Wood processing activities generate large quantities of related products – also known as by-products – which can be used to produce paper and wood panels, but also to generate energy.
Companies that transform “raw” wood into a (semi-)finished product (sawmills, pulp mills, panel factories, joinery, furniture factories, wood construction, frameworks,etc.) generate by-products in the form:
- Lines, edges, sawdust, scrap
- Sawdust, chips, shavings, sanding dust
- Barks
- Black liquor (special case of pulping)
These products may consist of wood in the natural state (primary processing enterprises) or process wood that could contain glues or treatment products(secondary processing).
Two valorisation routes:
A large proportion of by-products are valued as material. Sawdust, cutting scraps,chips that do not contain bark or treatments can mainly be used by panels or pulp mills industries.
The second major valorisation route is the use as fuel for energy production. By-products are reconditioned (sorted, crushed, dried, sized, densified) according to their end use in either domestic heating, industrial boilers, cogeneration biomass plant, etc.
Other applications are possible, although still marginal: inclusion of sawdust in biocomposite materials or insulating materials; bedding for horses; biorefining the black liquor to extract lignin (a platform molecule); gasification; etc.