Liquefaction of lignocellulose in light cycle oil: A process concept study

Lignocellulosic biocrude can be produced by direct liquefaction of lignocellulosic biomass, which can be further upgraded into biofuels in an oil refinery. Refinery streams, namely vacuum gas oil (VGO) and light cycle oil (LCO), were found suitable liquefaction solvents in our previous study. This paper reports a process concept based on the liquefaction of wood in LCO followed by recovery and recycling of the LCO. The LCO is recovered from the reactor effluent by spontaneous liquid–liquid phase split upon cooling. The feasibility of this process concept was demonstrated experimentally by conducting a series of refill experiments with LCO recovery and recycling. This series shows a steady-state liquefaction of pine wood with constant product yields (liquid yield ∼ 57 C%) and constant oil qualities over eight recycles. Most of the ash present in the wood was concentrated in the char. A techno-economic assessment estimated that the biocrude could be produced at 13.9 $/GJ, which corresponds to an energy-equivalent crude oil price of 61 $/bbl (at a wood cost of 85 $/t dry).