原油/碱水相互作用热力学

从化学平衡、相平衡原理和Gouy-Chapman扩散双电层理论建立了原油/碱水体系表面活性剂的吸附等温式和界面张力及界面电势方程。测定了大港油田羊三木原油与碱水的界面张力和Zeta电位。结果表明,原油/碱水界面表面活性剂的吸附量虽随水相中NaOH和NaCl浓度而变化,但本质上取决于水相中就地生成的表面活性剂的吸附自由能和表面活性阴离子与其反离子的活度积。碱水中加入NaCl可在低碱浓度时大大促进界面吸附但使界面电势显著下降。理论预测结果与实验结果较为符合。

The Thermodynamics of Crude Oil/Alkaline Solution Interaction

An adsorption isotherm and the interfacial tension and interfacial potential equations at the interface of crude Oil/alkaline solution are established based on chemical and phase equilibrium principles and Gouychapman theory of the diffuse double layer. The interfacial tension and Zeta potential between Dagang Oil Field Yangsanmu crude oil and alkaline solution are measured. The results show that the surfactant adsorption varies with NaOH and NaC1 concentrations in aqueous solution and essentially depends on the adsorption molar free energy of surfactantin situ produced and the activity product of surface active anion and its counterion. By adding NaC1 to the alkaline solution, the adsorption at lower NaOH concetration is promoted greatly but the interracial potential is decreased evidently. Fair agreements are obtained between theoretically predicted and experimentally measured results.