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.