Charcoal or other carbonaceous solid organic materials react at high temperatures with steam and oxygen to produce carbon monoxide and hydrogen. This generated gas, which is called "syngas" (from synthesis gas), is combustible and often used as a fuel source or as an intermediate for the production of other chemicals.
2.1 Carbon Recovery Unit
The solid residues of a pyrolysis process often contain a lot of chemical bound energy. This energy could be used by a so called "Carbon Recovery Unit" (CRU). The gasification takes place in a rotary kiln. The ratio of the feeded air and steam has to be balanced to heat up the char to approximately 900 °C.
The exothermic reaction of atmospheric oxygen with carbon is compensated by the endothermic reaction of steam with carbon. The so called Boudouard reaction, which describes the composition of the gas, is influenced by the temperature and the oxygen content. The obtained syngas is incinerated in a downstream combustion chamber. The thermal energy of the flue gas is converted in further process steps into electric energy.