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Q & A: removing water from fluid

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Most recent answer: 05/31/2009
Our Heavy equipment uses hydraulic fluid to run many of its functions. Sometimes this fluid gets contaminated with water and after a short time is whipped into the oil turning it a light tan milky color. I was told that centrifuging was the only way to separate the two. Iíve discovered that by putting the oil in a container about a ľ inch deep that the water will evaporate off the top but you have to stir it often and takes about two weeks before all visible signs of water have disappeared. Now my question. How much heat should I apply to speed this process up? And will the hydraulic fluid also evaporate?
- tim michels (age 48)
canton texas, zan zandt
You're certainly right that heating the fluid will speed up the water evaporation. How hot you can safely get the hydraulic fluid without it also significantly evaporating or (worse) starting to degrade, I can't say. You'd have to check the specs on your specific fluid. It's even possible that the extensive exposure to air at room temperature in your current method could reduce the lifetime of the fluid.

If it turns out that the hydraulic fluid isn't degraded by air, water, and and heat,  you will need to supply the latent heat of vaporization, 2.3kJ (a bit less than the 3.6 kJ of a kW-hour), for each kilogram of water evaporated. That won't cost much unless you're running a very big operation, in which case you could consider more energy efficient ways to remove the water.

Mike W. and Lee H.

(published on 05/31/2009)

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