Question

How many moles of H2 are recycled?

(a) 1.5

(b) 2.2

(c) 2.8

(d) 3.9

The question was asked during an online interview.

My question is based upon Bypass and Purge in chapter Recycle, Bypass, Purge, Ideal Gases and Real Gases of Basic Chemical Engineering

Answer 1

Right choice is (d) 3.9

For explanation: Moles of H2 in G stream = 10*0.8 – 3*10*0.2*0.8 = 3.2 = moles of H2 in H stream. Moles of H2 in P stream = 0.95*7.5 = 7.125, => moles of H2 in R stream = 7.125 – 3.2 = 3.925.