Screening the factors affecting torrefaction of palm kernel shell by using Plackett-Burman Design

Abstract

Torrefaction is a thermochemical treatment for the production of solid fuel from biomass which promotes the increasing of fuel quality. This process involves the heating of lignocellulose at temperature range 200°C – 320 °C in the absence of oxygen. The decomposition of cellulose, hemicellulose and lignin depends on several parameters. This research aims to investigate the screening of factors affecting torrefaction of palm kernel shell (PKS) which is a waste from oil palm tree. A Plackett–Burman experimental design is applied for screening the influence of operation parameters such as temperature, time, oxygen feed ratio, heating rate and biomass size. Mass yield (MY), moisture content (MC), volatile matter (VM), fixed carbon content (FC), ash content (AC) and calorific value (CV) are analyzed as the response to evaluate the performance of torrefaction conditions. The significant parameters are selected based on the analysis of variance (ANOVA) results. The results show that the temperature, time, oxygen feed ratio and biomass size are significant parameters. The fuel properties of torrefied product were compared with the standard for solid fuel. These results show that the quality of torrefied PKS satistifies the standards. Therefore, the torrefaction process can be used as the potential technique for improve the quality of PKS fuel properties.