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The Optimisation of Drying Schedules for Pinus radiata Sapwood Boards
Author(s) -
Langrish T.A.G.,
Nijdam J. J.,
Keey R. B.
Publication year - 2004
Publication title -
developments in chemical engineering and mineral processing
Language(s) - English
Resource type - Journals
eISSN - 1932-2143
pISSN - 0969-1855
DOI - 10.1002/apj.5500120402
Subject(s) - water content , pinus radiata , moisture , bulb , limiting , horticulture , radiata , materials science , mathematics , zoology , environmental science , composite material , botany , engineering , biology , geotechnical engineering , mechanical engineering , vigna
Optimal drying schedules have been predicted for the drying of Pinus radiata sapwood from an initial moisture content of 140% over a drying time of twenty‐four hours for 50mm‐thick boards. Initially, a single pair of dry and wet‐bulb temperatures (108d̀C. 60d̀C) over the full time period is estimated to keep the total tangential strain under 50% of the predicted limiting failure value. However, after twelve hours drying, more severe conditions may be used, with the final moisture content predicted to be reduced from 8.2% for a constant set of conditions throughout the schedule (108d̀C, 60d̀C) to 2.4% when the dry‐bulb temperature is raised from 108d̀C to 122d̀C after twelve hours. It is also possible to use a linearly increasing dry‐bulb temperature after twelve hours, rising from 108d̀C to 155d̀C at the end of drying with a predicted final moisture content of 0.2%. However, to reduce the moisture content to only 10%, there is little difference between the ramped and two‐step schedules, both yielding a total drying time of eighteen hours. The two‐step schedule would be the easier to in practice.