The production of hydrogen through the use of a 77 wt% Pd 23 wt% Ag membrane water gas shift reactor
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Date
2016
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
Hydrogen as an energy carrier has the potential to decarbonize the energy sector. This
work presents the application of a palladium-silver (PdeAg) membrane-based reactor. The
membrane reactor which is made from PdeAg film supported by porous stainless steel
(PSS) is evaluated for the production of hydrogen and the potential replacement of the
current two-stage Water-Gas Shift (WGS) reaction by a single stage reaction. The permeability
of a 20 mmPdeAg membrane reactor was examined at 320° C, 380° C and 430° C. The
effect of continuous hydrogen exposure on the PdeAg membrane at high temperature and
low temperature was examined to investigate the thermal stability and durability of the
membrane. During continuous operation to determine thermal stability, the membrane
reactor exhibited stable hydrogen permeation at 320° C for 120 h and unstable hydrogen
permeation at 430° C was observed. For the WGS reaction, the reactor was loaded with
Ferrochrome catalyst. The membrane showed the ability to produce high purity hydrogen,
with a CO conversion and an H2 recovery of 84% and 88%, respectively. The membrane
suffered from hydrogen embrittlement due to desorption and adsorption of hydrogen on
the membrane surface. SEM analysis revealed cracks that occurred on the surface of the
membrane after hydrogen exposure. XRD analysis revealed lattice expansion after
hydrogen loading which suggests the occurrence of phase change from a-phase to the
more brittle b-phase.
Description
Keywords
Hydrogen, Energy, Thermal stability, Membrane reactor, Palladium-silver, Hydrogen permeation, Hydrogen flux, Water-gas shift reaction
Citation
Baloyi, L. N. et al. (2016). The production of hydrogen through the use of a 77 wt% Pd 23 wt% Ag membrane water gas shift reactor. South African Journal of Chemical Engineering, 22: 44-54