NOVELTY - A fluidized bed contaminant separator and water-control loop (10) comprises water-control loop pump (84) secured in fluid communication with loop conduit; and ion exchange bed (88) secured in fluid communication with loop conduit for directing flow of separated contaminant and water stream through ion exchange bed and for removing separated contaminants from water in the stream within the bed; loop conduit return line secured in fluid communication between an outlet (92) of ion exchange bed and water inlet (94) of separator scrubber.    USE - As fluidized bed contaminant separator and water-control loop for a fuel reactant stream of a fuel cell; used in e.g. transportation vehicles, portable power plants, or as stationary power plants; as contaminant removal system for efficiently removing contaminants such as ammonia and particulates from a fuel reactant stream passing into a fuel cell.    ADVANTAGE - The fluidized bed contaminant separator and water-control loop achieves extremely efficient removal of contaminants within the fuel cell fuel reactant stream and achieves maintenance of optimal temperature and moisture content of the fuel reactant stream; operates efficiently for long period of time without high frequency maintenance. The thermal control function is separated from the contaminant removal function which permits more flexibility in designing the fluidized bed. By removing thermal energy from the fuel reactant stream prior to the stream entering the scrubber, the scrubber contains light weight, low-melting temperature contact materials which can be easily fluidized.    DETAILED DESCRIPTION - A fluidized bed contaminant separator and water-control loop (10) for a fuel reactant stream of a fuel cell (12), comprises a separator scrubber (58) secured in fluid communication with a fuel reactant inlet line (26) of the fuel cell, the separator scrubber including an ammonia dissolving media (61) disposed within a fluidized bed (62) within a scrubber container (64) of the separator scrubber for dissolving ammonia and removing particulates from the fuel reactant stream into a separated contaminant stream within the separator scrubber; a water discharge (66) secured adjacent the ammonia dissolving media and configured to discharge water to flow through the ammonia dissolving media; a fuel reactant discharge (60) secured adjacent the ammonia dissolving media and configured to discharge the fuel reactant stream to flow through the ammonia dissolving media; an accumulator secured in fluid communication with the ammonia dissolving media and configured to receive and accumulate a separated contaminant and water stream; a scrubber fuel outlet secured within the scrubber container and configured to direct flow of the fuel reactant from the ammonia dissolving media and from the separator scrubber back into the fuel reactant inlet line; a fuel-control heat exchanger (57) secured in heat exchange relationship with the fuel reactant stream upstream of the separator scrubber for adding thermal energy to or removing thermal energy from the fuel reactant stream; and, water-control loop (78) secured in fluid communication with the separator scrubber, the water-control loop including a loop conduit (80) configured to direct the separated contaminant and water stream out of the accumulator (68) from the water outlet (82); a water-control loop pump (84) secured in fluid communication with the loop conduit for pumping the separated contaminant and water stream through the loop conduit; an ion exchange bed (88) secured in fluid communication with the loop conduit for directing flow of the separated contaminant and water stream through the ion exchange bed and for removing separated contaminants from the water in the stream within the bed; a loop conduit return line secured in fluid communication between an outlet (92) of the ion exchange bed and a water inlet (94) of the separator scrubber for returning decontaminated water from the water-control loop back into the separator scrubber. An INDEPENDENT CLAIM is included for method of decontaminating a fuel reactant stream for a fuel cell, involving flowing the fuel reactant stream through a fluidized ammonia dissolving media within a fluidized bed for dissolving ammonia and removing particulates from the fuel reactant stream within a separator scrubber while simultaneously flowing water through the fluidized ammonia dissolving media within the fluidized bed to separate contaminants from the fuel reactant stream into a separated contaminant and water stream; accumulating the separated contaminant and water stream from the fluidized bed within an accumulator; circulating the separated contaminant and water stream from the accumulator through a water-control loop; decontaminating the separated contaminant and water stream by flowing the stream through an ion exchange bed secured in fluid communication with the water-control loop; then circulating a decontaminated water stream from the ion exchange bed back through the ammonia dissolving media; and, controlling a temperature of the fuel reactant stream upstream of the separator scrubber to produce a predetermined temperature of the fuel reactant stream passing through the separator scrubber.    DESCRIPTION OF DRAWING(S) - The figure shows schematic view of fluidized bed contaminant separator and water-control loop.    Water-control loop (10)    Fuel cell (12)    Fuel reactant inlet line (26)    Separator scrubber (58)    Fuel reactant discharge (60)    Ammonia dissolving media (61)    Fluidized bed (62)