القسم: قسم العلوم الطبيعية
الجهة البحثية: الجامعة اللبنانية الامريكية
عنوان البحث المنشور: Effects of Sea Salts on the Phase Behavior and Synthesis of Methane Hydrates + THF: An Experimental and Theoretical Study
سنة النشر: 2023
ملخص البحث المنشور:
Methane hydrate, also known as methane clathrate or gas hydrate, is a crystalline compound containing methane molecules trapped within a lattice structure formed by water molecules. It is abundant in permafrost, deep lakes, and the ocean floor, attracting significant attention due to its potential as an energy resource and its impact on climate change. Methane hydrate is regarded as an untapped energy reservoir, with projections indicating reserves that contain twice the carbon content of all recognized fossil fuel reserves combined. Nevertheless, the extraction of energy from methane hydrates presents technical and environmental hurdles. Moreover, the extraction process can contribute to global warming by releasing methane, a potent greenhouse gas. The examination underscores the significance of comprehending the scientific principles governing methane hydrates, including their conditions of dissociation. Gas hydrates have been studied since the 30’s, when they posed challenges to gas pipelines. Despite initially being an impediment, they are now acknowledged for their various applications, including carbon dioxide capture, natural gas storage and transportation, air conditioning, water desalination, and gas separation. However, the formation of hydrates necessitates high pressure and low temperature, and the sluggish formation rate obstructs technological progress. Researchers have investigated the use of additives, such as tetrahydrofuran (THF), to modify the conditions of hydrate formation and enhance the formation rate. THF has shown potential in forming mixed hydrates with methane, and studies have examined its concentration in water solutions. The influence of salinity, particularly salts like NaCl and MgCl2 found in seawater, on the equilibrium data of methane hydrate has also been explored. Salts impact the stability and phase behavior of hydrates, thus affecting large-scale hydrate-based technology projects. Limited models exist for assessing the phase stability of methane hydrate in the presence of salts, with various thermodynamic models developed based on experimental data. The present study concentrates on investigating the impact of NaCl and MgCl2, primary salts in water, on the equilibrium data of THF-methane hydrate. Experimental data was obtained using the isochoric pressure search method, revealing that THF can effectively address the issues related to methane hydrate formation in saline water. The inhibitory effect of salts on THF solutions was more prominent at higher concentrations and pressures. In order to forecast equilibrium conditions, a thermodynamic model based on the Chen and Guo theory was formulated. The model incorporated the Soave-Redlich-Kwong equation of state for gas properties and the Extended UNIQUAC model for assessing activity coefficients of THF and water in the electrolyte solution. The model demonstrated satisfactory agreement with experimental data, with an average absolute relative deviation of 6.05%. Overall, the study contributes to the comprehension of the intricate interplay between salts, additives, and methane hydrate formation conditions, thereby providing valuable insights for the advancement of hydrate-based technologies.
رابط البحث المنشور:
https://pubs.acs.org/doi/full/10.1021/acs.iecr.3c00351