(396b) Biomass Processing to Fuel Intermediates By Pyrolysis and Electrocatalysis Depots
Biomass processing depots, or stations, are small-scale facilities that serve to densify raw feedstocks into transportable and salable commodities with increased energy and economic value. Decentralized systems seek to find the optimum balance of “economies of scale” and “economies of transportation,” while creating a venue for value addition to rural communities. Several biochemical and thermochemical pretreatment technologies have been considered for deployment in biomass depots, including ammonia fiber expansion (AFEX), gasification, torrefaction and pyrolysis, discussed in this presentation. All such pretreatment technologies serve to improve the transportability of biomass, which has low bulk and energy density, leading to high costs. Fast pyrolysis depolymerizes biomass by rapid heating in an oxygen-free environment to make a dense liquid known as bio-oil after vapor condensation. However, bio-oil is limited as a fuel intermediate because of its poor chemical properties, namely high oxygen content, corrosiveness, and proneness to condensation reactions that form sludge. As a remedy, electrocatalytic hydrogenation and deoxygenation (ECH) is proposed to partially upgrade bio-oil to create a stable fuel intermediate. ECH works by saturating carbon-carbon and carbon-oxygen double bonds as well as cleaving certain ether linkages on a catalytic cathode. This mild approach, occurring at 80°C and 1 atm, can couple alternative energy from wind turbines or solar photovoltaic cells to maximize the renewable energy content of finished fuels. ECH could be the keystone for converting biomass into liquid biofuels while leveraging other forms of renewable energy. In addition to describing pyrolysis and electrocatalysis depots, a centralized refinery configuration will be introduced for fractionating and fully upgrading bio-oil into hydrocarbon fuels.