Characterization of CO2 hydrate formation and dissociation kinetics in a flow loop

The objective of this work is to investigate CO2 hydrate formation and dissociation kinetics in the aim of designing a circulation loop with heat exchangers for secondary refrigeration applications. The formation of gas hydrates is a crystallization process which requires a supersaturated environment. The majority of the experimental formation data from the literature were obtained in semi-batch stirred tank. It was found that the hydrate growth for CO2 hydrate formation was approximately 1.8 x 10(-3) %hydrate.s(-1) for a stirring velocity about 450 rpm. The study reveals that for our system, an isothermal circulation loop, the kinetic varied from 4.3 x 10(-3) to 8.3 x 10(-3) %hydrate s(-1), respectively for two protocols with water and water-additives selected for their dispersive and promoter properties. The first results of CO2 hydrate dissociation kinetics with or without additives were equivalent with various systems (semi-batch stirred tank reactor or loop) with approximately 5 x 10(-3) %hydrate s(-1). (C) 2010 Elsevier Ltd and IIR. All rights reserved.