Carbonization is a pyrolytic reaction and a complex process involving the breakdown of different substances where many reactions – such as dehydrogenation, condensation, hydrogen transfer, and isomerization – take place concurrently. Here we focus on the carbonization of wood. The first step in carbonization is either to pre-dry the wood or dry out the wood in the kiln at 100C to zero moisture content. During the second step, the temperature is raised to 280-300C and the wood starts to break down and produce charcoal. During this initial process, the energy comes from some of the wood charged to the kiln combined with oxygen and energy released from the carbonization process. During the third step, the temperature is raised to 400C using only energy from the carbonization process. To reach higher temperatures it might be necessary to add more heat, but this will depend on the type of wood, type of kiln, and moisture of the material being carbonized. With increasing temperatures, the amount of fixed carbon increases, and the number of volatiles decreases. The following chart is an example of this.
White Paper Carbonization Technology
