Abstract: A fuel cell system having a cathode, anode and auxiliary loop is provided. The anode loop may be configured to deliver reformed and unreformed fuel to the fuel cells. Unreformed fuel may be provided to the fuel cells by bypassing a portion of the fuel around a reformer. The unreformed fuel may be reformed in the fuel cell block. The cathode loop may direct a portion of oxidant exhausted from said fuel cells back to the fuel cell through a cathode ejector. The ejector may be supplied with pressurized oxidant that may be heated prior to entering the cathode ejector. The auxiliary loop may combust unused fuel and oxidant to provide the heat transferred to the oxidant prior to the oxidant entering the cathode loop.

Abstract: A reforming unit for a fuel cell system is provided. The reforming unit may comprise a reforming section, a heat exchanging section and a bypass plenum. The reforming section reforms a hydrocarbon containing fuel. The heat exchanging section effects a heat transfer between a fluid flowing therethrough and the fluid flowing through the reforming section, the bypass plenum, or both. The bypass plenum provides a flowpath for the hydrocarbon-containing fuel to bypass the reforming section. The bypass plenum may comprise a flow restrictor in the outlet of the bypass plenum to control the amount of fluid communication between the outlet of the bypass plenum and the outlet of the reforming section.