Characterisation of Oil Palm Empty Fruit Bunches for Fuel Application

This study was an attempt to produce bio-oil from empty fruit bunches (EFB) of oil palm waste using fast pyrolysis technology. A 150 g/h fluidised bed bench scale fast pyrolysis unit operating at atmospheric pressure was used to obtain the pyrolysis liquid. A comparison of the elemental composition of unwashed and washed feedstock was made in this study. With the five methods of treatment being considered, elements such as Al, P, Cl, Ti, Fe and Cu were removed during the washing. However, Na, S and K decreased with the reduction of the ash content of the feedstock. The properties of the liquid product were analysed and compared with wood derived bio-oil and petroleum fuels. The liquids produced had high acid content, with a High Heating Value (HHV) of about 50% of conventional petroleum fuel. The char content was in the range of 0.2–2.0%. The composition and particle size distribution of the washed and unwashed feedstock were determined, and the thermal degradation behaviour was analysed by thermogravimetric analysis (TGA). The product yield for washed EFB was similar to that of low ash wood, while the product yield for unwashed EFB was much closer to that of higher ash feedstock. The pyrolysis liquids derived from unwashed EFB were found to be in both an aqueous and an organic phase, which presents challenges for their commercial application as a fuel. Some possibilities of upgrading were also discussed in this work.