The microfibrous structured catalytic packings for miniature fuel processor consisting of a methanol steam reformer and a subsequent CO cleanup train has been investigated experimentally. A highly void and tailorable sinter-locked microfibrous carrier consisting of 3.5 vol% 8 mu m diameter Ni-fibers is used to entrap 35 vol% 150-250 mu m catalyst particulates for both methanol steam reforming (MSR) and CO preferential oxidation (PROX). We demonstrate a microfibrous entrapped Pd-ZnO/Al(2)O(3) catalyst packings for high efficiency hydrogen production by the MSR reaction. The use of microfibrous entrapment technology significantly enhances the catalyst utilization efficiency by a 4-fold improvement of the weight hourly space velocity (WHSV), compared to the single Pd-ZnO/Al(2)O(3) particulates as keeping the methanol conversion at >98%. The microfibrous entrapped Pt-Co/Al(2)O(3) catalyst packings can drive the CO from 2% down to <50 ppm at 150 degrees C with O(2)/CO ratio of 1 using a gas hourly space velocity (GHSV) of 32,000 h(-1). Finally, a prototype fuel processor system integrating MSR reformer and CO PROX train is demonstrated as three reactors in series. Such test rig is capable of producing roughly 1700 standard cubic centimeter per minute (sccm) PEMFC-grade H(2) (equivalent to similar to 163W of electric power) in a longer-term test, in which the MSR reactor is operated at 300 degrees C using a methanol/water (1/1.1, mole) mixture WHSV of 9 h(-1) and CO PROX reactors at 150 degrees C using an O(2)/CO molar ratio of 1.3, respectively. In the test of this prototype system, MSR reactor delivers >97% methanol conversion throughout the entire 1200-h test; the CO cleanup train placed in line after 800-h MSR illustrates the capability to decrease the CO concentration from similar to 3.5% to similar to 1% at PROX-1 and then to less than 20 ppm at PROX-2 until to the end of test. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.