Specific and bulk weight of charcoal in 1 m³

Charcoal is a porous carbon material obtained by heating wood without air access or with a very limited supply of oxygen. This process is called pyrolysis or dry distillation of wood. It usually begins at temperatures above 280 °C and is carried out in special furnaces or charcoal production units.

The quality of finished charcoal depends on several factors:

• wood species and moisture content;
• method of heating the wood mass;
• temperature mode;
• type of furnace or charcoal equipment.

Charcoal production can be divided into several stages:

• preliminary drying of the wood mass;
• thermal decomposition of wood within a specified temperature range;
• holding and cooling of the finished product.

After carbonization, the mass of the finished product is usually much lower than the mass of the initial dry wood. Losses are caused by removal of moisture, volatile substances and wood decomposition products.

Physical features and chemical composition of charcoal

The composition of charcoal depends on the production temperature. At higher temperatures, the carbon fraction increases, while the content of hydrogen, oxygen and nitrogen decreases. Due to its porous structure, charcoal has good sorption capacity.

During storage, charcoal should be protected from moisture, open flame and conditions that may cause self-heating. Large batches are best stored in a dry, ventilated place with fire-safety rules observed.

By piece size, charcoal may be fine or coarse. In practice, fractions of about 6-12 mm and large pieces of 25 mm or more are common.

The main calculated indicators depend on wood species and carbonization conditions. Approximate values are given in the table.

The heating value of charcoal depends on carbonization temperature, moisture content and raw material quality. After unloading from the furnace, moisture may be about 2-4%, and during storage it may increase to 7-15%. For charcoal obtained at about 380-500 °C, the heat of combustion may be around 7500-8100 kcal/kg.

Calculation of important indicators for dry charcoal

The weight of charcoal after production is affected by:

• quality and species of wood;
• size of the loaded material;
• type of charcoal production unit;
• temperature fluctuations during carbonization stages;
• moisture content of the finished product during storage.

The specific weight of charcoal changes depending on the wood species. Birch charcoal is characterized by about 0.38 g/cm³, pine charcoal by about 0.29-0.30 g/cm³, and spruce charcoal by about 0.26 g/cm³. For warehouse estimates, the bulk weight of dry charcoal per 1 m³ is often used.

Applications of charcoal

Charcoal is used in industry, crafts and everyday life. Main applications include:

• ferrous metallurgy;
• non-ferrous metallurgy;
• production of sorbents and filter materials;
• pharmaceuticals and absorbent preparations;
• blacksmithing;
• household use for heating, cooking and practical tasks.

The sorption capacity of charcoal is caused by its developed porous structure.