High Seas Oil Research Articles

COMBINED SKIMMER-BARRIER HIGH SEAS OIL RECOVERY SYSTEM1

ABSTRACT This paper describes the development of an oil recovery system to be used in conjunction with the U.S. Coast Guard's high seas oil containment barriers. The system was tested at the EPA's OHMSETT facility in 1975. Its oil recovery capability was shown to be good, with promise for yet better recovery when used on a large spill. Operational practicality was demonstrated in sea trials during May 1976, when the barrier was string towed, catenary towed, and moored in a tidal current. Because of the difficulty of handling large or complicated equipment in offshore conditions, a major design criterion was that the system be as simple as possible. Weir skimmers are particularly simple, but collection of more oil than water or air requires that the weirs follow the vertical motion of the waves. Simplicity and efficiency were achieved by utilizing the wave-following ability of the Coast Guard barrier design. Weirs were built into six struts at the center of a length of barrier, so that barrier deployment results in simultaneous skimmer deployment. To recover oil, it is only necessary to attach pump hoses to the barrier. Three double-acting diaphragm pumps are used. These self-priming pumps were specifically designed to pass any debris that can enter through the three-inch diameter suction hoses. Hydraulic drive was chosen so the pumps could be powered by the Coast Guard's ADAPTS diesel-engine-driven hydraulic power units.

FAST SURFACE DELIVERY SYSTEM FOR POLLUTION RESPONSE EQUIPMENT1

ABSTRACT The U.S. Coast Guard has undertaken the development of a Fast Service Delivery System in order to provide an efficient means to deliver pollution response equipment to the scene of a high seas oil spill. A planing hull sled, towable by surface vessel or helicopter, was designed by the U.S. Naval Coastal Systems Laboratory as the transportation vehicle. The all-aluminum sled has a 15-foot beam and is 45 feet long and weighs 10,000 pounds. The system can deliver a 20,000-pound payload and can be unloaded at sea manually. Test results have shown that the equipment-loaded sled can be safely and efficiently towed by an HH3F helicopter at speeds up to 50 knots and by a Coast Guard 82-foot WPB at speeds up to 17 knots in sea state 3 or less. The empty sled, at rest in the water, lies with the aft end submerged. Sled-mounted hand winches are used to inhaul and secure the floating payload. After the sled is underway, the water drains, the stern comes up, and the sled hydroplanes. At the deployment site, quick-release hooks on the lines securing the equipment to the sled are tripped and the stern submerges, leaving the payload floating free.

High Seas Oil Pollution: Particulate Petroleum Residues in the North Atlantic

The results of a continuing investigation into the occurrence and distribution of particulate petroleum residues on the surface of the North Atlantic are presented. From 1971 to 1974 more than 850 samples were collected from the North Atlantic on transects between the east coast of Canada and South America, the Caribbean, Baffin Bay and surrounding waters, the Labrador Sea, and the Azores. Repeated sampling was carried out in the Gulf of St. Lawrence and the region between Nova Scotia and Bermuda. The results indicate that the waters north of the Gulf Stream–North Atlantic Current system were virtually free from floating petroleum residues, while the waters of the Gulf Stream, Sargasso Sea, and Caribbean Sea were much more heavily polluted. Although concentrations as high as 91.8 mg/m2 were encountered, the general level of pollution was much less with tar contents in southern waters following a lognormal distribution with a geometric mean of 0.16 mg/m2. The geographical distribution of tar is interpreted in terms of inputs from shipping and tanker traffic, and surface circulation patterns.

Coast Guards response to spilled oil.

The Coast Guard's responsibilities for oil spill control within and outside the territorial limits of the United States are defined. An extensive remote sensing program, using in-situ and airborne sensors, of the Coast Guard's Office of R and D detects oil spills. Five types of each in-situ and airborne sensors are described. After a spill has been detected, the next step involves containing and recovering the oil. Several different systems used by the Coast Guard include: air deployable anti-pollution transfer system, high seas oil containment system, rotating-disc-drum-high-seas-oil-recovery system, and fast-current-oil-recovery devices. After the spill has been detected and recovered, the next problem is to determine the violator so that he may be required to reimburse the Coast Guard's oil spill cleanup revolving fund. The Coast Guard R and D Center is developing a system for determining the source of the spill with sufficient confidence that violators can be prosecuted. (GMC)

UNITED STATES COAST GUARD HIGH SEAS OIL CONTAINMENT SYSTEM (HSOCS)*

ABSTRACT A detailed technical description of the High Seas Oil Containment System (HSOCS), presently being procured by the U.S. Coast Guard for operational use, is presented. Fifteen of the systems are scheduled for completion of delivery by March 1974. Each of the major subsystems of the HSOCS is described in detail. The HSOCS will be part of the equipment inventory of the Coast Guard Strike Teams of the National Strike Force for use in response to major oil spills on the high seas.

