Study on the effect of wax on hydrate formation in the presence/absence of span 80

Abstract

Scholars have been unable to arrive at a consistent verdict on the effect of wax on hydrate nucleation, as the influence of emulsifiers on the dispersion of wax in oil has been neglected. Accordingly, we discuss the effects of wax, span 80, and their coupling on hydrate nucleation utilizing CO2 as the hydrate guest molecule to clarify the precise role of wax on hydrate nucleation. It was discovered that the incorporation of either 10 wt% wax or 2 vol% span 80 prolonged the induction period, and their combined addition led to a longer induction period. This phenomenon indicates that wax and span 80 negatively impact on hydrate nucleation, and their combination strengthens this process. A combination of macroscopic and microscopic techniques was employed to illustrate the mechanism underlying the effect of wax on hydrate nucleation. The study found that both wax and span 80, as well as their coupling, facilitated the dispersion of water droplets in the oil. However, the waxes alone had a needle-like shape and could not entirely encase the water droplets, resulting in the aggregation of hydrate particles. While span 80 changes the shape of the wax, the coupling effect completely encapsulates the water droplets, preventing gas mass transfer and inhibiting hydrate nucleation. Furthermore, the wax stabilizes the structure of the span 80-containing emulsion, thus enhancing the anti-aggregation of span 80.