Question

When distillate contains highest possibility of light key, D/F approaches

(a) Infinity

(b) Zero

(c) Unity

(d) Double

I got this question in an interview for job.

This is a very interesting question from Process Design and Optimization in chapter Column Process Design, Optimization and Shortcut Calculations of Distillation Design

Answer 1

Correct choice is (c) Unity

Explanation: When distillate contains highest possibility of light key D/F approaches Unity and lowest when D/F approaches Zero.