Evaporatively cooled fuel cell systems with cathode exhaust turbine boost

A fuel cell system (10, figure 1) comprises a fuel cell assembly (21) having an anode inlet (24), a cathode inlet (25), an anode exhaust (26) and a cathode exhaust (27), an expansion turbine 200 for receiving an expansion exhaust stream 150, an anode off-gas burner (84) and an intercooler 250 disposed in the flow path of the expansion exhaust stream prior to the expansion turbine, wherein the intercooler is fluidly connected to a compressed flow stream 155 and configured to transfer heat from the compressed flow stream to the expansion exhaust stream, the expansion exhaust stream comprises at least a portion of an anode gas purge stream that is burned in the anode off-gas burner to increase the temperature of the expansion exhaust stream before it reaches the expansion turbine. The expansion turbine may comprise or be coupled to a compressor 300.