Page 93 - Applied Process Design For Chemical And Petrochemical Plants Volume II

82 Applied Process Design for Chemical and Petrochemical Plants

Example 8-26: Distillation With Two Sidestream Feeds

Data for Example 8-26, which includes two sidestreams

Relative Mole Fraction

- ___ - -
~~
1 (LK)
2 (HK) .025
3 (HK+ 1) 0.5 00 1
~ _ _ ~ ~
Feeds: F1 = 50 mol/hr, qF1 = 1 (saturated liquid)
F2 = 100 mol/h, qF2 = 0 (saturated vapor)
Sidestreams: S1 = 20 mol/h, qs, = 1 (saturated liquid)
S2 = 20 mol/h, qs2 = 1 (saturated liquid)
Distillate: D = 36 mol/h

Minimum reflux and other results for Example 8-26

1. UNDERWOOD THETAS:
FORFEED 1 THETA (1) = 1.164
FOR FEED 2 THETA (2) = 1.485
2. MINIMUM REFLUX CANDIDATES:
FOR FEED 1 RMIN (1) = 3.450271
FOR FEED 2 RMIN (2) = 4.375502
3. TRUE MINIMUM REFLUX RATIO:
RMIN = 4.38

Column representation of results of Example 8-26