Wood densification consists of processing wood by-products such as sawdust and chips into uniformly sized particles that are compressed into wood-based fuel products (pellets and briquettes). The main advantages are related to handling improvements of residual wood and energy generation opportunities when compared with wood chips from other forms of wood residues. The objective of this study was to evaluate the energy balance for production of briquettes from wood residues.

This research involved determining the energy consumption required to perform the main manufacturing operations to produce wood briquettes: size reduction, drying, and densification of wood. The amount of energy that can be obtained from the combustion of wood briquettes was also measured. The effects of several factors such as wood species, material dimensions, and raw material moisture content on the energy requirements for manufacturing briquettes were studied.

Four densification strategies were evaluated from an energy consumption standpoint: single size reduction (shredding) of dry lumber and wood chip densification; single size reduction (shredding) of wet lumber, drying, and wood chip densification; double size reduction (shredding and hammermilling) of dry lumber and wood particle densification; and primary size reduction (shredding) of wet lumber, wood chip drying, secondary size reduction of wood chips, and wood particle densification. At most 8 percent of total energy available from combustion of briquettes is required to produce briquettes. Moreover, drying wet wood residues consumes about 80 percent of the energy used in producing the briquettes.

This study shows that manufacturing briquettes from wood residues is feasible from an energy consumption perspective.