International Journal of Hydrogen Energy, Vol.41, No.24, 10193-10201, 2016
Steam methane reforming in a Pd-Au membrane reactor: Long-term assessment
In this work, electroless deposition was used to fabricate a 5.0 mu m thick Pd-28Au (wt. %) membrane (16.10 cm(2)) supported on a YSZ/PSS substrate. After annealing in hydrogen, steam methane reforming (SMR) was conducted continuously for 530 h, with permeate purity remaining above 99.2% for the duration. The reactor used a 0.5 wt. % Ru/Al2O2 catalyst and ran at 2.8 MPa and a steam-to-carbon ratio of 3, with temperature varied between 480 degrees C and 580 degrees C. Methane conversion was as high as 94% depending on temperature and space velocity. This represents a significant improvement over the thermodynamic equilibrium shift of 35% under similar conditions. Additionally, the hydrogen flux and overall methane conversion showed stable performance over time. The membrane thickness and composition were verified using SEM/EDS, XRD, XRF and ICP-AES. Furthermore, cross sectional EDS and XRD data indicated uniform gold composition throughout the film, suggesting homogeneous alloy formation. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Keywords:Palladium-gold composite membrane;Steam methane reforming;Catalytic membrane reactor;Hydrogen separation;Electroless plating