An apparatus for carrying out a multi-step process of converting hydrocarbon fuel to a substantially pure hydrogen gas feed includes a plurality of reaction zones arranged in an insulated, box-shaped, compact fuel processor. The multi-step process includes preheating the hydrocarbon fuel utilizing integration with the inherent exothermic processes utilized with the fuel processor, reacting the preheated hydrocarbon fuel to form the hydrogen rich gas, and purifying the hydrogen rich gas to produce a gas that is suitable for consumption in a fuel cell.