Upgrading Petroleum Terminal Separators Using Coalescing Plates

In 1999, a project was instituted to replace two oil-water separators at Mobil de Colombia's terminal facilities in Cartagena, Colombia to bring the facility into compliance with environmental law.The separators are concrete in-ground pits equipped with rudimentary baffles and skimmers as well as built-in tanks for accumulation of separated oil. They process water from equipment washing as well as from rainwater runoff. Inlet to the separators is by gravity flow sewers.It was suggested that it might be possible to inexpensively upgrade the performance of the existing separators using multiple-angle coalescing plates instead of providing above-ground steel separators. This would also avoid the additional cost of pumps and utilities to pump the oily water into the proposed new separators.The existing pit separators were evaluated using a proprietary computer program and it was determined that the existing pits were large enough to meet the national environmental regulations for effluent oil content if fitted with multiple-angle coalescing plates.The paper will present information on legal requirements, a discussion of how the operating conditions were determined, the new internals designed, and a discussion of how the new internals will affect the quality of the water exiting the facility.