Vapour–liquid interfacial tension of water and hydrocarbon mixture at high pressure and high temperature conditions

Interfacial tension values of two liquid–liquid–vapour systems, a ternary water–decane–methane and a quaternary water–cyclohexane–decane–methane, were measured using a pendant drop technique at 150 °C and high pressures up to 28.1 MPa. The tested ternary mixture showed a maximum liquid–liquid interfacial tension by increasing pressure whereas it only slightly increased liquid–liquid interfacial tension in the quaternary system. The predicted interfacial tension values by some models are compared and the application of liquid–liquid interfacial tension models for predicting the liquid–vapour interfacial tension at high pressure conditions is discussed.