This work investigates the proportion of generated fines in a pilot-scale experiment using a belt conveyor and commercial fuel pellets. For this, a belt conveyor with a length of 3.1 m was used and operated at varying conditions: speeds, percentages of material loading on the belt, two combinations of the inclination angle of the belt and the falling height, and a different number of handling steps. We considered a design of experiments approach based on response surface methodology to investigate the effect of different conditions on the potential of fines generation. Moreover, a comparison between the results of the belt conveyor and three common benchmark experimental approaches (tumbling box, rotary impact tester, and mechanical compression test) was made. Results show that the number of handling steps and the combined effect of drop height and inclination angle directly affected the fines generation. However, the tested belt speed range and the level of loading were of lower significance. A polynomial quadratic model was derived based on the regression analysis and showed a high accuracy to predict the proportion of fines. Moreover, the tumbling box method showed good potential to predict the proportion of fines in a belt conveyor when transported several times.

Container terminal capacity is often limited by (in)efficiency bottlenecks. This paper provides the design and proof of concept for the bottleneck mitigation cycle (BMC), consisting of three steps: bottleneck classification, detection and alleviation. While, often, the literature only focuses on alleviation of a single bottleneck and ignores bottleneck detection and interdependencies, this research uses the shifting bottleneck method and thereby considers a variety of possible infrastructural and operational bottlenecks. An empirical approach is adopted to find the cause of the detected bottleneck and to suggest suitable alleviation measures. Application of the BMC to a simulation model of the Fergusson Container Terminal in the Port of Auckland resulted in productivity improvements of 2–6%. To further improve the BMC, future research directions are to improve the empirical approach used for bottleneck alleviation and to apply the BMC in real-time.

The change in physical properties of wood pellets, with a focus on particle size distributions due to pellet breakage and attrition, was studied in a large-scale (∼450 ton/h) transportation system. Critical locations with a high probability of breakage through the whole transportation system were chosen and sampled to study the effect of transportation system design and operation on the mechanical properties of pellets. Bulk density, mechanical durability, moisture content, and particle size distribution of pellets were characterized for each sample. Analysis of variance showed that there were significant differences between the percentages of small particles (< 5.6 mm) in the samples taken at different locations, especially at one with a vertical free fall of 7.8 m. On average, this relatively long drop increased the proportion of particles < 5.6 mm in the samples from 8.73% to 14.09%, and that of particles < 3.15 mm from 4.82% to 9.01%. Moreover, the measurements showed a wide deviation in the mechanical durability values, between a minimum of 90.8% and a maximum of 98.7%, which were not correlated to the sampling points but related to pellet properties. It can be concluded that pellet transportation systems require more dedicated design strategies to prevent breakage and attrition.