Stability and cell distortion of sI clathrate hydrates of methane and carbon dioxide: A 2D lattice-gas model study

LONGONE P.; MARTIN A.; RAMIREZ PASTOR A. J.

FLUID PHASE EQUILIBRIA

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 402 p. 30 - 37

0378-3812

methods.Thermodynamic models of the stability of clathrate hydrates are important for different applicationssuch as the storage, separation and transport of gases. The development of improved models relies on abetter understanding of the relationships between the macroscopic stability of clathrate hydrates andtheir structure. In particular, lattice distortion is an important parameter that is difficult to incorporate inthermodynamic models of clathrate hydrates. In this work, a 2D lattice-gas model has been applied forthefirst time for the study of the stability and lattice distortion of sI clathrate hydrates of methane andcarbon dioxide. Results show a direct relationship between cell distortion and cell occupancy: theminimum distortion is found at cell occupancies near 1. In addition, in the case of carbon dioxidehydrates, a complex behavior is observed due to the partial occupancy of small cavities by guest CO2molecules. By relating lattice distortion with hydrate stability, phase diagrams can be calculated whichare in qualitative agreement with experimental diagrams and with results of more complex simulationmethods.