Evaluation of thermochemical routes for hydrogen production from biomass: A review

H-2 is regarded as one of the cleanest future energy carrier that can be generated from renewable sources and will give rise to a reduction of CO2 emissions and environmental problems related to the use of petroleum based feedstock. Thus, the thermochemical routes from biomass for sustainable H-2 production compared to other biomass treatment routes have a great potential for its industrial implementation. Gasification of biomass and reforming of the bio-oil produced by biomass pyrolysis are the most researched pathways, although some studies dealing with supercritical water gasification and bio-oil gasification can also be found in the literature. Nevertheless, pyrolysis and in-line catalytic steam reforming strategy is gaining great attention due to its advantages compared to gasification and bio-oil reforming, especially those related to the optimization of each step (pyrolysis and catalytic steps) and bio-oil feeding. This review deals with the different reactor configurations, operating conditions and catalysts used in each process and compares the different alternatives in terms of H-2 production, with emphasis placing on the advantages of the two-step strategy.