Vacuum Dehydration - low temp high vacuum would be better than other methods . basic reasons - disolved additives are not seperated as would be in case of centrifuge. Also you can use a hybrid system which removes moisture / water and gasses from the lube oil (turbine oil) and then though the princ. of surface filteration removes physical impurities - if present upto recomended level by the OEM.
you need to have a carefull installation as you would require to have an filteration process which would be online. Also you need to take professional help to get the oil tested after 3-4 passess and get the same doped with the depiliated additives - due to age of the oil, process per say should not depiliate the additive levels.
Just a question - what is the capacity and do you have foaming in the system too ?