Batch distillation column with top vessel and bottom vessel is a new and promising structure. In the basis of it, a new operation strategy that two columns operate in parallel with liquid exchange under total reflux is proposed to separate binary mixtures in this article. A mathematical model is setup for the simulation. Operation time and yield of different feeding concentration and holdup in vessels are compared and discussed. The results show that there is an optimal holdup for different feeding concentration and the total yield increases with the growth of total charge. Furthermore, the proposed operation mode is verified experimentally and it reveals significant potential for separation with higher efficiency and lower pressure drop. (C) 2015 Elsevier B.V. All rights reserved.