Hydrogen Production by Steam Reforming of Bio-Oil Using Coprecipitated Ni−Al Catalysts. Acetic Acid as a Model Compound

Abstract

Catalytic steam reforming of bio-oil is a promising process for hydrogen production from biomass. Bio-oil is a complex mixture of a large number of compounds (acids, aldehydes, alcohols, and ketones, among other compounds), and acetic acid has been selected as a model compound. The experimental work has been conducted in a fluidized-bed reactor. Noncatalytic steam reforming of acetic acid has been performed from 450 °C to 700 °C. For catalytic experiments, coprecipitated Ni−Al catalysts, some promoted with lanthanum, have been selected, because of their high mechanical strength and suitable performance in biomass steam gasification. The presence of the catalyst, its reduction, promotion with lanthanum, and the influence of space velocity on gas yields have been analyzed at 650 °C. Catalytic experiments show a significant increase in total gas, H2, and CO2 yields, whereas CH4 and C2 yields decrease, when compared with those from noncatalytic experiments. Gas yields obtained in the catalytic process present a shift from the noncatalytic process to equilibrium gas yields. Promotion with lanthanum does not increase the H2 yield achieved with the Ni−Al catalyst. Simple first-order kinetic equations have been proposed for the formation of H2 and CO2 and the disappearance of CH4 and C2.