Binary Distillation
University of Illinois at Chicago
Binary Distillation–Pre Lab
This schematic illustrates what happens in a distillation column. A liquid mixture is fed into the
distillation column. On entering the column, the heated feed is partially vaporized and rises up
the column. However, as it rises, it cools by contacting the descending cooler liquid and partially
condenses so that, while part of vapor continues to flow upward, the condensed portion is
enriched in the less volatile component(s) and flows downward. As the vapor continues to flow
upward, it undergoes partial condensation a number of times and each time becomes richer in the
more volatile component(s).
Unit Operations Lab 4
March 11, 2010
Group 3
Shrikant Shah
Brandon Farr
Alex Georg
Michael Ogiefo
Mohammed Khatib
Ghassan Alkhateeb
Unit Operations ChE-382 Group No. 3
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Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
3/11/2010
Binary Distillation
University of Illinois at Chicago
Table of Contents
1.
WP&C .................................................................................................................................................. 2
1.
Introduction ......................................................................................................................................... 4
2.
Theory .................................................................................................................................................. 5
3.
Apparatus .......................................................................................................................................... 13
4.
Materials and Supplies ..................................................................................................................... 18
5.
Procedure ........................................................................................................................................... 19
8.
Error Analysis ................................................................................................................................... 21
9.
References .......................................................................................................................................... 22
1. WP&C
What is the purpose of this experiment?
Unit Operations ChE-382 Group No. 3
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Spring 2010
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Binary Distillation
University of Illinois at Chicago
The purpose of this experiment is separate a mixture of a 5% wt methanol-water solution in a binary distillation
column. About 0.1-2 GPM of methanol-water mixture will be introduced into the round bottom flask of the column.
The column will operate at temperatures ranging from 0-100oC. The column will be run and allowed to reach steady
state before samples from the six stages will be obtained and tested with a Refractometer to eventually obtain the
methanol concentration in each stage.
What are the hazards associated with the experiment?
1.
2.
3.
Methanol is relatively toxic fluid. It can cause eye, skin and respiratory tract irritation when carelessly
exposed to lab personnel.
The electrical wires for the thermocouples are carelessly exposed. If lab personnel were to accidentally touch
them while conducting experiment, they run the risk of an electric shock.
The persistent use of fluids like water and methanol could lead to fluid spillage. If lab personnel were to walk
over an affected area, they run the risk of injuries due to a fall.
How will the experiment be conducted in a safe manner?
1.
2.
3.
Lab personnel should wear gloves, goggles, slip resistant shoes, and a facemask when conducting experiment
especially when handling the methanol.
Paper towels or task wipers should be in close proximity to clean up any fluid spills that may occur during
experiment.
The Distillation column should not be heated until the mixture has reached the Reboiler section of unit.
What safety controls are in place?
1.
There is a failsafe valve present that allows the removal of fluids incase the unit gets flooded.
Describe safe and unsafe ranges of operations.
1.
The operating flow rates of water should be between 0-2 GPM. All relevant data can be obtained in this
range. An increase flow rate between 3-10 GPM could be hazardous due to increased pressure.
Signatures:
Shrikant Shah
Brandon Farr
Alex Georg
Michael Ogiefo
Mohammed Khatib
Ghassan Alkhateeb
Unit Operations ChE-382 Group No. 3
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Binary Distillation
University of Illinois at Chicago
1. Introduction
Distillation is a physical separation process that uses the differences in volatility between
compounds in a liquid mixture. Binary distillation separates two liquid components from one
another. All fluids possess some degree of volatility that is a measure of their tendency to
vaporize. A higher volatile compound such as methanol will vaporize more quickly when
compared to water under the same atmospheric conditions. Boiling the two components would
also make the difference even more apparent, as the less volatile water would boil at a higher
temperature than the methanol. More importantly, even when two components are mixed
together, the unique physical properties of the individual component still causes the more volatile
component to vaporize faster. This is what ultimately makes distillation possible.
A single step of distillation uses these principles of volatility to achieve a separation of
compounds at equilibrium. At the boiling point of a mixture, the more volatile component exists
as a greater fraction in the vapor than it will in the liquid. In a methanol-water mixture,
distillation would yield a greater mole fraction of methanol in the vapor than in the liquid.
Condensing the vapor and adding more distillation steps or stages in series is the basis for
continuous distillation. When a continuous system is arranged vertically, the system is defined
as a distillation column. In such a column, falling liquids vaporize at lower stages and rising
vapors condense at higher ones. A heat source at the bottom of the column enables this action,
creating a decreasing temperature gradient up the column. With more distillation steps greater
purity can be achieved in top and bottom of the column.
Distillation columns are widely used for separations in industry, most notably in
petroleum, natural gas, and chemical processing, as well as any other large-scale liquid
Unit Operations ChE-382 Group No. 3
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Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
3/11/2010
Binary Distillation
University of Illinois at Chicago
production. In processing petroleum, different hydrocarbons can be separated according to their
volatility. Medicinal herbs can be distilled from plant matter in the pharmaceutical industry.
Methanol is distilled for high alcohol content products such as whiskey.
In this experiment, we will distill a mixture of methanol and water in a column distiller.
The apparatus has six trays that will act as the stages of the continuous distillation. Collection of
the condensate at each of these stages will allow an analysis of the composition at each plate.
The temperature will also be recorded at each stage. Ultimately, decreasing temperatures and
increasing compositions of methanol will be observed up the column. Finally, vapor-liquid
equilibrium data will allow a comparison between experimental results and theoretical trends.
2. Theory
Distillation is the separation, by vaporization, of different components in a mixture
because of the different volatilities that they possess at a given boiling point of the mixture.
When a mixture reaches a specific temperature and pressure a certain amount of the mixture
moves into the vapor phase until the vapor reaches the mixture’s vapor pressure. This point is
known as the vapor-liquid equilibrium. Volatility is a measure of a pure component’s vapor
pressure at a set pressure and temperature in a specific mixture. It is incorrectly assumed that the
components of a mixture will separate based on their boiling points when pure. Rather, the
boiling point of a mixture is based on the total vapor pressure of a mixture, which is a sum of the
vapor pressures of each individual component in the mixture. This is known as Dalton’s law.
𝑃 𝑠𝑎𝑡 = ∑(𝑣𝑝𝑎 + 𝑣𝑝𝑏 … )
(1)
Where,
Unit Operations ChE-382 Group No. 3
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Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
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Binary Distillation
University of Illinois at Chicago

