Application of a Pd-Ru composite membrane to hydrogen production in a high temperature membrane reactor

The long term operation on this membrane revealed the potential suitability of this Pd-alloy to be a candidate for use in SMR membrane reactors at temperature as high as 580 °C. The permeate hydrogen flux was very stable at 580 °C, 2.9 MPa feed pressure, and a steam-to-carbon ratio (SCR) of 3 for more than 1000 h of continuous testing. The hydrogen permeate purity remained >93% over the course of testing. Stable methane conversions as high as ∼80% were obtained for the duration of the long term test which may be further improved by optimizing the fluid mechanics of the reactor design or geometry. 1-Dimensional process simulations were carried out and the results suggested that the methane conversion and hydrogen flux during the membrane reactor experiments were reduced by gas phase mass transfer due to concentration polarization effects. Ongoing work will focus on further optimization and testing of scaled-up Pd-Ru membranes in SMR reactor environments.