Structured palladium catalysts suitable for three-phase reactions have been developed based on woven fabrics of active carbon ÿbres (ACF) as the catalytic supports. The Pd=ACF were tested in liquid-phase hydrogenation of 2-butyne-1,4-diol showing a selectivity towards 2-butene-1,4-diol up to 97% at conversions up to 80%. The catalyst multiple reuse with stable activity=selectivity in a batch reactor was also demonstrated. The reaction kinetics was studied and the main kinetic parameters were obtained. Assuming a Langmuir-Hinshelwood kinetics and a weak hydrogen adsorption a suitable kinetic model was developed consistent with the experimental data. ?

Novel micro-structured string-reactor designed as catalytically active wires placed in parallel into a tube was developed. The small diameter of the channels (∼100 m) leads to a short radial diffusion time, a narrow residence time distribution (RTD), and a low pressure drop. This reactor was applied for the oxidative steam-reforming of methanol (OSRM) to produce hydrogen in autothermal mode for fuel cells. The heat generated during methanol oxidation at the reactor entrance is axially transferred to the reactor zone of the endothermic steam-reforming. The brass metal wires (Cu/Zn = 4/1) were used as precursors for the preparation of string-catalysts. The brass wires have high thermal conductivity (120 W/(m K)) and the chemical composition is similar to the active phase of the Cu/ZnO/Al 2 O 3 traditional catalyst during the steam-reforming of methanol. Brass-based string catalysts are obtained by metal/aluminium alloy formation on the outer surface of wires followed by an acid treatment leaching out aluminium. This treatment leads to an increase of the specific surface area (SSA) due to the formation of porous outer layer on the wire surface. The porous outer layer has the morphology of Raney metals. The catalysts were first tested for the steam-reforming of methanol and showed high activity together with selectivities close to 100% towards hydrogen and carbon dioxide. Then, the optimized catalyst was tested during the methanol partial oxidation (POX) and during OSRM. Oxygen was observed to be totally converted via total oxidation and therefore, higher methanol conversion in the OSRM together with CO 2 selectivity of 99% and H 2 selectivity of 60% were obtained.

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 mm 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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