Wooden charcoal is a solid, porous, high carbon containing product obtained from wood by heating it up without air (or with little access of air) in retorts, stoves or heaps.
The heat capacity of wooden charcoal depends on its humidity and production temperature. The average specific heat capacity of absolutely dry charcoal is 0.2 kcal/kg. The calorific value of charcoal burned at 380°-500° is 7500-8170 kcal/kg. The moisture content of just produced in the retorts or stoves wooden charcoal is 2-4%. When coal is stored in a closed warehouse, its moisture content rises to 7-15%.
The ash content of wooden charcoal can not exceed 3%, the volatile content can not exceed 20%, the weight of 1 L. wooden charcoal produced from hardwood is not less than 210 g.
Non-volatile and volatile carbon is distinguished in charcoal, it can be removed while calcination as CO, CO2, CH4 and other hydrocarbons.
The elemental composition of wooden charcoal mainly depends on the charring temperature: the higher is the temperature, the more carbon is in the charcoal and less hydrogen, oxygen and nitrogen. For example, wooden charcoal produced at 450°C contains (in ashless and dry weight): 84,9% C, 3,1% H and 12% (O + N). The phosphorus content in the wooden charcoal obtained from unbarked wood is: 0, 016% in pine, 0, 017% in spruce and 0, 037% in birch. Wooden charcoal is capable to add oxygen at common temperatures, what explains its tendency to spontaneous combustion.
Wooden charcoal can be produced from hardwood or mixed deciduous woods. Wooden charcoal is divided into two groups: small (at least 6-12mm.) and large (at least 25 mm.).
The outcome of wooden charcoal is 30-40% of the weight of dry wood used to produce it.
The main application area of charcoal:
- As a fuel for fireplaces, barbecues and other similar devices
The difference from common fuel (for example, firewood), charcoal does not produce smoke and open flame, if properly ignited, it gives only the required temperature – heat. That is the reason why many bars and restaurants use wooden charcoal for cooking various dishes in their barbeques. There is no need to wait when the wood burns out – because charcoal is ready fuel. It is also important that charcoal is also great as a fuel for home fireplaces. Due to the absence of impurities and high carbon content, wooden charcoal burns for a long time (gives heat) and it does not emit smells (smoke) into the room.