Hydrofaction™ of forestry residues to drop-in renewable transportation fuels

Abstract Hydrofaction™ targets the lack of renewable fuel alternatives for heavy transportation by converting forestry residues into drop-in renewable diesel and marine fuel, by supercritical HTL, and by subsequent hydrotreating. A process block diagram of the Hydrofaction™ process is presented, subprocesses are described, and experimental data on both the HTL and hydrotreating stages are summarised. A comparison of six renewable Hydrofaction™ crude oils produced by continuous and supercritical HTL from different pine, spruce, birch, and bark mixtures shows similar quality independent of the woody feedstock. Two continuous hydrotreating campaigns were successfully carried out on a presulphided NiMo/Al 2 O 3 catalyst for 300 and 700 h. The characteristic low sulphur content (100–200 ppm S) of the renewable crude oil was shown to inhibit catalyst activity, relative to an oil that was spiked to 1 wt% S. Nonsulphided catalysts (NiW/SiO 2 /Al 2 O 3 and Pd/Al 2 O 3 ) were screened in batch reactors to simulate a two-zone deoxygenation and hydrogenation reactor system, where H 2 S in the gaseous upgrading products may be avoided. The initial screening of this upgrading approach shows complete deoxygenation and improved devolatilisation relative to the sulphided catalysts. Finally, a life-cycle GHG emission analysis estimates that drop-in renewable diesel and marine Hydrofaction™ fuels can be associated with GHG emission reductions of 77%–108% depending on the Hydrofaction™ process configuration.