Both pickup and saltation mechanisms of solid particles have been examined from an experimental viewpoint, in relation to the prediction of the minimum conveying velocity required in horizontal pneumatic transport systems that operate in dilute-phase. Several experiments were carried out to determine pickup, saltation, and particle velocity of a wide variety of materials using different techniques. The use of dimensional analysis and the experimental findings led to a simple correlation useful to predict pickup velocity of coarse particles (above 100 mum). Noteworthy is the existence of a pipe diameter effect on the pickup mechanism, an important result to consider in scale-up procedures. For the first time in pneumatic transport, pickup and saltation mechanisms of solid particles in horizontal pipelines have been related, with the aid of branching and stability analysis. These ideas open new avenues to full understanding of the complex behavior of particles conveyed pneumatically through pipelines.
