The program of charcoal charcoal in the first special Hongfa earth kiln
ZHITONG PIPE VALVE TECHNOLOGY CO.,LTD , https://www.ztongvalve.com
First, the drying stage. The temperature at this stage is between 120-150 degrees Celsius, and the pyrolysis process is very slow. This is mainly because the moisture in the wood evaporates due to external heat supply, and the chemical composition of the wood remains largely unchanged during this phase.
Second, the carbonization stage. At this stage, the temperature ranges from 150-275 degrees Celsius, and the pyrolysis reaction becomes more noticeable. The chemical structure of the wood begins to change as unstable components like hemicellulose start to decompose, producing gases such as carbon dioxide, carbon monoxide, and small amounts of acetic acid.
Third, the second carbonization stage. The temperature now rises to 275-400 degrees Celsius. During this phase, the wood undergoes rapid thermal decomposition, generating a significant amount of by-products. The liquid produced contains high levels of acetic acid, alcohol, and other compounds like hibiscus oil. The gas produced gradually increases in water content, while methane levels decrease. This stage is also known as the exothermic reaction phase due to the large amount of heat released during the process.
Fourth, the calcination stage. The temperature reaches 450-500 degrees Celsius. In this phase, the charcoal is further heated to remove any remaining volatile matter, increasing its fixed carbon content. At this point, the formation of liquid by-products is minimal, and most of the material is converted into solid char.
Fifth, the refining carbon stage. The temperature increases to 500-1200 degrees Celsius, marking the final and most critical phase. During this stage, the charcoal is fully refined, and the structure becomes more stable and pure. This step ensures the production of high-quality charcoal with minimal impurities.
This entire process is crucial for producing quality charcoal, ensuring that each stage contributes to the transformation of raw wood into a valuable and durable product. Understanding these stages helps in optimizing the pyrolysis process for better efficiency and environmental impact.
