High Power Radio Frequency Heating for Innovative Thermal Applications

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Radio frequency (RF) heating is energy efficient and suitable even for large-scale commercial applications, but has been implemented mostly at a low power laboratory-scale using a parallel electrodes based applicator design. To adopt RF heating technology in industrial applications, we need to investigate the feasibility of using higher power levels. The goal of my research program is to enhance the quality and safety of food and agricultural products by conducting a pioneering study that explores three applications of high power RF heating. WORK PACKAGE 1: DISINFESTATION OF PEST INSECTS IN STORED WHEAT FLOUR Disinfestation of pest insects by selective heating is innovative, safe, environmentally friendly, and cost effective compared to the current fumigation method. It can eliminate pest insects at different life stages without sacrificing host product quality. High power RF heating is extremely important for efficient targeted heating because short treatment time limits thermal equilibrium. We will conduct theoretical and experimental studies of high power RF selective heating for pest insect control. The investigation will analyze the effects of level of RF heating speed on target insect mortality, post RF treatment flour quality, and energy consumption. WORK PACKAGE 2: BIODIESEL PRODUCTION ENHANCEMENT The transesterification process in conventional base-catalyzed biodiesel production is an energy intensive process requiring high thermal kinetic energy for the conversion. It is important to find an efficient way to provide the thermal kinetic energy. We will investigate the optimum combination of RF power, temperature, residence time, catalyst type, and molar ratio of alcohol/oil. The study will also test the RF applicator’s design (electrode shape, size, and configuration). WORK PACKAGE 3: SOLID-LIQUID EXTRACTION ENHANCEMENT The extraction of natural medicinal compounds (e.g., anti-cancer compounds) can be significantly improved by fast RF heating. When the water molecules embedded in the micro-pores of the cell wall structure are subjected to high power RF energy, the rapid rise in vapour pressure can result in the rupture of the cell wall microstructure and an increase in the diffusion speed of molecules of interest from inside the cell wall to outside. We will study a continuous solvent flow packed-bed extraction system with podophyllotoxin as a model compound for extraction. We will also determine the effects of cell wall rupture. It is clear that the results of these three areas of research will have a significant positive impact and will add value to a wide array of bioresources in Canada. The program will also provide quality training for HQP through advanced and innovative interdisciplinary research.