表面活性剂疏水链长对高温下泡沫稳定性的影响

选用不同疏水链长的α-烯烃磺酸盐(AOS)形成泡沫, 分别用泡沫衰减法和泡沫岩芯封堵法测定不同温度下的泡沫稳定性, 并采用动态表面张力、界面流变、分子模拟等方法研究了表面活性剂在气/液界面的吸附行为和界面吸附层的性质, 分析了高温下泡沫的稳定机制. 实验结果表明, 在高温下, 极性头的“锚定作用”减弱, 表面活性剂疏水链难以在气液界面保持以直立状态吸附, 疏水链碳数大于20的表面活性剂分子难以分立吸附, 其疏水链相互交叉缠绕, 增强了泡沫膜的强度, 减缓了气体通过液膜的扩散, 形成的泡沫在高温下具有较好的稳定性.

Effect of Hydrophobic Chain Length of Surfactants on Foam Stability at High Temperature

The foam stability stabilized by α-olefin sulfonate(AOS) with different hydrophobic chain lengths at temperature below 100 ℃ and above 200 ℃ was investigated by foam column decay method and foam block in sand-pack pipe, respectively. The results show that the foam stability increases with the increase of hydrophobic chain length. Dynamic surface tension, interfacial rheometer and molecular simulation were used to study the foam stablity mechanism at a high temperature. From the experiment results, we can see that when the hydrophobic chain length was longer than 20 carbon atoms, the hydration of surfacrtant head could not support the hydrophobic chain to keep vertical or unattached, and the hydrophobic chains cross-link with each other, which increase the strength of the foam film, decrease the diffusion of the gas through the film and make the foam stable at a high temperature.