Question

If x=0.4 and y =0.6633 and point xD (0.9, 0.9). Then estimate Rmin

(a) 0.9

(b) 0.4734

(c) 0.4

(d) 0.66

The question was posed to me in a job interview.

My question is taken from Minimum Stages topic in division Column Process Design, Optimization and Shortcut Calculations of Distillation Design

Answer 1

The correct answer is (a) 0.9

The explanation is: As Rmin/R+1 = (0.9-0.6633)/ (0.9/0.4) = 0.4734 then 0.4734/1-0.4734 = 0.9.