Pyrolysis

Pyrolysis is a process in which organic matter is exposed to heat and pressure in the absence of oxygen. The primary components of this process are syngas molecules like those found in gasification, as well as bio-oils and charred solid residues [26]. Pyrolysis methods are de­fined by the rate of heating, which directly affects the residence time of the reaction [27]. In slow pyrolysis, for example, the material is exposed to reactor conditions for five minutes; in fast pyrolysis, residence time is reduced to one to two minutes and in flash pyrolysis to less than five seconds. The residence time of the pyrolysis reaction greatly influences the compo­sition of oils, gases and chars that are formed [2830]. Several studies have been performed to identify the effect of operational variables— reactor conditions and variations in feed­stock material —on the quality of the pyrolysis oils, gases, and chars [27, 30]. The oils typi­cally produced during pyrolysis reactions are high in moisture content, and corrosive due to low pH. Pyrolysis of biomass is typically constrained by the high water content of the raw material, and current pyrolysis methods for biomass conversion have not reached the stage of commercial development. Ongoing research, however, aims at maximizing energy poten­tial from biomass and optimizing conversion methods to achieve commercialization at mar­ketable levels [31, 32].