Crystallization Mechanisms and Rates of Cyclopentane Hydrates Formation in Brine

Clathrate hydrates most often grow at the interface between liquid water and another fluid phase (hydrocarbon) acting as a provider for the hydrate guest molecules, and some transfer through this shell is required for the hydrate growth to proceed, thus self‐limiting the reaction rate. An optical microscope and a horizontal reaction cell are utilized to capture the shell growth phenomenology and to estimate the hydrate layer growth rates from sequential pictures. Cyclopentane (CP) is chosen as the hydrate‐forming molecule to obtain hydrates at low pressure. Experimental hydrate layer growth rates are provided for the CP+brine system, using various combinations of salts and degrees of subcooling. Cyclopentane hydrates are considered to be a candidate for hydrate‐based desalination, so the mechanism of cyclopentane hydrate crystallization in pure water and in brine is crucial. Various salts at different concentrations and under three driving forces (subcooling) were considered to explore the phenomenology of hydrate formation by microscopy. The hydrate growth speeds were also determined.