𝑃 𝑠𝑎𝑡 [=] Vapor pressure of mixture [kPa]

𝑣𝑝𝑎 [=] Vapor pressure of component a [kPa]

𝑣𝑝𝑏 [=] Vapor pressure of component b [kPa]
This means that a component will not boil off “cleanly” meaning it is impossible through
distillation to obtain a pure substance. The vapor created above a mixture is also a mixture of
components. The composition of the vapor is based on the volatility of each of the substances.
Raoult’s law helps us to determine what the volatility, or “K value” of a substance. This in turn
allows us to find the mole fraction of a component in the vapor phase.
𝑦𝑎 =
𝑣𝑝𝑎 ∙𝑥𝑎
(2)
𝑝𝑠𝑎𝑡
Where:

𝑦𝑎 [=] mole fraction of component a in vapor phase (dimensionless)

𝑣𝑝𝑎 [=] vapor pressure of component a [kPa]

𝑥𝑎 [=] mole fraction of component a in liquid phase (dimensionless)

𝑃 𝑠𝑎𝑡 [=] Vapor pressure of mixture [kPa]
Not all mixtures obey Raoult’s law. Some components that have high solubility with each
other form azeotrope. An azeotrope is a mixture that has either a higher or lower boiling point
than the boiling point of any of the pure components. This means that when a mixture reaches an
azeotrope, such as ethanol and water at 95.6 % water, it behaves as a pure substance.
The simplest of all distillation techniques is called flash distillation. Flash distillation occurs
when a mixture at a specific temperature and pressure is allowed to drop in pressure. This
Unit Operations ChE-382 Group No. 3
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Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
3/11/2010
Binary Distillation
University of Illinois at Chicago
changes the vapor-liquid equilibrium of the mixture and creates a vapor rich in the most volatile
component(s). This is also the crudest form of distillation and does not allow for refinement of
the distillates.
A more complicated form of distillation is batch distillation. Batch distillation uses both a
boiler and a condenser, but only allows one separation, or cut, to be taken from the mixture.
Figure 1: A schematic of a typical continuous distillation tower. A is the kettle that holds the
liquid mixture, B is the Reboiler that adds heat to the mixture, C is the distillation column that
holds the trays or packing, D is the condenser that turns the distillate to a liquid product.
Continuous distillation is the most complicated and most common form. It has a boiler,
condenser and multiple trays or packing which allows the vapor to condense as it moves up the
column and cools. The trays or packing allows for a better separation of the components in the
mixture which in the end gives purer products. It also adds a lot of complexity to the system.
Unit Operations ChE-382 Group No. 3
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Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
3/11/2010
Binary Distillation
University of Illinois at Chicago
Figure 2: A typical tray in a distillation column. A is the tray itself, B are the holes in the tray
that allow the vapor to pass through the tray, C and D are the tubes that allow liquid to pass from
one tray to another. As the vapor moves up the column it gets progressively cooler which allows
some of the mixture to condense and further concentrates the vapor with the lightest
component(s).
Figure 3: This shows a simple McCabe-Thiele diagram. The number of steps corresponds to the
number of trays needed for a given mixture.
Unit Operations ChE-382 Group No. 3
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Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
3/11/2010
Binary Distillation
University of Illinois at Chicago
Determining the size of the tower and the number of trays needed was historically a very
difficult process involving many calculations. The McCabe-Thiele method greatly simplified that
process. The method uses a graphical representation of the material balance equations as
operating lines on a graph of the liquid composition (x-axis) and the vapor composition (y-axis).
The bottom line in Figure 3 is the x-y line. This starts at the origin and ends where x and y both
equal 1.This line would represent a distillation column that operated at total reflux and total boilup, meaning that all of the vapor and all of the liquid is recycled back into the system. The next
line added is the vapor –liquid equilibrium line for a binary system which is found
experimentally. By moving step-wise between the two lines we can find the number of
theoretical plates needed for a specific separation of a binary mixture and the liquid and vapor
composition at any point in the distillation column. These stage lines can be seen in Figure 3.
Unit Operations ChE-382 Group No. 3
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Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
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Binary Distillation
University of Illinois at Chicago
Figure 4: McCabe-Thiele diagram with operating lines and feed line added.
In practice, we want to draw a purified product out of the column in the form of either a
distillate (top of the column) or the bottoms product (bottom of the column) or both. This
requires a column that operates at a partial reflux and/or a partial boil-up ratio. This means that
we cannot use the x-y line for such a column. In Figure 4 we see the addition of a line for reflux
ratio (slope L/V) and a line for the boil-up (slope L’/V’). The boil-up line’s slope increases as we
increase the amount of bottoms product that we remove from the system. Subsequently, as we
remove more distillate as product we decrease the slope of the top operating line, which is the
line for the reflux ratio. By changing the amount of liquid re-boiled, which is liquid returned to
the column as a vapor, or by changing the amount of vapor refluxed, returned to the column as a
Unit Operations ChE-382 Group No. 3
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Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
3/11/2010
Binary Distillation
University of Illinois at Chicago
liquid, we change the number of theoretical plates necessary for a given separation. The q
(quality) line in Figure 4 is the feed line which is the composition of the stream entering the
distillation column. We can see from the diagram in Figure 4 that where that line intersects with
the two operating lines is the feed stage, or the tray at where the incoming stream enters.
The quality q is defined as:
𝑞=
𝐿̅ −𝐿
𝐹
≈
𝐻−ℎ𝑓
(3)
𝐻−ℎ
Where:

𝑞 [=] quality of the feed (dimensionless)

𝐿̅ [=] liquid flow rate below the feed (mol/hr)

