distillation column november 14, 2002 troy hall 615...

Distillation Column

Troy Hall November 14, 2002 1

November 14, 2002

Troy HallRed - Yellow Team: Distillation ColumnCollege Of Engineering and Computer ScienceUniversity of Tennessee at Chattanooga615 McCallie AvenueChattanooga, TN. 34705

To: Dr. Jim Henry, P.E. Professor of Engineering University of Tennessee at Chattanooga 615 McCallie Avenue Chattanooga, TN. 34705

Dr. Henry:

The following report is describing the continuous distillation for constant reflux of 95%but different wattage added to reboiler in the distillation column. This report details theobjectives, theory, procedure, equipment analysis, findings, and conclusions obtained.

Troy HallRed – Yellow TeamSenior Undergraduate StudentChemical EngineeringUniversity of Tennessee at Chattanooga

Distillation Column


Distillation Column Experiments, Continuous DistillationUniversity of Tennessee at Chattanooga

College of Engineering and Computer ScienceEngineering 435 Chemical Process Laboratory

Author: Troy HallTeam Members: John Mayes

Sidney SpencerAnthony PaolucciTo: Dr. Jim Henry

Cc: Dr. Frank Jones

Distillation Column


Abstract:

The distillation column at the University of Tennessee at Chattanooga was part of a

study for a continuous distillation with constant reflux of 95% using a binary mixture of

methanol and water. The university’s column was used for continuous distillation

experiments with constant reflux of 95% but different wattage added to reboiler in the

distillation column. The data was collected from the continuous distillation at different

wattages supplied to the reboiler and the average temperature was found for the top tray

when the system had reached steady state. Perry’s Handbook for Chemical Engineering

provided an X, Y vs. T diagram of methanol and water. By using the average temperature

of the top tray the distillate composition was found from the graph.

The composition of the column trays was calculated. An energy balance on the condenser

and reboiler was performed. A material balance was performed on the different wattages

being added to the reboiler.

A fifth experiment was conducted with the reflux ratio being lowered to 66% after steady

state was achieved.

Distillation Column


Table of Contents: Page

I Introduction………………………………………………………………………5

II Theory………………………………………………………………………...…6

III Equipment……………………………………………………..…………...…10

IV Operation Procedure…………………………………………………………..17

V Experimental Procedure………………………………………………………..19

VI Results………………………………………………………………………...21

VII Discussion of Results…………………………………………………………

VIII Recommendations……………………………………………………………

IX References………………………………………………………………………

X Appendices……………………………………………………………………….

Distillation Column


Section I -Introduction:

The purpose of this study of the distillation column by the Red – Yellow Team was to

study the continuous distillation for constant reflux but different wattage added to

reboiler in the distillation column. This process was conducted on the system at steady

state conditions.

The University’s distillation column was used to perform this investigation. The

distillation column consists of a liquid storage tank with cal rod for a heating element

called the reboiler, 12 distillation trays aligned in a vertical column. The trays serve to

allow the liquid and vapor phases to come in contact and into equilibrium with each

other. The vapor that is produced from the heating of the liquid in the reboiler is

condensed by cooling water that is located inside the condenser at the top of the

distillation column. This vapor is known as reflux and is collected. The collected reflux is

returned to the reboiler.

A theoretical background describing the distillation column and process is contained

in this report. Equipment section will describe the distillation column. Procedure will

describe the procedure used in the investigation on the system. Results will provide the

data that was recorded. The discussion of the results will follow with recommendations

for future experiments. References and Appendices will conclude this report.

Distillation Column


Section II-Theory:

Distillation is a process used to separate the substances composing a mixture. It

involves a change of state, as of liquid to gas, and subsequent condensation. The

distillation column at the University of Tennessee at Chattanooga was used to separate a

non-ideal mixture of methanol and water. This is known as a binary system since it

contains only two components.

A vapor - liquid equilibrium diagram, figure 1,was created from tabulated data in

Perry’s Handbook for methanol and water mixture. The diagram was used to determine

the composition of each tray.

Figure 1 represents a diagram of the vapor – liquid equilibrium for methanol and water.

