Designing a Sustainable Bioenergy System That Integrates Localized Fast Pyrolysis and Electrocatalytic Hydrogenation with Centralized Hydroprocessing for the Production of Gasoline-like Fuels: Technoeconomic and Life Cycle Analyses

According to the 2016 Billion Ton Report, the annual harvestable biomass in the U.S. (that can be produced at $60/ton or less) by the year 2030 is not sufficient to meet the annual energy demands of the U.S. transportation sector alone. Therefore, processes must be developed to upgrade the energy content of biofuels to match that of petroleum-based fuels. Such upgrading must also overcome the barriers resulting from biomass’ dispersed nature and high costs of transporting a low bulk density feedstock. Depot-based fast pyrolysis partially overcomes these barriers by densifying biomass into bio-oil—however, this mixture is reactively unstable and corrosive. Subsequent electrocatalytic hydrogenation (ECH) potentially stabilizes this bio-oil to a form that can be transported and stored at a centralized refinery for further upgrading to final fuel. ECH involves using mild temperature, atmospheric pressures, and renewable electricity, such as wind or solar, to split water on a catalytic cathode to produce in situ hydrogen and consequently perform the reduction of reactive aromatic compounds present in bio-oil. Localized fast pyrolysis and ECH, followed by centralized hydroprocessing has great potential as a sustainable bioenergy system for producing biofuels from biomass. Investigation of the system’s thermodynamics has revealed its advantages over traditional cellulosic ethanol fermentations in terms of energy and carbon yields. Therefore, full scale techno-economic and life cycle analyses were performed to quantify the environmental impacts and economic viability of the bioenergy system and ultimately determine its large-scale commercial application.