(537d) Hydrogen Production by Steam Reforming of Bio-Oil

Catalytic steam reforming of bio-oil is a promising process for hydrogen production from biomass. Bio-oil is a complex mixture of oxygenated compounds produced by the thermal decomposition of biomass (fast pyrolysis). These liquids have a higher energy density than biomass, can be readily stored, transported and can be used either as a renewable liquid fuel or chemical production. Using procedures such as water addition, the bio-oil can be separated into a water-rich phase that contains mostly carbohydrate-derived compounds and a hydrophobic phase composed mainly of lignin-derived oligomers. Steam reforming of pyrolysis oils has been reported to have some advantages compared to direct steam gasification of biomass. One of those advantages is the potential production and recovery of valuable compounds that could improve the economy of the entire process. For instance, we can use the lignin-derived phase mentioned before for the production of chemicals, such us phenols or other aromatics compounds. The by-product of this extraction, the water-rich phase, could be steam reformed for hydrogen production to enhance the economy of the process. In the present work, it was investigated the possibility of reforming the water-rich phase that is left after the extraction of the lignin-derived chemicals. This phase is a complex mixture of oxygenated compounds including complex sugars with high tendency for thermal decomposition and cooking. Direct steam reforming of the aqueous phase of the bio-oil becomes difficult. For this reason steam reforming and catalytic steam reforming of model compounds have been performed in the first stage of this study. Most compounds of bio-oil are organic acids. Acetic acid is present in a significant amount and has been selected for this study. Acetol is another one of the major compounds. The experiments were carried out in a fluidized-bed reactor with or without catalyst to find the optimum operating conditions. The catalyst selected has been a Ni-Al coprecipitated catalyst. A comparative work has been performed at 650 ºC for the two model compounds: acetic acid and acetol. Results of catalytic steam reforming of the aqueous phase at 650 ºC will be presented as well.