Experimental and Modeling Study on Phase Equilibria of the Methane plus Ethane Gas Mixture

The study on phase behavior and physical properties ofnaturalgas has great significance for its safe exploitation and transportation.Consequently, we studied the phase equilibria of the methane + ethanegas mixture in this work. The hydrate formation conditions (gas-liquid-hydrateequilibria) of the methane + ethane gas mixture were measured firstin pure water. Then the gas solubility (gas-liquid equilibria)of the gas mixture in water was measured with/without hydrate. Finally,the bubble point and dew point (vapor-liquid equilibria) andthe hydrate formation conditions and gas solubility in the presenceof hydrate were calculated. The results show that before hydrate formation,the gas solubility in water decreases with temperature and increaseswith pressure. However, after hydrate formation, the gas solubilityincreases with temperature and decreases with pressure. The calculationmodels in this work have satisfactory accuracy for phase equilibriaprediction of the methane + ethane gas mixture. Therefore, it hasa good guiding significance for describing the phase behavior of naturalgas.