Abstract: A method for humidifying a mixture of dry fuel and air for use in a fuel processor may include receiving a mixture of dry fuel and air at a first temperature such as ambient temperature, heating the mixture of dry fuel and air to a second temperature greater than the first temperature, and combining the mixture of dry fuel and air at the second temperature with water. A fuel cell system incorporating such method may include a humidifier for humidifying a mixture of dry dry fuel and air which is processed in a fuel processor to produce reformate, and a fuel cell for receiving the reformate and generating electricity. A heat exchanger is provided for heating the mixture of dry fuel and air prior to humidification in the humidifier. The heat exchanger may be provided in the fuel processor or operably connected to an anode tail-gas oxidizer.

Abstract: A fuel cell system includes a fuel cell stack that generates electrical energy during operation by reacting two streams of reactant gases. The fuel cell stack also produces a fuel cell exhaust stream. An oxidizer unit is positioned to receive the fuel cell exhaust stream. The oxidizer unit oxidizes at least a part of the fuel cell exhaust stream in an oxidizing gas stream during operation. A temperature sensor is positioned to sense a temperature of the oxidizer unit and an input system provides the oxidizer unit with at least the stoichiometric amount of the oxidizing gas stream during operation. The input system controls the amount of the oxidizing gas stream in excess of the stoichiometric amount provided to the oxidizer unit in response to the temperature of the oxidizer unit.

Abstract: A fuel cell system includes a fuel cell stack, which during operation generates electrical energy by reacting a first stream of reactant gas and a second stream of reactant gas. The fuel cell stack also produces a fuel cell exhaust stream. An oxidizer unit is positioned to receive the fuel cell exhaust stream and oxidize at least a part of the fuel cell exhaust stream during operation, to produce an oxidizer exhaust stream. A heat recovery system is positioned to receive the oxidizer exhaust stream. The heat recovery system transfers at least some heat from the oxidizer exhaust stream to an input stream to generate a heated stream of water. In some embodiments, a temperature sensor is positioned to sense the temperature of the heated input stream. A control system maintains the heated stream of water at a target temperature based on the sensed temperature by controlling the amount of the heat from the oxidizer exhaust stream that is transferred to the input stream.