Performance of Rh/Al2O3 catalyst in the steam reforming of ethanol:: H2 production for MCFC

The steam reforming of ethanol on 5% Rh/Al2O3 catalyst has been investigated to produce H-2 adequate to feed a molten carbonate fuel cell (MCFC). The influence of reaction temperature, H2O/EtOH molar ratio, gas hourly space velocities (GHSV) and O-2 were investigated in order to maximize the hydrogen content at the outlet of ethanol reformer. Endurance tests to assess the feasibility of a FC system fed by simulated bio-EtOH stream (H2O/EtOH molar ratio = 8.4) were also performed. Experiments carried out at MCFC operative conditions allowed to obtain a H-2 reach mixture close to 60% on dry basis. In steam reforming (SR) conditions an extensive formation of encapsulated carbon was registered while a great benefits, both in terms of catalyst stability and coke formation were evidenced adding 0.4 vol.% of oxygen in the reaction stream. Oxygen however promoted metal sintering. Consideration on reaction mechanism, mainly investigated to distinguish the reaction pathway influencing the H-2 production, is reported. (C) 2003 Elsevier Science B.V. All rights reserved.