Uncertainty analysis for techno-economic and life-cycle assessment of wet waste hydrothermal liquefaction with centralized upgrading to produce fuel blendstocks

Abstract

Hydrothermal liquefaction is a promising technology that can produce fuels from waste with much lower greenhouse gas emissions and potential to supply 24% of total U.S. jet fuel demand. However, existing techno-economic and life-cycle assessment of hydrothermal liquefaction are subject to considerable uncertainties, which should be quantified to accelerate deployment. This work presents a comprehensive uncertainty analysis in both economic and environmental measures of the entire wet waste-to-fuel blendstock supply chain using the most recent developments in hydrothermal liquefaction and biocrude upgrading technologies. The results of a U.S. based analysis suggest an estimated biocrude yield from 42.2% to 52.4%, an estimated fuel yield from 34.7% to 42.7%, an estimated minimum fuel selling price from $2.28/gge to $3.45/gge, and an estimated supply chain greenhouse gas emissions reduction from 73.4% to 81.8% relative to petroleum-derived diesel. In addition, an open-source reduced order process model embedded with predictive reactor model is made available in the supplementary information, allowing communities interested in waste-to-energy to assess technology feasibility of hydrothermal liquefaction with their own regional data and track the technology development from economic, environment, and uncertainty perspectives. To the authors’ knowledge this model is the most comprehensive predictive model for hydrothermal liquefaction to date with regard to commercial relevancy (based on continuous testing of bench and engineering scale system), the number of data sets, and the breadth of wet wastes represented.