A Study On The Weathering And Predicting Model Of Spilled Oils At Sea

The high frequency of accidental spill at sea has greatly raised the public's concern. Oil spill weathering model can be used in the prediction of oil spill weathering character, such as the remnant, the density, the viscosity, water uptake, the emulsification rate, according to the meteorological condition. It is useful for the correlative departments to choose the most effective method of removing spilled oil, and it can provide the marine environment department with scientific information as to make a wise policy.The weathering processes, such as evaporation, emulsification, dissolution, dispersion, photo-oxidation, sedimentation, biodegradation process have been studied in this thesis. And it reviews the domestic and foreign universal applications to weathering model of oil spill, obtains various weathering processes mechanism and the major effect factor, it points out each model good and bad points.When crude oil is spilled at sea, the weathering processes start to change the physical and chemical properties of the oil. The main factors that control the rate and extent of these changes are: (a) the properties of the crude oil, and (b) the prevailing conditions ( temperature , wind speed and sea state).As the oil spreads over the water and forms a thin film, evaporation of the more volatile components of the crude oil will occur. Evaporation is one of the most important processes that eliminate oil from the water surface. Some of the lower molecular weight components, especially the aromatic compounds such as benzene and xylenes, dissolve in water only to a small extent. However, these compounds are also volatile, so most of them will evaporate. Only a small volume of the oil spill will be lost as dissolved components, although this will have a very important influence on acute toxicity to marine organisms. Exposure to the UV radiation of sunlight will cause the more polar oil components to...