Comparison of measured values from single pellet durability tester and standard tumbler tester.

A major use of residual biomass from forestry and agriculture is densification into biomass pellets. Laboratory-scale fuel pellet research involves data analysis and model building, often using a single pellet mechanical press to make the biomass pellets (mass < 1 g) at a slow production rate. However, this single pelletising approach is considered not practically possible to produce the mass of pellets (∼500 g) required for determining their mechanical durability in accordance with the ISO standard method (ISO 17831-1) adopted by industry. In this study, wood pellets were tested for single pellet durability in a single pellet durability tester. The first test was done to mimic the situation when wood pellets are exposed to humid environmental conditions during storage. It involved six treatments – three types of pellets and two levels of moisture content. The second test mimicked the situation when light rain may expose the pellets to liquid water during the loading and unloading of ships. The main objective was to develop a quantitative relationship between the tumbler durability Dt (industry standard) and Dsp the single pellet durability. Results showed that the variability of Dsp was much larger when single pellet durability had lower values. Dsp was found to be strongly correlated with Dt (R2 = 0.94) when single pellet durability had high values. A linear equation can accurately convert Dsp to Dt when wood pellet moisture content is below 10% w.b. • Single pellet (Dsp) and tumbler (Dt) durability were determined for wood pellets. • Dsp variability was much larger when single pellet durability had lower values. • Dsp strongly correlated with Dt (R2 = 0.94) when single pellet durability was high. • Linear equation accurately converts Dsp to Dt if pellet moisture content <10%. [ABSTRACT FROM AUTHOR]