A computational approach to determine the residence time distribution of biomass particles in rotary drum dryers

Wood pellet manufacturing involves drying of wet biomass from 50% m.c. down to 5%-7% m.c. Rotary drum dryers are the most common dryers in pellet industry. Mis-prediction of biomass residence time leads to fires and low-quality products due to over drying or under drying. The current study uses a CFD and DEM modeling approach to determine the residence time of particles with properties similar to biomass feedstock in a rotating drum. The developed model uses a Lagrangian approach to track the 3D particle trajectory from drum inlet to the outlet. The novelty of the current model is that it includes the contribution of biomass interactions with drum wall and internal baffles, which is mostly missing in the published models. Particles with an increasing mass and aspect ratio stayed longer in the dryer than particles with an aspect ratio closer to unity. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Wood pellet manufacturing involves drying wet biomass to a suitable moisture content; rotary drum dryers are the main drying equipment; misjudging particle residence time may lead to poor quality products and fires.