A method for distilling ethanol from a mash includes feeding a fluid to a first distillation column. The fluid and a distillate of the first distillation column are delivered to a second distillation column. The fed fluid and / or distillate of the second distillation column is / are purified in a first and / or last step of the method by a membrane separation process.
A system for dehydrating lubricating and hydraulic fluids includes a heating circuit and circuitry for creating a vacuum. The heating circuitry introduces a stream of heated fluid into a vacuum chamber in which a partial vacuum is drawn by the vacuum circuit. Aqueous components of the fluid stream are flashed in the vacuum chamber by virtue of the elevated temperature and reduced pressure. Dehydrated fluid is then collected and evacuated from the vacuum chamber. Vapor from the vacuum chamber, including the aqueous components of the fluid stream are collected, condensed and separately evacuated. The heating circuit limits surface temperature of a heating element in a closed-loop manner to avoid degradation of the fluid. The fluid stream is introduced into the vacuum chamber or is recirculated through the heating circuit to maintain a desired level of fluid temperature in a closed-loop manner. The system includes circuits for evacuating dehydrated fluid in a closed-loop manner and for automatically discharging condensate. The technique avoids undesirable foaming of dehydrated fluid within the vacuum chamber. A vacuum pulsing circuit is provided for periodically pulsing vacuum pressure within the vacuum chamber to aid in flashing aqueous components from the heated fluid stream.