Effect of subcooling and amount of hydrate former on formation of cyclopentane hydrates in brine

As a concept for a new water desalination technology, the use of gas hydrates is under development. In support of this work, experiments have been conducted to observe the behavior of cyclopentane hydrates and to provide data on thermodynamics, kinetics, the effective hydrate number and the purity of the water recovered from the hydrates. The cyclopentane hydrate formation experiments are performed at subcooling temperatures of 5.6 K and 3.6 K at atmospheric pressure. The brine used is 3 wt.% NaCl. The results show that the kinetics of hydrate formation at a subcooling of 3.6 K is significantly slower than the kinetics for a subcooling of 5.6 K. The effective hydrate number seems to be a function of the subcooling temperature, with 3.6 K subcooling giving a number close to the theoretical value. The quality of the desalinated water is strongly dependent on the experimental procedure and the general observation is that subcooling at 5.6 K provides better purification of the water.

Research highlights
► Effect of cyclopentane concentration and subcooling on hydrate formation.
► 5.6 K subcooling gives faster hydrate formation.
► Higher purity of the recovered water and larger hydrate amount at 3.6 K subcooling.
► Effective hydrate numbers are function of subcooling.
► Cyclopentane concentration influences hydrate formation in a minor degree.