Title:
Experimental Analysis of Intermittent Drying Cycles in Lumber: Product Quality
Author(s):
Frantzen, B.S., Silveira, E.A., de Oliveira, T.F.
Document(s):
Paper
Poster
Abstract:
Kiln drying is crucial for ensuring the dimensional stability and commercial quality of hardwood lumber; however, continuous schedules often lead to surface checks, internal stresses, and warping. This study experimentally evaluates the influence of intermittent drying cycles on the product quality of Tauari (Couratari spp.) wood under a conservative schedule. Samples were dried in a laboratory-scale convective kiln under continuous (6/6) and intermittent heating time fractions (3/6, 2/6, and 1/6). The results showed that intermittent cycles significantly reduced both visible and measurable defects. The 3/6 cycle with a short period (1.2 hours) yielded the best trade-off between drying time and quality, reducing warp crook from 1.77 mm to 0.66 mm, warp twist from 3.27 mm to 2.02 mm, and case hardening index from 0.77 ×.10–3 mm–1 to 0.45 ×.10–3 mm–1. No visual defects were observed in the samples dried using intermittent cycles, in contrast to those dried under continuous conditions, which presented surface and end checks. Although lower heating time fractions further reduced internal stresses, they required longer drying durations. These findings confirm that intermittent drying with moderate heating fractions is a promising strategy for improving product quality in dense hardwoods. Future research will focus on a three-pillar evaluation of energy, economic, and environmental performance to support the optimization of sustainable kiln-drying systems.
Keywords:
wood drying, intermittent drying, drying defects, convective kiln
Topic:
Biomass Conversion for Bioenergy
Subtopic:
Biomass pre-treatment and production of intermediates
Event:
33rd European Biomass Conference and Exhibition
Session:
4CV.3.26
Pages:
814 - 819
ISBN:
978-88-89407-25-7
Paper DOI:
10.5071/33rdEUBCE2025-4CV.3.26
Price:
FREE
