Statistical analysis and mathematical modelling of Plackett-Burman screening design to improve the fuel properties of oil palm fibre by torrefaction process

In this study, the two-level Plackett-Burman design (PBD) was applied to screen the significant variables of torrefaction process of oil palm fibre (OPF). The independent parameters such as temperature, time, oxygen feed, heat rate and OPF size were studied. The %mass yield (%MY) and fuel properties including %moisture content (%MC), %volatile content (%VC), %ash content (%AC), %fixed carbon content (%FC) and heating value (HV) were selected as response variable. The results indicated that temperature, time, oxygen feed rate and heat rate performed statistically significant to the response of torrefied OPF. All obtained mathematical models showed a good fit with high coefficient of determination and their reliability was demonstrated by diagnostics plot. At the maximum experimental result, the %FC and HV of torrefied OPF increased by 13,483% and 27.42%, while the value of %MC and %VC decreased by 93.71% and 42.55%, respectively, as compared with the raw OPF. Thus, the torrefaction seems to be a potential process to improve the quality of fuel properties of OPF.