Eucalyptus is utilized in the timber and paper industries. The eucalyptus bark must be peeled off during the production process, which results in a large amount of biomass residue. The objectives of this research were (i) to study the physical properties of eucalyptus bark, (ii) to investigate the crushing process using a hammer mill, and (iii) to examine the pelletizing factors of biofuel from eucalyptus bark residue using a pellet machine. Eucalyptus bark was crushed to reduce particle size and then sieved through different screen sizes (3, 4, and 5 mm) at a drum speed of 1200 rpm. The resulting eucalyptus powder was used to study the pelletizing factors of biofuel at various levels of moisture content: 17.69, 20.21, 24.27, and 26.74% w.b. and various pelletizing speeds of 250, 275, and 300 rpm. It was found that the eucalyptus powder could be pelletized at a speed of 275 rpm. Pellets with screen sizes of 3 and 4 mm could be pelletized at a moisture content of 17.69% w.b., while a screen size of 5 mm could be sued to pelletize at a moisture content of 20.21% w.b. The specific energy consumption from the particle size reduction process to the pelletizing process ranged from 667.92 to 854.64 kJ/kg. The results of bulk density, durability, and fines were 603.20-645.73 kg/m3, 96.34-96.88%, and 1.83-2.02%, respectively. The heating value was 16.19 MJ/kg. The energy value was calculated by using a eucalyptus pellet as boiler fuel (at a boiler efficiency of 38%). Eucalyptus pellets have the potential to produce energy worth 644 million THB/year or 20.6 million USD/year.
Keywords: Biomass; Eucalyptus; Palletizing; Pellets.
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