L [=] liquid flow rate above the feed (kJ/kg)

F [=] feed flow rate (mol/hr)

H [=] saturated vapor enthalpy of feed (kJ/kg)

hf [=] enthalpy of feed (kJ/kg)

h [=] saturated liquid enthalpy of feed (kJ/kg)
The feed line can then be defined as:
𝑞
𝑍
𝑥+ 𝐹
)
𝑞−1
1−𝑞
𝑦=(
(4)
Where:

y [=] vapor mole fraction of methanol (dimensionless)

q [=] quality of the feed (dimensionless)
Unit Operations ChE-382 Group No. 3
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Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
3/11/2010
Binary Distillation
University of Illinois at Chicago

x [= ] liquid mole fraction of methanol (dimensionless)

ZF [=] mole fraction of methanol in feed (dimensionless)
The top operating line is defined as
𝑦=
𝐿0
𝐷
𝐿
(1+ 0 )
𝐷
𝑥 + (1 −
𝐿0
𝐷
𝐿
1+ 0
𝐷
) 𝑥𝐷
(5)
Where:

y [=] vapor mole fraction of methanol (dimensionless)

L0 [=] liquid reflux rate into column (mol/hr)

D [=] distillate flow rate (mol/hr)

x [=] liquid mole fraction of methanol (dimensionless)

