Charcoal is made with a method called Pyrolysis. Pyrolysis is a decomposition brought by a high temperature in the absence of oxygen. The trick to make charcoal is to burn wood in high temperature by passing hot smoke across wood. Since all the oxygen is burnt up in smoke wood does not catch fire and thus it becomes charcoal.
The arrangement to produce charcoal:
A metal drum was stuck with another half metal drum to form the basic structure of the kiln.The smaller drum opens up on the top to the bigger drum .The bigger drum is connected to a chimney from the bottom portion of it.
There is a small pipe attached on the bottom of the bigger drum for the outlet of wood sap.
The bigger drum is filled with wood up till the top.
Dry wood is ignited in the smaller chamber.
The opening of the bigger chamber is concealed with mud paste,so that no smoke can escape and also no oxygen can enter to ignite the fire and turn the potential charcoal into ash.
The wood in the smaller chamber is set on fire and is kept to be with wood. It takes some efforts like blowing oxygen into the small chamber to set the movement of smoke from the small chamber into to big chamber and then out of the chimney.
After sometime this movement catches pace and we have to just feed fire wood to keep fire alive. It is done for 4 to 6 hours. The colour of the smoke changes from dark grey to light grey and eventually to white. It is ideal for the smoke to turn transparent.
The opening of the chimney and smaller chamber is then closed with a lid and then concealed with mud paste.
The drums are then let to cool down for two days and then charcoal is ready to be taken out.