Effect of Organic Additives and Crude Oil Fractions on Interfacial Tensions of Alkylbenzene Sulfonates

Abstract

The dynamic interfacial tension (IFT) behavior of two alkylbenzene sulfonates systems have been researched with the addition of organic additives to pure alkane oil phase, n-Nonane. The results showed that IFTs increased with increasing chain length and concentration of carboxylic acids and alcohols due to the deviation of hydrophilic-lipophilic balance. Moreover, the IFT minimum appears in long-chain alkane by adding organic components in n-alkane model oil phase in the light of the matching of the alkane carbon number (ACN) for the minimum IFT (n_min) and equivalent alkane carbon number (EACN) values. In addition, four crude oils were separated into saturates, aromatics, resins, asphaltenes, and acidic fractions. We have found that acidic fractions in crude oil is the dominant factor affecting the stable value of IFT and antagonism has been observed when EACN/n_min value is far from unity by adding acidic fractions in jet fuel. The results presented here suggest that organic additives in oil phase and acidic fractions in crude oil can influence the partition of surfactants between the oil phase and aqueous phase, which resulted in the change of IFTs.

Keywords:

• Acidic fraction
• antagonism
• crude oil
• EACN
• interfacial tension
• organic additive
• synergism

Acknowledgments

The authors thank financial supports from the National Science & Technology Major Project (2011ZX05011-004), National High Technology Research and Development Program (2008AA092801), and the Knowledge Innovation Program of the Chinese Academy of Sciences (KJCX1-YW-21-03) of China.