This method of distillation similar to conventional distillation except that it operates at very low (near vacuum) pressure. This method of distillation allows the mixture to boil at a lower temperature and thus avoids the thermal degradation problem. In addition, to handle the larger volume of vapors that result from distillation at reduced An example flow sheet for a crude distillation column (using steam distillation) and a vacuum distillation column is shown in Fig. .