Energy can be produced from biomass by biochemical, biological and thermal process. Pyrolysis is a thermal process that operate at temperature between 400-600C in absence of oxygen or with very low amount, to produce a bio-oil, char and gas. The best technology is fast pyrolysis that produce higher amount of liquid bio-oil, particularly 75% of liquid, -at 500oC without oxygen, contact time lesser 2sec a drying of biomass till 10%, with dimension of particles of biomass of 3mm, using mainly bubbling fluid bed, However the bio-oil obtained with fast pyrolysis present a lot drawbacks: it presents a high amount of oxygen, high acidity, high viscosity, high moisture and chemical instability. Fast pyrolysis can be upgraded operating in the presence of a catalyst (in-situ) or with a downstream catalytic reactor to the that one of fast pyrolysis (ex situ). Besides it is possible upgrade the bio-oil transforming it in fuels and chemical products realizing the catalytic pyrolysis in presence of H2 (hydropyrolysis) or realizing hydrodeoxygenation reactions downstream the fast pyrolysis or using as reductants wastes from plastics, from rubber of tires or from organic wastes in order to realize a catalytic co-pyrolysis.
Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels. Thermochemical Research Pathways with In Situ and Ex Situ Upgrading of Fast Pyrolysis Vapors