Question

Rectification. McCabe-Thiele Method. A mixture of benzene-toluene is to be distilled in a fractionating tower at 101.3 kPa. The column is fed 120 kg mol /h of a saturated liquid at the boiling point with 60 mol % benzene and 40 mol % toluene. The content of the distillate is 92 mol % benzene, and of the bottoms 5 mol % benzene. The reflux ratio is 3:1.

(a) Calculate the kg mol/h distillate: D=_______

(b) Calculate the kg mol/h bottoms: W=_______

(c) Attach the plot with the equilibrium line, 45? degree line, q-line, enriching and stripping operating lines, and stepping off the trays. Show with the dashed lines the stepping off assuming the Murphree tray efficiency is 0.5.

(d) Identify the position of the feed (the tray number) and inidicate the relative position of the feed to the tray: feed from bottom, from top, or both from top and from bottom.

Feed on tray _______from ___________

(e) Determine graphically the theoretical number of trays:

N= __________plus a reboiler

(f) Determine graphically the actual number of trays for the case of Murphree efficiency

0.5:
N= ____________plus a reboiler

(g) Calculate the overall tray efficiency in case of 0.5 Murphree tray efficiency: E0 =____________

(h) Attach the plot with the equilibrium line, 45? degree line, q-line, and enriching and

stripping operating lines for the case of minimum reflux ratio.

(i) Identify the point of intersection of the enriching operating line and q-line for the case of minimum reflux ratio:

x= ______ y=______

(j) Find minimum reflux ratio:

Rm=__________

Attach the plot with the equilibrium line, and enriching and stripping operating lines, and stepping off the trays for the case of total reflux.

Determine graphically the minimum number of theoretical trays at total reflux: N= ______________plus a reboiler

Answer 1