Breaking of Water-in-Crude Oil Emulsions. 10. Experimental Evidence from a Quartz Crystal Resonator Sensor and an Oscillating Spinning Drop Interfacial Rheometer

Abstract

The presence of asphaltenes in crude oil is a key factor in stabilizing water-in-oil emulsions. Changes in asphaltene aggregation have a definite effect on the formation of an elastic and highly resistant film that stabilizes such emulsions. Herein, we report asphaltene aggregation changes using two different methods. First, with a quartz crystal resonator sensor, clear changes in the resonant parameters (Δf n and ΔΓ n ) of the quartz sensor fully immersed in a heavy crude oil + cyclohexane solution were observed when the asphaltene concentration in the solution reached approximately 1000 ppm. Second, using an oscillating spinning drop interfacial rheometer, a distinct discontinuity of the trend of the optimum formulation is found when the asphaltene content C A attains this threshold value. The formulation variation was obtained by two kinds of scans, which were shown to be equivalent: an increase in water salinity for an anionic surfactant-containing system and an ethylene oxide number (EON) decrease of a non-ionic surfactant. In both cases, the hydrophilic surfactant was used as a demulsifier in a fixed concentration C D. It is seen that the variation of the asphaltene concentration C A generates an unexpected sudden change at the interface, according to Winsor’s affinity ratio R and hydrophilic–lipophilic deviation (HLD) premises about the compensation of the effect of asphaltenes by a formulation variable change. These newly reported results happening around C A = 1000 ppm could help to further understand how the asphaltene aggregation models and the HLD equation can be tools for the formulator to find fast and efficient answers to crude oil dewatering.

Fine-Tuning the Surface and Interfacial Chemistry of Silica Nanoparticles to Control Stability in High Ionic Strength Electrolytes and Modulate Assembly at Oil–Water Interfaces

“…When the IFT reached an equilibrium value, the oil droplet was sinusoidally dilated using 1000 rpm amplitude and 0.1 Hz to determine the dilatational modulus of the interfacial layer. The variation of the surface area and IFT was recorded, and the following equation was used to determine the complex dilatational modulus − E = A ∂ γ ∂ A where γ is the interfacial tension and A is the surface area of the oil droplet.…”

Advantages and limitations of different methods to determine the optimum formulation in surfactant–oil–water systems: A review

“…Recent publications have also introduced other variables, such as interfacial elasticity, where a minimum is reached at the optimum formulation (Marquez, Forgiarini, Fernández, et al, 2018; Marquez, Forgiarini, Langevin, & Salager, 2018; Zamora et al, 2018). This is also related to certain properties of the emulsified system, such as the minimum stability (Antón & Salager, 1986; Marquez et al, 2023; Marquez, Bullon, Forgiarini, & Salager, 2021; Marquez, Forgiarini, et al, 2019; Marquez, Meza, Alvarado, Johnny, et al, 2021). These techniques can be further extended with the use of other measurements that allow describing certain structural features of the domains present far away and around HLD N = 0, among them, dynamic light scattering (DLS) and small angle scattering (SAXS and SANS) (Fukumoto et al, 2016).…”