Temperatura da madeira como alternativa de controle do processo de secagem

Abstract

Eight loads of sawn lumber of slash pine, with 25 mm of thickness, were exposed to four drying temperatures (50, 70, 90 and 110°C) and two air speed levels (2.3 and 5.0 m/s) for correlating wood temperature and moisture content (MC), as well as to establish statistical models to be applied in kiln drying process control. Diode type temperature sensors, introduced into ¼ of the piece thickness, and a tension type load cell was used to weight the lumber pile, which allowed the determination of temperature and MC of the wood, respectively. The drying process was managed by an automated process control consisting of a PC and a data acquisition system. The results showed that, for high temperature drying, exists an excellent correlation between wood temperature and MC. Models that include wet bulb temperature explained better the two variables relationship and can be used as an end of the drying schedule indicator, specially for temperatures above 100°C.