New Particle Dryer Design Reduces Emissions and Eases Permitting Process, 1997 Environmental Conference Proceedings

Faced with a diminishing supply of kiln-dried furnish, several particleboard facilities across the nation are attempting to install dryers that can utilize green furnish (moisture content approximately 50 percent, wet basis). Permitting these facilities can be challenging due to the amount of volatile organic compounds (VOCs), among other pollutants, emitted from wood furnish dryers.

VOC emissions from particle dryers are generated in the combustion process and through the heating of the wood particles. Naturally occurring organics in the wood such as tars, resins, fatty acids, and terpenes, are volatilized when exposed to the high dryer temperatures. Conventional three-pass rotary dryer design consists of three concentric cylinders, with wet furnish and furnace flue gases entering the innermost cylinder and proceeding through the outer shells. This design can actually increase VOC emissions.

However, the 3PHV Rotary Drum Dryer (3PHV), manufactured by Productization Incorporated, uses a state-of-the-art design that reduces the amount of VOC, particulate, and carbon monoxide emissions generated in the drying process. As a result, add-on controls are often unnecessary. Recently, Boise Cascade Corporation’s (Boise Cascade’s) facility in LaGrande, Oregon, was permitted to install a 3PHV and ROEMMC sanderdust burner. This paper discusses the design of the 3PHV, the methodology of emission reduction in a 3PHV, the permitting effort involved with the Boise Cascade facility, and the performance of a 3PHV compared to conventional dryers.