Torrefied wood an alternative to charcoal for reducing deforestation

Torrefaction is a feasible method for improvement the properties of biomass as a fuel . It consists of a slow heating of biomass in an inert atmosphere to a maximum temperature of 300 °C. The treatment yields a solid uniform product with a lower moisture content and a higher energy content compared to those in the initial biomass.
The process may be called mild pyrolysis, with removal of smoke producing compounds and formation of solid product, retaining approximately 70% of the initial weight and 90% of the original energy content.

The torrefied biomass have the following properties:

• Hydrophobic nature: the material does not regain humidity in storage and therefore unlike wood and charcoal, it is stable and with well defined composition.
  
• Lower moisture content and higher calorific values compared to biomass
  
• Formation of less smoke when burnt.
  
• Higher density and similar mechanical strength compared to the initial biomass
  
• Desired form
  
• Suitable for various applications as a fuel - in the steel industry, combustion and gasification.

Torrefied products can substitute charcoal in a number of applications:

• Fuel for domestic cooking stoves. Torrefied wood kindles very quickly, which makes the stoves management much more simple and flexible compared to wood and particularly charcoal.
  
• Fuel for residential heating.
  
• Raw material for manufacture of improved solid fuel products such as fuel pellets, compacted fireplace logs and barbecue briquettes for commercial and domestic uses. Torrefied briquettes have superior combustion characteristic as compared with ordinary briquettes.
  
• Fuel for industrial uses. Important advantage of torrefied wood compared to wood is its uniformity. It is as a predictable, flexible fuel with optimum combustion and transport economies. Due to the low moisture content of torrefied wood the transport cost is lower and the quality as a fuel better. It is easily packaged and transported, and thus constitutes an efficient fuel.
  
• With a 30-35% fixed carbon content, torrefied wood has a promising potential as a reducer.
  
• Torrefied biomass can be blended with coal and co-fired in a Pulverized Coal Boiler.
  
• The properties of torrefied biomass should lead to an improved operation in gasifiers for which the stability of the process is important.

The homogeneity and the seasonal regularity of torrefied wood makes it an appropriate substitute for charcoal. While having the same utilisation as charcoal, torrefied wood offers more efficient utilisation of the wood and hence reduction in wood consumption. As a fuel it competes with the conventional sources of energy which often are imported.

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