Akademik Veri Yönetim Sistemi
JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING, cilt.34, ss.1148-1158, 2016 (SCI-Expanded)
In this research, first, hydrate with high saturation in porous media (sand sediments) was formed in fully filled high pressure cell by using a mixture of the following gases at 4 degrees C: methane (CH4), propane (C3H8) and carbon dioxide (CO2). The feed mole percent of the gases used was selected as follows: CH4 (95%), C3H8 (3%), CO2 (2%). This selection was made in order to form natural gas hydrate of thermogenic origin (sII type hydrate). Thereafter, CO2 injection into the high saturation hydrate media was performed in order to elucidate possible CH4 recovery. However, it was observed that injected CO2 was not able to flow through sediments, because of the impermeable barrier created by hydrate, and because of the fact that no free space was left in the cell as it was completely filled with porous media resulting in mass transfer limitations. Therefore, it was proposed that methane recovery occurred only near the hydrate interface. Taking into consideration obtained results, in the next step we decreased the volume of the sand, to create a space for the free gas evolution above the high saturation hydrate, and further completely replaced free gas composition by CO2. We observed that this time not only CH4, but C3H8 was recovered from hydrate phase implying further reconsideration of the injection of CO2 into sII hydrate. The results of this study imply that it is possible to recover hydrocarbon gases from hydrates more stable than CO2 hydrate by creating a CO2 rich environment. (C) 2016 Elsevier B.V. All rights reserved.