CE 408
Plant Design
Shaquille Louis
2/04/16
Homework 4
“ I love my Tesla P85D.”
-Elroy after using his job as a Chemical Engineer to buy a Tesla P85D.
Question 1
1. Set up a happy UniSim flowsheet for the distillation column in Flowsheet #1 as a Distillation
Column object. Set the Property Package to use the NRTL Activity Model (with Ideal Vapour
Model). Set the Pressure to 101.3 kPa for all streams. Use Reflux Ratio and Boilup Ratio as the
two Column Specifications, and set their numerical values on the basis of the answer to
Homework #1, problem 3, i.e., L=D = 6:0, V =B = 9:4. Set the number of trays and specify the
feed tray using rounded integer values also on the basis of the answer, i.e., 29 trays; feed enters
on tray 23 (counting down from top of column). State the UniSim-computed flow rates,
temperatures and compositions of the distillate and bottom product streams. Important note: be
sure to set up a happy UnSim flowsheet; sad UniSim flowsheets will receive zero credit.
Answer 1
Distillate Properties
99.67 Degrees C
.316 kgmole/h
11% acetic acid by mol
89% water by mole
Bottoms Properties
106.3 Degrees C
.2840 kgmole/h
72% acetic acid by mol
28% water by mol
Question 2
This problem is a variation on problem 1. Change the feed to a 10 mol/min saturated liquid
stream with composition 59.9 mole % water, 40 mole % acetic acid and 0.1 mole % carbon
dioxide. Leave everything else the same. State the UniSim-computed ow rates, temperatures and
compositions of the distillate and bottom product streams.
Answer
Distillate Properties
-5.572 Degrees C
.2910 kgmole/h
11% acetic acid by mole
88.8% by mole
2% CO2 by mole
Bottoms Properties
105.2 Degrees C
.3090 kgmole/h
67.3% acetic acid by mole
32.7% water by mole
0% C02 by mole
Question 3
3. This problem is a variation on problem 2 (which itself is a variation on
problem 1). Make the (further) change that the total condenser is replaced
with a partial condenser. Specify that the vapor (purge) stream leaving the
top of the condenser has a ow rate of 0.02 mol/min. State the UniSimcomputed ow rates, temperatures and compositions of the distillate and bottom
product streams.
Answer
Answer
Distillate Properties
83.34 Degrees C
.3077 kgmole/h
11% acetic acid by mole
88.8% by mole
2% CO2 by mole
Bottoms Properties
106 Degrees C
.2911 kgmole/h
71% acetic acid by mole
29% water by mole
0% C02 by mole
Question 4
4. This problem is a variation on problem 1. Change the feed to a 20 mol/min saturated liquid
stream with composition 30 mole % water, 20 mole % acetic acid, 15 mole % methanol and 35
mole % ethanol. Leave everything else the same. State the UniSim-computed flow rates,
temperatures and compositions of the distillate and bottom product streams.
Answer
Distillate Properties
74.91 Degrees C
.7316 kgmole/h
.05% acetic acid by mole
18% water by mole
0% CO2 by mole
25% methanol by mole
57% ethanol by mole
Bottoms Properties
102.4 Degrees C
.4672kgmole/h
51% acetic acid by mole
49% water by mole
0% CO2 by mole
0% methanol by mole
0% ethanol by mole