NOVELTY - A fuel cell system includes: (i) a polymer electrolyte membrane fuel cell operating at at least 120 degrees C; (ii) a cathode and a fuel blowers each connected to a controller; and (iii) fuel processing reactor with an inlet and an outlet. The inlet and outlet of the fuel reactor are connected with a catalyst that converts a hydrocarbon into a gas containing hydrogen and carbon monoxide.    USE - The fuel cell system is used as electrochemical device for converting chemical energy into electrical energy.    ADVANTAGE - The inventive fuel cell system ensures clean emissions. It does not require a ruthenium-based catalyst or platinum ruthenium alloy to improve carbon monoxide tolerance, as in common in the prior art, thus reducing the cost associated with the fuel cell stack.    DETAILED DESCRIPTION - A fuel cell system comprises:    (i) a polymer electrolyte membrane (PEM) fuel cell operating at at least 120 degrees C;    (ii) a cathode and a fuel blowers each connected to a controller; and    (iii) fuel processing reactor with an inlet and an outlet.    The fuel cell has a cathode inlet and outlet. The cathode blower varies air flow from the cathode inlet to the outlet according to a first control signal from the controller. The inlet and outlet of the reactor are connected with a catalyst that converts a hydrocarbon into a gas containing hydrogen and carbon monoxide. The outlet is connected with an anode chamber of the fuel cell. The fuel blower varies a fuel flow through the reactor according to a second control signal form the controller. The cathode outlet is connected with the reactor inlet.    An INDEPENDENT CLAIM is included for a method of operating the above fuel cell system comprising:    (a) operating a first blower according to a first control signal;    (b) reacting a portion of air in the fuel cell to produce electricity;    (c) exhausting a remaining portion of air containing water vapor;    (d) mixing a portion of the exhausted air with a hydrocarbon gas to form a feed mixture;    (e) modulating the first control signal to maintain a predetermined amount of oxygen in the feed mixture;    (f) operating a second blower according to a second control signal to flow the feed mixture;    (g) flowing the fuel gas into an anode chamber of the fuel cell; and    (h) modulating the second control signal to maintain a predetermined amount of hydrogen in the fuel cell.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic of a control system for an integrated high temperature polymer electrolyte membrane fuel cell system.