The letter A represents the Dew Point on the liquid equilibrium line and the letter B

represents the Bubble Point on the vapor equilibrium line. In this example a temperature

of 78.0 °C is reached giving a dew point mol fraction of 0.30 for the light composition

methanol. The bubble point mol fraction is 0.67 of methanol.

A constant reflux of 95% was used in the first four experiments and the last

experiment the reflux ratio was switched to 66%. The distillate is the product from the

Vapor Equilibrium line

Liquid Equilibrium Line

AB

Perry's Data for Methanol-Water

60

65

70

75

80

85

90

95

100

0.0 0.2 0.4 0.6 0.8 1.0

x,y

Temperature, °C

A B

Distillation Column


top of the distillate column. At 95% reflux, the 5% product is collected in the condenser

and the remaining 95 % of the mixture is returned to the column. The remaining 95 % is

returned to the distillation column for further distillation. The successive distillation

improves the purity

of the product. Therefore, the higher the reflux percentage, the greater amount of liquid is

sent back to the column for further separation.

The university distillation column contains a rectifying and a stripping section. The

rectifying section is above where the feed is introduced. The stripping section is below

where the feed is introduced.

Energy balance

At steady state the energy added to the distillation column is equal to the energy

removed from the column minus the heat loss to the surrounding environment. Equation

1 was used to find the overall heat loss.

Q reboiler= Q condenser + Q loss (1)

Q reboiler is the energy added to the reboiler, Q condenser is the energy removed from the

condenser, and Q loss is the energy loss by the distillation column to the surrounding

environment.

Q is defined in Equation 2 as:

Q= m Cp ∆T (2)

The above equation was used to perform the energy balance for the condenser. Q is the

energy, in watts, removed by the condenser. The m is the mass flow rate of cold water

entering the condenser. Cp is the heat capacity of water. ∆T equals the Tout minus Tin

and is in ° Celsius.

Distillation Column


Material balance

Over all balance was achieved with the following formula.

F=B+D (3)

F is the feed rate entering, B is from the reboiler and D is the distillate.

A balance was performed on the condenser. The following equation was used for the

condenser balance.

RD = L/D (4)

RD is the reflux ratio, L is the liquid in the condenser, and D is the distillate.

Distillation Column


Section III-Equipment:

The distillation column is approximately 15 feet tall and a diameter of 0.5 feet. The

distillation column contains 12 trays, condenser, reflux valves, pumps, Reboiler, and feed

location.

The section of the distillation column located above the feed tray is known as the

rectifying section. The section below the feed tray is known as the stripping section.

Condenser:

“A condenser is heat transfer device used to liquefy vapors by removing their latent

heat. The latent heat is removed by absorbing it in a cooler liquid. In the shell and tube

condenser the condensing vapor and coolant are separated by a tubular heat transfer

surface." (McCabe, Smith, and Harriott) The condenser is of the shell and tube type with

cold water flowing in the tubes and condensation on the shell. The condenser can be seen

in the photograph below.

Photograph P1 shows the condenser.

Distillation Column


Pumps:

There are four pumps connected to the distillation column located in the 435 lab. The

computer using Labview can control these pumps.

Feed Pump

The feed pump will pump the binary mixture of methanol and water from the feed tank

into the column. The feed is controlled by lab view through Mevan 2002 remote 1.vi.

Reboiler Pump

Reboiler pump is normally used to pump the bottom product out of the reboiler when

the binary liquid level reaches an undesired state. The reboiler pump and the level control

device work together in order to control the level in the reboiler.

Distillate Pump

The distillate pump will pump out the distillate from the distillate receiver. The

distillate is the overhead product.

Distillation Column


Reboiler:

The distillation column uses a counter current motion inside the column. The reboiler

boils the liquid to create vapor that travels up the column. The reboiler consists of an

electrical heating element called cal rods. As the methanol content inside the reboiler is

turned into vapor, the remaining liquid molar percent becomes more water. The

temperature of the reboiler will rise and the level has to be controlled to ensure the cal

rods remained covered by liquid and don’t burn up. The reboiler is shown in the

photograph below.

