A dynamic theoretical simulation model was built to study cryogenic distillation separation of hydrogen isotopes. Dynamic behavior of DT concentration was obtained. The effects on separation performance of parameters such as reboiler holdup and reflux ratio were studied. The result indicates that the increase of reflux ratio brings about a substantial improvement of the system detritiation efficiency. DT concentration in reboiler is related with time and reboiler holdup

and dynamic calculation shows that DT concentration in reboiler increases almost linearly with time under the proposed operation mode in this paper. The separation performance is satisfactory with 80 stages as the DT concentration in reboiler is enriched 1000-fold compared with that in condenser.