Relaxation time of thermal diffusion columns nonactive volumes

摘要

Analytical solutions for the time evolution of the separation factorQof an isotopic binary mixture in a thermal diffusion column with small reservoirs (dead spaces) at its ends are given. The simple expression obtained is checked against the numerical solution of the evolution differential equation. This shows its reliability to predict the nonstationary separation factor of a column with dead spaces up to 40percnt; of its active volume, and for equilibrium values of lnQup to 2 with no restrictions in the isotopic composition of the mixtures. These conditions take account of most of the experimental range that corresponds to the one stage units operating under total reflux. The obtained results support an empirical relation for the relaxation time proposed in a previous work.