Photograph P2 shows the reboiler.

Reflux Valve:

The reflux valve is the valve that divides the distillate flow from the condenser into a

product stream and a reflux stream that reenters the column at tray 1. The reflux valve is

controlled by an electromagnet. Photograph P3 shows the reflux valve.

Distillation Column


Photograph P3 shows the reflux valve on the distillation column.

Trays:

The separation process utilizes liquid and vapor phases that are at the same

temperature and pressure. The two phases are brought into contact on 12 separate trays.

The trays are stacked in a vertical position and enclosed in a cylindrical shell to form the

distillation column. The trays are designed in a bubble-cap design. Figure 2 depicts a

drawing of the bubble – cap tray.

The down comer zones generally occupy 10 to 30 percent of the total cross section area.

The cross – flow utilizes the liquid down comer due to its transfer efficiency and

operating range. The down comer also helps to control the liquid – flow pattern.

Depending on the efficiency of the tray, the vapor and liquid phases reach thermal,

pressure, and composition equilibrium. The tray efficiency depends on the following:

1. The system – composition and properties

2. Flow condition – rates of throughput

3. Geometry – tray type and dimensions

Downcomer area

Distributing zone

Downcomer area

Distributing zone

Active area

Periphery waste

Distillation Column


Figure 3 shows the side view of the bubble – cap tray.

The feed is introduced under most circumstances at tray 6 but the design of the tray

allows the feed to be introduced at any of the 12 trays along the column shell. The section

above the feed tray is known as the rectifying section and the trays below the feed tray is

the stripping section. The trays stacked on top of each other in a vertical position are

pictured in photograph P4.

Photograph P4 shows the distillation trays.

Distillation Column


Photograph P5 shows the sample port on each of the trays in the column.

Feed Location:

When determining the optimal design for the location of the feed the desired outcome

of the system must be considered. Placing the feed toward the stripping section increase

the number of rectifying stages. Placing the feed toward the rectifying section increases

the stripping stages. For a saturated feed the optimal location of the feed is to stage whose

liquid mostly closely approximates the feed composition. P5 shows the feed location.

Photograph P5 shows tray #6 where the feed comes in to the column.

Distillation Column


Level control system:

Reboiler

The level control system has a small analog pressure transmitter with two sensors. One is

connected with tubing to the lower outlet of the reboiler. This sensor had to wired and

taped to the reboiler in order for it to work properly in the experiment. The other sensor is

open to the atmosphere. A pressure differential is measured and transmitted to the

computer. The computer is able to convert the differential measurement in to a level

reading for the reboiler.

Distillate Receiver

This system is the same as the reboiler control system. A pressure differential is

measured and converted in to a level reading which signals the lever controlled by the

computer.

Distillation Column


A schematic of the system is depicted on this page. Figure 4 shows the entire system.

Reboiler Pump

Calrod HeatersLiquid Mixture

Reboiler

Feed /Product

Tank

TI PI

LI

Tray 12

Tray 11

Tray 10

Tray 9

Tray 8

Tray 7

TI

TI

TI

TI

TI

TI

Feed

Tray 6

Tray 5

Tray 4

Tray 3

Tray 2

Tray 1

LI

TI

TI

TI

TI

TI

Feed Pump

Reflux

TI

TI

CondenserTI

TI

Supply

Return

Cooling WaterTI

Cooler DistillateReceiver

DistillatePump

F

Heat Loss vs. Reboiler Temperature

0

200

400

600

800

1000

1200

1400

2 0 30 40 50 6 0 70 80 90 100

Reboiler Temperature (°C)

Hea

t L

oss

(W

)

ComputerController

CoolingWater Flow

Valves

Figure 3 -Distillation ColumnSchematic Diagram

Cooling Water

Distillation Column


Operation Procedure:

Distillation Column Procedure – Start Up:

Turn on the main power switch located above the computer station. (See picture P6 on

the next page).

In order to start the Lab View program for the distillation column, double click on the

short cut to distillation icon. This will open the Mevan 2002 program.

