Binary Distillation

Report
Group 5
Alex Guerrero
Andrew Duffy
Bernard Hsu
Daniyal Qamar
Jeff Tyska
Ryan Kosak
Tomi Damo
ChE 382 Group 5
4/14/2011
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Binary distillation involves only 2
components
 It works by using the differences in boiling
points for separation

› Methanol BP: 65°C
› Water BP: 100°C

This column uses multiple trays for
separation
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
The column runs under total reflux
› Therefore no methanol vapor leaves
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
The purpose of this experiment is to:
› Separate a binary mixture of methanol and
water
› Learn how to use a refractometer
› Create a calibration curve
› Use live data from the refractometer to
determine the degree of separation
throughout the column
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Works by the difference in component
volatilities
 Lighter compounds (lower boiling point) will
have a higher concentration in the vapor
phase
 Like wise the heavier compounds will be
found in the liquid phase
 Relative volatility is the ratio of the volatilities
of the lighter component over the volatility
of the heavier component

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Heat is supplied in the reboiler
 The condenser at the top uses cold
water and runs under total reflux

› Total reflux = no operating lines on McCabe-
Thiele diagram
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
Murphee tray efficiency

Where:
› η = plate efficiency
› yn = mole fraction of component in vapor phase
at tray n (dimensionless)
› yn+1 = mole fraction of component in vapor
phase at tray n+1 (dimensionless)
yn* = the composition in equilibrium with Xn
(dimensionless)
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No. Component
1 Condenser
2 Water Supply
3 Liquid Rotameter
4 Stages (6)
5 Filling Tank
6 Ladder
7 Distillation Column Drain
8 Drain/Fill Valve
9 Pressure Gauge
10 Control Valve (flow rate)
11 Pressure Gauge Valve
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No.
Component
12 Heater
13 Thermometer
14 Digital Thermometer
15 Round Bottom Flask
16 Reboiler
17 Vapor Release Valve
18 Gas Tube
19 Liquid Release Valve
20 Liquid Tube
21 Funnel
22 Filling Tank Valve
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No.
Component
23 Refractometer
24 Eyepiece
25 Thermometer
26 Fine Tuning Knob
27 Focus Knob
28 Light Source
29 Scale Illumination
30 Illumination Prism
31 Cold Water Tubing
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No.
Component
32 Ice Bath
33 Liquid Controller
34 Temperature Controller
35 Switch
36 Digital Thermometer
37 Heating Coil
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No.
Material/Supply Description/Use
1 Tap Water
Used to make 5 wt% MeOH solution and supplied to condenser
2 Methanol
99.8% Anhydrous. Used to make 5 wt% MeOH working solution
Protect hands from toxic MeOH and prevent MeOH from drying
hands
3 Gloves
4 Goggles
Graduated
5 Cylinders
Eye protection
Measure MeOH amount to make 5 wt% solution
6 Ladder
To elevate operator so that he or she can add MeOH to filling tank
To collect samples of liquid and vapor at each stage of distillation
7 Small Test Tubes column
To clean the refractometer between readings, to make different
8 Distilled Water
MeOH wt% solutions when doing calibration curve
9 Ice
To create an ice bath for refractometer to maintain 34ºF temperature
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Creating the Calibration Curve:
1.
Plug in the Refractometer (23) and ice bath (32).
2.
Obtain ice from the Chemical Engineering office, fill the ice
bath about half way with ice, and add water.
3.
Adjust the heating to keep the system at 32°F.
4.
Create samples of methanol and water by mixing solutions of 0100% (use increments of 10) methanol by volume in small test
tubes (cover with para-film until testing).
5.
Place sample under the illumination prism (30), look through the
eye piece (24), press the illumination button near the back of
the machine then adjust the X to line up with the vertical line
using the fine tuning knob (26) and record the value of
refraction.
6.
Clean off sample with the provided Kimwipes and repeat for
all the samples to create a calibration curve of refraction versus
volume percent of methanol.
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Using the Batch Distillation Column:
1.
Make sure the drain valve for the filling tank (5) is set to the “Fill” setting and the tank is
closed.
2.
Measure out 1.6 L of methanol and pour it through the funnel (21) into the filling tank
(5) then add 32 L of water to the tank using the filling tank hose just above the funnel
to create 0.05% by volume mixture.
3.
Once the tank is full turn the Fill/Drain valve to “Drain” then open the filling tank valve
(22) to allow the mixture to fill the round bottom flask (15) of the distillation column.
4.
When the filling tank (5) is empty close the filling valve (22) and call the TA or instructor
to turn on the reboiler (16).
5.
Record the temperatures of thermocouples using the digital thermometer (14) every
20 minutes until steady state is met.
6.
Obtain samples of vapor and liquid from each stage using the vapor and liquid
release valves (17 and 19).
7.
Use the refractometer (23) to obtain the refraction index of each sample (Use the
same procedure as the calibration curve).
8.
Once all the samples are collected and measured turn off the column and allow it to
drain.
9.
Unplug and clean the refractometer (23) and ice bath (32).
10.
Dispose of samples accordingly.
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






The reboiler gets hot so avoid contact
The samples taken from the column are
very hot
Be careful when using the ladder
Avoid spilling any methanol
Avoid skin contact with methanol
Ensure the area around the column is
cleaned of any spilled water
Make sure no methanol vapor leaves the
top of the column
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







“Binary Distillation.”University of Illinois at Chicago - UIC. Web. 13
Sept. 2010.
<http://www.uic.edu/depts/chme/UnitOps/entry.html>.
Gilbert, John C., and Stephen F. Martin. Experimental organic
chemistry: a miniscale & microscale approach. 4th. BrooksCole
Pub Co, 2006. 137. Print.
http://www.separationprocesses.com/Distillation/DT_Chp05.htm
McCabe, Warren L., Julian C. Smith, and Peter Harriott. Unit
Operations of Chemical Engineering. New York: McGraw-Hill,
1993. (pp: 578-579) Print.
Stichlmair, Johann. 2000. “Distillation and Rectification.”
Encyclopedia of Industrial Chemistry. 7th. 40. New York, NY:
Wiley-VCH Verlag GmbH & Co., 2010. (pp: 1-97) Print.
Wankat, Phillip C. Separation Process Engineering. (2nd Edition).
Boston, MA: Pearson
Education, Inc., 2007. (pp: 187 – 284) Print
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