Li Zhengkai, Lee Kenneth, King Thomas, Boufadel Michel C, Venosa Albert D
Centre for Offshore Oil and Gas Environmental Research, Bedford Institute of Oceanography, Fisheries and Oceans (DFO) Canada, One Challenger Drive, Dartmouth, NS, Canada B2Y 4A2.
Mar Pollut Bull. 2009 May;58(5):735-44. doi: 10.1016/j.marpolbul.2008.12.014. Epub 2009 Jan 20.
Testing dispersant effectiveness under conditions similar to that of the open environment is required for improvements in operational procedures and the formulation of regulatory guidelines. To this end, a novel wave tank facility was fabricated to study the dispersion of crude oil under regular non-breaking and irregular breaking wave conditions. This wave tank facility was designed for operation in a flow-through mode to simulate both wave- and current-driven hydrodynamic conditions. We report here an evaluation of the effectiveness of chemical dispersants (Corexit EC9500A and SPC 1000) on two crude oils (Medium South American [MESA] and Alaska North Slope [ANS]) under two different wave conditions (regular non-breaking and plunging breaking waves) in this wave tank. The dispersant effectiveness was assessed by measuring the water column oil concentration and dispersed oil droplet size distribution. In the absence of dispersants, nearly 8-19% of the test crude oils were dispersed and diluted under regular wave and breaking wave conditions. In the presence of dispersants, about 21-36% of the crude oils were dispersed and diluted under regular waves, and 42-62% under breaking waves. Consistently, physical dispersion under regular waves produced large oil droplets (volumetric mean diameter or VMD > or = 300 microm), whereas chemical dispersion under breaking waves created small droplets (VMD < or = 50 microm). The data can provide useful information for developing better operational guidelines for dispersant use and improved predictive models on dispersant effectiveness in the field.
为改进操作程序和制定监管指南，需要在类似于开放环境的条件下测试分散剂的有效性。为此，制造了一种新型波浪水槽设施，用于研究在规则非破碎波和不规则破碎波条件下原油的分散情况。该波浪水槽设施设计为以流通模式运行，以模拟波浪和水流驱动的水动力条件。我们在此报告了在该波浪水槽中，在两种不同波浪条件（规则非破碎波和 plunging 破碎波）下，两种原油（中南美原油[MESA]和阿拉斯加北坡原油[ANS]）上化学分散剂（Corexit EC9500A 和 SPC 1000）有效性的评估。通过测量水柱中的油浓度和分散油滴尺寸分布来评估分散剂的有效性。在没有分散剂的情况下，在规则波和破碎波条件下，近 8 - 19%的测试原油被分散和稀释。在有分散剂的情况下，在规则波下约 21 - 36%的原油被分散和稀释，在破碎波下为 42 - 62%。一致地，规则波下的物理分散产生大油滴（体积平均直径或 VMD≥300 微米），而破碎波下的化学分散产生小油滴（VMD≤50 微米）。这些数据可为制定更好的分散剂使用操作指南和改进现场分散剂有效性的预测模型提供有用信息。
