Hydrogen by glycerol steam reforming on a nickel–alumina catalyst: Deactivation processes and regeneration

Hydrogen energy has attracted considerable attention because of its efficiency and environmental benefits, and the increasing demand requires finding renewable sources of raw materials to produce it. Glycerol, by-product of biodiesel production and coming from renewable raw materials, could be a bio-renewable substrate to produce hydrogen. The glycerol steam reforming to obtain hydrogen was evaluated using a 5.1 wt% Ni impregnated on Al2O3 catalyst, characterized by nitrogen adsorption, XRD, and FTIR. Deactivation processes were analyzed in successive cycles of reaction at 700 °C, atmospheric pressure, 5 h−1 WHSV, and 3:1 water:glycerol molar ratio, during 12 h. Between reaction cycles, regenerating took place using a He/Air stream. Hydrogen was the main product on the fresh catalyst, following by CO and CH4; during reaction, carbonaceous deposits deactivated catalyst, decreasing H2 and increasing both CO and CH4. Carbonaceous deposits were characterized by TPO, showing a main peak centered at 690 °C; the carbon content reached 11.9%.

► Glycerol, by-product of biodiesel, could be a renewable substrate to produce hydrogen.
► Deactivation processes were studied in successive cycles of reaction-regeneration.
► On the fresh catalyst, the main product was hydrogen followed by CO and methane.
► Carbonaceous deposits deactivated catalyst, being possible the recovery of activity.
► Carbon content was 11.9%, appearing the main combustion peak centered at 690 °C.