Solution Provided | Root-cause Analysis and Mitigation Strategy
Discipline | Process, Mechanical
Following a number of failures in indirect steam heaters within an Alumina Refinery, Carnac was engaged to investigate these events and develop a mitigation strategy. Holes were forming in the tubes resulting in process slurry passing through to the shell side of the heaters, which have led to significant production loss as this key equipment was taken offline for repairs.
Carnac concluded that the root-cause of the failures could be attributed to aggressive scale formation in the heat exchanger tubes that have resulted in blockages and uneven scale formation on the tube wall. Carnac conducted Computational Fluid Modelling to determine the fluid velocity profile associated with these blockages and found that the flow velocity past the lumps of scale formed in the tubes was sufficient to erode the steel tube.
Carnac also identified that the likely cause for the aggressive scale growth was a chemical imbalance combined with the presence of a foreign contaminant found throughout the process circuit.