Experimental study on the evaporation of typical oil spills in the Bohai Sea.

With the rapid expansion of offshore oil exploration, production, and shipping, oil spill accidents have become increasingly frequent and pose growing threats to the marine environment. This study investigates the physicochemical properties and evaporation kinetics of five typical oil spill samples from the Bohai Sea (northern China, East Asia). The oils (three crude oils and two fuel oils) differ markedly in composition (SARA fractions and distillation cuts). Density, viscosity, and composition were characterized, and empirical models linking composition, temperature, and viscosity were developed. Evaporation experiments were conducted in a shallow-plate system (0.5 mm oil film) under controlled temperatures (7-40 °C) and wind speeds (0-6 m s-1) for eight days. Evaporation rate and maximum loss increased significantly with temperature and wind speed, following a strong logarithmic relationship with time (r 2 > 0.95). Kinetic parameters were correlated with oil composition to establish a multi-factor empirical prediction equation. Changes in density and viscosity during evaporation were quantified, providing a basis for predicting oil-spill behavior in the Bohai Sea.