Kinetics of solid hydrate formation by carbon dioxide: Phase field theory of hydrate nucleation and magnetic resonance imaging

Impact of water film thickness on kinetic rate of mixed hydrate formation during injection of CO2 into CH4 hydrate

“…The pressure is kept constant at 83 bars and the initial temperature is uniform and 277.15 K. These conditions have been used in this initial study since these conditions were applied in a number of experiments conducted in ConocoPhillips laboratory in Bartlesville over more than a decade. See for instance Kvamme and coworkers, 19,21 for examples and description of the experimental setup. Comparison with these experimental data will also require inclusion of realistic mineral surfaces, and that is a future goal.…”

Modelling of hydrate formation kinetics: State-of-the-art and future directions

“…This approximation is valid whenever the thickness of the interfacial region is considerably smaller than the critical radius. The diffuse character of the interface can be incorporated in the modelling of the nucleation process with the aid of the so-called phase field theory, as recently shown by Kvamme et al (2004) for the carbon dioxide hydrate. The model, naturally more complex, is based on a balance of the Helmholtz free energy of the system in terms of two parameters which characterise the local state of the matter and vary within the interfacial region: the structural order parameter, which describes the transition between the disordered liquid and ordered crystalline structures, and the conserved field, which may be either density or solute concentration.…”

“…The model, naturally more complex, is based on a balance of the Helmholtz free energy of the system in terms of two parameters which characterise the local state of the matter and vary within the interfacial region: the structural order parameter, which describes the transition between the disordered liquid and ordered crystalline structures, and the conserved field, which may be either density or solute concentration. As discussed by Kvamme et al (2004), accurate predictions of the nucleation rate with this approach require precise input values of the superficial energy and the thickness of the interfacial region, which, according to these authors, could be obtained by dynamic molecular simulations with more realistic interaction parameters. This theory is still at an initial development stage, but the results obtained for typical conditions of CO 2 hydrate formation indicated that the critical radius and the thickness of interfacial region have the same order of magnitude and, hence, the classic nucleation theory could not be applied to this problem.…”

A Review on Research on Replacement of CH4 in Natural Gas Hydrates by Use of CO2

“…PFT is applied to describe complex solidification morphologies, including thermal and solutal dendrites and eutectic/peritectic fronts [42]. The technique of Magnetic Resonance Imaging (MRI) is supposed to be a useful tool to visualize the process of hydrate formation and decomposition [43].…”

“…Kvamme et al [42,43] applied MRI to observe the replacement process by use of liquid CO 2 and developed a corresponding model based on PFT. The model was used for describing the nucleation of hydrate in aqueous solution and the transformation of CH 4 hydrate to CO 2 hydrate.…”