The effect of formate brines on the emulsification of ionic, non-ionic, and enzymatic surfactants

• Published in: Chemical engineering science 2022-12, Vol.263, p.118016, Article 118016
• Main Authors: Tatiana Lezama, Linda, Rafati, Roozbeh, Sharifi Haddad, Amin
• Format: Article
• Language: English
• Subjects: Alpha Olefin Sulfonate; Coco Glucoside; Critical Micelle Concentration; Emulsification; Formate Brine; Gibbs Energy
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2022.118016

•Surface and Interfacial properties of environmental-friendly surfactants were compared with a commercial surfactant for sodium and potassium formate and sodium chloride.•Emulsification ability of environmental-friendly and commercial surfactant was evaluated for heptane, light and medium crude oil.•Surface tension reduction in brine presence depends on the type of surfactant used.•Ionic surfactants reduce its repulsion between head groups in salt presence.•Polyglucosides have a similar effect as with ionic, the molecules are slightly more negatively charged linked to the OH groups in the molecule.•Coco glucoside has similar thermodynamical properties as AOS which would indicate that it could be used to replace sulfonates, when environmental restrictions are in place.•Emulsification for Sodium Formate and Sodium Chloride behave similarly, however, for those made with Potassium Formate pH needs to be considered since it can affect the behaviour of asphaltenes, or resins present in the crude oil.•For most emulsions, the result of the rheology behaviour was shear thinning.•Coco Glucoside presented a Newtonian behaviour for crude oil which could indicate that these emulsions would remain stable even at high shear rates that can be achieved in the production stage. Environmental concerns on contamination of subsurface porous media by toxic chemicals have motivated the petroleum industry to replace them with environmentally sustainable (green) and biodegradable alternatives. Green surfactants have emerged such as sugar, enzymatic, and microbial based surfactants. However, their emulsification with different oils and salinity conditions is unknown. In this study, different oil and brine systems are tested to measure interfacial properties, rheology and emulsification of Coco Glucoside (CG), a sugar-derived surfactant; and Greenzyme (GZ), an enzymatic-environmentally friendly surfactant. Emulsification with light and medium crude oil in the presence of sodium chloride and sodium formate brines gave similar results with 10–20 μm average droplet size. However, medium-heavy crude oil with potassium formate produced 98 vol% emulsion with 3–6 μm average droplet size. Most of the emulsions demonstrated a shear thinning behaviour apart from emulsions resulting from Coco Glucoside and medium-heavy crude oil in which a clear Newtonian behaviour was observed.