Abstract
This study addresses the development of a compact reactor for oxidative
steam-reforming of methanol (OSRM) to produce hydrogen in autothermal
mode for fuel cells. The string reactor uses catalytically active
brass wires with a diameter of 500 mum placed in parallel into
a tube. The micro-channels in the reactor for gases are formed between
the wires presenting hydrodynamics similar to the one in multi-channel
micro-reactors. Due to the high thermal conductivity of brass, the
heat generated during methanol oxidation at the reactor entrance
is transferred to the zone of the endothermic steam-reforming. The
catalysts are prepared by Al-alloy formation on the surface of the
brass wires followed by the partial leaching of Al. The catalyst
presents a porous layer with the morphology of Raney metals and the
chemical composition consistent with the Cu/Zn/Al-mixed oxide. The
catalyst surface was additionally modified by incorporating chromium
leading to Cr/Cu-spinel. This decreases the degree of the reduction
of copper oxide and sintering leading to a stable catalyst. The catalyst
was tested in OSRM showing high activity and selectivity to carbon
dioxide and hydrogen. The string reactor presents nearly isothermal
profile since the temperatures gradient within the reactor length
is about 3 K. Micro-structured string reactor presents a short start-up
and a fast transient behavior showing a rapid temperature change
when adjusting the oxygen amount introduced into the reactor.
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