Acetone is to be removed from air in an isothermal dilute absorber using pure water as solvent. The incoming air contains 5 mole% of acetone (yin = 0.05). The design equation to be used for obtaining the number of trays (N) of the absorber is, N+2 = 6 log (yin/yout).For 98% recovery of acetone, the number of trays required is/are ?

Question

Accepted Answer

9. Given 98% recovery, the outlet mole fraction (yout) is $0.05 	imes (1-0.98) = 0.001$. Plugging into the equation: $N+2 = 6 \log(0.05/0.001) = 6 \log(50) \approx 6 	imes 1.7 = 10.2$. Thus, $N allingdotseq 8.2$, which rounds to 9 trays.