Patent ID: 7972585

Claim:
A method of operating a fuel reforming system in order to obtain a fuel gas to be supplied to a polymer electrolyte fuel cell including, a reformer for reforming a raw fuel in a feed gas containing the raw fuel and steam into a first mixture gas as reformed gas containing hydrogen and carbon monoxide, a carbon monoxide shift converter accommodating a carbon monoxide shift catalyst for converting the carbon monoxide contained in the first mixture gas thereby forming a second mixture gas as shift converted gas containing hydrogen and carbon monoxide, and a carbon monoxide removal reactor accommodating a carbon monoxide removal catalyst for removing carbon monoxide contained in a reactant gas formed by adding an oxidizer to the second mixture gas discharged from the carbon monoxide shift converter and prior to the carbon monoxide removal reactor, the method including an introducing step of introducing the reactant gas to the carbon monoxide removal reactor, wherein said reformer, said shift converter and said carbon monoxide removal reactor are pipe-connected in the mentioned order to be capable of communicating gas therebetween, and there is provided a heat exchanger for communicating a heat transfer medium capable of effecting heat exchange with said second mixture gas or said reactant gas communicating within a pipe interconnecting between said carbon monoxide shift converter and said carbon monoxide removal reactor, and said oxidizer being added to the second mixture gas before said heat exchanger or after said heat exchanger; wherein said carbon monoxide removal catalyst consists of alumina as a support, and a member selected from the group consisting of ruthenium, rhodium, and palladium supported on said second mixture gas or said reactant support; wherein by said heat exchange between said heat transfer medium and said gas communicating within the pipe interconnecting between said carbon monoxide shift converter and said carbon monoxide removal reactor, the reactant gas communicating within a pipe portion downstream of a portion where said heat exchanger is disposed is maintained at 100° C. or lower, and by providing the heat exchanger and a drain trap to the pipe interconnecting between said carbon monoxide shift converter and said carbon monoxide removal reactor to allow condensation of steam present in the reactant gas flowing through the pipe, a dew point of the reactant gas introduced to an inlet of the carbon monoxide removal reactor is set to 40° C. or lower under the processing pressure.