Intensification in electrodesalter performance using modulation in electric field

In the petroleum industry, the removal of salt and water from the crude oil-brine emulsion is crucial for the subsequent stages of processing and refining. The dehydration and desalting are typically done in specialized and sizable equipment called electrodesalters. Improving the efficiency of an electrodesalter involves the capacity to accelerate the dehydration of the emulsion while ensuring a safe operation. This study demonstrates an improvement in separation through electric field modulation. The modulated waveform is composed of a high electric field step, succeeded by a low electric field step each lasting for two distinct time periods, and this sequence is then repeated. The primary objective of modulation lies in its ability to promote the clustering of drops during the high electric field period, succeeded by their effective coalescence in the low electric field period. The present work evaluates the efficacy of the technique for a tabletop portable bottle electrodesalter as well as a conventional tri-grid electrodesalter. The study is further extended to the emulsions formed by brine containing different salt concentrations. This establishes the commercial relevance of this technique while bringing out the role of brine conductivity and the desalter geometry specificity. The work conclusively establishes that the electric field modulation exhibits enhanced separation over an unmodulated scheme for both sunflower oil and crude oil emulsion systems. The specific values of electric field modulation parameters can change with the type of electrodesalter, temperature and brine concentration.