Comparative Laboratory-Scale Testing of Dispersant Effectiveness of 23 Crude Oils Using Four Different Testing Protocols*

Abstract

A controlled laboratory study was conducted to measure the dispersion effectiveness of Corexit 9500 on 23 different crude oils. This study was a part of a larger project initiated by the Bureau of Safety and Environmental Enforcement (BSEE) testing 20 oils to compare the predictive value of laboratory dispersant effectiveness tests with their larger scale test conducted at Ohmsett, BSEE's national oil spill response test facility located in Leonardo, NJ. The test used in this study was the Baffled Flask Test (BFT), which is planned for adoption as EPA's official testing protocol for listing commercial dispersant products on the National Contingency Plan Product Schedule, replacing the current Swirling Flask Test (SFT) [1]. In addition, the results of 3 additional oils, the 2 used in the SFT and BFT as currently written plus another reference oil, are presented. The temperature used for the tests was 15˚C, to match the temperature used at Ohmsett. The dispersion effectiveness ranged from 3.4% to 93%. The BFT is a laboratory test with results that are inversely correlated with oil viscosity and therefore has predictive value in the decision to use a dispersant in the event of a spill.

Oxygen Isotopes (δ18O) Trace Photochemical Hydrocarbon Oxidation at the Sea Surface

“…To test how diffusion could impact the measured δ 18 O O2 fractionation of DWH oil (a light, sweet crude with low viscosity and density; Holder et al, 2015), we also measured δ 18 O O2 fractionation of Alaskan North Slope crude oil (a medium crude with higher viscosity and density; Holder et al, 2015). This is because our experimental system measures the kinetic isotope fractionation imparted to the remaining pool of dissolved O 2 after reaction with sunlight, rather than the direct measurement of oxygen photochemically incorporated into oil.…”

Sugar based amphiphiles: easily accessible and efficient crude oil spill thickening agents

“…Crude oils are generally classified as very light, light, medium and heavy based on API (American Petroleum Institute) values. According to Holder, 34 SLCO, ALCO, and PBCO are in the category of very light, light and medium respectively, whereas, according to the American Petroleum Institute, 35 PBCO belongs to the heavy category. Additionally, ALCO and PBCO are sour (high sulfur content) while SLCO is sweet (low sulfur content); PBCO is most naphthenic (least paraffinic and most aromatic/naphthenic content) while SLCO is most paraffinic (most paraffinic content) (see Table S2 in the ESI†).…”

“…Additionally, ALCO and PBCO are sour (high sulfur content) while SLCO is sweet (low sulfur content); PBCO is most naphthenic (least paraffinic and most aromatic/naphthenic content) while SLCO is most paraffinic (most paraffinic content) (see Table S2 in the ESI†). 22–26,34,35 …”

A Proposed New Laboratory Protocol for Dispersant Effectiveness Testing Adapted for Subsea Dispersant Injection

“…The turbulence regime in a few of these laboratory test systems have been characterised and related to sea turbulence or sea states, for example, the Swirling-and Baffled flask test [8] [9]. Studies have tried to correlate results from different laboratory methods including correlating them towards effectiveness from basin studies [9]- [14]. Since the energy levels, dispersant application methods (premixed or applied on oil) and sampling regimes (static/dynamic) are different, it is often difficult to obtain high correlations between the effectiveness measured with the different laboratory methods.…”