A pneumatic conveying process transports plastic pellets from a manufacturing source to a bulk silo for storage before being delivered to the ultimate production utilization of the plastic pellets. Multiple types or multiple sources of plastic pellets can be fed through a common pneumatic conveying conduit to respective bulk silos for temporary storage with diverter valves being utilized to direct product into and out of the common conveying conduit. Expanded elbow fittings are deployed at each directional change in the conveying lines to eliminate the creation of streamers at conduit bends. The plastic pellets are conveyed at a medium velocity between dense and dilute phases to provide a gentle conveying operation. A closed loop air supply system is used for dedusting devices providing a final removal of dust and debris from the stored product before being delivered to the ultimate utilization facility.