EFFECTS OF MICROWAVE ABSORBERS ON THE TORREFACTION OF HIGHLY-MOIST MUNICIPAL SOLID WASTE (MSW) PELLETS

Abstract

The purpose of this research was to study the effects of microwave absorbers on the torrefaction of highly-moist municipal solid waste (MSW) pellets. The effects of the type of agricultural residue used as the microwave absorber (char from rice straw, from corncob, from palm shell, and from bagasse), the microwave power (500-800 W), and the torrefaction time (4-12 min) on the remaining mass, temperature, proximate and ultimate analyses, as well as the heating value of the torrefied MSW pellets were investigated. The results from the experiments revealed that the addition of char from bagasse yielded the lowest remaining mass and, the highest temperature of the torrefied MSW pellets. The addition of microwave absorber, also increases in microwave power and torrefaction time caused the remaining amounts of moisture and volatile matter in the torrefied MSW pellets to decrease. However, the addition of microwave absorber and an increase in torrefaction time had an insignificant effect on the remaining amount of fixed carbon in the torrefied MSW pellets. For the ultimate analysis, it was found that, after being heated by microwave irradiation, the amount of carbon in the torrefied MSW pellets increased, but the amount of oxygen decreased, while the amount of hydrogen was relatively constant, when comparing to their initial values. The heating values of the MSW pellets were found to increase after being torrefied.