give engine oil fltration process to be used in fire tube boilers?

Question

centrifugal process for separation of slidge and water contamination

Answer 1

Centrifuges can be used to separate water and sludge (for example on ships or oil platforms)

Answer 2

A centrifuge will throw out the heavy contaminants to the drum walls and the cleaned liquid will pass out of the drum.

Don't know how you clear water with a centrifuge. You'd use some sort of skimming process as the oil floats on water, OR an oil belt, that captures oil while the water is left behind.