Hose water system modelling and analysis of an alumina refinery

Centrifugal pumping systems are widely used throughout the Alumina (Process) industry and often are subjected to either ineffective design or gradual reduction in efficiency due to a lack of consistency in operating procedures or changing system parameters due to excessive scale build up in piping. By analyzing an existing system in use at an Alumina Refinery in Australia, common problems associated with dated pumping systems can be modeled and recommendations can be made on appropriate measures to resolve such issues through either redesign or the removal of scale deposits. It was evident from the analysis that in conditions where working pressure could not be increased, the most effective way to increase flow through discharge piping was to increase the diameter. This could be achieved through increasing the actual inside diameters of piping or through improved maintenance practices, such as regular pipe cleaning. It was found that the buildup of scale in discharge piping can severely increase the head losses in the system and therefore affect the flow conditions, as well as increase pump vulnerability towards discharge recirculation.