Adjust all inputs on the input screen by clicking on the scale below the input (Ex. Pump

speed, reflux value, reboiler). The inputs should agree with your experiments for the day.

Start the distillation column up by clicking on the green start button located in the upper

left corner of Mevan 2002.

Make sure cold water is circulating in the condenser at the top of the column.

Click on the distillation column files to open the data files for the distillation column.

Select the one marked with the days date.

Caution: DO NOT LET THE WATER LEVEL IN THE REBOILER TANK TO

FALL BELOW THE CALROD HEATERS.

This will result in damage to the calrods therefore resulting in damage to the reboiler

heating system. If the liquid level falls below the calrods turn the column off and the

condensation will return to the reboiler and cover up the calrods. If the condensation is

not enough to cover the calrods more solution will have to be pumped in from the

auxiliary tank.

Distillation Column


Distillation Column Procedure – Shut Down:

Turn off the all feed sources on the Lab View screen.

Turn the reflux percent up to 100 % to help cool the column.

Turn off all pumps

Click the red stop button located on the top left corner of the Lab View screen.

Save all data files collected for the days experiments.

Turn off the column power source lever located above the computer station.

Distillation Column Procedure- Emergency Shut Down:

Turn off the power control switch located above the computer station. Find Dr. Henry,

Dr. Jones, or Don Eberhart. Photograph P6 shows the main power switch to the

computer.

Picture P6 is the main power source for the distillation column.

Distillation Column


Experimental Procedure:

Five experiments were run for continuous distillation operation. The inputs for this

continuous distillation were reflux percent, wattage added to the reboiler, and feed pump

input. The P-only controllers maintained approximately 10 liters in the reboiler. Table 1

depicts the experiments that were run for continuous distillation.

Table 1 Experiments for Continuous Distillation

On the 3000 watts added to the reboiler experiments, the reflux ratio was dropped to

66% after the system reach steady state with the setting of 95% reflux. A 5 mL graduated

cylinder was filled with liquid from the feed tank. The liquid was weighted on the triple

beam balance. The density of the liquid, g/mL, could then be determined from Perry’s

data.

The composition of each tray was looked at each of the five experiments. The

composition of the distillate was calculated at steady state. Temperature data was used in

conjunction with the chart, displayed in figure 1, was used to figure the composition of

methanol in each tray.

Composition of the Column Trays

The distillation column was operated in a continuous distillation and the composition of

the trays was calculated as the system reached steady state. Temperature data was

recorded and used with the X, Y versus T chart to find the composition.

Experiment Number Reflux Ratio Heat Added to Reboiler Composition of wt% Methanol

1 95% 2250 watts 15% 2 95% 2500 watts 15% 3 95% 2750 watts 15% 4 95% 3000 watts 15% 5 66% 3000 watts 15%

Distillation Column


Result s:

The results section shows the data recorded for the four experiments.

Figure 5 shows the distillate receiver level recorded for continuous distillation at 2250

watts added to the reboiler.

Figure 5 shows the distillate receiver level recorded for 2250 watts added to the reboiler.

The x-axis is time in minutes. The y-axis is the distillate level recorded in ml. The reflux

ratio for this experiment was 95%.

Distillate Receiver Level

200

210

220

230

240

250

260

270

280

290

300

100 105 110 115 120 125 130

Time (min)

Dis

tilla

te le

vel (

ml)

Distillation Column


Figure 6 shows the X, Y versus T diagram for 2250 watts added to the reboiler

Figure 6 shows the X, Y versus T diagram for the 2250 watts added to the reboiler

experiment. The y-axis gives the temperature in degree Celsius. The x-axis gives the

fraction of liquid and vapor composition in the distillation column. The chart can be used

to determine the dew point and vapor point of the mixture at a given temperature.

X,Y versus T diagram (2250 watts)

60 65 70 75 80 85 90 95

100

0 0.2 0.4 0.6 0.8 1

X, Y

Temp °C

Distillation Column


Figure 7 shows the distillate receiver level recorded for continuous distillation with 2500






200

210

220

230

240

250

260

270

280

290

300

100 105 110 115 120 125 130 135 140 145 150

Time (min)

Dis

tilla

te le

vel (

mL

)

Distillation Column


Figure 8 shows the X, Y versus T diagram for 2500 watts added to the reboiler



fraction of liquid and vapor composition in the distillation column. This data recorded

with a 95% reflux ratio.


