NOVELTY - A hydrocarbon reformer system comprises first and second reactors and a heat exchanger. The first reactor is configured to generate hydrogen-rich reformate (1) by carrying out at least one of non-catalytic thermal partial oxidation, catalytic partial oxidation and/or steam reforming. The second reactor is in fluid communication with the first reactor to receive (1) and has a catalyst for promoting a water gas shift reaction into (1).    USE - For producing hydrogen-rich reformate gas for use in an associated fuel cell(claimed). Also used in portable power units, transportation and small power plant (e.g. household backup or primary power systems).    ADVANTAGE - The process utilizes the waste reformate to assist in the preheating of unreformed fuel before its entry into the reforming chamber and simultaneously converts the harmful constituents of the waste reformate into acceptable emissions.    DETAILED DESCRIPTION - The heat exchanger has a first mass of two-phase water and is configured to exchange heat between the two-phase water and (1) in the second reactor. The heat exchanger is in fluid communication with the first reactor so as to supply steam as a reactant to the first reactor. The ratio of the mass of catalyst to the first mass of the two-phase water is greater than 1. INDEPENDENT CLAIMS are also included for:    (A) a method (M1) of controlling a hydrocarbon reformer during dynamic load operation;    (B) a method of operating the hydrocarbon reformer;    (C) a high efficiency system (I) for reforming the hydrocarbon fuel to generate (1) for use in an associated fuel cells;    (D) an auxiliary reactor (2) comprising a first burner for burning a first fuel and creating a heated gas stream and a first heat exchanger for transferring the heat from the gas stream and a heat transfer medium to the reformer reaction zone for additional heat exchange;    (E) a preferential oxidation reactor (3) comprising a first zone with an inlet for directing (1) stream into the zone; a second zone adjacent to the first zone; a catalyst within the second zone; and several flow paths for directing flow of (1) stream in diverging directions from the first zone and into the second zone, with the flow paths of the reformate stream continue in the same diverging directions through the second zone;    (F) a system comprising a first (3) and a condenser, with hydrogen also oxidized to produce water, and the water condenser down-line of the first (3) for receiving (1) stream containing water and condensing and recovering the water from the (1) stream;    (G) a method (M2) for preferentially oxidizing CO to CO2, comprising introducing (1) stream containing CO into the first (3), oxidizing at least a portion of the CO to produce CO2, and condensing water from (1) stream;    (H) an apparatus comprising a catalyst bed for oxidizing CO to CO2, inlet for introducing the reformate stream into the catalyst bed, and a cooler for cooling the reformate in the catalyst bed;    (I) a heat exchange system comprising a shift catalyst bed within a shift reaction vessel; and a preferentially oxidation catalyst within a preferential oxidation vessel, where the shift catalyst bed contains a cooler for cooling reaction stream flowing through the bed, the oxidizing catalyst bed is sequentially coupled to the shift reaction vessel, and the shift catalyst bed cooler is in fluid communication with the cooler of the oxidizing catalyst bed to allow a single coolant fluid to circulate in both the beds;    (J) a method (M3) for operating (3), comprising providing hydrogen reformate to a reactor, determining the amount of CO in the stream, adding oxygen to the stream to produce a desired ratio of oxygen to CO, flowing the mixture through (3), and adjusting the amount of oxygen containing gas which is added to the stream based upon CO concentration fluctuation;    (K) an apparatus for operating (3), comprising an inlet for supplying hydrogen containing CO-rich reformate to the reactor, a detector for determining the amount of CO in the stream, a conduit for adding oxygen to the stream, an outlet for flowing the mixture through (3), and a controller for adjusting the amount of oxygen containing gas;    (L) a reactor system comprising a reformate source, a first catalyst bed and a second catalyst bed, each having a catalyst, and a first manifold connecting both the catalyst beds to the reformate source, where the manifold has a flow director for directing a flow of the reformate through one or the other of the first and/or second beds in the case of an increase in reformate source flow so as to accommodate the added flow;    (M) a shift reactor for subjecting CO and water to a water-gas shift reaction comprising a shift reactor vessel including a first shift reaction zone, and a first helical tube disposed within the first shift reaction zone, where the first shift reaction zone has an input side for receiving reformate constituents including CO and an outlet side for discharging shift reacted constituents including CO2 and hydrogen gas, and the first helical tube has an inlet end which communicates with an oxygen containing gas supply source and an outlet end communicating with a fuel processing vessel;    (N) a hydrocarbon fuel reformer;    (O) a fuel processor;    (P) a reactor (R1) comprising a reaction vessel, a first shift reactor zone contains a first shift catalyst, and a boiler tube carrying the heat transfer medium and permitting a heat transfer between a first portion of the tube and reaction constituents in the first shift zone.