(WO9506335-A1)      A power plant system produces utility grade electrical AC power from gaseous or liquid hydrocarbon fuels using a fuel cell stack employing ion exchange membranes. The fuel is desulphurised, mixed with water, heated and vaporized before being introduced into a reformer. The latter produces a hydrogen-rich gas which is then directed through a series of heat exchangers, shift converters and a selective oxidizer.    The processed fuel stream is combined in the fuel cell stack with a pressurized oxidant stream to generate DC power. Oxidant pressure is supplied by compressors driven by turbines using heated system exhaust gases. The DC power is converted into utility grade AC power using an inverter augmented by a battery peaking unit for rapid load following. The water generated in the fuel cell stack is recycled and used to cool the fuel cell stack and to humidify the fuel stream and oxidant stream prior to their introduction to the fuel cell stack.    ADVANTAGE -   System integration results in electrical efficiency of at least about 40 per cent, and with heat recovery the overall fuel efficiency is greater than approximately 80 per cent.    (JP8502855-W)      A power plant system produces utility grade electrical AC power from gaseous or liquid hydrocarbon fuels using a fuel cell stack employing ion exchange membranes. The fuel is desulphurised, mixed with water, heated and vaporized before being introduced into a reformer. The latter produces a hydrogen-rich gas which is then directed through a series of heat exchangers, shift converters and a selective oxidizer.    The processed fuel stream is combined in the fuel cell stack with a pressurized oxidant stream to generate DC power. Oxidant pressure is supplied by compressors driven by turbines using heated system exhaust gases. The DC power is converted into utility grade AC power using an inverter augmented by a battery peaking unit for rapid load following. The water generated in the fuel cell stack is recycled and used to cool the fuel cell stack and to humidify the fuel stream and oxidant stream prior to their introduction to the fuel cell stack.    ADVANTAGE -   System integration results in electrical efficiency of at least about 40 per cent, and with heat recovery the overall fuel efficiency is greater than approximately 80 per cent.