60

70

80

90

100

110

0 0.2 0.4 0.6 0.8 1

X, Y

Temp °C

Distillation Column


Figure 9 shows the distillate receiver level recorded for continuous distillation with 2750






200

210

220

230

240

250

260

270

280

290

300

50 52 54 56 58 60 62 64 66 68 70

Time (min)

Dis

tilla

te le

vel (

mL

)

Distillation Column


Figure 10 shows the X, Y versus T diagram for 2750 watts added to the reboiler.






60.0

70.0

80.0

90.0

100.0

110.0

0 0.2 0.4 0.6 0.8 1

X, Y

Temp °C

Distillation Column


Figure 11 shows the distillate receiver level recorded for continuous distillation with

3000 watts added to the reboiler.



ratio for this experiment was 95% then when steady state was achieved the reflux ratio

was changed to 66%.


200

210

220

230

240

250

260

270

280

290

300

80 85 90 95 100 105 110 115 120

Time (min)

Dis

tilla

te le

vel (

mL)

Distillation Column


Figure 12 shows the X, Y versus T diagram for 3000 watts added to the reboiler and a

reflux of 95%.






60.0

70.0

80.0

90.0

100.0

110.0

0 0.2 0.4 0.6 0.8 1

X, Y

Temp °C

Distillation Column


Figure 13 shows the X, Y versus T diagram for 3000 watts added to the reboiler and a

reflux of 66%.




with a 66% reflux ratio. This data appears to be bogus and should be retested.


90.0

95.0

100.0

105.0

0 0.1 0.2 0.3X, Y

Temp °C

Distillation Column


Table 2 shows the calculations of the distillate rate for continuous distillation and a 95%

reflux rate. Table 2 shows 2250, 2500, and 2750 watts being added to the reboiler.

Minutes Dist. Level (ml) Minutes Dist. Level (ml) Minutes Dist. Level (ml)119 248.77 128.01 239.88 56 274.65115 241.74 125 230.41 55 271.04

4 7.03 3.01 9.47 1 3.61

1.76 mL/min 3.15 mL/min 3.61 mL/min

Minutes Dist. Level (ml) Minutes Dist. Level (ml) Minutes Dist. Level (ml)123 259.9 141 243.59 60 280.8121 252.3 138 242.81 57 275.53

2 7.6 3 0.78 3 5.27


Minutes Dist. Level (ml) Minutes Dist. Level (ml) Minutes Dist. Level (ml)129 267.42 148 242.71 70 291.84127 262.83 145 236.95 67 282.56

2 4.59 3 5.76 3 9.28


Minutes Dist. Level (ml) Minutes Dist. Level (ml) Minutes Dist. Level (ml)126 268.2 134 235.78 65.01 283.54124 263.8 130 234.61 63 275.82

2 4.4 4 1.17 2.01 7.72


2750 Watts

2750 Watts

2750 Watts

2250 watts 2500 watts 2750 Watts

2250 watts

2250 watts

2250 watts

2500 watts

2500 watts

2500 watts

Distillation Column


Table 3 shows the calculations of the distillate rate for continuous distillation, 3000 watts

added to the reboiler, and a 95% reflux rate changing to a 66% reflux ratio.

Minutes Dist. Level (ml) Minutes Dist. Level (ml)114.67 256.09 176.67 283.93

114 252.09 176.33 273.934 4 4 10

1.00 mL/min 2.50 mL/min

Minutes Dist. Level (ml) Minutes Dist. Level (ml)113.67 254.24 173.67 385.39113.33 250.82 173.33 385.29

4 3.42 4 0.1



4 0.87 4 0.29



4 0.29 4 1.95


3000 watts 66%

3000 watts 66%

3000 watts 66%

3000 watts 66%

3000 watts 95%

3000 watts 95%

3000 watts 95%

3000 watts 95%

Distillation Column


Table 4 shows the average of the data recorded for the distillate rate for the experiments

conducted on the distillation column.

