Simulation and Design of Microwave Heating Oven for Interaction Study of Microwave and Oil Palm Fruit

Abstract

In the small-scale palm mill industries, the processes have produced low-quality crude palm oil. The oils have high free fatty acid content (FFA) and low deterioration of bleachability index (DOBI), classified as grade B oils. Since, the palm fruits are being treated with hot air for too long time for pretreatment, drying and pressing. In this research, a microwave will be used as a heating source for pretreatment to shock the fresh palm fruits by rapidly increasing the temperature. Microwave heating can inhibit the action of lipase in the reaction hydrolysis to decrease FFA content. At the same time, microwave heating will melt crude palm oil in mesocarp, increasing DOBI. To develop microwave heating system, microwave propagation in the waveguide and cavity are modeled and simulated, therefore optimum dimensions of cavity and positions of waveguide installation were obtained. At the optimum conditions, the electric intensities of 2.45 GHz microwaves are strongest at the position of palm fruit placement. The optimum dimension of the cavity is 33 cm x 33 cm x 33 cm. Verification of the microwave field distributions in the cavity was consistent with the experimentally heating profile of the water load. And analysis of CPO from oil palm fruit heated by microwave, FFA decreased to 1.5±0.3 percent. DOBI increased in lower power microwaves and fell in higher power microwaves.