壬基酚聚氧乙烯醚溶液与原油组分界面张力的研究

Study of interfacial tension between nonylphenol polyoxyethylene ether solutions and components of crude oil

制备了不同氧乙烯基团数的系列壬基酚聚氧乙烯醚二聚体（GNP）和系列壬基酚聚氧乙烯醚单体（NP）两组表面活性剂。用旋滴法测定了GNP和NP水溶液与原油各组分在不同温度（25℃～50℃）和不同pH（5～9）下的界面张力。实验结果表明,在25℃,pH=7时,GNP和NP降低油水界面张力的大小顺序相同。尽管两组表面活性剂的HLB值近似相等,但GNP系列水溶液与原油各组分界面张力的吸附平衡浓度随着氧乙烯基团数的增大而降低,而NP系列水溶液与原油各组分界面张力的吸附平衡浓度随着氧乙烯基团数的增大逐渐升高。随着温度的升高,油水界面张力呈线性降低。随着pH的增大,油水界面张力减小。

Two kinds of nonionic surfactant including a series of gemini nonylphenol polyoxyethylene ether（GNP） with different number of ethylene oxide group and a series of monomer nonionic surfactant of nonylphenol polyoxyethylene ether（NP） with different number of ethylene oxide group were prepared in laboratory,and the interfacial tension between the aqueous solutions of the above-mentioned surfactants and various components of crude oil was measured by using a spinning drop tensiometer under the temperature from 25 ℃ to 50 ℃ and the pH from 5 to 9.The experimental results showed that under the condition of temperature 25 ℃ and pH=7,the capacity of both the GNP series surfactants and the NP series surfactants for reducing interfacial tension shows the same order against the varieties of the crude oil component.For the GNP and the NP series surfactants with same number of ethylene oxide groups,their HLB values are approximately the same,but the interfacial adsorption equilibrium concentration of interfacial tension between the aqueous solution of GNP surfactants and components of crude oil,will decrease with increase of number of ethylene oxide groups in the GNP molecule,while that of the corresponding NP surfactants will increase with increase of number of ethylene oxide groups in the NP molecule.The interfacial tension shows a linear decrease with the increasing temperature and a decrease with the increasing pH.