Method for removal of contaminants from a hydrogen processor feed stream, as in a fuel cell power plant

Method and apparatus are provided for removing contaminants from a hydrogen processor feed stream, as in a fuel cell power plant ( 110 ). Inlet oxidant ( 38 ), typically air, required by a catalytic hydrogen processor ( 34 ) in a fuel processor ( 14 ) for a fuel cell stack assembly ( 12 ) in the power plant ( 110 ), may contain contaminants such as SO2 and the like. A cleansing arrangement, which includes an accumulator/degasifier ( 142, 46 ) acting as a scrubber, and possibly also a water transfer device ( 118 ), receives the inlet oxidant and provides the desired cleansing of contaminants. Water in the water transfer device and in the accumulator/degasifier serves to dissolve the water-soluble contaminants and cleanse them from the oxidant stream. The cleansed oxidant stream ( 138 ') is then delivered to the hydrogen processor and to the fuel cell assembly, with minimal inclusion of detrimental contaminants such as sulfur.