Syngas conversion is needed for the production of liquid fuels and/or chemicals from renewable or remote feedstock at capacities much smaller than the conventional FischerTropsch (FT) plant. Here, we present a multiscale-engineered, modular-type design approach toward the development of a compact reactor unit to make syngas-to-liquids economically feasible at small scales. The fundamental design idea is tested by using a Re-Co/alumina catalyst coated on a monolith support of channel size about 0.9 mm. One-pass CO conversion (9298%) with <10% of CH4 selectivity is obtained with the structured bed under typical FT reaction conditions. The gas superficial linear velocity was found as one critical parameter that may allow scale-up of the hydrodynamics from the small-scale laboratory tests directly to practical sizes of the reactor with the proposed design strategy. A pore wetness and surface perspiration model is proposed to explain the experimental data and rationalize the new design concepts. (c) 2011 American Institute of Chemical Engineers AIChE J, 2012