Variable stage-number model for simulating batch operation of water distillation column for tritium isotope separation.

Abstract

A batch distillation of tritiated water (10 nCi/cm3) has been performed in a packed column 1, 6 cm inner diameter × 100 cm high. Packings were Dixon rings made of SUS. Time variations of tritium activity were measured by changing vapor flow rate within the column, and then the separative performances, such as the separation factors and the separative power per unit charge, were obtained. The maximum values of the total separation factor and the separative power per unit charge were 1.45 and 2.0×10-2, respectively. The vapor flow rate from the reboiler decreases as the batch operation proceeds, so that a simulation with a fixed stage-number, the usual case, could not sufficiently predict the experimental values. We have therefore developed a simulation procedure where the number of hypothetical stages can be changed during the batch operation in order to predict the dynamic column behavior obtained from the experiments. The simulation result with the variable stage-number agreed with the experimental one.