Performance evaluation of a benchtop wood pellet length analyser based on visual imaging

Wood pellet is a densified solid biofuel with the highest level of standardization. Geometric characteristics of pellets, such as length and diameter, are proprieties considered by the technical specification ISO 17225–2 for the definition of quality classes. Reason for this is that pellet length affects many aspects such as how the biofuel fills the available space in the brazier and therefore impacts on mass and energy density. Currently, the standard ISO 17829 describes the methodology for measuring pellet length using a precision caliper on a small pellet sample. This operation, even though performed on small sample quantities, is time-consuming. An alternative method for measuring the length of the pellets is proposed in this paper. Our results suggest that the benchtop prototypal IR instrument MetaLab allows assessing pellet length and diameter with high accuracy, which makes IR instrument MetaLab a reliable and quicker alternative to the measuring method defined by ISO 17829. Standardizing the measurement procedure with the instrument proposed in this paper might lead to the development of a new measurement standard. Furthermore, the development of a portable version of Meta Lab may allow business operators to apply this innovative measurement method along the supply chain, ensuring an easier quality control of the product.