Abstract: The numeric method of dimensionless minimum total operation time of batch distillation of a binary ideal mixture under “total reflux” and ideal operating conditions is introduced.The energy consumption of batch distillation of a binary ideal mixture under “total reflux”and ideal operating conditions is compared with partial reflux using the calculated results of examples，and the conclusion shows that the batch distillation of binary mixture under “total reflux” can be adapted to the separation process characterized by a small relative volatility,low concentration of light component in the feedstock and high yield of light component in the overhead product.