FUEL 263 |
| The process and kinetics of CH4 replacement in CH4 hydrate formed in sodium dodecyl sulfate(SDS) system and pure water system with pressurized CO2 were observed with self-designed device at temperatures of 271.2K, 273.2K and 276.0K and at constant pressure 2.8 MPa, 3.25 MPa. The effect of operating temperature and pressure on replacement process were investigated. Experimental data show that the decomposition rate is faster in the first 50 hours than later time and the water phase in hydrate phase might have an important effect on the replacement process, And the decomposition rate of CH4 hydrate above ice point is faster than that below ice point. The Surface-Active Agents SDS may be useful in enhanced CH4 recovery from CH4 hydrate by improving the mass transfer during the replacement process. Based on the rate data, a kinetic model was developed for CH4 hydrate decomposition and CO2 hydrate formation. In the process of CH4-CO2 replacement in the hydrate, the calculated activation energies were determined to be 28.81kJ/mol for CH4 hydrate decomposition and 68.40 kJ/mol for CO2 hydrate formation, respectively. The analysis of the experimental data and activation energies indicate that CH4 hydrate decomposition was probably dominated by re-arrangement of water molecules in the hydrate and the CO2 hydrate formation was probably dominated by diffusion in the hydrate phase. |
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Chemistry of Solid, Liquid, and Gaseous Fuels
8:15 AM-12:15 PM, Thursday, August 23, 2007 Boston Park Plaza -- Arlington Rm, Oral
Division of Fuel Chemistry |