Wood and its fuel properties

Wood and its fuel properties

A growing tree consists of the following parts: bark – 6%, foliage – 9%, stump, roots – 9%, branches – 16%, trunk – 60%.
Wood is a perennial tissue formed as a result of secondary growth in the trunk, branches and roots of trees and shrubs
All solid fuels consist of a combustible part and ballast. Ash and moisture are ballast. The combustible part determines the amount of bound carbon and volatiles.
The carbon content in the wood is 48 – 50%, in the bark – 51 – 66%.

An important indicator that plays a significant role in the production of charcoal and is reflected in the duration of the charcoal process and the quality of the finished product is its moisture content. Woody biomass moisture is a quantitative characteristic showing the moisture content of biomass. Free moisture is in the cell cavities and intercellular space, it is easily removed during drying. Bound moisture is inside the cell walls and is difficult to remove. Initially, the natural moisture content of wood can be – 45 – 60%, after drying – 15 – 25%.

Ash content is the content in the fuel of minerals remaining after the complete combustion of the entire combustible mass. Ash is an undesirable part of the fuel, as it reduces the content of combustible elements and complicates the operation of combustion devices. Ash content of wood is 0.1-1.2%.

Volatile substances are gaseous and vaporous products that are released when wood is heated in air to 900 ° C for 7 minutes. In the energy sector, the volatiles content of the fuel determines the flammability of the fuel.

Data on coal processing to Hydrogen

1 kg. (C) + 1.5 kg. (H2O) = 2.333 kg (CO) + 0.167 kg (H2) or 1.86 m3 (CO) + 1.87 m3 (H2)

The combustible mass of fuel is biomass from which moisture and ash have been removed. Its composition is determined by the equation:
Cr + Ng + Og + Nr = 100%

The heat of combustion of biomass is the amount of heat released during the combustion of 1 kg of a substance. The heat of combustion of stem wood depends only on two values: ash content and moisture content.

Cellulose is the main component of wood. The main building material of the plant world, forming cell walls. The cellulose content in wood is 45-50%. Only two sources of cellulose are of industrial importance – cotton and wood pulp. Cellulose is used for the manufacture of paper and cardboard, for chemical processing into artificial fibers (acetate, viscose, copper-ammonia), for the production of plastics, polymer films, film and photographic films, varnishes and enamels, smokeless powder, etc.


Lignin is a complex polymeric compound found in the cells of vascular plants. The deposition of lignin in cell membranes causes stiffness of cells and increases their strength. Hardwood contains 20-30% lignin, conifers – up to 50%. The stiffened cell walls have an ultrastructure that can be compared with the structure of reinforced concrete: cellulose microfibrils correspond in their properties to reinforcement, and lignin, which has a high compressive strength, corresponds to concrete

Lignin is a valuable chemical raw material: it can be used as a filler for polymeric materials, as a component of adhesives, as a plasticizer in ceramic production, to obtain lignin coal, activated carbon, in the production of porous bricks, etc. It can serve as boiler fuel.
Inorganic substances in wood are emitted as ash.

The main groups of low molecular weight compounds:

  • Aliphatic acids. Wood contains saturated and unsaturated higher fatty acids, mainly in the form of esters with glycerin (fats and oils) or higher alcohols (waxes). It also contains acetic acid in the form of esters.
  • Alcohols. Aliphatic alcohols are present as esters. There are both aromatic and alicyclic alcohols in the form of steroids and glycosides.
  • Inorganic substances. In the mineral substances of the wood of the temperate climatic zone, the main elements are potassium, calcium, magnesium. In tropical tree species, other elements may also be the main ones, for example, silicon. Remains completely in ash.

Extractive substances are substances that can be extracted from wood and bark by extraction with water and organic solvents (steam, alcohol, ether). Examples are terpenes, phenols, hydrocarbons, lignins, fats, oils, waxes, etc.

Tannins and dyes and gums are extracted with water. Tannins have an astringent effect, they are used for dressing (tanning) leather from raw animal skins. Gums are water-soluble resinous substances, consisting mainly of polysaccharides. Used for the manufacture of medicines (cough tablets), for processing fabrics, straw, etc.

Resin and fatty acids, waxes, sterols, and other resins are isolated from wood with organic solvents. The resin of conifers contains about 40% terpenes and resin acids. Terpenes form the basis of the technical product – turpentine. Gum is a liquid that stands out when the trunk is injured. Contains a liquid, easily mobile and volatile part with water vapor and a resin part containing resin acids. When resin acids are boiled down, a technical product is formed – rosin.

illiquid wood - raw material for the production of charcoal



Charcoal production from woodworking waste

The production of charcoal does not mean the need for deforestation, the destruction of valuable trees and “lungs” of our planet. Alternative sources of raw materials are tree pruning, illiquid wood and other plant waste.

Since 2001, GreenPower has been developing and manufacturing industrial equipment for the processing of various waste.




The tasks that our company solves:

  • Provide the most efficient processing of human waste;
  • Development of alternative energy technologies;
  • Reducing harmful emissions into the environment.