University of California Santa Barbara
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Last updated - November 21, 2005 |
Research In general Oil spills at sea can cause significant damage to the environment and impact commercial activities such as fishing, aquaculture, and tourism, as evidenced by the tragedy unfolded off the shores of northern Spain, or by the Exxon Valdez spill in Alaska. Immediate response to a spill using optimized contingency techniques can reduce negative impacts considerably. The efficiency of contingency measures is an issue of national and international significance, relevant for many regions around the world. The magnitude of the impacts to coastal ecosystems as well as the time and cost of operations depend on the selected response strategies and techniques. Before oil spill response actions are developed or implemented, it is important to understand the chemistry and physical behavior of the spilled oil and how its characteristics change over time, in particular its adhesion to collection devices. Oil is a complicated mixture of many components, and its fate and behavior on the sea surface largely depends on its initial properties and composition as well as on specific local environmental conditions. Spreading, evaporation, dispersion, and emulsification can rapidly alter oil properties within several hours, leading to formation of water-in-oil emulsion. The same type of oil released under different environmental conditions weathers in dramatically different patterns due to the influence of air and sea temperature, wind speed, and sea state on the weathering processes. Oil weathering can have significant ramifications with respect to appropriate recovery strategies. Failure to consider these ramifications can dramatically reduce the recovery effectiveness and ultimately the success of the emergency response. Mechanical recovery is one of the most popular and effective oil spill containment techniques. Various types of weir, oleophilic and suction skimmers currently exist for recovering oil from the sea surface. Each of these devices has a defined "window of opportunity" when it can be most successfully applied, which is determined by the specific environmental conditions and oil/oil emulsion properties. Low temperature, high waves, strong winds as well as the formation of water-in-oil emulsion may dramatically change oil slick properties within a short period following the spill, leading to a decrease in the mechanical recovery efficiency. Most of the existing mechanical recovery equipment was designed to collect oil using its property to adhere to the surface material of the recovery unit. This equipment can efficiently collect oil with certain physicochemical properties at standard conditions and cannot be used with equal competence both in warm and ice-infested waters or on variable oil types and properties. The recovery efficiency significantly changes with time due to the oil slick property changes and emulsion formation. Therefore, multiphase interactions between oil, seawater, material of recovery unit, and ice (if present) need to be studied thoroughly due to their strong influence on the oil recovery process. One of the key oil slick properties influencing the efficiency of oil recovery is its adhesion to the surface of the recovery device. Adhesion, which is a function of the initial oil properties, oil weathering degree and water content of emulsion, undergoes significant changes during the time following the oil spill. Increase of the pour point and viscosity as well as emulsion formation may dramatically decrease the recovery efficiency. Thus, the knowledge about the adhesive properties of oils and oil emulsions at different weathering degrees towards various surfaces (steel, polymers, ice, etc.) will be extremely useful. It will help to better understand the interactions between the oil slick and recovery device over time and will allow an increase in the mechanical recovery efficiency. In more details Two reports summarizing my recent research work are available now. (March 7th, 2006) A laboratory phase: · Tailored Polymeric Materials to Increase Oil Spill Recovery in Marine Environments . Full-scale oil spill recovery test: · Optimization of Oleophilic Skimmer Recovery Surface .
Supervisor Arturo Keller (Bren School of Environmental Science & Management, UCSB) Advisors Trish Holden (Bren School of Environmental Science & Management, UCSB) |
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