## 2 Literature Overview
[15] experimentally observed hydrate film formation at the interface between water and CO\({}_{2}\). Their paper has also presented a theoretical analysis of the two-dimensional formation of a hydrate film, which is uniform in thickness and has a semicircular front. This model assumes that, firstly, the hydrate will only form at the film front where the temperature remains constant at the corresponding triple point (water/guest fluid/hydrate) value, and secondly, the rate of heat released by hydrate formation will be equal to the rate of heat removal by means of conduction through the film surfaces. Their study estimated the hydrate film thickness based on the lateral growth rate alongside the interface (still not fully reliable). In 2001, [PERSON] [16] extended their 1997 model by incorporating both heat and mass transfer involved in hydrate film formation and dissociation. Their steady-state (more accurately, quasi steady-state) one dimensional simulation of mass and heat transfer included the exothermic effect of hydrate formation and its inverse in the case of hydrate melting. They have also investigated the transient heat and mass transfer processes occurring during hydrate film formation, with their conclusion being that some mechanism other than heat transfer dominates the hydrate film formation, and heat transfer can be safely neglected when dealing with hydrate film thinner than 0.3 \(\upmu\)m. In 2001, [PERSON] et al. [17] applied a moving boundary model of heat transfer for the film hydrate formation to estimate the film thickness. They compared the obtained value with their own experimental result from a water/methane hydrate film and concluded that heat conduction was the dominant driving force. However, they denied the validity of their own conductive heat transfer model and proposed a model combining interfacial attachment kinetics via the Arrhenius expression and convective heat transfer instead. In 2006, [PERSON] and [PERSON] [18] carried out a numerical study of heat transfer across the water/hydrate-former phase boundaries. They applied two analytic models for methane and CO\({}_{2}\) hydrate film formation, derived by assuming two different film front geometries. Both models presumed a uniform film with constant thickness, with the thermodynamic triple point temperature set as the film front temperature. Their model assumed two-dimensional conductive heat transfer from the film front to hydrate formation sites and was able to predict the film formation rate if provided the film thickness. They estimated that a CO\({}_{2}\) hydrate film will be much thinner than a methane hydrate one at the same sub-cooling range. In addition, both CO\({}_{2}\) and methane films have exhibited a tendency to become thinner as the sub-cooling rate increased. There is a need for a realistic kinetic model able to describe how the coupled processes of mass and heat transport will impact the formation and dissociation of hydrate, while accounting for all independent thermodynamic variables. The bulk of available hydrate film formation studies fall into the hydrodynamic spatial range (micrometer and up), i.e., far beyond the scale of phase transitions itself. Phase transitions are nano-scale phenomena occurring across a thin interface only several nanometers in thickness. Many of the studies are based solely on estimates of film front propagation in terms of V\({}_{\text{f}}\) and hydrate film thickness, while other papers also theoretically model the axial growth of hydrate films [19]. An obvious limitation of all models listed in Table 1 is that they account for heat transport only and ignore mass transport. This is an interesting and unusual assumption since heat transport through aqueous systems will be faster by a factor of two or three than mass transport [21,22].