NAMS 2002 Workshop - ICOM 2008

Inorganic Membranes I – 4
Tuesday July 15, 4:00 PM-4:30 PM, Moloka’i
Upgrading of a Syngas Mixture for Pure Hydrogen Production in a Pd-Ag
Membrane Reactor
A. Brunetti, National Research Council - Institute for Membrane Technology, Rende (CS), Italy -
a.brunetti@itm.cnr.it
G. Barbieri (Speaker), National Research Council - Institute for Membrane Technology Rende
(CS), Italy - g.barbieri@itm.cnr.it
E. Drioli, University of Calabria, Rende CS, Italy, e.drioli@itm.cnr.it
In integrated plants for hydrogen production a fundamental step is the upgrading
of stream outletting reformers. These streams contain H2 (50%), CO2, N2 etc. and
about 10-15% of CO which could be converted producing in the meantime more
hydrogen. In a traditional reactor (TR), the presence of hydrogen in the feed
stream depletes CO conversion owing to the constraint imposed by the
thermodynamics. In the temperature range of interest (220-330°C) the maximum
achievable conversion could not be higher than 25%. In Pd-Ag membrane
reactor (MR), the selective removal of hydrogen allows the thermodynamics
limitation of a TR to be overcome and hence CO conversion might be
significantly higher. This value depends on the MR extractive capacity which is a
function of the operating conditions and particularly of the permeation driving
force. In this work it was realized by feed and permeate pressures and no sweep
gas was used. CO conversion in this MR was measured 4-5 times higher than
that of equilibrium of a TR. Hydrogen recovered as a pure permeate stream is
about 80% of the total present in the feed stream and also produced by (water
gas shift) reaction. The hydrogen produced was fed to a PEMFC for energy
production which showed stable performance not depending on the MR
operating conditions and equal to that measured feeding hydrogen from a
cylinder.