Development of an aggregation kernel for the electrocoalescence process

Abstract

Water is normally coproduced along with oil in petroleum reservoirs. During the production of crude oil, the mixture is subjected to intense turbulence, providing sufficient dispersion for the formation of water-in-oil (W/O) emulsions. The presence of W/O emulsion causes practical problems in the industrial equipment. Electrocoalescence is accepted as the principal industrial process to break the W/O emulsions and separate the aqueous and oil phases. The application of a high electric field to the W/O emulsions polarizes the water droplets and enhances the rate of their coalescence. In order to improve the understanding of desalting/dehydration processes and to select the best operational parameters and control strategies of the process, attempts have been made to model this process. In this work, the coupling of computational fluid dynamics (CFD) and population balance equation (PBE) is used as the principal idea to conduct the modeling. Moreover, a new concept named “free phase” is introduced to model the creation of segregated water phase (capture). In the first stage of the study, a mathematical model based on population, mass and momentum balance equations for disperse, oil and free phase is developed to interpret the batch electrocoalescence process. The parameters of the aggregation and capture kernels are estimated using the experimental data. In the second stage of the study, the continuous electrocoalescence pilot plant is simulated by implementing the derived kernels in the Ansys Fluent (R) software. The results show a decent performance of the models in predicting the separation of the phases inside the batch and continuous electrostatic vessels.