The Effects of Partial Extraction on Drying Behavior for Pinus radiata Sapwood

Abstract

An experimental procedure has been developed to analyze the effect of individual components of Pinus radiata sapwood on overall drying behaviour by partially extracting hemicellulose through hot-water extraction. It was found that after 32 h of extraction, 3% of the overall solids content on an oven-dry mass basis was removed from the timber samples, the overall drying time decreased by 15–20%, sorption capacity reduced by 8%, and the predicted diffusion coefficient fitted to experimental data increased by 160% compared with nonextracted samples. Thermogravimetric analysis coupled with the sorption and drying results suggests that the loss of solids is mainly a loss of hemicellulose, indicating a loss of 11–13% of the hemicellulose content, so the modification to the wood composition is suggested to be responsible for the change in drying behavior.

Keywords:

• Drying
• Hemicellulose
• Partial extraction
• Softwood timber
• Thermal analysis