Evaluation of conventional and microwave drying of tropical Amazonian wood indicated for the manufacture of EGP (Edge Glued Panels)

Abstract

Wood drying is an important process in the forestry industry since the quality of manufactured products is directly related to the moisture content of the raw material. In the Amazon region, the complexity of the drying process is accentuated by the vast diversity of species, each with distinct technological profiles. This study focused on the evaluation of oven and microwave drying of five species of tropical Amazonian wood: Angelim-pedra (Hymenolobium pulcherrimum), Angelim-vermelho (Dinizia excelsa), Breu-vermelho (Protium puncticulatum), Murici (Byrsonima crispa) and Piaozinho (Micrandropsis scleroxylon), recommended for the production of laterally glued panels (EGP). Samples of these species were collected in areas of terra-firme forest in Amazonas, Brazil, and subjected to oven-dry for 25 days and in semi-industrial microwaves for 120 minutes (100 ± 3 °C). Additionally, analyses of the wood properties were carried out. The results indicate that microwave drying surpassed the efficiency of oven-dry. Specifically, Breu-vermelho and Murici wood presented the best results in terms of moisture content. This drying method not only significantly reduced the drying time but also resulted in defect-free wood. Furthermore, the energy consumption was lower compared to conventional drying. The physical-mechanical properties of wood showed a significant correlation with heat-treatment. In particular, microwave drying proved to be effective in obtaining standard moisture for manufacturing EGP panels and could be an advantageous alternative for the region.