Chemical Engineering Science, Vol.64, No.9, 2020-2026, 2009
DSC measurements and modelling of the kinetics of methane hydrate formation in water-in-oil emulsion
The kinetics of formation of clathrate hydrates of methane was investigated in a water-in-oil emulsion using high-pressure differential scanning calorimetry in the range 10-40 MPa, at various temperatures. At high driving force, the heat peak related to the formation of hydrates has a regular and symmetric shape, and its height and width depend on the gas pressure and sub cooling degree. At near equilibrium conditions, hydrate formation is delayed by more than I h, but is still clearly observable. A model based on crystal growth theory, coupled with a normal distribution of induction times to take into account the germination in a population of micro-sized droplets, is proposed to represent the hydrate formation rate versus time in the particular case of water-in-oil emulsions. It uses four parameters which appear strongly correlated to the experimental conditions: the growth rate constant, the over saturation of gas in the water phase, the average and standard deviation of the induction time distribution. (C) 2009 Elsevier Ltd. All rights reserved.
Keywords:Gas hydrates;Crystallization;Kinetics;Emulsion;Differential calorimetry;Mathematical modelling