Abstract

Natural gas hydrates are solid, non-stoichiometric compounds of small gas molecules and water. They form when methane from organic decomposition comes together with water at low temperatures and high pressures to trap individual gas molecules within atomic scale crystalline cages of water ice. Natural gas hydrates have the potential to meet global energy needs for the foreseeable future. The total amount of methane gas which is entrapped in hydrates is more than twice the known fossil fuel. Intensified research worldwide is attempting to find a practical, safe, and environmentally acceptable approach to produce for the production of methane gas.

To test the concept of methane production via in-situ heating [1] and characterize other alternative production schemes, a reactor vessel has been designed, manufactured and built to test the concept model. Preliminary tests show that the reactor satisfies the conditions for methane hydrate and carbon dioxide formation. The thermocouples in the reactor detected the temperature change associated with methane hydrate formation. Hydrate was formed at 2.2 oC and about 600 psi with a concentration of 99.97% pure methane gas and DI water. Based on the mass balance calculation, 4.45% of hydrate was formed in the reactor at these conditions. Measurement and simulation suggest that hydrate was initially formed at the top section of the reactor followed by the hydrate formation within the sediment. During the dissociation via depressurization, a cooling effect from the endothermic reaction was observed. Also within a narrow range of temperature and pressure, a transition regime was observed during the hydrate dissociation test in which a large increase of gas production was recorded. It is first time reported as an experiment result, since Tsypkin's [2] predict the phenomenon in his calculation.