Influence of Torrefaction on Gasification of Torrefied Palm Kernel Shell

Abstract

In this study, torrefaction pretreatment on palm kernel shell (PKS) was investigated using fixed bed reactor. The PKS was torrefied at the temperatures of 210, 230, 250, 270 and 290 °C. The characteristics between untreated and torrefied PKS were compared. The results showed that, the mass and energy yield lessened, while the calorific value augmented with the increasing torrefaction temperature. Furthermore, with the rise of temperature, the oxygen composition, O/C ratio, oxygenated compounds and volatile matter of torrefied PKS decreased, but, the carbon and fixed carbon content increased. The composition of carbon in torrefied PKS was toward coal where equivalent calorific values was achieved. The gasification of torrefied PKS enhanced the product yield which produced higher gas, lower tar and char yield than the gasification of untreated PKS. Gasification of torrefied PKS increased the gas yield by 16.9 % than the untreated PKS. The tar and char yield of torrefied PKS decreased by 19.4 % and 25.9 %, respectively than the untreated PKS. Therefore, the torrefied PKS, by which their physical and chemical properties have been improved through torrefaction pretreatment is more suitable to be used in gasification and co-gasification as their influences are significant than the untreated PKS.