Study on Characteristics of Oil Palm Empty Fruit Bunch to Predict Condensation Temperature of Tar from its Pyrolysis Gas

Abstract

Palm oil is one type of plants that has various advantages since almost all parts of the plant, such as trunk, empty fruit bunch (EFB) and the extracted oil, can be utilized as energy. Utilization of EFB for energy, especially the use of combustible gas as direct feed of combustion engines to generate electricity is still rarely used. This is related to the water content and existence of tar in the syngas which is unfavorable. To overcome the problem, information on the characteristics and thermophysical properties, such as dew point, of tar in the pyrolysis of EFB is indispensable. In this study, the kind and quantity of tar was experimentally measured and dew point of the tar was calculated. Three EFB samples were taken from three different environmental conditions, namely samples EFB1, EFB2 and EFB3, to be analyzed. The elemental and proximate analysis as well as GCMS pyrolysis test of the samples were then used to characterize tar in the syngas and to determine its thermo-physical properties in terms of its dew point. The elemental analysis of the EFB samples showed disparity of its content, which was around 52.08±7.59% (C), 7.05±0.53% (H), 2.28±0.43% (N), 0.35±0.36% (S) and 34.84±4.45% (O). Likewise, the proximate analysis showed differences around 4.49 ± 2.60% (MC), 5.80±1.97% fixed carbon (FC) and 73.44±3.78% volatile matter (VM). From the elemental and proximate analysis, it can be predicted that tar compounds produced from pyrolysis of the EFB at a temperature of 400 °C, was in the form of mixed oxidation compounds (mixed oxygenates). The compounds were classified as the first tar compound (class 2) consisting of phenols (ketones, phenol and guaiacol). The dew point temperature and the concentration of the tar in its pyrolysis gas were predicted to be 204.22 °C, tar 1720.79 mg Nm 3-1 (sample EFB1); 256.02 °C, tar 92.97 mg Nm 3-1 (sample EFB2); and 154.85 °C, tar 359.02 mg Nm 3-1 (sample EFB3), respectively. This information can be useful in designing the tar elimination devices from the pyrolysis gas.