(301d) Reaction Engineering of Photochemical Upgrading of Biomass

We use the term ?photochemical upgrading? to mean a new class of reaction in which there is photolytic transfer of hydrogen from water to a feed molecule so as to convert C-OH bonds to C-H bonds or to saturate double bonds. In a preliminary analysis we have estimated that concentrated sunlight can be used to directly convert either cellulose-based or lignin-based biomass to fuel-like products economically at scales greater than thousands of barrel- oil-equivalents per day. Moreover, photochemical upgrading processes promise roughly 50% gains in productivity compared to the conventional processes of fermentation and gasification+Fischer-Tropsch synthesis.

Here we analyze the case where, because we wish to achieve high conversion, the absorption of light by the reaction medium cannot be ignored. We find that performance of a flat, thin reactor, much like that employed for photovoltaics, can be substantially improved by using reactors that permit much more efficient contacting among all of the reactants.