Unformatted text preview: r with APISRK for Kvalues, with the immiscible
option and the threephase flash model. The following results are obtained:
T = 70.8oC Vapor mole fractions are toluene 0.23, ethyl benzene 0.13, water 0.64 Exercise 4.74
Subject: Bubble, dew, and 50 mol% flash conditions for watern butanol mixture.
Given: Mixture of 60 mol% water (W) and 40 mol% nbutanol (B) at 101 kPa
Find: (a) Dewpoint temperature and liquid composition.
(b) Bubblepoint temperature and vapor composition.
(c) Temperature and phase compositions for 50 mol% vaporization.
Analysis: Use the CHEMCAD simulator with UNIFAC LLE for Kvalues, with the threephase
flash model. The following results are obtained:
(a) 100.1oC with liquid mole fractions of 0.242 for W and 0.758 for B.
(b) 93.5oC with vapor mole fractions of 0.773 for W and 0.227 for B. Note that the liquid
consists of two phases, with the waterrich phase containing mole fractions of 0.969 for W and
0.031 for B. The less Wrich phase contains mole fractions of 0.564 for W and 0.436 for B.
(c) 94.5oC with vapor mole fractions of 0.742 for W and 0.258 for B and a single liquidphase
mole fractions of 0.458 for W and 0.542 for B.
The results deviate somewhat from Fig. 4.8. Exercise 4.75
Subject: Isothermal threephase flash of 6component mixture.
Given: Feed mixture with composition given below.
Find: Flow rates and compositions for 25oC and 300 kPa.
Analysis: Use the CHEMCAD simulator with UNIFAC LLE for Kvalues, with the threephase
flash model. The following results are obtained:
kmol/h:
Component:
Feed
Vapor Liquid I Liquid II
Hydrogen
350
349.90
0.07
0.03
Methanol
107
4.87
14.31
87.82
Water
491
3.32
3.04
484.64
Toluene
107
0.75
106.16
0.09
Ethyl benzene
141
0.37
140.59
0.04
Styrene
350
0.57
349.19
0.24
Total:
1,546
359.78
613.36
572.86 Exercise 5.1
Subject: Threecolumn interlinked cascade for a fourcomponent system. Given: Configuration for a twocolumn interlinked cascade for a threecomponent
system
Find: Devise the threecolumn cascade.
Analysis: The system is shown in the sketch below. Assume that the feed is
comprised of components A, B, C, and D in the order of decreasing volatility. Starting
from the feed end at the lefthand side, Column 1 performs a sloppy split to separate the
feed into an overhead of A, part of B, and part of C; and a bottoms of part of B, part of C,
and D. In the second column, the overhead is A and part of B, the middle sidestream is
part of B and part of C, while the bottoms is D and part of C. In the third column, the
four products are removed in nearly pure states. Exercise 5.2
Subject:
Given: Batch cascades for liquidliquid extraction
Batch process in Fig. 5.19 Find: (a) Cascade diagram for Fig. 5.19.
(b) Type of cascade in Part (a).
(c) Comparison of process in Fig. 5.19 to a single stage process.
(d) Modification to achieve a countercurrent cascade.
Analysis: (a) A cascade diagram representing Fig. 5.19 is the following: Exercise 5.2 (continued)
(b) The above cascade is a twodimensional triangular cascade of the crosscurrent type.
(c) For a single batch extraction...
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 Spring '11
 Levicky
 The Land

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