混合型烷醇酰胺组成对油/水动态界面张力的影响

摘要

为了探究混合型烷醇酰胺复杂组成对油/水界面张力的作用机制，采用GC-MS联用分析了混合型烷醇酰胺（GYD）的组成，并用自制的不同烷基链长醇酰胺（简记为 CnDEA，n=8，10，12，14，16）在大庆原油条件下研究了GYD组成对油/水界面张力的影响规律。结果表明，降低油/水界面张力能力强弱为C14DEA>C12DEA≈GYD>C16DEA>C10DEA>C8DEA，C14DEA、C12DEA和GYD在一定浓度范围内能降低油/水界面张力至10−3mN/m数量级；CnDEA之间复配体系的界面活性取决于体系中各单分子结构烷醇酰胺相对含量，其中C14DEA/C12DEA相对含量是影响体系油/水界面活性的关键因素，当C14DEA/C12DEA复配比大于1时，体系达到超低界面张力浓度窗口更宽，界面动态特性更好；适量助剂（月桂酸和二乙醇胺）的加入对体系降低界面张力有一定的协同效应；GYD/C14DEA复配体系随C14DEA浓度增加，体系界面活性明显改善。%In order to investigate the mechanism of the composition of mixed alkanolamide on oil/water interfacial tensions(IFT),the compositions of the mixed alkanolamide(GYD) were analyzed by GC-MS method and the different alkyl-carbon chain length amide(abbreviated as CnDEA,n=8, 10,12,14,16) were synthesized to study the effects of compositions of GYD on the oil/water IFT under Daqing conditions. The results showed that the ability of lowering oil/water IFT was in the following order:C14DEA>C12DEA≈GYD>C16DEA>C10DEA>C8DEA, and C14DEA,C12DEA and GYD can reduce the oil/water IFT to 10-3mN/m within a certain range of concentrations. The interface activity of complex system between CnDEA depended on the relative content of each single molecular structure in alkanolamide and the relative content of C14DEA/C12DEA was a key factor on interfacial activity of the complex system. When complex ratio of C14DEA/C12DEA>1,the wider concentration window of the system reached ultra-low IFT,with the better interface dynamic characteristics. The addition of proper amount ofco-surfactant(lauric acid and diethanolamine)could reduce the IFT to a certain extent. The interfacial activity of C14DEA/GYD was significantly improved when the concentration of C14DEA increased.