Mechanism of VOC release from high-temperature southern pine lumber drying

Hydrocarbon (Method 25A) emissions from drying southern pine lumber have been measured in full-scale experiments. The mechanism proposed comprises three components: release of turpentine dissolved in the surface layer of water on the wood, water-mediated transport of turpentine from the interior of the wood to the surface, and evaporation of turpentine during the falling rate period. The result allows the total Method 25A release to be estimated without knowledge of the airflow through the kiln. Full-scale Method 25A emissions from lumber can be predicted from laboratory work on sawdust, indicating that the mechanism is independent of the type of furnish.