Apparatus (10) for drying particles derived from wood such as sawdust,
wafers, flakes, paper sludge, and strands. The wood particles are
introduced into a first drying stage (12) and conveyed through a dryer
(16) in which the wood particles are heated to an elevated temperature
(900 F.) to drive off moisture and VOC's from the particles. The wood
particles are then delivered to a second drying stage (14) through which
they are also conveyed. The particles are now heated to a second elevated
temperature (600 F.) to substantially eliminate any moisture in the
particles so the particles can now be used to make wood products. A
heating system includes a combustion chamber (22) to combust fuel to
commonly heat the wood particles in both drying stages. The heating system
includes a separator (28) for collecting the VOC's driven off from the
particles in the first drying stage so the VOC's can be heated in the
combustion chamber to a temperature at which they breakdown into shorter
chain hydrocarbons which are readily combusted. This substantially
eliminates any VOC's which might otherwise be exhausted to the atmosphere.