Modelling of the rate of oil spill disappearance from seawater for Kuwaiti crude and its products

In this paper a semi-analytical model has been developed to estimate the amount of oil disappeared from an oil spill floating on seawater surface. The model considers evaporation, dissolution and sedimentation of oil components. Crude oil and wide boiling range fractions are divided into several pseudocomponents using distribution model developed by Riazi (Ind. Eng. Chem. Res., 36 (10) (1997) 4299-4307). Heavy components with densities above density of water, sink to the bottom of sea while light components vaporize or dissolve into water. In the model, oil spill thickness is considered variable versus time. The input data for the model are distillation data (or composition) for oil, API gravity of oil, initial volume of oil spill, initial area of oil spill, air temperature, wind speed and water surface velocity. The only adjustable parameter is a constant in the relation for the mass transfer coefficient for evaporation. The model estimates area, volume and composition of oil spill versus time. It also calculates the amount of oil vaporized, dissolved or sunk into water versus time. Three sets of experiments were conducted for a Kuwaiti export crude oil and four different Kuwaiti petroleum products also used for export to determine the rate of oil disappearance at ambient temperature. Data obtained in these experiments were used to determine the model parameter as well as evaluation of the proposed model. (C) 1999 Elsevier Science S.A. All rights reserved.