NOVELTY - A fuel processing system includes a combustor, a steam reformer, a water-gas shift reactor, a combustor preheater, and a water preheater connected downstream from the water-gas shift reactor to receive the reformate flow and transfer heat from the reformate flow to a water flow that is supplied to a reformer feed mix that is directed to the reformer.    USE - For distributed hydrogen production used in a transportation fuel cell infrastructure.    ADVANTAGE - The inventive fuel processing system can deliver high purity hydrogen. It can also overcome the heat transfer limitations of previous designs, and achieve a high level of hydrogen product efficiency without extremely high metal temperatures.    DETAILED DESCRIPTION - A fuel processing system comprises a combustor, and a steam reformer located in heat transfer relation to the combustor. A water-gas shift reactor is connected downstream from the reformer to receive a reformate flow. A combustor preheater is connected downstream from the water-gas shift reactor to receive the reformate flow and connected upstream from the combustor to supply a combustor feed to the combustor after heat has been transferred from the reformate flow to the combustor feed in the combustor preheater. A water preheater is connected downstream from the water-gas shift reactor to receive the reformate flow and transfer heat from the reformate flow to a water flow that is supplied to a reformer feed mix that is directed to the reformer.    An INDEPENDENT CLAIM is also included for a method of operating a fuel processing system, comprising transferring heat from a combustor to a reformate flow passing through a steam reformer, providing the reformate flow from the reformer to a water-gas shift, transferring heat from the reformate flow to a combustor feed flow after the reformate flow has passed through the water-gas shift, supplying the combustor feed flow to the combustor, transferring heat from the reformate flow to a water flow after the reformate flow has passed through the water-gas shift, and supplying the water flow to a reformer feed mix flow.    DESCRIPTION OF DRAWING(S) - The figure is a section view of an integrated fuel processing unit of the invention.