Give reasons why each of the following conditions can result in oil being carried over with the water discharge from lubricating oil centrifuges:
(a) High throughput of mixture, (6)
(b) Abnormally high temperature of mixture, (6)
(c) Appreciable accumulation of solids in bowl. (4)
Structured for DG Shipping MEO Class II examination scoring criteria.
When the throughput of the mixture is high, the centrifuge may not have enough time to separate the oil from the water effectively. This results in a lower oil-to-water interface because of higher throughput and separation will not be efficient. This can result in oil being carried over with the water discharge.
High temperatures can reduce the viscosity of the oil, making it more difficult for the centrifuge to separate the oil from the water. Lower viscosity results in lower density which does not comply with the principle of centrifuge to separate lower density of fluid from higher density of fluids. This can result in oil being carried over with the water discharge.
Centrifuge bowl should be cleaned in regular intervals based on the quality of oil and viscosity. If not bowl will be filled with sludge and deposits. If there is a significant accumulation of solids in the bowl, the centrifuge may not be able to effectively separate the oil from the water. This can result in oil being carried over with the water discharge.