A microchannel membrane configuration was tested by applying a thin self-supported Pd/Ag23 wt.% membrane (similar to 1.4 mu m) on top of six parallel channels with dimensions 1 mm x 1 mm x 13 mm. The influence of feed flow rate and pressure was investigated and analyzed with respect to effects arising when hydrogen permeates from mixtures. A permeance of 1.7 x 10(-2) mol m(-2) S-1 Pa-0.5 was calculated from measurements in pure hydrogen at 573 K. The membrane was found to withstand differential pressures up to 470 kPa, without reaching the burst pressure. The high pressures employed conveniently allowed hydrogen separation from mixtures without the use of a sweep gas. Increasing the total feed flow rate resulted in increased hydrogen flux but decreased recovery. A simple simulation showed that only the first part of the membrane was utilized for lower total feed flow rates and higher total absolute feed pressures. During the similar to 7 days of testing and pressure cycling in H-2/N-2 feed mixtures a small nitrogen leakage evolved, resulting in the H-2/N-2 separation factor to decrease from similar to 5700 to similar to 390 at similar to 300 kPa differential pressure. The design represents a first step to a compact and efficient microchannel membrane reactor system for production and separation of hydrogen. (c) 2008 Elsevier B.V. All rights reserved.