Microwave heating of silicon carbide and polypropylene particles in a fluidized bed reactor

Microwave-assisted recycling of plastics has become an increasingly attractive technology. In this study, the effects of microwave power, fluidization velocity, particle size and mass ratio on heating performances of polypropylene (PP), silicon carbide (SiC), and the binary mixed (PP/SiC) particles in a microwave fluidized bed reactor were experimentally investigated. The maximum temperature of SiC particles was increased when the microwave power, particle size increased and fluidization velocity decreased. The maximum temperature of SiC particles was 965.7 °C in this study, whereas the maximum temperature of PP particles was only 113.5 °C, and the heating rate of SiC particles was about 7.8–77.2 times that of PP particles. For SiC/PP mixture particles, when the microwave power was 400 W, fluidizing velocity was 3.54 × 10⁻³ m/s, and the mass ratio of SiC-to-PP was 40:5, the temperature of the mixture particles increased to 600 °C rapidly and then fixed at 600 °C. However, when the fluidizing velocity was slow (1.18 × 10⁻³ m/s) or the mass ratio was changed (40:1 and 40:10), the temperature decreasing phenomenon appears during the microwave heating process of mixture particles.