High Seas Oil Recovery System

Abstract

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that oil thickens in front of the primary weir and then further thickens in front of the secondary weir, where it is withdrawn.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.