Application of CFD for Troubleshooting and Hydrodynamic Analysis in an Industrial Three-Phase Gravity Separator

Multiphase separation in gravity separators is one of the important processes in different industries. This study presents a computational fluid dynamics (CFD) simulation of an industrial three-phase boot separator applying a coupled volume of fluid (VOF)- dispersed phase model (DPM) method for hydrodynamic analysis and troubleshooting of the separation process. Noted that despite the wide application of the boot separator in different industries, no research has been performed on this type of separator to investigate the macroscopic and microscopic behavior of the separation process. The results of numerical calculations based on three-phase flow profile, secondary phase behavior, separator performance, and size distribution of the droplets were investigated in this research. Results showed that the CFD model is well capable of estimating the separation behavior in a three-phase boot separator. Troubleshooting of the studied separator was also investigated to detect the parameters that might decrease the separation performance. Based on the results, it is concluded that the separator suffers from the type of the inlet diverter, lack of an efficient mist extractor at the gas outlet and also lack of an appropriate vortex breaker at the oil outlet. The effect of increasing the inlet water flow rate on the separator performance was another parameter that was studied in this research. Results demonstrated that increasing the inlet water flow rate from 11823-47295 kg/hr caused an increase in the mass of droplets at the gas outlet from 0.09 to 1.6 kg/hr, but this increase did not lead to a significant decrease in the separation efficiency.