Wood briquette

Wood briquettes are a type of wood fuel, which are produced by mechanical pressing of dry untreated wood particles, such as wood shavings or sawdust. The resulting briquettes have a minimum diameter of 25 millimeters, smaller compacts are referred to as wood pellets. The briquettes have a uniformly high density and a uniform cross section, and often a uniform length.

General

Due to the high compression in the briquetting takes the natural product wood roughly to the burning behavior of lignite.

Wood briquettes produce less ash ( 100 kg briquettes produce less than 1 kg of ash ) and have a lower sulfur content than lignite. The CO2 balance is neutral - if you do not take into account the energy required for transport and production of wood briquettes - because the wood briquettes give when they burn only as much CO2 into the atmosphere as a renewable tree absorbs through photosynthesis.

For wood briquettes in Europe Euro standard EN 14961 applies " Solid biofuels - Fuel specifications and classes ." To apply "Wood briquettes for non-industrial use " come Part 1 " General Requirements " and Part 3. By September 2011, requirements and tests for untreated wood briquettes and pellets in DIN 51731 were standardized in Germany.

Calorific value and burning time

The low water content of below 10 % is a cause for the 4.8 kWh to 5.5 kWh per kg of high energy content.

For comparison:

• Forest Fresh wood has at a water content of 50 % approximately 2.5 kWh / kg,

• (1000 kg) of wood briquettes correspond to the energy content of approximately 2.25 cubic meter of dry firewood (moisture 20%).

When briquette hardwood also has advantages over softwood. Although the briquettes are pressed in the same specific gravity ( 1 to 1.2 t / m³). The biggest disadvantage of resinous softwoods is the too rapid burn-up and the conditional by the evaporating resin mold instability. Briquette decays faster and the escaping steam resin can not be fully used in standard stoves, which is also reflected in the black panes of the stove. Good hardwood briquettes burn much cleaner and produce less particulate matter.

To Burn time: the smoother and firmer is a surface, the longer the flames in order to " durchzufressen ". Hardwood briquettes are often produced from fine grinding chips (eg parquet production ); they therefore have a more homogeneous and firmer surface. Softwood briquettes are, however, often pressed wood shavings. Their surface is rough and therefore to spark faster. They are therefore suitable for kindling the fire and for rapid generation of heat, hardwood briquettes rather to glow old and for a longer heat generation.