Biomass pyrolysis involves heating biomass in the absence of oxygen to produce pyrolysis oils, char, and synthesis gas. Pyrolysis oil can be refined to produce transportation fuels. Alternatively, it can serve as a fuel in combustion systems used in the power and materials processing industries.
Pyrolysis is feedstock neutral, uses the entire biomass, and can be conducted at small-scale (e.g., farm level). The process is amenable to establishing a system of regionally distributed biorefinery facilities utilizing a variety of biomass feedstocks.
Instability during storage is the major technical limitation to using pyrolysis oil. High acidity and viscosity create storage, pumping, and corrosion problems.
Upgrading technologies are being developed to address the instability issues. Upgrading is designed to reduce the increase in viscosity of the pyrolysis oil as it ages. Removal of the oxygen content of the numerous organic compounds that comprise pyrolysis oil is the most effective approach. Several thermochemical upgrading methods are being explored including catalytic cracking, hydrogenation, and aqueous reforming. Pyrolysis oil stabilization and upgrading are the principal focus of research in the U.S.
Commercial scale quantities of pyrolysis oils are available from two Canadian companies--Ensyn Technologies Inc. and Dynamotive Inc.