Mechanical Engineering

Burning of spilled oil on the ocean surface or in-situ combustion is one of the techniques used in oil spill clean up operations. With the passage of time, as the crude oil stays on the ocean surface, evaporation of the lighter components of the crude oil and mixing of water with the oil due to wind and ocean turbulence create emulsions that are more dense and more viscous than oil.This makes the ignition of the oil harder to achieve.Prior studies have shown that emulsions containing more than a certain fraction of water do not burn,and thus present a difficulty in applying the in-situ combustion technique. Many normally incombustible materials can be ignited when subjected to a certain minimum heat flux,and sustained fire and flame spread can be achieved on these materials.In the present work,this principle is applied to the emulsion combustion problem so that,if successful,the window of opportunity for in-situ combustion of oil spills can be widened.It is proposed that there exists a threshold heat flux level for most of the emulsions such that,when emulsion is exposed to a heat flux equal to or greater than the threshold heat flux,sustained fire and flame spread can be achieved.