INVESTIGATION OF THE GAS HYDRATE EQUILIBRIUM IN CH4 - CO2 - H2O MIXTURE IN THE PRESENCE OF THF - SDS PROMOTERS

Abstract

The present study deals with the investigation of a unique technology – gas hydrate crystallisation. This technology is proposed as an alternative approach to natural gas purification from acid gases, particularly from CO2. To implement the gas hydrate crystallisation technology at CO2 recovery from natural gas we experimentally determined the gas hydrate dissociation pressures of the CH4 (81.70 mol.%) - CO2 (18.30 mol.%) gas mixture in THF (3.80 wt.%) aqueous solution with and without SDS (0.30 wt.%) in the temperature range of 283.71–288.00 К. It was found that the gas hydrate dissociation pressures of the mixture under consideration with and without SDS (0.30 wt.%) were in the range of 0.7570–1.9328 MPa at these conditions. The thermodynamically simulated gas hydrate dissociation pressures of the considered mixture without THF (3.80 wt.%) were 6.0828–10.179 MPa at the same temperature range. An average pressure decrease of 6.79 times was observed for the considered temperature range at the addition of THF (3.80 wt.%). According to the experimental results, the enthalpies of the gas hydrate dissociation of the CH4 (81.70 mol.%) - CO2 (18.30 mol.%) gas mixture in THF (3.80 wt.%) aqueous solution with and without SDS (0.30 wt.%) were calculated and were in the ranges of 20.85–33.64 and 22.04–39.81 kJ/mol, respectively.