Grouping tropical wood species for kiln drying using mathematical models

ABSTRACT Because of the large variety and diffuse occurrence of tropical hardwood species in the forest, an efficient method to kiln dry these hardwoods in groups is needed. However, tropical hardwoods have a wide variety of drying properties, which makes drying mixtures of species difficult. This paper describes a mathematical model for grouping species by similar drying times. Our goal is to kiln dry so that all species emerge at the same time within set limits of moisture content. The model, which uses previously reported data, incorporates specific gravity, initial moisture content, and thickness as criteria for grouping species based on estimated drying time. The model can be used to calculate drying times and moisture content distributions within multiple-step kiln schedules, followed by calculations to equalize all members of the mixture within final moisture content specifications. The model can also be used to base grouping on green weight density, thus eliminating the need for direct information...