SOLIDS FLOW IMAGING AND ATTRITION STUDIES IN A PNEUMATIC CONVEYOR

This work describes the first application of a non-invasive capacitanc e tomographic technique to monitoring the behaviour of industrial-scal e pneumatic conveyors. Dynamic images of the solids distribution withi n a pipe have captured the movement of slugs in dense-phase solids con veying, and the presence of saltation in dilute-phase conveying. It ha s also been possible to acquire images downstream of a pipe bend and t o use this information to establish a suitable location for obtaining a representative sample of a material stream. The information provided by cross-sectional images facilitates the validation of theoretical m odels and ultimately will allow improved design as the sensitivity and resolution of the technique are enhanced. A study of particle (sea sa lt) attrition is reported using a conveying line 32 m in length. It is demonstrated that particle breakage can be described as a function of the conveying velocity and solids-gas loading factor. Particle breaka ge is described in terms of the mass-specific surface area, and is see n to increase with conveying velocity. Particle breakage rates are fou nd to be inversely related to the solids loading factor.