Figure 14 shows the graph of the methanol composition in the liquid tray. Thesecalculations were performed once the continuous distillation reached steady state.

Figure 14 shows the continuous distillation with variable wattage graph. The x-axis is thetrays in the distillation column. The y-axis is the mole fraction of methanol. Figure 14illustrates the difference in the liquid composition for the continuous distillation but withdifferent watts added to the reboiler.

Continuous distillation with Variable Wattage

0

0.5

1

0 5 10

Tray

Mole Fraction Methanol

2250, 2500, 2700,3000 watts @ 95%

3000 watts@ 66%

2250 watts 2500 watts 2750 watts 3000 watts 3000 watts95% reflux 95% reflux 95% reflux 95% reflux 66% refluxAvg. ml/min Avg. ml/min Avg. ml/min Avg. ml/minAvg. ml/min

2.015 1.4075 3.075 0.5375 0.77

Distillation Column


Energy balance

Table 6 shows the energy balance that was performed on the condenser. Reflux and

wattage settings are represented under the continuous distillation column. Cws is the cold

water source and cwr is the cold-water return. Diff t is the difference in the temperature

of the cold-water source and cold water return. Cwf is the cold-water flow is in liters per

minute. A correction factor of 2.8 was need because lab view displays the wrong flow

rate for the system.

ContinuousDistillationReflux % CWS (K) CWR (K) Diff T CWF (L/min) Corr factor Watts absorbed by condenser

95 (2250 watts) 19.48 20.39 1.21 1.14 2.8 202.3395 (2500watts) 18.43 20.93 2.5 1.17 2.8 571.1295 (2700 watts) 18.16 21.28 3.12 1.18 2.8 718.8495 (3000 watts) 15.95 18.33 2.38 1.2 2.8 557.6466 (3000 watts) 15.83 19.55 3.72 1.19 2.8 864.35

Cws is the cold-water source, Cwf is the cold-water flow, Corr factor is the correction

factor added to the cold water flow because the displayed rate on the computer is

inaccurate.

Table 7 displays the watts absorbed by the condenser and the heat loss to the reboiler.

Reflux %Watts absorbed by

condenser Heat Loss-Reboiler (Watts)95 (2500 watts) 202.33 1945.6795 (2250 watts) 571.12 1928.8895 (2700 watts) 718.84 1781.1695 (3000 watts) 557.64 1942.3666 (3000 watts) 864.35 1635.65

Distillation Column


Table 8 shows the results of the material balance perfomed on the distillation column.

Watts added Refux Ratio F D B L V L' RD Xf XD XB2250 95% 4 0.53 3.47 10.1 10.62 14.09 19 0.15 1 0.022500 95% 4 0.53 3.5 9.5 10 13.5 19 0.14 0.98 0.022750 95% 4 0.34 3.66 6.4 6.74 10.4 19 0.09 0.96 0.013000 95% 4 0.25 3.75 4.75 5 8.75 19 0.09 0.97 0.013000 66% 4 0.23 3.77 0.45 0.69 4.45 1.94 0.02 0.3 0.003

In the table above F is the feed, D is the distillate, B is the bottom of the column, is the

liquid, L’ is the liquid on solute bases, V is the vapor, RD is the reflux ratio, Xf is the

mole fraction of feed in the feed system, XD is the mole fraction of methanol in the

distillate, and XB is composition at the bottom of the column.

Distillation Column


Discussion of Results:

The composition of each tray from temperature calculations was shown in Figure 14.

The highest methanol percent was found in tray 1 which was consistent with our theory.

Tray 2 through 12 showed subsequently lower mole fraction of methanol.

Using a constant reflux ratio of 95% and various watts added to the reboiler, it was

shown that the mole fraction of methanol was close to the same in the distillation trays.

The 66% reflux ratio showed a lower mole fraction of methanol in the trays in the

rectifying section of the column. The stripping section of the column showed a more

consistent mole fraction of methanol with either 66% or 95% reflux ratio. This was not at

all what I expected to find when making conclusions about the column.

