Understanding particle attrition is vital to the optimisation of a wide range of industrial processes. Lean phase pneumatic conveying is one such process, whereby the high energy particle impacts can cause undesirable loss in product quality or change in bulk behaviour. The attrition process is resolved into a material function and a process function; the combination of these functions dictate the attrition mechanism present, and the magnitude of failure observed. Subsequently, the forces applied to the particles are examined within the context of lean phase pneumatic conveying. Finally, empirical and numerical models are reviewed along with comments on experimental method. To summarise some of the findings of this review: the requirement of standardised test equipment is recognised in order to compare the wide variety of particulate materials under comparable loading conditions; stronger correlation between the results obtained from different particle attrition test methods is required; and finally, seldom are the manufacturing conditions (where applicable) linked to the particulate attrition behaviour.

Pneumatic conveying is utilised in a variety of industries to convey food products exhibiting diverse handling characteristics. Attrition of particles caused by this conveying process can result in a number of undesirable outcomes such as loss in product quality or issues in subsequent handling processes. The ability to predict the breakage behaviour of particulate materials is desirable in both new system design and resolving issues in existing plants. This work considers two different particulate materials (Salt and Golden Breadcrumbs) across a range of particle sizes, and quantifies their breakage behaviour under varying impact conditions. Narrow size fractions of each material was degraded; material retained on 250 µm and 355 µm sieves for salt, and 500µm, 710µm and 1000 µm sieves for Golden Breadcrumbs.Velocity was found to be the most influential factor with respect to particle attrition. The results from the narrow size fraction tests were superimposed to form a simulated full size distribution breakage behaviour, which was then compared to the experimentally determined behaviour. A good agreement was found, however the proportion of material predicted for size fractions smaller than 355 µm for Golden Breadcrumbs and 180 µm for Salt was under-predicted. Recommendations for increasing accuracy of the prediction method are given.