Torrefaction of oil palm frond: Effects of torrefaction temperature and holding time

In this study, the effects of torrefaction treatment on the physicochemical properties of oil palm frond were investigated. The fibrous oil palm fronds (OPF) were torrefied under mild (250 °C) and severe torrefaction conditions (275 °C and 300 °C) for 30 and 60 minutes holding time in a tube furnace. Based on the observation, solid mass yield of torrefied OPF was reduced as torrefaction temperature and holding time increased. The results also showed that after torrefaction, fixed carbon content and high heating value (HHV) of the solid products increased while O/C and H/O atomic ratios decreased resulted in the buildup of carbon in the solid product. However, torrefaction temperature has more significant effect on torrefied product as compared to that of holding time. On the other hand, the influence of holding time became more apparent at torrefaction temperature >275 °C. It is also observed that oil palm frond has the lowest mass yield but highest fixed carbon content with enhanced HHV value when torrefied at 300 °C at 60 minutes. The present study found out that torrefaction temperature >275 °C resulted to a much better solid fuel than that of lower torrefaction temperature. Therefore, optimization of torrefaction parameters of OPF is highly recommended in future which may include other important fuel characteristics.