From the start of ignition to the temperature of the furnace rising to 160 ° C, the moisture contained in the mechanism charcoal rod is mainly evaporated by the amount of external heating and the heat generated by the combustion itself. The chemical composition of the mechanism charcoal stick has hardly changed.
The initial stage of carbonization
At this stage, the heat of the rod itself is mainly generated to increase the furnace temperature of the carbonization furnace to between 160 and 280 °C. At this time, the wood material undergoes a thermal decomposition reaction, and its composition begins to change. Among them, the unstable composition, such as hemicellulose, decomposes to form CO2, CO and a small amount of acetic acid.
Comprehensive carbonization stage
The temperature at this stage is 300 to 650 °C.
At this stage, the wood material undergoes thermal decomposition abruptly, and a large number of liquid products such as acetic acid, methanol, and wood tar are produced. In addition, flammable gases such as methane and ethylene are produced, and these flammable gases can be burned through a valve control cycle. Thermal decomposition and gas combustion generate a large amount of heat, causing the furnace temperature to rise, and the wood material is dry-distilled to char at high temperatures.
In order to calcine high-temperature carbon, in addition to the above three stages, we need to increase the heat so that the temperature in the furnace continues to rise to about 800 ° C ~ 1000 ° C, so that the volatile substances remaining in the charcoal can be discharged and the charcoal can be raised. The carbon content of the carbon increases the graphite structure of the carbon and enhances the electrical conductivity.