NOVELTY - The low pressure drop fuel processor (15) comprises a reformer configured to receive reformer fuel and to output hydrogen, and a burner including a chamber (103), a chamber air inlet (112), a chamber fuel inlet (114) and a chamber outlet. The burner chamber air inlet is configured to receive air. The burner chamber fuel inlet is configured to receive burner fuel. The burner includes a catalyst in the burner chamber that is selected to facilitate combustion of the burner fuel. The burner chamber outlet is configured to output combustion exhaust from the burner chamber.    USE - The low pressure drop fuel processor is useful for producing hydrogen from a fuel, and in a portable fuel cell system (claimed).    ADVANTAGE - The low pressure drop fuel processor is portable, can be manufactured with light-weight, high reliability, high durability and high thermal efficiency, and permits the use of a low pressure air supply such as a fan to move products and reactants through the burner, hence it is cost-effective.    DETAILED DESCRIPTION - The low pressure drop fuel processor (15) comprises a reformer configured to receive reformer fuel and to output hydrogen, and a burner including a chamber (103), a chamber air inlet (112), a chamber fuel inlet (114) and a chamber outlet. The burner chamber air inlet is configured to receive air. The burner chamber fuel inlet is configured to receive burner fuel. The burner includes a catalyst in the burner chamber that is selected to facilitate combustion of the burner fuel. The burner chamber outlet is configured to output combustion exhaust from the burner chamber. The burner is configured to permit air flow from the burner chamber air inlet to the burner chamber outlet and through the burner chamber with a pressure drop of less than about 25 Pa. The burner chamber has a volume of less than 5 cubic centimeters. The maximum air flow into the burner chamber is less than 50 liters per minute. The maximum burner fuel flow into the burner is less than 100 milliliters per hour. The burner chamber includes a single chamber with no turns from the burner chamber air inlet to the burner chamber outlet, and includes a length of less than 15 centimeters between the burner chamber air inlet and the burner chamber outlet. The burner catalyst is coated onto pellets with a diameter of less than 1/8 inch. The fuel processor comprises a monolithic structure including a single material that forms a shared wall between the burner chamber and the reformer chamber so as to permit conductive heat transfer from the burner chamber to the reformer chamber. The burner includes a set of fins and plates that include a wash coating of the burner catalyst. An INDEPENDENT CLAIM is included for a portable fuel cell system.    DESCRIPTION OF DRAWING(S) - The diagram shows a top perspective view of a low pressure drop fuel processor.    Fuel processor (15)    Boiler (34)    Burner chamber (103)    Air inlet (112)    Burner fuel inlet. (114)