Centrifuging Low Flashpoint Liquids

Naphtha, diesel, and kerosene have flashpoints between 100-175°F, however gasoline has a very low flashpoint of -45°F. Centrifuging low flashpoint liquids presents specific hazards due to the large volume of flammable vapors produced.

The centrifuge should be mounted in a well-ventilated area. The centrifuge must be securely gasketed and tightly closed to prevent vapors from leaking out and air from leaking in.  Before starting, the centrifuge system should be purged with inert gas such as nitrogen to remove oxygen from the centrifuge, piping and tanks. The inert gas feed should be maintained during operation to prevent ingestion of air. The centrifuge should not be opened until all flammable vapors have been purged.

Low flash point liquids may be chilled below the flash point and output lines may be chilled to condense vapors. All equipment including tanks should be grounded to prevent sparks and tanks should be vented outside to prevent accumulation of vapors inside the building. Gasoline vapors are heavier than air and flow across the ground. The explosive limits for gasoline are between 1.2% and 7.1%.

Three phase motors are preferred as single phase motors have sparking contacts in the starting circuit. Open frame motors are prohibited in the work area.