Processes for analysis and optimization of multiphase separators, particularly in regard to simulated gravity separation of immiscible liquid dispersions

A method for optimizing liquid-liquid separation efficiency in a multiphase separator system comprising the steps of:

• providing a multiphase separator having an inlet for receiving a multi-liquid and multiphase immiscible liquid dispersion comprising a gas phase, an oil phase, and a water phase;
• passing the immiscible liquid dispersion into the separator;
• electronically providing operational input parameters from a connected electronic device to a hardware processor of a controller computing device, wherein the processor is configured by executing code that is in the form of one or more software modules and stored in a non-transitory storage medium, and wherein the operational input parameters include:
• fluid property data for the immiscible liquid dispersion including one or more of density, viscosity and surface tension,
• static or dynamic settling data for the immiscible liquid dispersion,
• and geometry of an internal volume of the separator including one or more internal geometric components therein;
• generating, with the processor, a computational fluid dynamics (CFD) model of the separator system, wherein generating the CFD model includes:
• defining, with the processor executing code comprising a CFD model generator module, based on the geometry, a three-dimensional geometric model of the internal volume of the separator and the internal components therein,
• defining, with the processor executing code comprising the CFD model generator module, based on the three-dimensional model, a computational mesh representing the internal volume of the separator,
• determining, with the processor with the processor executing code comprising an input parameters module and the CFD model generator module, an initial droplet size distribution of the immiscible liquid dispersion contained within the internal volume,
• representing, with the processor with the processor executing code comprising the input parameters module and the CFD model generator module, volumes for each of a continuous or dispersed gas phase, a continuous or dispersed heavier liquid phase and a continuous or dispersed lighter liquid phase within the interior volume of the separator using a Eulerian multiphase model,
• representing, with the processor executing code comprising the input parameters module and the CFD model generator module, for a volume of a dispersed liquid phase within the interior volume, a droplet size distribution using population balance modeling, wherein the distribution is modeled by solving a population balance equation according to multivariate methods,
• applying, with the processor executing code comprising the input parameters module and the CFD model generator module, coalescence and breakage kernels to model droplet size evolution in the population as a function of droplet size and the fluid property data, and
• generating, with the processor executing code comprising a simulation module and the CFD model generator module, a model of a phase interaction between the continuous liquid phase and the dispersed liquid phase, wherein the model of the phase interaction is a function of a dispersed phase fraction concentration between a dilute regime, a semi-dilute regime and a concentrated regime of the dispersed liquid phase volume and is a function of a dispersed phase droplet diameter and the liquid phase properties;
• adjusting, with the processor executing code comprising an adjustment module and the CFD model generator module, based on the CFD model, one or more of the operational input parameters to maximize the liquid-liquid separation efficiency;
• controlling, with the processor, the separator according to the one or more operational input parameters, wherein the controlling step comprises sending, by the processor to the separator over a communication interface, a control signal configured to adjust a setting of one or more of a water stream outlet control valve, an oil stream outlet control valve, an operating temperature of the separator, a demulsifier chemical injection, an inlet control valve and a gas outlet control valve as a function of the one or more operational input parameters;
• outputting from the separator one or more streams of processed liquids separated from the immiscible liquid dispersion and containing minimal amounts of the immiscible liquid dispersion, wherein the one or more processed liquid streams are selected from the group consisting of a water outlet stream and an oil outlet stream;
• monitoring a liquid-liquid separation efficiency of the separator in real-time during operation of the separator using one or more sensors exposed to respective outlet streams, wherein the liquid-liquid separator efficiency is determined by measuring one or more of a fraction of water in the oil outlet stream and a fraction of oil in the water outlet stream;
• and
• dynamically performing, by the processor based on the monitoring step, the steps for providing operational input parameters, generating the CFD model, adjusting the operational input parameters, controlling the separator, outputting and monitoring the one or more liquid streams, such that the separation efficiency is maximized and the one or more streams of processed liquids separated from the immiscible liquid dispersion contain less than a prescribed amount of the immiscible liquid dispersion therein.