Stable isotope concentration method

Abstract

The object of the present invention is to provide a stable isotope concentration method that reduces equipment cost and power without prolonging the start-up time and enables efficient concentration, and the present invention provides a stable isotope concentration method using multiple cascaded distillation columns (1st column to mth column; m is an integer of 2 or more), wherein the method includes a step in which one of gas and liquid is supplied from a position in the vicinity of the bottom of a (n−1)th column to a position in the vicinity of the top of an nth column (1<n≤m), and the other of liquid and gas is returned from a position in the vicinity of the top of the nth column to a position in the vicinity of the bottom of the (n−1)th column; and wherein in each distillation column, when a flow rate of an ascending gas in the column is a first flow rate and a flow rate of the gas or the liquid supplied from a previous column or a next column is a second flow rate, the second flow rate is 4% by volume or more with respect to the first flow rate.

Dependencies are inferred from the claim text.