Influence of a nonionic surfactant on hydrate growth in an oil-water emulsion system

Abstract

As pipeline transportation operation moves into deep seas, the formation of hydrate has become a major flow assurance challenge for transmission pipelines. Some nonionic surfactants can play emulsification and anti-agglomeration effects in the oil-water two-phase system. Studying the mechanism of surfactants is helpful to solve the problem of hydrate blocking pipelines and ensuring good fluidity in the pipelines. This study investigated the influence of HLB of nonionic surfactants on the types of emulsions and the formation kinetics of methane hydrate. The experimental results showed that with the increase of the hydrophilic-lipophilic balance (HLB), low water content emulsion successively formed water/oil (W/O) and oil/water (O/W) emulsions, as well as a phase transition zone. The increase in the hydrophilic component had an inhibitory effect on the kinetics of hydrate formation. Under the low water content system, the anti-agglomeration effect of the composite surfactant was better than that of the single surfactant. The slurry-like hydrate generated by the 65% Span 80 + 35% Tween 80 compound system ensures good fluidity in the pipeline.

GRAPHICAL ABSTRACT

Keywords:

• Methane hydrate
• hydrophilicity
• hydrophobicity
• emulsion type
• nonionic surfactant

Additional information

Funding

This work was supported by the Doctoral Research Start-up Fund Project of Liaoning Province (2019-BS-159), Scientific Research Fund Project of Liaoning Education Department (L2019024) and Key Scientific Research Project of Liaoning Provincial Department of Education (L2020002).