Experimental simulation of methane hydrate extraction under high pressure conditions: Fid-Bau Portal

Experimental simulation of methane hydrate extraction under high pressure conditions

Aciudo, J.R. / Park, J. / Lee, J. / Kim, H. / Nagel, M. / Rauh, C. / Wierschem, A. / Delgado, A.

Methane hydrate (MH) is a clathrate solid consisting of methane molecules enclosed in frozen water which is usually found in deep ocean floor at low temperature and high pressure. MH is currently considered as one of the most important future source of hydrocarbon fuel, being a more environmentally clean alternative to other fossil fuels. The low thermodynamic stability of MH, however, makes the exploitation of MH oceanic deposits a potential geohazard. Latest research reveals its possible implication for the formation of tsunamis and continental slope failures. Even though MH has been studied a lot over the last years, a lack of a rigorous study of transport phenomena involved on the physic-chemical and microbiological process taking place in natural ocean deposits is found. This is, however, of vital importance to ensure a safe and ecological extraction of MH. To this end, we have installed at the FAU Busan campus (South Korea) a high pressure vessel which mimics the submarine conditions of MH on deep oceanic deposits. The vessel allows maximum pressures up to 150 bars, minimum temperatures of 3 to 4 °C, and the seawater volumes of 475 liters. The design of this simulator includes 8 sapphire windows that ensure best optical accessibility and, thus, the use of non-invasive optical methods as Particle Image Velocimetry (PIV) or Digital Liquid Crystal Thermography among others. We experimentally study how fluctuations in the environment, as for instance caused by changes in pressure, water temperature, flow velocity, sediment bed properties, salinity, or pH, affect the stability of MH inside the high pressure vessel. Besides, microbiological experiments with methanogenic microorganisms from waste water treatment plants have been carried out in order to check their adaptability to high pressure conditions. They demonstrated high level of survival under these special conditions.