(511b) Aqueous Platform for Conversion of Cellulosic Biomass Into “Drop-In” Hydrocarbon Fuel Precursors

Biomass is unique among sustainable resources for production of organic fuels on which our society is so dependent, and only cellulosic biomass offers low enough costs and sufficient supplies to make a large impact on petroleum use.  However, despite biomass costing about $60/dry ton being equivalent to oil costing about $20/barrel, conversion of cellulosic biomass into fuels is expensive, and new processes are needed that overcome recalcitrance as the primary barrier to competitive costs.  Although ethanol and other oxygenates are currently made from biomass carbohydrates, mostly sugar and starch, they are not fully compatible with the current fuel infrastructure, and enzyme loadings and costs tend to be too high.  In addition, hydrocarbon fuels with higher energy density are preferred for heavy-duty vehicles and air travel, and catalytic routes are being developed to convert biomass sugars into such “drop-in” hydrocarbon fuels.  Most of the latter developments to date have focused on pure sugars and their breakdown products, and low cost processes are needed that effectively integrate aqueous processing of cellulosic biomass to fuel precursors with their catalytic conversion to hydrocarbons compatible with the existing fuel infrastructure.  A potential advantage of aqueous processing of cellulosic biomass to “drop-in” fuels can be that only thermochemical conversion is needed to make such fuel precursors as furfural, 5-hydroxymethyl furfural, and levulinic acid.  However, because yields for traditional approaches to producing such intermediates are too low to support making cost competitive fuels, the key economic challenge is developing low cost routes that realize high yields of fuel precursors that can be integrated with catalytic conversion to make hydrocarbons.  In this presentation, processing options and key needs are outlined to achieve low cost production of fuel precursors. In addition, recent findings from our laboratory for different strategies to increase yields of fuel precursors are summarized and promising paths to reduce costs of commercial processing are discussed.