Utilizing waste and wood pellets in gasification reactors is a promising solution to the waste and energy problem. However, plant shutdowns often occur due to failures in the feedstock handling systems. Unfortunately, research focusing on the flow properties and the impact of mechanical degradation on the flow properties of pellets is lacking. In this study, the flow properties of RDF, fresh wood pellets, and waste wood pellets with fines contents ranging from 0% to 30% were analyzed by Schulze Ring Shear Testing, angle of repose, angle of tilt, and Hausner ratio. The collected data was used to design a mass flow hopper and establish relationships between flowability and the angle of repose, angle of tilt, and Hausner ratio.

Our findings revealed that the fines fraction significantly influenced wall friction at a fines content of just 10%. The fines could increase or decrease the wall friction angle depending on the material. Additionally, the fines content adversely affected the flowability, with flowability reaching the flowability of the fines fraction at 30% fines content. Mixtures of RDF with waste or fresh wood pellets showed consistent wall friction and flowability similar to the base materials. We observed that a higher angle of repose, angle of tilt, and Hausner ratio indicated lower flowability. However, their predictive accuracy was limited, and we do not recommend relying on them for hopper design.