In our Vacuum Distillation Unit we have a vacuum system consisting of overhead water coolers, two ejectors with condensers and a liquid ring vacuum pump. During the summer time when the cooling water to overhead coolers and ejector’s condensers increase above 23C we observe increased pressure on the top of the vacuum column to approx 5-6 Kpa (from 3 Kpa) which is of course logical. In this situation when we want to increase the temp to the vacuum column in order to maximize yields , the pressure will increase too and the result is quite opposite. The significant fluctuation of temp of cooling water (sometimes during the day it is about 5C) makes it also impossible to optimize yields from the vacuum column. Please advise what to do in this situation in respect to our plant, how we can keep pressure steady and low , how to improve yields in this circumstances from the vacuum column. Maybe you have similar problems and please write how you deal with that. Some recommended literature/web sites on this subject would be very helpful too.