Loss Prevention Mitigation in Sour Water Stripper (SWS) Cooler Using Process and Computational Fluid Dynamics (CFD) Modelling

Sour water stripping (SWS) units are similar to other process units that can bring many operational challenges to meet target stripped water specifications. Failure of any equipment in the unit leads to unplanned shutdown and hence increases the downtime of the unit. In this study we investigated the outlet nozzle and elbow downstream the finfan cooler as they occasionally leak due to apparently metal thinning. Process simulation using appropriate electrolyte thermodynamic package to predict vapour liquid equilibrium and streams flow rates was used. Subsequently, Computational fluid dynamics (CFD) simulation was use to predict the erosion patterns. To mitigate and prevent unit upset, many option have been recommended to change the operating mode of the finfan cooler so as to circumvent alloy change. The CFD simulation results matched the erosion pattern that caused the loss of wall thickness. Different cases were investigated addressing elbow size, flow regime and elbow angle. The results, however, have indicated that the erosion is unavoidable irrespective of the fluctuation in the throughputs to the unit.