Researchers test skimming system in ice

In a project led by the U.S. Coast Guard Research and Development Center, researchers have tested new technology for improving the effectiveness of skimmers when recovering oil spilled in ice-laden seas. The tests were conducted at the Bureau of Safety and Environmental Enforcement’s Ohmsett test tank in New Jersey. A skimmer is an oil spill response device that picks up oil floating on the sea surface and delivers the oil to some form of storage system.

Following previous research that showed that floating sea ice can interfere with a skimmer’s ability to pick up oil, the Coast Guard solicited the development of an ice management system that would improve oil recovery in a 70 percent sea-ice cover, according to the most recent edition of a newsletter published by Ohmsett. Under a contract subsequently awarded by the Coast Guard, Marine Pollution Control developed a device called an “ice cage,” a mesh structure in the form of an inverted cone, the newsletter says.

The cone floats in the water and has a fence that projects above the water surface to prevent ice chunks from drifting inside the cone. A skimmer operating inside the perimeter of the cage is protected from floating ice, while oil can flow through the mesh of the cage to reach the skimmer.

Tests at Ohmsett involved placing a variety of sizes of 8-inch thick ice sheets in the water of the facility’s tank, to simulate sea-ice coverage ranging from 30 percent to 70 percent. An oil slick 1-inch thick was placed in the icy water. Three different type of skimmer, each placed in the ice cage device were tested, with thermal and digital imaging techniques being used to measure oil slick thicknesses and the ice coverage during skimmer operation. The data gathered from the tests are still being evaluated, the Ohmsett newsletter says.

- Alan Bailey