Energy production features of miscanthus pellets blended with pine sawdust

Abstract

The primary objective of this study was to evaluate the qualities of Miscanthus pellets blended with pine sawdust at various ratios (Miscanthus/pine sawdust—0:100, 25:75, 50:50, 75:25, and 100:0) and relate them to energy generation potential under typical production conditions of the widely used bioenergy production technologies according to literature. Samples of each material were milled to the required sizes and blended in the proportions mentioned above. Water was added (6%) to each mixture to achieve a uniform moisture content of 10% on wet basis. The mixtures were then subjected to pressure agglomeration in the form of mechanical compression using a single pellet press so that homogeneously sized fuel pellets were obtained. Thereafter, the pure and blended pellet samples were examined using a range of analytical techniques to reveal any alterations in characteristics important to the utilization of the pellets as a green energy source. The results showed that, although temperature variations generally caused an estimated 6% moisture loss on a wet basis during pelleting with positive influence on the features of the pellets, the quality of the pellets in terms of ash composition (2–4%), hardness (41–46 kg/pellet), and heating value (20–21 MJ/kg) was in general more desirable for the blended pellets than for pure Miscanthus pellet. Structural analysis also revealed low levels of hydrophobic groups in the blends relative to pure Miscanthus, which were consistent with the fractions of pine sawdust and were also the reason for the pellets’ increased hardness.