Modelling of an integrated hydrothermal liquefaction, gasification and Fischer-Tropsch synthesis process for conversion of forest residues into hydrocarbons.

The aim of this work was to develop a model of an integrated biomass-to-liquid process consisting of hydrothermal liquefaction, evaporation, gasification and Fischer-Tropsch synthesis process using lignocellulosic forest residues as feedstock to produce hydrocarbons suitable for upgrading into drop-in biofuels. The energy, mass and carbon efficiencies achieved were 35%, 20% and 32%, respectively. The Fischer-Tropsch crude carbon chain length distribution peaked at carbon chain length 10 with a heavy right tail, a profile favorable for upgrading to jet fuel. The life cycle assessment showed high greenhouse gas performance in the Norrbotten coastal area and in Kalmar, both in Sweden. The reduction of life cycle greenhouse gas emissions, compared to the fossil fuel comparator and according to the European Union Renewable Energy Directive II, amounted to 85-95% for the Fischer-Tropsch crude produced in Norrbotten, and to 92-97% in Kalmar, depending on transportation distances and feedstock used.