ABSTRACT
A technique using a free vortex to recover oil from high sea, stream, and harbor waters is presented. Initial results of a current concept development program are given.
An oil slick will be drawn into the center of the vortex due to water flow induced by an impeller and other rotating hardware. As a result, a significant “captive radius” is demonstrated which draws in oil from appreciable distances from the device—useful around piers, ships, etc., in harbors. Upon approaching the vortex, the oil will submerge and accumulate within a center region of the vortex. This pocket will contain a concentrated mass of oil which can be removed by conventional pumping. Since oil collection is not directly performed by hardware, but rather by the induced vortex flow, essentially the same hardware was also used to collect sorbent materials of various sizes and shapes.
Tests were performed with a free vortex oil recovery device having an impeller diameter of two feet. Performance data were obtained both under quiescent water conditions and also under environmental conditions that simulated a severe sea state four with 20 knot winds and two knot currents. Oil recovery rates and oil/water ratios are reported for oil film thickness ranging between 1/16 to one inch thick using No. 2 Fuel Oil, Heavy Crude Oil, and a Residual Fuel Oil. Scaling considerations based on this test data indicated performance characteristics of larger sized prototypes.