H2 from bio-ethanol to feed a molten carbonate fuel cell: catalytic and technological aspects

Catalytic and technological aspects involved in the use of bio-ethanol as a fuel to produce hydrogen in both DIR-MCFC and IIR-MCFC have been considered. The presence of huge amount of water seems not to significantly affect the electric and thermal efficiencies of the overall process. In MCFC conditions the ethanol is completely converted but thehydrogen productivity is linked to the catalyst efficiency in converting methane formed through a mechanism which foresees as the first step the dehydrogenation of ethanol to acetaldehyde andas a second step the decomposition of acetaldehyde to CO and CH4. Potassium-doped Ni/MgO, Ni/La2O3 and Rh/MgO resulted to be the more promising catalysts to be used for the hydrogen production by steam-reforming of bio-ethanol. Coke formation can be drastically depressed by adding to the reaction stream a low amount of oxygen. Indirect internal reforming configuration should be the more appropriate to be operated with a bio-ethanol since the large amount of water involved in the reforming process reduces the concentration of un-reacted methane.