Fluidized Bed Drying of Southern Pine Veneer

Green loblolly pine veneer of two thicknesses (1/10 inch and 3/16 inch) was dried at three temperatures (250, 325, and 400? F.) in two media (sand and Ceraspheres) at two air velocities (30 and 60 cfm) in a fluidized bed. Drying time required to reach 50 percent MC was as low as 1-3/4 minutes for 1/10 inch veneer dried at 400?F. at the higher air flow in sand. The drying rates are three times faster for sand and two times faster for Ceraspheres than those for jet driers run at the same temperature. Increasing temperature had the greatest effect on increasing drying rate; sand gave greater drying rates than Ceraspheres. Air flow rate had an effect at lower temperatures and on the slower drying rate media (Ceraspheres) but had little effect at higher temperatures and in the faster drying rate media (sand). Preliminary gluing studies indicate that there is some difficulty in gluing fluidized bed-dried veneer. This may have been due to several factors: overdrying of the veneer, improper adhesive mix, or non-optimum gluing conditions. These difficulties may be easily overcome with further experimentation in adjusting these parameters and also examination of different drying rates during a single drying run.

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