Attrition of Feed Pellets during Pneumatic Conveying: the Influence of Velocity and Bend Radius

Feed pellets for livestock are susceptible to attrition during pneumatic conveying. The effects of air velocity, bend radius and number of repeated impacts were investigated for three commercially available feeds in a 100 mm diameter pipeline. Weibull analysis was used to assess the technical pellet quality. Particle attrition differs between feeds, but product damage increases exponentially with conveying air velocity for all three feeds. Short radius bends (15 cm) cause more product damage compared to bends of longer radius for all conveying air velocities tested (20–50 m s−1). Product attrition was lower for a 35 cm bend radius compared to a bend with a radius of 30 cm, but the damage was not higher in a 60 cm bend radius relative to a 90 cm bend radius. The volume independent 37% Weibull tensile strength was used to normalise the pellet strength, and this result was used in connection with the results of the pneumatic conveying-attrition experiments in order to establish an attrition model. This model could adequately describe the physical degradation of three heterogeneous materials that differs widely in susceptibility to attrition.