CHAPTER 4 Fractionation of Lignocellulosic Material With Pyrolysis Processing F.-X. Collard Stellenbosch University, Stellenbosch, South Africa M. Carrier University of Concepcio´n, Concepcio´n, Chile J.F. Go ¨rgens Stellenbosch University, Stellenbosch, South Africa 4.1 Introduction to Pyrolysis Technology The pyrolysis reaction has received great interest from the scientific communities, both as a key intermediate stage of various thermochemical processes and as a conversion process to high-quality fuels. Pyrolysis is defined as a controlled process that converts solids with a limited amount of water by the action of heat into a solid residue and volatiles under an inert atmosphere. Depending on the operating conditions and targeted products, the volatiles are further condensed, while the remaining permanent gases may be adequately used. Contemporary pyrolysis processes adopted a wide range of designs to process and valorize inhomogeneous and (un)processed lignocelluloses, thus indicating the flexibility to feedstocks of pyrolysis technology (Section 4.2.1). The functional groups of the lignocellulose are thermally degraded into lower and heavier molecular weight compounds during pyrolysis process to provide the main reaction products of char, bio-oil, and non-condensable gases. These permanent gases (CO, CO 2 , CH 4 ,H 2 , etc.) are produced through the primary, secondary, and even tertiary reactions between reactive intermediates (free radicals), whose extent significantly influences the overall product distribution. Pyrolysis is thus a complex chemical process, considering the number of components in lignocellulose that participates in the numerous simultaneous reactions occurring during the process. Pyrolysis processes thus require an elaborate strategy to control the yield and quality of complex final products. In addition, the availability of the wide range of (un)processed biomasses as potential feedstocks to pyrolysis has led the scientific community to develop Biomass Fractionation Technologies for a Lignocellulosic Feedstock Based Biorefinery. http://dx.doi.org/10.1016/B978-0-12-802323-5.00004-9 Copyright © 2016 Elsevier Inc. All rights reserved. 81