Fundamentals of Hydrofaction: Renewable crude oil from woody biomass


As a response to the global requirement for renewable transportation fuels that are economically viable and fungible with existing petroleum infrastructure, Steeper Energy is commercializing its proprietary hydrothermal liquefaction (HTL) technology as a potential path to sustainable lignocellulosic-derived transport fuels. Hydrofaction utilizes high-density, supercritical water chemistry at distinctly higher pressures and temperatures than most literature on HTL. The paper presents a direct relation between density and the chemical properties that make near-critical water an appealing HTL reaction medium. Further, the fundamentals of Hydrofaction and how these are carefully chosen to favor certain chemical reaction paths are explained, including the use of high-density supercritical water, homogenous alkaline metal catalysts at alkaline conditions and recycling of aqueous and oil products. Steady state operational data from a campaign producing 1 barrel (>150 kg) of oil at a dedicated pilot plant is presented, including closure of mass, energy, and three elemental balances. A detailed oil assay specifying the oil quality as well as mass and energy recoveries from wood to oil of 45.3 wt.% and 85.6%, respectively, reflect that Hydrofaction is an energy-efficient technology for sourcing renewable biofuels in tangible volumes.

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The authors are thankful for the collaboration with Professor Lasse A. Rosendahl, Aalborg University, Denmark, and the funding provided by EASME Horizon 2020 (Grant No. 666712), Danish Energy Technology Development and Demonstration Program (Grant No. 64013-0513), and Innovation Fund Denmark (Grant No. 4135-00126B).

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Correspondence to Steen Brummerstedt Iversen.

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Jensen, C.U., Rodriguez Guerrero, J.K., Karatzos, S. et al. Fundamentals of Hydrofaction: Renewable crude oil from woody biomass. Biomass Conv. Bioref. 7, 495–509 (2017).

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  • Hydrofaction
  • Hydrothermal liquefaction
  • Supercritical water
  • Biofuel
  • Renewable oil