NOVELTY - The process for purification or separation of gas flow supply (1) containing hydrogen and carbon monoxide ( greater than or equal to 1000 ppm) in molar content, comprises introducing the gas flow in a first purification unit of pressure swing adsorption type, recuperating the resultant gas with partial purification of carbon monoxide, introducing the resultant gas into a downstream adsorber (20), and recuperating the gas enriched in hydrogen. The first purification unit contains a monolithic first adsorbent on which the carbon monoxide is adsorbed. The downstream adsorber contains a granular second adsorbent (21).    USE - The process is useful for purification or separation of gas flow supply containing hydrogen and carbon monoxide ( greater than or equal to 1000 ppm) in molar content.    ADVANTAGE - The process ensures simple and efficient purification and uniform separation of gas flow supply containing hydrogen and carbon monoxide, with less consumption of energy and time and without any environmental pollution.    DETAILED DESCRIPTION - The process for purification or separation of gas flow supply (1) containing hydrogen and carbon monoxide ( greater than or equal to 1000 ppm) in molar content, comprises introducing the gas flow in a first purification unit of pressure swing adsorption type, recuperating the resultant gas with partial purification of carbon monoxide, introducing the resultant gas into a downstream adsorber (20), and recuperating the gas enriched in hydrogen. The first purification unit contains a monolithic first adsorbent on which the carbon monoxide is adsorbed. The downstream adsorber contains a granular second adsorbent (21) on which the carbon monoxide is adsorbed, and another different adsorbent. The first and second adsorbents are same or different nature. The recuperated gas presents a molar carbon monoxide content (T) of less than or equal to 100 ppm and a first maximum carbon monoxide content (TM0) of greater than or equal to 2x T. The gas enriched in hydrogen presents a maximum carbon monoxide content (TM1), which is less than TM0 and satisfies (TM1-T) less than 1/10(TM0-T). The first adsorbent is present in the form of sheets. The second adsorbent has Henry constant at 20 degrees C for the carbon monoxide of greater than or equal to 5 (mmole/g)/bar and a kinetic adsorption lower than that of first adsorbent, and is present in the form of bills or sticks. The gas flow is obtained by vapor reforming, by partial oxidation of hydrocarbons or alcohols, by gasification of carbon or its residues, or by a mixed process. The gas enriched in hydrogen is intended to a pipeline network, a chemical unit, a petrochemical unit, a refinery unit, or to fuel cell.    DESCRIPTION OF DRAWING(S) - The figure shows a device for purification or separation of gas flow supply.    Gas supply (1)    Fluid (3)    Purification unit (10)    Downstream adsorber (20)    Second adsorbent. (21)