In Situ Burn Testing of Weathered and Emulsified Crude Oils

Abstract

This paper investigates the ignitability and effectiveness of burning crude oil spills at sea with respect to the type of oil, weathering time, and seawater emulsion content. In the event of an oil or fuel spill at sea, in situ burning can be a practical method of removing the oil and preventing it from reaching vulnerable coastlines. However, the specific chemistry of the oil and its resulting behavior dictates how well this method works. In order to understand this behavior, Santa Barbara Channel crude oils were tested and burned in combinations of fresh, weathered, and seawater-emulsified at discrete ratios. A cone calorimeter was used to monitor time to ignition, mass loss, heat release rate, and smoke production for laboratory-scale burn tests. Weathering generally increased ignition time, but also changed the miscibility with water; this changed both heat released and burn efficiency. Emulsions with seawater fractions below approximately 20 % were found to improve the heat release rate and burn efficiency compared to oil-only burns; suggesting that some water emulsification can benefit oil burning. The results indicate that a targeted approach to the type of oil and degree of emulsification can expand the window of opportunity for in situ oil burns.