Bio-oil: the future of hydrogen generation

Depleting non-renewable energy sources combined with stringent environmental norms necessitate researchers to search for alternative energy sources. Hydrogen (H-2) is one of the most promising alternatives if produced, stored and harnessed properly. Biomass derived bio-oil extracted through fast pyrolysis is an alternative source for sustainable H-2 generation via the reforming process. This review summarizes recent work done in the field of H-2 generation using steam reforming of bio-oil and the influence of operating parameters such as temperature, S/C ratio and type of catalyst used. Other than steam reforming, several other reforming techniques, such as oxidative steam reforming, aqueous phase reforming and partial oxidation, have also been discussed. Various catalytic systems with Ni, Pt and Ru on different supports have been investigated. Coke deposition on the catalyst surface over a long period of operation is the major shortcoming for reforming reaction which lowers the catalytic activity and requires frequent regeneration. Use of additives like MgO, K, Ca and addition of a small amount of O-2 reduces coke formation as well as increases the catalytic activity.