NAVY DEVELOPMENT OF SUITABLE SHIPBOARD BILGE OIL/WATER SEPARATORS

Abstract

ABSTRACT The evolutionary development and evaluation of a suitable Navy shipboard bilge oil/water separator is detailed. Evaluations were performed at four levels: laboratory screening tests, shipboard screening tests, formal shipboard technical evaluations (TECHEVALS) and operational evaluations (OPEVALS). Gravitational and filter/coalescer systems, as well as systems combining these techniques were evaluated. Initial shipboard screening tests revealed significant problems caused by particulates and detergents in the bilge fluids. Although effluent goals could be met, severe penalties in terms of costs to process, logistics support, and size of separation equipment were evident. Screening tests produced three promising systems for formal TECHEVALS: a parallel-plate gravity separator, and two designs for gravity/filter/coalescer systems. TECHEVAL included in-port and at-sea performance tests, bulk oil removal, oily waste holding tank and detergent-contaminated waste processing demonstrations, and reliability and maintainability assessments. Performance goals were established for effluent oil levels during in-port and at-sea periods, water content of separated oil, average element set life, cost to process, mechanical/electrical reliability, and mean time to repair. As a result of TECHEVAL, the parallel-plate separator was selected for OPEVAL and modified to improve its structural adequacy and machinery/personnel interface. The OPEVAL was structured to determine if the unit could be operated and maintained by ship's personnel, while processing both actual and deliberately contaminated bilge water on a daily basis for six months.