Formation Characteristics of Carbon Dioxide Hydrate in a High-pressure Flow Loop
Siyuan Liao, Bo Yuan, Yuxi Wang, Zhenbo Lv, Liyan Shang, Li Zhou, Zhiming Liu
Abstract
The formation of hydrate in the system with a high carbon dioxide (CO 2 ) content will block the pipeline and threaten the transportation efficiency and security of deep-sea oil and gas pipelines. To guarantee the security of the hydrate flow in pipelines, the characteristics of CO 2 hydrate formation in a pure water system utilizing a high-pressure flow loop were investigation. On the properties of CO 2 hydrate formation, the impacts of initial pressure, velocity, and two inhibitors, polyvinylpyrrolidone (PVP) and glycine, were examined. It was found that as the initial pressure increased, the induction time shrank and the initial formation rate rose. However, increasing the initial pressure did not increase the supersaturation of the system. The mass and heat transfer conditions of the system were impacted by the velocity simultaneously. The initial formation rate decreased first and then increased when the velocity increased, while the induction time and subcooling first increased and then declined. The experiments also showed that the CO 2 hydrate formation was significantly inhibited by both the environmentally friendly glycine and the traditional kinetic inhibitor PVP, according to the relative inhibitory performance factor that was experimentally determined. The inhibition effect of PVP was stronger at higher concentrations, and the two compounds combined had a synergistic inhibition effect. In the final part, the inhibition mechanism of glycine and PVP was proposed. An essential resource for the study of new hydrate inhibitors is provided by this work.