Effect of a weak electric field on THF hydrate formation: Induction time and morphology

Abstract

The kinetics of bulk hydrate formation is of crucial importance in the application of hydrate-based technique involving energy storage, desalination and flow assurance. Various procedures have been found to significantly impact the kinetics of hydrate formation; yet with few studies touching the effects of a weak electric field. A voltage across the solution could likely affect the activity and orientation of the molecules inside, thereby playing a potential role in the hydrate nucleation, crystal growth and even diffusion of water and guest molecules. In this study, the effect of a weak electric field on the induction time, bulk surface characteristics and growth rate of THF (tetrahydrofuran) hydrate were investigated by controlling the voltage across the two electrodes placed on the two sides of the reactor. The results showed that an increasing voltage intensity could result in a longer induction time of hydrate formation. The memory effect was fading at an increasing voltage intensity, indicating that the relic components helping the fast formation could be destroyed by the electric field. The following formation under the electric field can be identified by a neat zigzag surface of hydrate generated from the periphery of the reactor. The formation rate of THF hydrate was found to increase with a rising voltage intensity during the hydrate growth period. The results could be of help in the application of hydrate-based techniques in industries where a fast and successive hydrate growth is expected.