Effects of temperature and wave conditions on chemical dispersion efficacy of heavy fuel oil in an experimental flow-through wave tank

摘要

The effectiveness of chemical dispersants (Corexit 9500 and SPC 1000) on heavy fuel oil (IFO 180 as test oil) has been evaluated under different wave conditions in a flow-through wave tank. The dispersant effectiveness was determined by measuring oil concentrations and droplet size distributions. An analysis of covariance (ANCOVA) model indicated that wave type and temperature significantly (p < 0.05) affected the dynamic dispersant effectiveness (DDE). At higher temperatures (16 ℃), the test IFO180 was effectively dispersed under breaking waves with a DDE of 90% and 50% for Corexit 9500 and SPC 1000, respectively. The dispersion was ineffective under breaking waves at lower temperature (10 ℃), and under regular wave conditions at all temperatures (10-17 ℃), with DDE < 15%. Effective chemical dispersion was associated with formation of smaller droplets (with volumetric mean diameters or VMD ≤ 200 μm), whereas ineffective dispersion produced large oil droplets (with VMD ≥ 400 μm).