ABSTRACT
Pyrolysis is the thermochemical decomposition of organic matter in the absence of oxygen and produces a wide range of useful products. The word is coined from the Greek-derived elements pyr “πυ´ρ-fire” and lysis “λυ´σις-breakdown/separation” emphasizing the disintegration of matter due to heat. It is a standalone process or one of several reaction steps in gasification and combustion processes1 and is considered as the basic thermochemical process to produce valuable fuels and energy from biomass. Pyrolysis is also known as thermolysis, thermal cracking, dry distillation, destructive distillation, etc.; however, there are differences in those terms. During pyrolysis, complex macromolecules of biomass break down into relatively smaller molecules producing 3 major products which can be classified as follows:
• a solid residue (which mainly consists of carbon and ash) known as char • gases (mainly CO, CO2, CH4, H2 and other light hydrocarbons) • Vapors/liquids known as bio-oil or bio-crude (mainly oxygenates, aromatics, water, products
of low degree of polymerization, tars, etc.).