Volumetric Determination of Marine Oil Spills Using Coordinated Airborne and Surface Sampling Data

ABSTRACT The detection, measurement, and monitoring of oil pollution in the marine environment are receiving increased attention owing to: I) the growing incidence of oil spills; 2) the associated need for improved cleanup procedures; and, 3) the need for more effective surveillance systems, capable of gathering legal evidence for the prosecution of violators. The Geography Remote Sensing Unit and the Department of Chemical and Nuclear Engineering at the University of California, Santa Barbara for 2 1/2 years has been conducting experiments related to the application of remotely sensed data to these problem areas. As part of a United States Coast Guard test of a high seas oil containment device, a system for estimating the volume of oil loss resulting from oil pollution incidents was developed. This system involved the coordination of remote sensing data acquisition with simultaneous collection of surface sampling data. Results indicate that remotely sensed data, when effectively correlated with surface sampling data, can provide a base for volumetric estimations of a given oil slick. Refinements of these techniques can lead to more efficient, real-time day/night, operational monitoring of marine oil pollution incidents.

High Seas Oil Recovery System

ABSTRACT A system for recovery of petroleum products from accidental offshore spills has been developed and tested. The testing has included both model testing and full scale testing of a 60 foot long system capable of recovering oil at a rate of 2,000 gallons/minute. The tests have shown the system capable of recovering spilled oil at high efficiencies (less than 10 percent water in the recovered oil) at the 2,000 GPM rate under environmental conditions ranging from calm to low State five Seas (8 feet significant wave height) and in currents up to three knots. The system efficiency (percent of oil in the recovery stream) is relatively independent of oil specific gravity, viscosity, oil film thickness, wind and wave conditions, oil-water interfacial tension, surface temperature and variation in significant oil type when towed at speeds of one to three knots. As indicated, efficiencies of 90–100 percent can be expected under these conditions. The oil recovery rate is relatively independent of wind and wave conditions, surface temperature, oil specific gravity, oil-water interfacial tension and significant oil type variation. It is not affected by viscosity except for discharge hose pressure limitations above 10,000 SSU. The oil recovery system is air and truck transportable for rapid deployment to a remote spill location. It is completely self-contained having its own power unit, control system, and pumps. In its preferred deployment configuration it is used with oil containment booms for funneling the oil to the recovery system. A double weir system is employed to obtain the high performance of the system. The system is operated in such a way that oil thickens in front of the primary weir and then further thickens in front of the secondary weir, where it is withdrawn. Typically, the system concentrates free slicks from a thickness of 0.1 inches or less to a depth of approximately two feet in front of the secondary weir. The testing reported upon includes both model testing and full scale testing of the system. The work reported upon was partially supported by the U.S. Coast Guard.

FREE VORTEX RECOVERY OF FLOATING OIL

ABSTRACT A concept employing a free vortex for use in recovering oil from high seas oil spills is presented. An experimental evaluation program has been completed which demonstrates the feasibility of this concept as well as design limitations. An oil slick will migrate toward the center of the vortex due to the action of the water flow induced by an impeller. At an appropriate speed of rotation, the oil will submerge and accumulate within a central region of the vortex. This pocket will contain a concentrated mass of oil which can readily be removed by conventional pumping. Advantages of this technique include effective operation in high seas and the ability to both collect and concentrate an oil slick in a single operation. Tests were performed with a free vortex oil recovery model having an impeller diameter of one foot. Performance data were obtained both under quiescent water conditions and also under environmental conditions that simulated 10-foot deep water waves, 20-knot winds, and 2-knot currents. Detailed scaling considerations based on the test data indicate that a prototype device, with diameter on the order of 4-feet and larger, would be operable in all typically occurring 10-foot seas. Depending on its size, the prototype will recover in excess of 100 gallons per minute of oil with an oil-to-water ratio greater than 1.2 when operating with a crude oil film of only 0.1 inches in thickness.