چكيده به لاتين
Langmuir model is the adsorption modeling that has been used in van der Waals-Platteeuw (vdWP) model in order to consider the forces between gas and solid molecules. In this model three parameter function of kihara potential was utilized. The utilized kihara parameters had a considerable effect on the accuracy of hydrate modeling. Therefore, choosing a suitable method for setting kihara parameters would improve hydrate formation modeling.
Changing parameters of the spherical core, α, in kihara model has no significant effect on the hydrate dissociation pressure. Thus, in this research, in order to achive facilitation in fitting kihara parameters, just two parameters σ and ɛ were considerd. For increasing the accuracy of hydrate modeling, kihara parameters were fitted to pure component hydrate and mixed gas hydrates.
In this research, fugacity-based model was used for hydrate modeling. In this method, accuracy of water fugacity in liquid phaseis very significant: therefore, in current study, CPA Eos presented by Zoghi et al was used.This Eos is highly accurate in calculating liquid fugacity and x. therefore, the mentioned equation of state can appropriately model the behavior of water and plor compounds existiong in the system.
As previously mentioned, it is known from experiment that the size of the hydrate lattice depends on the guest, and therefore it is reasonable to expect that the vapor pressure of the hypothetical empty hydrate lattice will also depend on the guest. As a result, in the next steps, the parameters for the empty hydrate lattice vapor pressures for each guest separately and for each hydrate structure were fit to a subset of the experimental data. In the present study, absolute average deviation from experiment data in pure component hydrate calculation was 2.58% and in calculating gas mixed hyadrate was 8.36%.
