CONTROL OF THE DRYING PROCESS THROUGH THE RELATIONSHIP OF WOOD AND WET-BULB TEMPERATURES

Abstract

The ratio of wood temperature to wet-bulb temperature (WT/ WBT) with the wood moisture, aiming at its use in the control of the drying process in drying kilns, were correlated. Slash pine boards measuring 25 mm thick and 750 mm length were dried in an electric forced convection kiln, using four temperatures and two air velocities. The process was controlled through a computerized system comprising a microcomputer and data acquisition unit. The analyses indicated a good correlation (0.97 < r < 0.99) between the coefficient WT/WBT and the moisture content of the wood. The adjustment of polynomial models was satisfactory in the range from green condition to 10% moisture content, at the temperature range and air velocity studied. These results, variables, together with the ease and speed of measurement of the suggest that the coefficient WT/WBT can be used as an alternative for the control of the drying process. However, the practical application of this system still depends on further research and development.

Keywords:

• Drying control
• Kiln drying
• Slash pine
• Wet-bulb temperature
• Wood moisture content
• Wood temperature

Acknowledgments