xD [=] mole fraction of methanol in distillate (dimensionless)
The McCabe-Thiele method is widely used for binary mixtures. When dealing with multicomponent mixtures addition assumptions and calculations are necessary. There are a number of
issues that need to be watched when sizing a continuous distillation column properly. They are:
Foaming- foaming occurs when the gas passing upward causing the liquid to bubble
excessively. While this normally depends on the properties of the liquid, it can also be caused by
improper tray designs.
Entrainment- Occurs when the vapor velocity is too high due to a column having too
small of a diameter. This causes liquid to be held up at the trays and does not allow proper
circulation of the liquid.
Unit Operations ChE-382 Group No. 3
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Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
3/11/2010
Binary Distillation
University of Illinois at Chicago
Weeping- Occurs when the vapor velocity is too low. When the velocity drops too low,
liquid starts to fall, or weep, through the holes in the plates. This does not allow enough liquid to
get to the re-boiler which means that the entire column needs to be shut down and re-started.
Flooding- This occurs when liquid entrainment become too severe. This causes a large
pressure drop in the column and contaminates the distillate.
3. Apparatus
Unit Operations ChE-382 Group No. 3
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Binary Distillation
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Figure 5 represents the Binary Distillation apparatus without any of the support beams. The column is
constructed of a round bottom flask (7) which holds a methanol- water solution. This solution is distilled by
applying electrical energy to the heating jacket (24) which heats up the solution causing the volatile liquids and
gases to rise. Total reflux occurs in the system by feeding cooling water (10) into a cooling coil (16) at the top
of the column. Thermocouples (T1-T9) measure the temperatures at various points in the system and output
them onto an electrical temperature monitor (21). Liquid and gaseous samples are taken at ever one of the 6
stages via sample ports (L1-L6 &G1-G6) and tested with a Refractometer to calculate the density and
eventually the composition of the samples.
Unit Operations ChE-382 Group No. 3
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Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
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Binary Distillation
University of Illinois at Chicago
Table 1: Binary Distillation Apparatus Summary (For Figure 5)
Component No.
Apparatus Component
1
Water Connection for
Apparatus
Manufacturer
Description
Notes/Safety
ChE Unit Ops
Water supplied by lab
2
Water Supply Valve
MCD
Used to load water into Storage Tank.
3
Funnel
Na
4
13 Gallon Feed Tank
Nalgene
5
Feed Supply Valve
Nalgene
6
Three way valve
Swagelok
Used to ease filling of solutions
Used to load 5 mol% ethanol solution
before filling flask
Only open when filling round bottom
flask
Valve is labeled to either drain, fill or
prevent loss
7
Round Bottom Flask
Na
8
Valves & Sample Ports
Nalgene
9
Glass sections of column
Na
10
Cooling water Connection
for Apparatus.
ChE Unit Ops
Cooling water is supplied by lab
11
Cooling Water Supply Valve
Cold Chicago
Faucets
Used to start flow of cooling water
into system.
12
Cold Water Temperature
Gauge
Marsh Instrument
Company
Measures the temperature of the
incoming cooling water.
Range: 0-60 oF, Increments: 1 oF
13
Cooling Water Apparatus
Valve
Cold Chicago
Faucets
Used to start flow of cooling water
into apparatus.
Check for leaks and cracks.
Always open when distillation
column is in operation to supply
ample cold water.
14
Cold Water Rotameter
(Measures in liquid GPM)
Schutte &
Koerting Co.
15
Temperature Gauge
Moeller
16
Cooling Coil
Na
17
Temperature Gauge
Weksler
18
Cold Water Drain Valve
Cold Chicago
