Repeat the calculations of Example 12.1 but use 1 = methanol, 2 = water, and 3 = acetone. Are the results any different? If not, why not? Prove your conclusion mathematically.

EXAMPLE 12.1

This example is similar to Example 11.5.1 on page 283 of Taylor and Krishna [15]. The following results were obtained for Tray n from a rate-based calculation of a ternary distillation at 14.7 psia, involving acetone 

(1), Methanol 

(2), And water 

(3) In a 5.5-ft-diameter column using sieve trays with a 2-inch-high weir. Vapor and liquid phases are assumed to be completely mixed.

The computed products of the gas-phase, binary mass-transfer coefficients and interfacial area, using the Chan–Fair correlation of §6.6, are as follows in lbmol/(h-unit mole fraction):
k₁₂ = k₂₁ = 1; 955; k₁₃ = k₃₁ = 2; 407; k₂₃ = k₃₂ = 2; 797
(a) Compute the molar diffusion rates. 

(b) Compute the masstransfer rates. 

(c) Calculate the Murphree vapor-tray efficiencies.

Transcribed Image Text:

Component 1 23 Yn y₂₁ K 0.2971 0.1700 0.3521 2.759 0.4631 0.4290 0.4677 1.225 0.2398 0.4010 0.1802 0.3673 1.0000 1.0000 1.0000 Yn+1 Xn 0.1459 0.3865 0.4676 1.0000