and the temperature of the heated regenerating gas being 10° C. to 60° C. higher than the feed temperature.

Abstract: Reduction of water, CO2 and N2O in an air stream comprising: passing said air stream at a feed temperature through a first adsorbent, whose Henry's Law selectivity for CO2/N2O is at least 12.5, and a second adsorbent, whose Henry's Law constant for CO2 is less than 1020 mmol/g/atom and whose Henry's Law selectivity for CO2/N2O is at most 5; and passing a heated regenerating gas at a temperature which is between 20° C. and 80° C. to at least the second adsorbent, and passing a second regenerating gas at a temperature less than the temperature of the heated regenerating gas to the first and second adsorbents in a direction opposite to the feed direction; the second adsorbent occupying from 25% to 40% of the total volume of the adsorbents, and the temperature of the heated regenerating gas being 10° C. to 60° C. higher than the feed temperature.