High-Frequency Heating Controlled by Convective Hot Air: Toward a Solution for On-Line Drying of Softwoods

This article explores the potential of high-frequency heating combined with convective hot and moist air to dry softwood boards as fast as possible while maintaining a reasonable product quality. High-frequency drying experiments were performed in a multipurpose laboratory prototype. This device and the data logging equipment are briefly described in this article. The results obtained at different HF powers on Abies grandis board are presented and discussed. Our results prove that it is possible to dry a 50-mm-thick board from 150 to 5% in about 10 h while maintaining a good final quality by using air flow at 90°C for both dry-bulb and dew-point temperatures and an average HF power of 77 kW·m^?3.