Effectiveness of Polysorbate Polyester on Separation of Emulsions Made by Green Surfactants

Abstract

The surge of new technology in the oil industry with nonpollutant/green surfactants, new brines, and the addition of nanoparticles to emulsion systems imposes a question on how these systems are separated and if the current most commonly used method is still applicable to them. This paper showcases the study on the performance of a green demulsifier (polysorbate polyester) up to a maximum concentration of 1000 ppm in the separation of crude oil emulsions with different compositions. These emulsions varied from light to medium crude oil with three surfactants, Coco Glucoside (sugar-based), Greenzyme (enzymatic-based), and alpha olefin sulfonate (synthetic). These emulsion systems contained two environmentally friendly brines, sodium and potassium formate, and the results were compared with sodium chloride. Some compositions consider the addition of 0.25 wt % silica and magnetite nanoparticles. The demulsification efficacy was evaluated with a bottle test at 60 °C. The demulsifier produces a full separation with Coco Glucoside with light crude oil with any composition; however, a high concentration is needed. Emulsions with medium crude were more difficult to separate as the demulsifier was slower to act due to the viscosity increase and in some cases even presented no considerable changes in separation, like for 7 g/dL potassium formate salt. The demulsification with particle presence was dependent on the interaction between the surfactant-particle interaction. Emulsions containing silica decreased the demulsification between 10 and 20% with a stronger effect observed for the samples with magnetite between 10 and 40% depending on the surfactant type.