Faucets
19
Heat Controller
Na
20
Heat Supply for Heating
Jacket
Powerstat
Used to hold the Methanol-water
solution
Located at different heights along the
column to obtain experimental
samples
Each section at collection point is
pieced together. The top piece
contains the cooling water tubes and a
narrowed opening so that total reflux
can be assumed.
Measures flow of cooling water into
cooling coil.
(Measures in liquid GPM)
Measures temperature of cooling
water before entering cooling coil in
degrees Celsius.
Coil where heat transfer takes place
between distillate and cooling water
to provide total reflux.
Measures temperature of cooling
water exiting column in degrees
Celsius.
Allows cooling water to exit system
and drain.
Used to turn on heaters individually
including heating jacket.
Conducts electricity and passes it into
the heating jacket
Unit Operations ChE-382 Group No. 3
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Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Check for leaks and cracks.
Clean up spills immediately.
Check for leaks and cracks that
could cause malfunctions.
Do not overfill
Check for cracks and overall
structural integrity.
Check for leaks and cracks that
could cause malfunctions.
Check for leaks and cracks that
could cause malfunctions.
Do not heat when empty!!
Ensure flask is cooled before
adding any fluid Look for any
leaks or cracks before adding
solution or heat.
Check for cracks and leaks that
could cause malfunctions.
Examine entire column for any
leaks, cracks or anything that
could fracture structural integrity
Always open when distillation
column is in operation to supply
ample cold water.
Always open when distillation
column is in operation to supply
ample cold water.
Check for leaks and cracks that
could cause malfunction
Check for any leaks or cracks that
could cause malfunctions.
Check for any leaks or cracks that
could cause malfunctions.
Check for any leaks or cracks that
could cause malfunctions.
Check for any leaks or cracks that
could spill water
Check for any leaks or cracks that
could cause malfunctions.
Examine for loose wires or
malfunction
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University of Illinois at Chicago
21
Digital Temperature Monitor
Monogram
22
Thermocouples
Omega
Power switch for heater
Square D Safety
Switch
Electric Heating Jacket
Na
23
24
Component No.
T1
T2
T3
T4
T5
T6
T7
T8
T9
Check for loose wires or
malfunctions that may be
causedby leaks.
Displays temperature taken at the
different thermocouples.
Measure temperature at different
stages in distillation column.
Reading outputs on Digital
temperature display
Controls the electricity passing into
the electric heating jacket turning it
either on or off.
Heats the bottom of the distillation
column electrically.
Make sure probes are secure and
allow no leaks to touch them.
Do not turn on unless cold water
is flowing. Monitor temperatures
and adjust as needed.
Very HOT. Exercise extreme
caution during operation.
Table 2: Binary Distillation Thermocouple Summary (For Figure 5)
Apparatus Component
Manufacturer
Description
Notes/Safety
Round Bottom Flask
Thermocouple
Omega
Measures temperature of solution in
round bottom flask.
Stage 1 Thermocouple
Omega
Measures the temperature at stage 1.
Stage 2 Thermocouple
Omega
Measures the temperature at stage 2.
Pay close attention to
temperature so column does not
overheat.
Stage 3 Thermocouple
Omega
Measures the temperature at stage 3.
Pay close attention to
temperature so column does not
overheat.
Stage 4 Thermocouple
Omega
Measures the temperature at stage 4.
Pay close attention to
temperature so column does not
overheat.
Stage 5 Thermocouple
Omega
Measures the temperature at stage 5.
Pay close attention to
temperature so column does not
overheat.
Stage 6 Thermocouple
Omega
Measures the temperature at stage 6.
Pay close attention to
temperature so column does not
overheat.
Thermocouple above Stage 6
Omega
Measures the temperature above stage
