Improved Radio-Frequency Heating through Application of Wool Insulation during Phytosanitary Treatment of Wood Packaging Material of Low Moisture Content

Abstract

The International Standard of Phytosanitary Measures No. 15 (ISPM-15) requires signatory countries of the International Plant Protection Convention to use approved treatment methods on wood packaging materials used in international trade to significantly reduce the risk of spreading alien species. One of the approved methods utilizes dielectric heating (DH) to raise the temperature in the wood to 60°C through the profile of the workload for 1 minute to eradicate pests. To improve the uniform distribution of heat within a wood workload using radio frequency, a form of DH, we tested the use of a wool blanket as a thermal insulation material for wood pallet components. Three species commonly used in the pallet industry—yellow poplar (Liriodendron tulipifera L.), northern red oak (Quercus rubra L.), and eastern white pine (Pinus strobus L.)—of low moisture content were used to generate matched sets of stringer samples. Internal wood temperatures were monitored continuously during treatment to comply with the ISPM-15 schedule. Applying a wool (keratin) insulation blanket increased the rate of heating, improved heating uniformity throughout the workload, and reduced moisture loss compared to uninsulated controls for some wood species, but not all. These findings were most significant for pallet materials with higher moisture content and more permeability (white pine and yellow poplar). By reducing treatment time, power consumption costs can be reduced using wool insulation when implementing the ISPM-15 DH treatment schedule.

Isothermal Drying Kinetic of Sengon Wood (Paraserianthes Falcataria) Using Combined Infrared and Hotair: Experimental and Modeling Study

“…Wood packaging materials are susceptible to pests and plant diseases [2]. To reduce this risk, The International Plant Protection Convention (IPPC) applies the International Standard Phytosanitary Measure No.15 (ISPM No.15) [3], where the core temperature of the wood must reach a minimum temperature of 56 oC and the moisture content is below 20% [4] [5].…”

Applied Mathematics in the Numerical Modelling of the Electromagnetic Field in Reference to Drying Dielectrics in the RF Field

“…We elaborate and develop a program written in Fortran, which solves the electromagnetic, thermal, and mass coupled problems. In order to fulfil the imposed limited final value accepted of 70 • C, after establishing the temperature field evolution for the voltage value of 1100 V, the supply voltage is corrected with coefficient 70 T max , where T max represents the maximum temperature value in the load [70][71][72][73][74][75][76][77][78][79][80][81].…”