Investigations of torrefied biomass grindability using a modified Hardgrove test

Abstract

This paper presents results of investigations of torrefied biomass grindability using a modified Hardgrove test. The following types of torrefied biomass were used during the testing: alder chips, palm kernel shells and willow chips. Tests were conducted in a standard Hardgrove test mill for 50 cm3 volumetric samples (the same volume as applied in [1]). Volumetric samples of raw biomass were also tested for comparison purposes. Two ranges of the sample particle size were applied during the investigations: 0.6-1.18 mm (as in [2]) and 0.2-1.18 mm. As opposed to the standard Hardgrove test, the cumulative passing mass of the product was determined for a wider range of passing of standard sieves. The obtained results point to an increase in the grindability of torrefied fuels compared to raw biomass. They can be used to categorize torrefied biomass fuels due to their grindability, and as basic information in semi-technical scale studies on torrefied biomass comminution features.