Distillation under reduced pressure (less than atmospheric) which lowers the boiling temperature of the liquid being distilled. This technique with its relatively low temperatures prevents cracking or decomposition of the charge stock. For example water which boils at 212 degrees F. Under the atmospheric pressure of 14.7 lbs./sq. In. Boils at 102 degrees at a pressure of one pound. So vacuum distillation saves in refinery fuel costs and may prevent the breaking down or changing of molecules which might occur at higher distillation temperatures.
