Hydrogen from Biomass via Fast Pyrolysis and Catalytic Steam Reforming

Fast pyrolysis transforms biomass into "bio-oil", with yields as high as 75-80 wt.% of the anhydrous biomass. This bio-oil is a mixture of aldehydes, alcohols, acids, oligomers from the constitutive carbohydrates and lignin, and some water from the dehydration reactions. Tests performed using a microreactor interfaced with a molecular beam mass spectrometer and a benchscale, fixed bed reactor have demonstrated near stoichiometric hydrogen yields from steam reforming of the bio-oil aqueous fraction obtained after precipitation and separation of the lignin-derived oxyaromatics. Reforming of the aqueous fraction required proper dispersion of the liquid to avoid vapor-phase carbonization of the feed in the inlet to the reactor. A spraying nozzle injector has been designed and successfully tested. We will present and discuss the process developed for the pyrolysis and reforming operations and some preliminary product cost estimates. The economics of the process is favored when the separated lignin-derived oxyaromatics are converted to valuable co-products and the aqueous fraction of the bio-oil is used for hydrogen production.