The Potential of Pneumatic Conveying Systems for the Off-Loading of Bulk Materials from Ships

摘要

This paper provides a brief review of the types of pneumatic conveying system that are used for ship off-loading applications. Their capability in terms of tonnes per hour of material off-loaded and onward distance conveyed is considered, together with power requirements for the duty. The type of bulk material to be off-loaded has a major influence on both the system design (in terms of the air flow rate to be specified) and the capability of the system (in terms of tonnes per hour conveyed) and this is considered. Important system components are those for feeding the material into the pipeline and include vacuum nozzles and twin blow tanks, neither of which have moving parts, and so the operation and control of these devices is explained. For high tonnage applications high vacuum is required for off-loading and high positive pressure for the onward conveying. In both of these cases it would be recommended that the pipeline be stepped to a larger bore part way along its length and the benefits of this are illustrated. For flexibility in pipeline routing rubber hose is often employed, particularly in cases where ships cannot be docked or tidal changes have to be accommodated, but its use must be carefully considered.