Collection of Oil Slicks

Large oil spills, both at sea and in protected waters, require collection techniques with capacities beyond those of existing equipment. The basic collector, or skimmer configuration studied consists of a large V-shaped skimmer, pushed through the oil slick, with the oil pumped from the apex. In the V, a captive pool of oil forms, whose length and depth near the apex depends on the skimmer speed and oil density. This captive pool is much thicker than the undisturbed slick. In the apex of the V (the throat) the removal rate is limited by the occurrence of critical flow (in the densimetric sense) of the oil towards the removal device. Increased pumping rates merely pump more water with the oil. For a given removal device in the throat, the maximum removal rate is limited by the maximum pool depth, and by the skimmer length and speed. Another upper limit is given by the overall width of the skimmer. The dynamics of the captive pool and throat region are described, and design criteria given.