These burners can be operated on a number of recovered materials which represented an additional expense to these companies prior to the installation of a solid fuel burner. Cyclonic furnaces have become a major alternative to conventional burners. Applications include both large scale utility boilers and certain industrial processes where waste heat can be recovered profitably. In cyclonic combustion, the burning occurs at a positive pressure, rather than the slight negative pressure associated with most suspension fired wood systems. The combustion occurs in specially designed cylindrical reactors which discharge hot gaseous combustion products directly into the boilers or other vessels.
Pulverized wood is blown into the cyclonic burner where it oxidizes immediately.
Centrifugal action forces the particles toward the cylindrical wall of the burner where char oxidation occurs. Very high turbulance is generated in the cyclonic burner and char oxidation occurs within milliseconds. Combustion intensity in cyclonic burners is considerably higher than combustion intensity in conventional wood suspension fired furnaces. The vigor of the cyclonic action forces the wood particles to the burner wall, facilitating not only rapid combustion but also solid product removal.