Biomass pyrolysis has been practised for centuries in the manufacture of charcoal for industry and leisure. Only in the last two decades, however, has attention focussed on a better understanding of the science and technology, with the resultant benefits of better designed and controlled processes that give high yields of liquid products. These liquids, or 'bio-oil' as it is referred to, can be used in a variety of ways: -combustion to replace conventional fuel oil in boilers, process equipment such as kilns and in gas turbines for power generation; -upgrading by hydrotreating or with zeolites to gasoline, diesel and other hydrocarbon fuels, of chemicals; --extraction and upgrading to fuel additives and chemical specialities. Any charcoal produced can also be utilised to form char- water slurries, analogous to coal-water slurries, or bioi-oil slurries which may be used as liquid fuels in many combustion applications. A group of experts was set up in the EC Energy from Biomass programme to evaluate the status and opportunities for deriving useful liquid products from biomass pyrolysis. This book is a report of their findings and conclusions. It forms an authoritative guide to the wide range of technologies employed in biomass pyrolysis, and product upgrading, utilisation and characterisation. Recommendations and conclusions are included to identify promising areas of research and development that will be of value to researchers, planners and companies throughout the world.

This handbook is an edited and updated version of the final report of the IEA Bioenergy sponsored Pyrolysis Activity - PYRA - that officially finished in 1998 and accomplished many valuable contributions to the science and technology of fast pyrolysis. It is intended that this handbook will provide a useful guide both to newcomers to the subject area as well as those already involved in research, development and implementation. The IEA Bioenergy Pyrolysis Task is continuing this work as a collaborative project with the European Commission network on fast pyrolysis of biomass which is now known as PyNe. The European Network was first formed in 1995 as an EC sponsored project in the AIR Programme (AIR3-CT94-1857). At the end of the three-year lives of the Networks in 1997, both sponsoring organisations recognised the benefits from their integration. This led to the present PyNe Network, which is co-sponsored by the European Commission FAIR Programme (FAIR-CT97-3409) and IEA Bioenergy, and which itself is sponsoring the publication of this book as a contribution to the technology.

The Fast Pyrolysis Handbook Volume 2 is an edited version of the final report of the European Commission and IEA Bioenergy sponsored Pyrolysis Network that officially finished in 2001. It provides a companion volume to the first handbook published in 1999 and it is again intended that this will provide a useful guide both to newcomers to the subject area as well as those already involved in research, development and implementation. A significant feature of this second volume is the greater attention paid to addressing commercial issues such as marketability, transportation and safety. Fast pyrolysis is a high temperature process in which biomass is rapidly heated in the absence of oxygen. As a result it decomposes to generate mostly vapours and aerosols and some charcoal. After cooling and condensation, a dark brown mobile liquid is formed which has a heating value about half that of conventional fuel oil. While it is related to the traditional pyrolysis processes for making charcoal, fast pyrolysis is an advanced process that is carefully controlled to give high yields of liquid. The essential features of a fast pyrolysis process are: very high heating and heat transfer rates, which usually requires a finely ground biomass feed; carefully controlled pyrolysis reaction temperature of around 500C in the vapour phase, with short vapour residence times of typically less than 2 seconds; rapid cooling of the pyrolysis vapours to give the main product - bio-oil.