Investigation of Formation and Dissociation Processes of Tetrahydrofuran Hydrate Based on Electrochemical Impedance Spectroscopy

Abstract

The electrical properties of hydrous sediments are extremely complex and affected by many factors. The widely used resistivity parameter is unable to characterize the electrical properties of hydrous sediments fully. In this paper, the electrochemical impedance spectroscopy method was used to test the formation and dissociation processes of tetrahydrofuran hydrate. An appropriate equivalent circuit model was used to fit the measured impedance spectroscopy. Then the characteristics of the impedance spectroscopy were then discussed based on the analysis of the model parameters. Results are shown as follows.① The impedance spectroscopy of the tested tetrahydrofuran hydrate can be fitted by an equivalent circuit model of the electrode process controlled by charge transfer and diffusion. ② During the processes of temperature decrease and from the beginning to the end of the hydrate formation, the charge transfer resistance and Warburg impedance can mark the transitions of the three processes more significantly. ③ The variation trend of model parameters during the heating process is inverse to the trend during the cooling process. The electrochemical impedance spectroscopy provides an effective way to investigate the kinetic mechanisms of formation and dissociation processes of hydrate, whereas the parameters of the equivalent circuit model disclose the implicit information of the formation and dissociation processes.

Keywords

• tetrahydrofuran hydrate
• formation and dissociation process
• electrochemical impedance spectroscopy
• equivalent circuit model