Hydrogen by Catalytic Steam Reforming of Liquid Byproducts from Biomass Thermoconversion Processes

Abstract

Biomass, a product of photosynthesis, is a renewable resource that can be used for sustainable production of hydrogen. We propose an approach that combines production of hydrogen with valuable coproducts and shows promising economics. The concept is based on a two-stage process: fast pyrolysis of biomass to generate bio-oil, followed by catalytic steam reforming of the bio-oil, or a fraction thereof, to produce hydrogen. The preferred option is separation of the bio-oil into a lignin-derived fraction, which could be used for producing phenolic resins or fuel-blending components, and a carbohydrate-derived material, which would be reformed to produce hydrogen. The coproduct strategy can also be applied to residual fractions derived from pulping operations or ethanol production and to effluents from other biomass conversion technologies such as transesterification of vegetable oils or food processing residues. In addition, all of the biomass-derived liquids can be coprocessed with natural gas to produce hydrogen from mixed fossil−biomass feedstocks, a strategy similar to cofiring biomass and coal for power generation. This work focuses on the second stage of the process: catalytic steam reforming of various biomass-derived liquids. We have used a commercial nickel-based naphtha reforming catalyst in a fluidized-bed reactor to produce hydrogen from the various biomass-derived liquids. Yields have approached or exceeded 80% of those theoretically possible for stoichiometric conversion.