Carbonaceous material is removed from a catalyst within an autothermal reformer by introducing an isolated oxidant stream into the autothermal reformer prior to introduction of hydrocarbon fuel into the reformer. A hydrocarbon stream is introduced into the autothermal reformer following removal of the carbonaceous material. A concurrent supply of the hydrocarbon stream and the oxidant stream to the autothermal reformer is maintained such that an exothermic reaction driven by the oxidant stream provides heat to an endothermic reaction driven by water vapor in the hydrocarbon stream. In accordance with 37 CFR 1.72(b), the purpose of this abstract is to enable the United States Patent and Trademark Office and the public generally to determine quickly from a cursory inspection the nature and gist of the technical disclosure. The abstract will not be used for interpreting the scope of the claims.