A Review of Two Phase Flow Modeling and Its Applicability to the Bayer Process

摘要

The premature failure of interconnecting flash tank piping in theBayer Process costs the industry millions each year inreplacement of materials and downtime of process equipment.The underlying driving force of the recuperative heating unit of adigester is that slurry at saturation conditions is counter currentlyde-pressurized and cooled along the saturation curve by means ofstage wise flash evaporation. The movement of a near boilingslurry between flash tanks requires careful consideration asvapour forms whilst the slurry slowly de-pressurizes due to inpipe frictional losses and net changes in momentum energy as thefluid pressure falls below the vapour pressure. The failure tointerpret the specific points at which large rises in pipe velocitydue to a change in phase can result in mis-interpretations in designwhich in turn result in accelerated pipe erosion and eventualrupture with implications to operations, health and safety.