Fast pyrolysis is a process in which organic material is heated in the absence of oxygen to about 500 °C within a few seconds. Under these conditions organic and aqueous vapours, pyrolysis gas and charcoal arise. The vapours are rapidly cooled and condensed into a highly viscous liquid, so-called pyrolysis oil or fast pyrolysis bio-oil FPBO). This major product of the fast pyrolysis has about 70% of the energy content of the biomass and about half of the heating value of a conventional fuel oil. Additionally, valuable by-products (charcoal (10-15%) and low calorific gases (15-20%) emerge, which can be used to generate process energy. In the pyrolysis process the majority of the ash and minerals are bound in charcoal and can be removed and recycled. Therefore highly ash-containing biomass streams can be converted into a virtually low-ash bio-oil.
The pyrolysis process is energetically self-sustaining and the FPBO contains about 70% of the energy content of the input biomass. Fast-pyrolysis bio-oil can be produced from a wide range of biomass or biomass residues. Its use is not necessarily linked to the production process, because it is storable and transportable. FPBO can be used as a renewable 2nd generation biofuel in custom oil heaters for space heating.
The fast pyrolysis process is optimized for the conversion of biomass to liquids and is intended to achieve the highest possible yields. The pyrolysis process is energetically self-sustaining and suitable for the production of FPBO from a wide range of biomass or biomass residues. FPBO is easily storable and transportable and could be used in the future for space heating in adapted oil heaters due to its flexible availability at relatively high energy density as a renewable fuel of 2nd generation.
Research projects at OWI concerning the use of pyrolysis oil: