Comparison of Laboratory Protocols for Evaluating Oil Emulsification

Oil spilled onto fresh and marine waters can quickly form water-in-oil emulsions that have very different physical properties from the original oil, sometimes becoming almost solid mousses that resist many response options. The factors that affect this process have been studied for decades, but still resist a clear understanding. The intrinsic composition of the spilled oil, its degree of evaporative weathering, light intensity and turbulence are all known to be important in controlling emulsification, but the individual importance of these factors, and their interactions in different oils, remains obscure. Oil spill models require consistent quantitative measurements that are representative of field conditions to develop reliable algorithms to predict emulsification and its influence on oil fate and exposure. Understanding the mechanisms involved would allow better predictive models to be developed, which would be applicable to a range of oils with varying properties and compositions, as well as to different environmental conditions. This project seeks to identify lab-based protocols that represent or result in the same outcomes as field conditions to the best extent possible so that the properties measured from emulsions made with these protocols can be used to improve the accuracy of numerical modeling. To this end, a mesoscale testing protocol has been developed that aims to represent more closely the conditions that oil slicks encounter at sea. Results will then be compared with other emulsification protocols and used for model development. Here we report the experimental approach of this on-going project.