I am thinking it would be possible to modify a dieselcraft centrifuge to act as a flash evaporator by tapping a vacuum line into the outer casing somewhere above the bottom sump.

The high temperature, high pressure oil is already being forced out of a nozzle at the bottom of the rotor, by applying vacuum, you should be able to draw off the water that vaporizes .

Of course, you would need to be sure that the oil's gravity drain outlet is large enough to prevent the effluent oil from being sucked up too.

This would also let the rotor spin faster.

It already works great as a flash evaporator with no mods needed.

So where does the water vapour go? Is there an atmospheric vent in the housing?

It goes into the air at the exit from the CF, see the pics on page 1 of the Dieselcraft thread. Its one reason to keep the outlet open as on my original rig. Some of the water is removed by CF action and stays in the rotor until captured at shutdown.

help with oil not passing pan or spoon test
im running a spinner two for a yr now always removed water within 6 to 8 hr on a 40 gal batch recuculiating 100 psi 180 f - 220 f
any help please