Applicability of nonionic surfactant alkyl polyglucoside in preparation of liquid CO2 emulsion

The essential characteristic of CO 2 makes most surfactants futile to form stable CO 2 emulsion. In this work, a green surfactant named alkyl polyglucoside (APG) was applied to prepare liquid CO 2 emulsion. The performance of surfactant on CO 2 emulsion stability was assessed in a sapphire cell by delamination time of emulsion under the operating conditions about 284.5 K and 5.2 MPa. The results demonstrate that APG has a potential to be used in CO 2 emulsion preparation and the suitable dosage of APG is about 3.0 wt% water quality. The phase-inversion point of water-in-CO 2 and CO 2 -in-water was determined as ranging from 15 vol% to 17.5 vol% (water cut) after examining the systems at different water cuts with 3.0 wt% APG. Two surfactants, fatty alcohol polyoxyethylene ether (AEO) and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) were also tested. To consider the applicability of CO 2 emulsion in fields such as submarine hydrate exploitation and CO 2 sequestration, the performance of surfactants in saline solution was examined. The experimental results show that APG can be used as surfactant in preparing liquid CO 2 emulsion with or without NaCl. The adding of 1.0 wt% NaCl for CO 2 emulsion with 3.0 wt% APG was proved to change the phase-inversion point to higher water cut. In comparison, anion surfactant AOT was futile in saline solution.