Effect of a nonionic surfactant on the formation of natural gas hydrate in a diesel emulsion system

Abstract

In order to investigate the effect of different nonionic surfactants on hydrate formation in oil-water emulsion systems, the hydrate formation experiments were carried out in a diesel water-in-oil emulsion system with a water cut of 40% using nonionic surfactants such as Span80, Tween80, Span20 and Tween20, respectively. The results show that under the experimental conditions of 275?K and 7?MPa, a certain concentration of nonionic surfactant can promote the growth of hydrates in diesel emulsion systems, shorten the hydration reaction time, and have a significant effect on the improvement of gas storage density. The combination of Span80 and Tween80 in a mass ratio of 1:1 was the most effective in promoting the formation of hydrate in the emulsion system. When the mass fraction was 0.5%, the hydration reaction time was the shortest and the hydrate gas storage density was the highest. Due to the addition of the nonionic surfactant, a stable interfacial film and interfacial charge are formed around the water droplets of the emulsion system, making it difficult for the droplets to approach and polymerize, which maintains the stability of the water-in-oil emulsion system and has great reference value for the study of hydrate storage and transportation.