Ultra-compact microstructured methane steam reformer with integrated Palladium membrane for on-site production of pure hydrogen: Experimental demonstration

A novel metal-based modular microstructured reactor with integrated Pd membrane for hydrogen production by methane steam reforming is presented. Thin Pd foils with a thickness of 12.5 mu m were leak-tight integrated with laser welding between microstructured plates. The laser-welded membrane modules showed ideal H-2/N-2 permselectivities between 16,000 and 1000 at 773 K and 6 bar retentate pressure. An additional metal microsieve support coated with an YSZ diffusion barrier layer (DBL) facilitated the operation at temperatures up to 873 K and pressures up to 20 bar pressure difference. The membrane permeability in this configuration is expressed with Q = 1.58E-07*exp(-1460.2/T) mol/(msPa(0.5)). In the first proof-of-concept reaction experiments the influence of W/F ratio (0.33-1.32 g(Cat)h/mol(CH4)), S/C ratio (3 and 4), temperature (773 and 823 K) and retentate/reformate pressure (6-12 bar) was studied. Methane conversion of 87% and a hydrogen recovery of 92% were obtained at a W/F ratio of 0.33 g(Cat)h/mol(CH4), corresponding to a GHSV of 29,000 h(-1), a temperature of 823 K and a feed pressure of 12 bar without the use of sweep gas. The microstructured membrane reactor showed a promising performance for the production of pure hydrogen in a very compact and modular system. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.