NOVELTY - A contaminant removal system for a fuel processor having a hydrogen generator and a supply of oxidant for connection to the hydrogen generator, comprises a cleansing arrangement connected intermediate the supply of oxidant and the hydrogen generator for reducing the level of the contaminant in the supply of oxidant prior to admission of the oxidant to the hydrogen generator.    USE - For a fuel processor having a hydrogen generator for converting a fuel stream to a hydrogen-containing stream, a supply of oxidant for connection to the hydrogen generator to assist in converting the fuel stream to the hydrogen-containing stream (claimed) useful for a fuel cell power plant.    ADVANTAGE - The contaminant removal system provides improved removal of contaminants from catalytic fuel processors for making hydrogen. It also provides improved removal of sulfur as a potential contaminant to the catalyst(s) in the fuel processor and/or cell stack assembly of a fuel cell power plant. It is a relatively efficient and cost-effective arrangement for the improved removal of contaminants, i.e. sulfur, in a fuel cell power plant. It also reduces the level of sulfur present in the fuel and/or oxidant flow streams of a fuel processor and/or cell stack assembly for a proton exchange membrane fuel cell power plant.    DETAILED DESCRIPTION - A contaminant removal system for a fuel processor (14) having a hydrogen generator (34) for converting a fuel stream (33) to a hydrogen-containing stream, a supply of oxidant (38) for connection to the hydrogen generator to assist in converting the fuel stream to the hydrogen-containing stream, the supply of oxidant potentially containing a contaminant that is deleterious in one or more of the hydrogen generator and the hydrogen-containing stream, the contaminant removal system comprises a cleansing arrangement (116, 142, 46, 118) connected intermediate the supply of oxidant and the hydrogen generator for reducing the level of the contaminant in the supply of oxidant prior to admission of the oxidant to the hydrogen generator.    INDEPENDENT CLAIMS are also included for:    (1) a contaminant removal system for a fuel cell power plant having a fuel cell stack assembly (CSA) (12) and a fuel processing system (FPS) including a hydrogen generator and a shift reactor (41) for converting a hydrocarbon fuel stream to provide a hydrogen-rich stream for use as a reducing agent in the CSA, a supply of oxidant for connection to the hydrogen generator for converting some of the fuel stream to a hydrogen-containing stream, the supply of oxidant containing a contaminant deleterious to one or more of the FPS and the CSA, the contaminant removal system comprising a cleansing arrangement connected intermediate the supply of oxidant and the hydrogen generator for reducing the level of the contaminant in the supply of oxidant prior to admission of the oxidant to the hydrogen generator; and    (2) a method for removing water-soluble contaminants from a stream of inlet oxidant to a hydrogen generator, comprising passing the stream of inlet oxidant through a scrubber and contacting a stream of water flowing through the scrubber for dissolving the water-soluble contaminants and removing the dissolved contaminants from the stream of oxidant to cleanse the stream of oxidant; and subsequently passing the cleansed stream of inlet oxidant to the hydrogen generator.    DESCRIPTION OF DRAWING(S) - The figure is a simplified schematic illustration of a fuel cell power plant illustrating the improved contaminant removal system.    CSA (12)    Fuel processor (14)    Fuel stream (33)    Hydrogen generator (34)    Supply of oxidant (38)    Shift reactor (41)    Water injection device (70)    Fuel cell power plant (110)    Cleansing arrangement (116, 142, 46, 118)    Cleansed air connected to CSA (138', 37)    Exhaust connected to flow through mass transfer device (144)