The material balance showed that the column composition at the bottom of the column is

correct.

When the 3000 watts added to the reboiler experiment was run, there was a change in the

reflux ratio. The initial reflux ratio was 95% then switched to 66%. This experiment

need to be reran due to bogus XY versus T plot for 66%.

Distillation Column


Conclusions:

The methanol concentration in the trays decreases as you move from tray 1 to tray 12.

As the feed is entered in to the column the stripping portion of the column the methanol

is less than it is in the rectifying section.

The distillate level varied as the different wattages was being added to the reboiler.

Recommendations:

It would be interesting to see how the column would perform under a different separation

of a binary mixture; Acetone and water or some other mixture.

Distillation Column


References:

Unit Operations of Chemical Engineering, 6th Ed., Warren L McCabe, Julian C. Smith

and Peter Harriott, McGraw-Hill, Boston, 2001.

Cunningham, James R. Dr. Lecture Notes Fall 2002 for ENCH 432 at the University of

Tennessee at Chattanooga.

UTC Engineering Controls Lab Online. University of Tennessee at Chattanooga.

http://distillation.engr.utc.edu/data.htm

Engineering 536 Mass Transfer Operations. University of Tennessee at Chattanooga

http://chem.engr.utc.edu/webres/536f/FINALRPT.htm

Perry, Robert H. and Don W. Green. Perry’s Chemical Engineers Handbook, 7th Edition,

June 1, 1997. McGraw-Hill Professional

Engineering 435 Distillation Column Maintenance. University of Tennessee at

Chattanooga September 24, 2002.

Distillation Column


Appendices:

Figure 15 shows the tray temperature for 2250 watts added to the reboiler.

Trays Temperature Chart (2250)

6 0

6 5

7 0

7 5

8 0

8 5

100 105 110 1 1 5 120 125 130

Time (min)

Temperature °C

Tray 1 Temperature Tray 2 Temperature Tray 3 Temperature Tray 4 Temperature Tray 5 Temperature Tray 6 Temperature

Tray 7 Temperature Tray 8 Temperature Tray 9 Temperature Tray 10 Temperature Tray 11 Temperature Tray 12 Temperature

Distillation Column


Figure 16 shows the tray temperature for 2500 watts added to the reboiler.

Tray Temps 2500 W

65

66

67

68

69

70

50 100 150 200

Time (min)

Temp. ° C

Tray 1 Temperature Tray 2 Temperature Tray 3 Temperature Tray 4 Temperature



Distillation Column


Figure 17 shows the tray temperature for 2750 watts added to the reboiler

Tray Temps 2750 W

65

66

67

68

69

70

50 100 150 200Time

Temperature ° C

Tray 1 Temperature Tray 2 Temperature Tray 3 TemperatureTray 4 Temperature Tray 5 Temperature Tray 6 TemperatureTray 7 Temperature Tray 8 Temperature Tray 9 TemperatureTray 10 Temperature Tray 11 Temperature Tray 12 Temperature

Distillation Column


Figure 18 shows the tray temperature for 3000 watts added to the reboiler

Tray Temp. 3000 watts

60708090

100110

50 70 90 110

Time (min)

Temperature °C




Distillation Column


Tray composition data

2500 Tray Temp x comp ycomp xD

1 65.2 0.95 0.98 0.982 65.4 0.94 0.97 xB3 65.8 0.92 0.96 0.024 67.4 0.8 0.92 f5 69.7 0.67 0.86 0.21846 76.5 0.35 0.70 xF7 90.2 0.07 0.35 0.20648 93.0 0.05 0.26 effic9 97.0 0.02 0.12 0.510 96.5 0.02 0.14 11 96.9 0.02 0.12 12 99.8 0.00 0.01

reboiler 96.5 0.02 0.14 Feed 85.7 0.13 0.48

3000 (95%)

