• SARA NORIEGA OREIRO
3. semester, Kemiteknik, Kandidat (Kandidatuddannelse)
Natural gas hydrates are solid crystalline compounds containing hydrocarbons (mainly methane) presented in marine and permafrost environments. They are considered as a possible future energy resource, providing a feasible transition to a future low-emission energy system. CO2 injection in methane hydrates is a promising method that would allow both the production of energy and the reduction of global warming.
This project reviews the information available in the literature about the research advances at laboratory scale on the methane replacement by CO2, including its injection in gaseous, liquid and emulsion form, the injection of a mixture of CO2 and N2 without being subjected to purification and its combination with depressurization, technique that promotes the exchange and so far provides the highest replacement efficiencies and reaction rates.
Molecular quantum chemical simulation was performed using hybrid and long-range corrected density functional calculations in the two type of cages of sI hydrates. CH4 and CO2 were analyzed as the guest molecules. The interaction, cohesive and deformation energies between water framework and guest molecule were calculated for the study of the stability of the different structures, as well as the enthalpies, Gibbs free energies and changes in the lattice diameters when encapsulation. It has been shown that encapsulation of both guest molecules leads to the stabilization of the cages, and a higher deformation energy for the CO2 encapsulation in 512 cage shows the preference of CH4 molecules in the small cage.
SprogEngelsk
Udgivelsesdato2018
Antal sider72
ID: 317660286