6.
Pay close attention to
temperature so column does not
overheat.
Thermocouple placed before
cooling coil
Omega
Measures the temperature of the
cooling water before it is introduced
into the cooling coil.
Pay close attention to
temperature so column does not
overheat.
Unit Operations ChE-382 Group No. 3
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Make sure probe is secure and
tube is filled with white oil.
Pay close attention to
temperature so column does not
overheat.
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University of Illinois at Chicago
Table 3: Binary Distillation Sample Port Summary (For Figure 5)
Manufactur
Apparatus Component
Description
er
Notes/Safety
Gas sample collected from the stage 1 sample
plate via a sealed tube and release valve
(collection port).
Gas sample collected from the stage 2 sample
plate via a sealed tube and release valve
(collection port).
Keep watch for leaks. Close when not in use.
Keep samples cold by collecting samples with
ice. Clean up any spillage immediately.
Keep watch for leaks. Close when not in use.
Keep samples cold by collecting samples with
ice. Clean up any spillage immediately.
Na
Gas sample collected from the stage 3 sample
plate via a sealed tube and release valve
(collection port).
Keep watch for leaks. Close when not in use.
Keep samples cold by collecting samples with
ice. Clean up any spillage immediately.
G4
Gas Sample Collection Port
for stage 4.
Na
Gas sample collected from the stage 4 sample
plate via a sealed tube and release valve
(collection port).
Keep watch for leaks. Close when not in use.
Keep samples cold by collecting samples with
ice. Clean up any spillage immediately.
G5
Gas Sample Collection Port
for stage 5.
Na
Gas sample collected from the stage5 sample
plate via a sealed tube and release valve
(collection port).
Keep watch for leaks. Close when not in use.
Keep samples cold by collecting samples with
ice. Clean up any spillage immediately.
G6
Gas Sample Collection Port
for stage 6.
Na
Gas sample collected from the stage 6 sample
plate via a sealed tube and release valve
(collection port).
Keep watch for leaks. Close when not in use.
Keep samples cold by collecting samples with
ice. Clean up any spillage immediately.
L1
Liquid Sample Collection Port
for stage 1.
Na
L2
Liquid Sample Collection Port
for stage 2.
Na
Liquid sample collected from the stage 2 sample
plate via a sealed tube and release valve
(collection port).
Keep watch for leaks. Close when not in use.
Keep samples cold by collecting samples with
ice. Clean up any spillage immediately.
L3
Liquid Sample Collection Port
for stage 3.
Na
Liquid sample collected from the stage 3 sample
plate via a sealed tube and release valve
(collection port).
Keep watch for leaks. Close when not in use.
Keep samples cold by collecting samples with
ice. Clean up any spillage immediately.
L4
Liquid Sample Collection Port
for stage 4.
Na
Liquid sample collected from the stage 4 sample
plate via a sealed tube and release valve
(collection port).
Keep watch for leaks. Close when not in use.
Keep samples cold by collecting samples with
ice. Clean up any spillage immediately.
L5
Liquid Sample Collection Port
for stage 5.
Na
Liquid sample collected from the stage5 sample
plate via a sealed tube and release valve
(collection port).
Keep watch for leaks. Close when not in use.
Keep samples cold by collecting samples with
ice. Clean up any spillage immediately.
L6
Liquid Sample Collection Port
for stage 6.
Na
Liquid sample collected from the stage 6 sample
plate via a sealed tube and release valve
(collection port).
Keep watch for leaks. Close when not in use.
Keep samples cold by collecting samples with
ice. Clean up any spillage immediately.
Gas Sample Collection Port
for stage 1.
Na
G2
Gas Sample Collection Port
for stage 2.
Na
G3
Gas Sample Collection Port
for stage 3.
G1
Liquid sample collected from the stage 1 sample
plate via a sealed tube and release valve
