Effect of porous activated carbon particles soaked in cyclopentane on CP-hydrate formation in synthetic produced water

Hydrate-based desalination (HBD) could be an interesting alternative to more conventional processes for desalinating high-salinity waters such as those produced during oil & gas extraction. The present study investigates the hydrate formation stage of a recently patented HBD process, in which porous activated carbon particles (PACP) are used as guest (here cyclopentane (CP)) reservoirs and carriers for hydrate formation. The effects of the CP content (0.5-1 g of CP per gram of PACP), of the PACP particle size (400 and 700 mu m), the stirring rate (0-360 rpm), and the salinity of the synthetic produced water (3.5-16 wt% NaCl) on hydrate formation were investigated in batch reactor experiments. The results showed that the CP-soaked PACP drastically enhanced both the hydrate formation kinetics and the water-to-hydrate conversion, even in the case with the highest water salinity (16 wt% NaCl). The best compromise (high kinetics and conversion) was obtained with the largest particle diameter (700 mu m) loaded with 0.8 g of CP per gram of PACP. Stirring increases the initial formation kinetics but slightly reduces the final water-to-hydrate conversion, determined at the end of a 78h-experiment. This study demonstrates that using porous particles soaked in cyclopentane is a promising option for boosting hydrate formation in an HBD process for desalination of high-salinity waters.