What is the difference between pyrolysis, gasification and combustion?
Pyrolysis involves heating the feedstock in the absence of oxygen until volatiles are released, either as a “fast pyrolysis” or “slow pyrolysis”. Fast pyrolysis occurs at moderate temperatures (~930°F to 1500°F) with a short residence time resulting in a primarily low pH, liquid product with some char and gaseous products formed. Slow pyrolysis occurs at low to moderate temperatures (620°F to 930°F) with a longer residence time resulting in primarily char and gaseous products formed. If a limited amount of oxygen is available during the processing of the feedstock, gasification occurs rather than pyrolysis. Gasification is a process using heat to convert carbonaceous feedstock into a gaseous mixture composed of primarily carbon monoxide (CO) and hydrogen (H2) typically at temperatures above 1560°F. Two of the dominant reactions occurring during gasification are: C + ½ O2 → CO (partial oxidation) CO + H2O → H2 + CO2 (water gas shift reaction) Oxygen may be provided to a gasification rea
