Effect of Weathering on Piloted Ignition and Flash Point of a Slick of Oil.
Effect of Weathering on Piloted Ignition and Flash Point
of a Slick of Oil.
Wu, N.; Mosman, T.; Olenick, S. M.; Torero, J. L.
Arctic and Marine Oilspill Program (AMOP) Technical
Seminar, 21st. Environment Canada. Volume 2.
Proceedings. June 10-12, 1998, Alberta, Canada,
Environment Canada, Ottawa, Ontario, 633-649 pp, 1998.
Sponsor:National Institute of Standards and Technology,
oil spills; cleaning; weather effects; pilot ignition;
flash point; ignition; ignition delay; heat flux; crude
Ignition of a slick of oil on a water sub-layer has been
experimentally studied. The objective of this work is
to provide a tool that will serve to assess a fuels
ease-to-ignite under conditions that are representative
of oil spills. Two different techniques are used and
the results compared, piloted ignition when the fuel is
exposed to a radiant heat flux and flash point as
measured by the ASTM D56 Tag Closed Cup Test. For the
piloted ignition tests the fuel is exposed suddenly to
external radiation to increase its temperature until
ignition occurs. Temperature measurements and ignition
delay time are used to characterize piloted ignition and
an existing one-dimensional heat transfer model is used
to correlate the experimental results. For the flash
point test, the bulk temperature of the fuel is
increased until thermal equilibrium is attained and then
a pilot is introduced. The temperature at which the
first flashes are observed is called the flash point.
Two different crude oils were used for these
experiments, ANS and Cook Inlet. Crude oils were tested
in their natural state and at different levels of
weathering. Piloted ignition and flash point are strong
functions of the weathering level. Premature boiling of
the water sub-layer inhibits ignition. The flash point
temperature can be used as a characteristic pyrolysis
temperature and the weathering level has a negligible
effect on the thermal properties of the fuel. It was
determined that a critical heat flux for ignition could
be obtained and better serve as a parameter to
characterize the fuel propensity to ignite in the
presence of a strong pilot. The minimum heat flux that
will permit ignition before boiling of the water sub
layer occurs also needs to be considered.