The best column number for enrichment of heavy water in thermal-diffusion columns of countercurrent-flow Frazier scheme with total sum of column height fixed

The effect of column number N and the same column height h of each thermal-diffusion column, on the Frazier scheme performance with total sum of column height (L = Nh) fixed, has been investigated. The equations, which may be employed to predict the optimal number of columns (generally not integers) for the maximum performance are derived. Accordingly, the best number of columns, which are the integers nearest to, and small than the optimal column numbers, are obtained for practical applications. Considerable improvement in performance is obtainable if the scheme is constructed with the best number of thermal-diffusion columns, instead of using a single column with column height L (N = 1, h = L). This is because that increasing column height in a thermal-diffusion column, though increasing the performance, will decrease the increment in performance, and finally the performance reaches a limiting value.