Question

2. A fractionating column with two feed points operates with a reflux ratio of 3 at a total pressure of 1 atm. Feed one has a rate of 100 mols/s of saturated liquid mixture with composition of 50 mol % benzene and 50 mol % toluene. Feed two has the same rate of 100 mols/s of saturated vapor mixture with composition of 30 mol % benzene and 70 mol % toluenc. The bottoms product is 90 mol % toluene while that of overhead product, D is 90 mol % benzene. The equilibrium data is given below. 1.000 0.823 0.659 0.508 0.376 0 .256 155 1.058 0.0 1.000 0.922 0.830 0.720 0.596 0.453 0.304 .128 0.0 By McCabe Thiele method, find the number of theoretical plates and the feed plate location,

Answer 1

Criven data R=3 NDE ogo, Mw= 0110 po Fie F2=100 mw MF =0.5, NF = 0.3 First we write feed Equ => Feed CD F, MF, = 0.5, Saturated ein 1921) 7 ng nt na ory (19) = -92 & MF, LX0 = -ntno => NE NE 2015 NE 0.5 Feed line © » Feed @ F2: NF2=0.3, Saturated vapor [Voo) y = Oxn to 12= 0.3 / Feed line 0 => Rectifring sectioni. L= En a no R+ D SH 345 I= 0.150+ 0.225 s. we can draw Intercept = this 0.225 line with help of and passing through (org,0.9) (Mono)

CS3 0 5 FH 0.225 H a w, us coll, 0-1) No a Stage 2 en kleding Rebbile Feel 0 Fredo Stage ( Stage o Prom from topp top No. 8 Stage In Column ETHER

For plot, line of striping section we have one point (X_w X_w) i.e. (0.1 , 0.1) and another point is intersect point of Rectifying section line and feed 1 line ,

Because we know that all three line (rectifying, striping, and feed line) are meet on a single common point.

Now we can draw easily striping line and find number of stage by construct triangle and counting of triangle