Investigation on the reduction effect of QAs1 on the adhesion force between methane hydrate particles and wall droplets

• Published in: Fuel (Guildford) 2023-05, Vol.340, p.127521, Article 127521
• Main Authors: Wang, Zhiyuan, Li, Pengfei, Tong, Shikun, Zhang, Jianbo, Zhou, Chenru, Pei, Jihao, Yang, Hemin, Liu, Chenwei
• Format: Article
• Language: English
• Subjects: Adhesion force; Critical micelle concentration; Hydrate film growth; Methane hydrate particles; Steric hindrance effect
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2023.127521

•The effect of QAs1 on hydrate adhesion force and hydrate film growth rate was systematically investigated by the high pressure visualization microscopic force testing system.•The mechanism of QAs1 to reduce the hydrate adhesion force under lower levels of subcooling conditions is investigated.•The mechanism of QAs1 to reduce hydrate adhesion force under higher levels of subcooling conditions is investigated.•The optimal amount of QAs1 additive was discussed based on the steric hindrance and CMC. The adhesion force between methane hydrate particles and wall droplets is an important reference for studying the behavior of hydrate particles accumulating or detaching from the tube wall. In this work, a high pressure visualization microscopic force testing system was built to evaluate the effect of hydrate anti-agglomerants (AAs) in the methane gas phase. It was found that the hydrate adhesion force reached its lowest value at the QAs1 solution concentration of 0.2 wt% (CMC), and the adhesion force was 589.81 mN/m under 1 subcooling condition and 1123.63 mN/m under 10 subcooling condition. It was found that the mechanism of QAs1 in reducing adhesion force under lower levels of subcooling conditions is mainly to reduce the gas–water interfacial tension. The mechanism of action of QAs1 in reducing adhesion force under higher levels of subcooling conditions is mainly due to the steric hindrance effect of QAs1 molecules. The presence of QAs1 molecules on the droplet surface leads to the slowdown of tangential growth of hydrate film and the slowdown of thickening of hydrate film, resulting in a reduction in adhesion force. When the concentration of QAs1 solution is higher than the CMC, the steric hindrance effect of QAs1 molecules is no longer enhanced with the increase of QAs1 solution concentration, while the presence of micelles makes the hydrate easier to nucleate and makes the adhesion force gradually increase. These research data are useful to study the mechanism of action of quaternary ammonium salts as hydrate anti-agglomerants (AAs) and provide a basis for determining the optimal amount of additives for AAs used to prevent hydrate accumulation in natural gas pipelines, and for optimizing hydrate prevention solutions in deep-water gas wells.