Prediction of ISO 17831-1:2015 mechanical biofuel pellet durability from single pellet characterization

Abstract

In fuel pellet research, single pellet production methods are frequently used for model building in order to predict how raw material characteristics, formulas, and process settings affect product quality and the industrial process performance. For relevance, it is critical that bench-scale research results are correctly interpreted when transferred from the model system to the industrial application. In this study, the validity of different practically applicable single pellet durability/compressive strength methods as predictors for ISO 17831-1: 2015 standard fuel pellet durability was determined. To ensure correct interpretation a set of wood pellet samples with negligible relationship between durability and bulk density was used for calibration. Mean values from 20 replicate single pellet measurements on 12 assortments with pellet durability>90% was linearly correlated with the ISO standard durability with R2=0.83 (ISO tumbler) and 0.94 (Ligno tester). Compressive strength could be modelled (R2:0.89 and Q2:0.82) from pellet density and Ligno single pellet durability, concluding that compressive strength is equally affected by each of these two parameters, and thus, compressive strength cannot be considered as a reliable measure for ISO 17831-1: 2015 standard fuel pellet durability.