Dew pressure point and liquid dropout of CH4+alcohol (methanol or ethanol) system with high gas content at high-pressure and high-temperature

Hydrate inhibitor injection through gas-lift flow is used in production fields. The gas + inhibitor system's phase behavior provides essential information regarding monophasic regions and operational safety conditions. Methane is the main constituent of natural gas and is commonly used as a model component to represent gas reservoir fluids. However, pressure variation during a gas-lift injection can cause liquid dropout at valve injection. Therefore, phase behavior knowledge of methane + alcohol mixtures is potentially interesting in the oil and gas industry. In this work, dew pressure and liquid dropout data were experimental measured for methane + methanol (96.60 mol % CH4) and methane + ethanol (96.50 mol % CH4) systems in the temperature domain of 313.15 to 366.65 K and pressure up to 70 MPa. The CPA equation of state was used to correlate dew pressure and liquid dropout data for all systems, presenting a dew pressure absolute relative deviation of 6.89 and 5.22 % for methane + methanol (96.60 mol % CH4) and methane + ethanol (96.50 mol % CH4), respectively.