Fuel pellets from selected fast growing Philippine tree species

Utilization of Philippine fast growing tree species for fuel pellet has not been commercialized even in the abundance of these raw materials. The contributions of these different tree species and material preparation techniques to the properties of fuel pellet were determined. Likewise, fuel pellet properties related to handling, utilization and storage were evaluated for every species used and compared with European DIN 51731 (1996) and EN ISO 17225-2 (2014) standards for industrial use pellets. Falcata (Paraserianthes falcataria (L.) I.C. Nielsen), Gmelina (Gmelina arborea Roxb.), Ipil-ipil (Leucaena leucocephala, (Lam.) de Wit.), Mangium (Acacia mangium Willd.), and Palo verde (Piper adincum Linn.) were used in the study. For P. aduncum 20 plants with ten centimetre diameter at root collar were collected. The materials were debarked, reduced to 3 centimeter chips and hammermiled to less than 4 millimeters particle size. Ground materials were classified to less than 2 millimeters and 2-4 millimeters particle sizes by using sieves. For each particle size, six kilograms materials were dried to 10%, 15% and 20% moisture content. The materials were then converted to pellets by using flat-die pelletizer with 8 millimeter holes. Pellet dimension, moisture content, pellet particle density, pellet bulk density, abrasion resistance, proximate analysis, calorific values, ultimate analysis, combustion and emission tests were performed on the fuel pellets. The pellets produced from the five fast growing species exhibit considerable uniformity in dimension. Physico�mechanical properties, proximate analysis result and net calorific values generally passed the European DIN 51731 (1996) and EN ISO 17225-2 (2014) standards for industrial use pellets, except abrasion resistance which narrowly missed the standard. Results on ultimate analysis were generally beyond the level set by the standard. Elemental components of heavy metals were generally within the limit except for ash forming calcium and magnesium which are at least twice the value of DIN 51731 (1996). Combustion test results offers the possibility of automating the feeding system for pellet in stoves and furnaces for the values obtained flaming and glowing combustion. The influence of raw material moisture content and particle size is significant on pellet particle density, bulk density and abrasion resistance; while combustion duration varies significantly with raw material moisture content. The parabolic pattern of pellet densities and abrasion resistance with raw material moisture content offers the possibility of manipulating moisture content to produce high quality fuel pellets. Likewise, the possibility of using these species for commercial pellet manufacture is highly plausible.