Breaking emulsions in Navy bilge collection and treatment systems

Abstract

The new bilge waste collection and treatment system, which serves as the collector, transporter, and gravity separator for ship's bilge waste, was a suitable medium for the application of chemical demulsification techniques. Chemical demulsification methods were especially suitable for emulsified oily wastes that are reluctant to separate into the constituent phases. Laboratory tests indicated that certain quaternary ammonium compounds were effective in breaking 5% oil-in-seawater emulsions over a 20-h period at temperatures ranging from 4 C to 45 C. The demulsifier concentration required to break the emulsions generally ranged from 1% to 2% at 4 C to 0.1% to 0.2% at 45 C. At the low temperature the oil concentration in the separated water ranged from 100 to 500 ppm; at the higher temperature no more than 55 ppm was observed with most oil level readings of the order of 25 ppm or less. The demulsifiers were useful in breaking emulsions of Navy Distillate, used motor oil, turbine oil, and bilge wastes containing unknown oil mixtures. A field demonstration supported the laboratory tests.