Airflow versus pressure drop for bulk wood pellets

Data on the resistance of wood pellets to airflow are required for the design and control of ventilation, cooling, and drying of bulk pellets. In this study, pressure drops versus airflows were measured for several sizes of cylindrical wood pellets. The pellet diameter was 6.4 mm; the length varied from 4 to 34 mm. Experimental airflow rates ranged from 0.014 to 0.8 m3s−1 m−2. The corresponding measured static pressures ranged from 2 to 2550 Pa m−1. Three predictive models of Shedd, Hukill–Ives, and Ergun that relate pressure drop to airflow in bulk granular materials were fitted to the data. The Ergun equation provided the best fit. The results obtained from this study are comparable to those reported by other researchers for biomass such as 28 mm long cut willow chips and 6.4 mm diameter alfalfa pellets.