TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Function: The heat exchanger directs fluids between which heat is exchanged into adjacent laminar flows.Preferred Component: The mechanism for providing laminar flow includes a catalytically active surface in contact with fluid flow.Preferred System: The system further comprises a second heat exchanger for cooling the gas from the steam reformer; a water gas shift reactor; a preferential oxidation reactor, where a gas predominantly comprised of hydrogen is introduced into the fuel cell; storage tank(s) for separately storing a fuel cell off gas, a liquid hydrocarbon composition, and/or water; an in-line Zeolite cracker; and a start module comprising a heat exchanger with adjacent sections for laminar flow in which hydrogen from an external source is combusted to provide heat energy in one section and hydrocarbon fluids are vaporized in an adjacent section to initiate the vaporization of fluids and steam reforming in the system.Preferred Condition: The scalable power increments of a predetermined magnitude are determined by the capacity of a laminar flow unit. The laminar flow unit is a micro channel having a width to depth aspect ratio of 1:10 to 1:100. EXAMPLE - In a fuel processor, hydrocarbon fuel was vaporized and mixed with stored fuel cell off gas or hydrogen from storage tank in mixer (26) until the fuel processor (14, 22) is heated and running, at which point the vaporized liquid hydrocarbon fuel is mixed in mixer with fuel cell off gas from the fuel cell stack. The resulting mixture was introduced into and primarily catalytically burned in the water vaporizer (18) to vaporized water, raising the temperature of the water from ambient temperature to approximately 350degreesC. The vaporized fuel and water vapor from the water vaporizer were mixed and fed to the first heat exchanger (30). The mixture was heated to approximately 700degreesC and fed to steam reformer (34). The fuel and water vapor underwent a catalyst-introduced reaction to produce syn-gas comprising hydrogen, carbon dioxide, carbon monoxide, water, and methane. The syn-gas left the reformer and passed through a second heat exchanger (38) to cool the syn-gas to approximately 450degreesC. The gas was then passed through a first water gas shift reactor (42) to reduce the proportion of carbon monoxide component gas. The resulting syn-gas was passed through a third heat exchanger (46) to cool the gas to approximately 250degreesC, a second gas shift reactor (50), to a fourth heat exchanger (54) to reduce temperature to approximately 100degreesC, through the preferential oxidation reactor (60), and to the fuel cell bank.