Abstract: A fuel cell system includes a fuel cell stack, and a reactor to oxidize excess fuel exhausted from the fuel cell stack. A sensor associated with the reactor provides an output indication, and a controller detects a fuel-rich condition of the reactor based on the output indication from the sensor.

Abstract: A fuel cell system includes a de-sulfurization tank, a reformer, a pressure monitoring device and a fuel cell stack. The de-sulfurization tank includes an agent that is adapted to remove sulfur compounds and is capable of undergoing a conditioning cycle. The tank includes an inlet to receive a first hydrocarbon flow and an outlet to provide a second hydrocarbon flow. The reformer is adapted to convert the second hydrocarbon flow into a reformate flow, which is received by the fuel cell stack. The pressure monitoring device monitors a pressure of the second hydrocarbon flow, a circuit of the fuel cell system is coupled to the pressure monitoring device to determine whether the conditioning of the tank is complete based on the pressure.

Abstract: A technique includes providing a fluid to a heat exchanger to produce a gas. The technique includes humidifying a flow of a fuel cell system with the gas and regulating a level of the fluid in the heat exchanger based on a temperature of the gas.