Unveiling the CO2 Hydrate Phase Diagram from Computer Simulation: Locating the Hydrate-Liquid-Vapor Coexistence and its Upper Quadruple Point

Abstract

Carbon dioxide (CO2) hydrates hold promising applications in capturing and separating CO2 for climate change mitigation. Understanding their behavior at the molecular level is therefore essential, and computer simulations have become powerful tools for exploring their formation and stability, providing valuable insights into their underlying mechanisms. In this work, we perform molecular dynamics simulations to compute the three-phase coexistence line involving the stability region where CO2 is in the vapor phase: CO2 hydrate - liquid water - vapor. This computation was previously inaccessible using the traditional three-phase direct coexistence technique. To achieve this, we employ a novel solubility-based method, which allows us to accurately evaluate the coexistence line. Finally, we have determined the upper quadruple point (Q2) where the four phases, namely hydrate, liquid water, liquid CO2, and vapor, coexist. Our pioneering result for the Q2 value shows remarkable agreement with experimental observations, validating the accuracy of our findings and representing a significant milestone in the field of gas hydrate research.

References in corpus (14)

• Stability, Adsorption and Diffusion of CH4, CO2 and H2 in Clathrate Hydrates
• Solubility of carbon dioxide in water: some useful results for hydrate nucleation
• Three phase equilibria of the methane hydrate in NaCl solutions: A simulation study
• Molecular simulation of methane hydrate growth confined into a silica pore
• Three-phase equilibria of hydrates from computer simulation. I. Finite-size effects in the methane hydrate
• Three-phase equilibria of hydrates from computer simulation. II. Finite-size effects in the carbon dioxide hydrate
• Homogeneous nucleation rate of carbon dioxide hydrate formation under experimental condition from Seeding simulations
• Three-phase equilibria of hydrates from computer simulation. III. Effect of dispersive interactions in the methane and carbon dioxide hydrates
• Effect of pressure on the carbon dioxide hydrate-water interfacial free energy along its dissociation line
• Dissociation line and driving force for nucleation of the nitrogen hydrate from computer simulation
• Three-phase equilibria of CO${}_2$ hydrate from computer simulation in presence of NaCl
• Dissociation line and driving force for nucleation of the nitrogen hydrate from computer simulation. II. Effect of multiple occupancy
• Prediction of the univariant two-phase coexistence line of the tetrahydrofuran hydrate from computer simulation
• Dissociation Line and Driving Force for Nucleation of the Multiple Occupied Hydrogen Hydrate from Computer Simulation