(collection port).
Unit Operations ChE-382 Group No. 3
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Keep watch for leaks. Close when not in use.
Keep samples cold by collecting samples with
ice. Clean up any spillage immediately.
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4. Materials and Supplies
Table 4: Binary Distillation Materials and Supplies Summary
Material Name
Manufacturer
Tap Water
Lake Michigan
White Oil
Chevron Superla 5
Description/ Info
Notes/Safety
Used in preparation of
Methanol-water solution.
Used inside the
temperature probe tube
within the round bottom
flask.
Clean up any spillage
immediately.
Clean up any spillage
immediately. Do not ingest
Will vaporize at room
temperature and is toxic.
Do not allow to escape
through top of distillation
column by circulating
ample cold water. Clean
up any spillage
immediately. Do not ingest
Clean up any spillage
immediately. Try to keep
samples cold to ensure
vaporization does not
occur.
Methanol
Aldrich Chemical
Company
99.8% Methanol used to
prepare water-methanol
solution that is then fed
into the distillation column.
Ice
From Unit OPS Lab
Used to cool test tubes to
ensure vaporization does
not occur in samples.
Na
Used to transfer samples
from apparatus to test
tubes.
Clean up any glass
breakage immediately if it
occurs.
Kimble Glass Company
Used to hold test solutions
to use in Refractometer for
sample results.
Clean up any glass
breakage immediately if it
occurs.
Micropipette
Test Tubes
Refractometer
Graduated Cylinder
Task wipers
Bausch & Lomb
Nalgene
Kimberly Clark
Professional
Used in the experiment to
obtain the refractive index
that can be used to
calculate density once
calibrated.
Used to measure Methanol
and H2O to make the
solution
Used to clean equipment
before, during, and after
operations.
Unit Operations ChE-382 Group No. 3
p. 18
Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Use caution when
handling. Calibrate before
operation.
Clean up any spillage
immediately.
Clean any mess or spillage
promptly.
Spring 2010
3/11/2010
Binary Distillation
University of Illinois at Chicago
5. Procedure
Distillation Column Operation:
1. Make a 5 mol% methanol solution by mixing it with water in the 13 gallon feed tank (4)
using graduated cylinders for measurement.
Note: make sure not to over fill the round bottom flask (7). It only needs to be filled
halfway or until the thermocouple (T1) is in contact with the mixture.
2. Pour the methanol-water mixture into the feed container and turn ON the three-way valve
in order to fill up the round bottom flask.
3. Open the cooling water supply valves (11 & 13) to supply cooling water to the
distillation column.
4. Start up the distillation column by turning on the power supply switches (22) to supply
heat to the distillation column.
5. Record the temperature of each of the thermocouples (T1-T9) located throughout the
column by analyzing the digital temperature monitor (21). Also record the readings of
the inlet cooling water temperature gauge (12), the outlet cooling water temperature
gauge (17), the inlet cooling water pressure gauge (15), and the cooling water rotameter
(14).
6. Make sure to collect the samples at each stage via the sample ports (G1-G6 &L1L6) of the distillation column and record the index of refraction by using the
Refractometer.
7. After the distillation process is done, make sure to turn OFF the heater power
supply, and the cooling water supply.
Operating the Bausch & Lomb Abbe-3L Refractometer:
1. Make mixtures from 10% Methanol with water to 100% Methanol in small test tubes
using a pipette.
2. Turn ON the Refractometer and the water heating system.
3.
Open the prism assembly and remove the tissue.
4. Use a capillary tube to apply your liquid sample to the prism and close the prism
assembly.
Unit Operations ChE-382 Group No. 3
p. 19
Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
3/11/2010
Binary Distillation
University of Illinois at Chicago