2250 Tray Temp x comp ycomp xD

1 64.7 0.99 1.00 1.002 65.1 0.95 0.98 xB3 65.5 0.91 0.96 0.024 67.2 0.75 0.89 f5 70.0 0.66 0.86 0.21636 76.1 0.37 0.72 xF7 89.0 0.08 0.38 0.21578 91.7 0.06 0.30 effic9 95.4 0.03 0.18 0.810 94.7 0.03 0.2 11 95.2 0.03 0.18 12 96.7 0.02 0.13

reboiler 96.1 0.02 0.15 Feed 85.3 0.14 0.49

Distillation Column


TrayTemp

x compycomp

xD

165.40.940.970.97

265.70.910.96xB

366.20.880.950.01

468.40.750.90

f

571.40.580.82

0.2427

680.20.240.62xF

790.70.070.33

Distillation Column


0.1628

894.10.040.22effic

998.80.010.03

1098.20.010.07

1198.80.010.03

12101.50.000.00

Reboiler98.10.010.07

Feed88.90.090.39

2750Tray Temp x comp ycomp xD

Distillation Column


1 65.3 0.92 0.96 0.962 65.6 0.93 0.97 xB3 66.0 0.9 0.96 0.014 67.9 0.78 0.91 f5 70.6 0.62 0.84 0.24446 78.0 0.3 0.67 xF7 91.1 0.06 0.32 0.15338 94.1 0.04 0.22 effic9 98.5 0.01 0.06 0.45

10 97.7 0.02 0.09 11 98.0 0.02 0.08 12 100.8 0.00 0.00

Reboiler 97.8 0.01 0.09 Feed 89.3 0.08 0.38

3000 (66%) Tray Temp x comp ycomp xD

1 91.5 0.06 0.30 0.302 97.3 0.02 0.10 xB3 97.9 0.01 0.08 0.004 98.2 0.01 0.07 f5 97.8 0.01 0.08 0.30226 95.0 0.03 0.19 xF7 95.0 0.03 0.19 0.05328 98.8 0.01 0.03 effic9 103.3 0.00 0.00

10 101.8 0.00 0.00 11 101.8 0.00 0.00 12 103.4 0.00 0.00

Reboiler 99.4 0.00 0.02 Feed 96.7 0.02 0.13

Distillation Column


Material balances

Visual

RD 1.94 V (mol/hr) 0.69 Qc (kJ) y 0.30

D (mol/hr) 0.23

xD 0.30 L (mol/hr) 0.45 xexit condFeed (mol/hr) 4 xL 0.30

xF 0.02 f 0 VN+1 (mol/hr)

B (mol/hr) 3.77

Distillation Column


LN (mol/hr) xB 0.00265 xexit reboil Qr (kJ)

2250 watts

Material Balances Overall F=D+B B= 3.47 F*xF=D*xD+B*xB D= 0.53Condenser RD=L/D L= 10.09 V=L+D V= 10.62Feed Tray L'=L+(1-f)F L'= 14.09 V'=V-fF 10.62

Visual

RD 19 V (mol/hr) 10.00 Qc (kJ) y 0.98

D (mol/hr) 0.50



Distillation Column


B (mol/hr) 3.50 LN (mol/hr) xB 0.02 xexit reboil Qr (kJ)

2500 watts

Math Material Balances Overall F=D+B B= 3.50 F*xF=D*xD+B*xB D= 0.50Condenser RD=L/D L= 9.50 V=L+D V= 10.00Feed Tray L'=L+(1-f)F L'= 13.50 V'=V-fF 10.00

Visual

RD 19 V (mol/hr) 6.74 Qc (kJ) y 0.96

D (mol/hr) 0.34


xF 0.09

Distillation Column


f 0 VN+1 (mol/hr)


2700 watts


Visual

RD 19 V (mol/hr) 5.00 Qc (kJ) y 0.97

D (mol/hr) 0.25

xD 0.97

Distillation Column


L (mol/hr) 4.75 xexit condFeed (mol/hr) 4 xL 0.97



3000 watts 95% reflux


Visual

RD 1.94 V (mol/hr) 0.69 Qc (kJ) y 0.30

Distillation Column


D (mol/hr) 0.23




3000 watts 66% reflux


Distillation Column


distillation column november 14, 2002 troy hall 615...

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