NOTE: Be careful not to let the glass pipette tip touch the prism since this may scratch the
prism glass.
5. Adjust the toric lens, so the light shines on the prism and look through the eyepiece.
6. Analyze the index of refraction of the sample:
a. When the index of refraction of your sample is close enough, then you will see
lighter region on the top and darker region on the bottom.
b. If you cannot distinguish between these two regions then adjust the compensator
scale dial of the machine and the toric lens until the dark and light region is
completely separated.
Note: it is an iteration process between adjusting the light and the focus wheel located on the
front of the Refractometer.
c. Once the clear distinguishable line between dark and light region is seen then
press the momentary contact switch located on the left hand side of the machine
until you see the scale. Then read off the index of refraction by looking at the
top scale and the refined bottom scale.
7. After you have noted down the index of refraction, record the temperature by
reading the temperature scale.
8. Make sure to clean the prism after testing each sample with a solvent and dabbing it with
tissue.
Unit Operations ChE-382 Group No. 3
p. 20
Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
3/11/2010
Binary Distillation
University of Illinois at Chicago
8. Error Analysis
Table 5: Sources of Uncertainty for Binary Distillation Lab
Component
Manufacturer
Uncertainty Expected
Description
100 mL Graduated Cylinder
Nalgene
± 0.5mL
The 100mL graduated cylinder measures
liquid in increments of 1mL. The lines can
be accurately read to within ± 0.5mL
Electronic Balance
Denver Instrument Co.
±0.01g
Via the manufacture’s website, the scale
used in this experiment has an associated
uncertainty of ±0.01g
± 1 oF
The temperature gauges measure in
increments of 2 oF. By dividing the
increments by 2 the expected uncertainty
can be projected to be ± 1 oF.
± 0.1 oC
The temperature monitor measures in
increments of 0.1 oC. The readings are
accurate when the column reaches steady
state and according to the manufacturer’s
website, are accurate to ± 0.1 oC.
±0.0001
The Refractometer measures the refractive
index of a mixture in increments of 0.0002.
However, the values can be read accurately
to the nearest 0.0001.
Weksler
Temperature Gauges
&
Moeller
Digital Temperature Monitor
Monogram
Refractometer
Bausch & Lomb
Listed above are components of the binary distillation lab whose specific uncertainties would
directly affect our recoded data. If these uncertainties were to occur, they would affect our
overall results by adding specific uncertainties to them.
Unit Operations ChE-382 Group No. 3
p. 21
Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
3/11/2010
Binary Distillation
University of Illinois at Chicago
9. References
1. Wankat, Phillip C.; Separation Process Engineering, second edition, Prentice Hall,
2007
2. R. Bird, W. Stewart, E. Lightfoot. Transport Phenomena. Wiley, 2006
3. Towler, G. and Sinnott, R., Chemical Engineering Design: Principles. BH, 2008
4. W. McCabe, J. Smith, and P. Harriot, Unit Operations of Chemical Engineering. 7th
ed. McGraw-Hill, 2005.
5. M. J. Moran, H. N. Shapiro, Fundamentals of Engineering Thermodynamics. 5th ed.
Wiley, 2004
6. Edited by Don Green; John Perry’s Chemical engineering Handbook, seventh edition,
McGraw-Hill, New York, 1997
7. Dean, John A., “Lange's Handbook of Chemistry,” 15th edition. New York, NY: John
Wiley & Sons, Inc., 1998.
8.
Felder, Richard M., and Ronald W. Rousseau. Elementary Principles of Chemical
Processes. 3rd ed. New York, NY: John Wiley & Sons, Inc., 2000.
9. Bennett C.O., Myers J.E., Momentum, Heat, and Mass transfer. 3rd edition New York.
McGraw-Hill, 1982.
10. Wikipedia: http://en.wikipedia.org/wiki/Distillation
11. Website: http://lorien.ncl.ac.uk/ming/distil/distil0.htm
Unit Operations ChE-382 Group No. 3
p. 22
Shah, Farr, Georg, Ogiefo, Khatib, Alkhateeb
Spring 2010
3/11/2010