Experiment on Packed Bed Column- Mass Transfer

8/22/2019 Experiment on Packed Bed Column- Mass Transfer

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King Saud University

Chemical Engineering Dpt.

Prepared by:

Mohammed Al-Zamil ID # 424 10 4330

Group # 1

Lab - ChE- 403

Prepared For:Dr.M.Alahmad


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Packed bed column 2

TABLE OF CONTENT

Summery .................................................................................................3

Introduction ..................................................................................................4

Theory .........................................................................................5

Experimental Procedure.........................................................................................6

Schematic diagram .........................................................................................7

Result .................................................................................................8

Discussion ................................................................................................10

Conclusion ...............................................................................10

Appendix ............................................................................... 11

\


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Packed bed column 3

1.Summary:

In this experiment pressure drop was studied with changing air flow rate in six cases

(dry column, wet column, constant flow of water 1.5 L/ min, 2.5 L/min and 3 L/min).

The curves was plotted on logarithmic coronation between pressure drop and air flow

rate .

Loading point and flooding point for each case was founded

The objective of this experimental

1) Finding pressure drop through paced column as a function in air flow with a

different water flows.

2) Finding loading & fooling point for each flows of water.


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Packed bed column 4

2.Introduction:

Packed column is very common in chemical engineering, there are tow types of

packing (random and structured packing).

Random packing has a many types like raschig rings, metal ball ring..etc.

This experiment interested in pressure drop and loading & flooding through the

packing column. In a given packed tower with a given type and size of packing and

with a definite flow of liquid, there is an upper limit to the rate of air flow, called the

flooding velocity. Above this air velocity the tower cannot operate. At low air

velocities the liquid flows downward through the packing, essentially uninfluenced by

the upward air flow. As the air flow rate is increased at low air velocities, the pressure

drop is proportional to the flow rate. At an air flow rate called the loading point, the

air starts to hinder the liquid down flow, and local accumulations or pools of liquid

start to appear in the packing. The pressure drop of the air starts to rise at a faster rate.

As the air flow rate is increased, the liquid holdup or accumulation increases. At the

flooding point, the liquid can no longer flow down through the packing and is blown

out with the air.

In an actual, operating tower, the air velocity is well below flooding. The optimal eco-

nomic air velocity is about one-half or more of the flooding velocity. It depends upon

a balance of economic factors including equipment cost, pressure drop, and

processing variables. Pressure drop in the packing is an important consideration in

design of a tower and is covered in detail below.


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Packed bed column 5

3.Theory:

Loading:

Amount of liquid accumulate in side packed column that generate pressure drop.

Figurer 1 : loading in side packed column

Fooling :

Amount of the liquid flood in the top of column with increasing pressure drop due to

accumulation of liquid in side packed column

Figure 2 :flooding in packed column

)....(..

)....(..100

)....(

10

12

pa

pa

cm

ghP

gh

P

hh

hhh

=

=

=

=

loading

flooding


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Packed bed column 6

4.Experimental Procedure:

1- passing the maximum air flow until all evidence of moisture in the packinghas disappeared.

2- run on the pump of air .

3- pressure differential cross the column was readied At ( 0 ) flow of air.

4- flow rate of air was increased (20 L/min) , and the pressure differential

cross the column was readied. This step rebated until 160 L/min air flow was

reached.

5- Take care about loading and flooding cause the water maybe come out from

the top of the column .


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Packed bed column 7

5.Schematic Diagram:

Figure3: schematic of experiment

Picture 1 : packed bed column


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Packed bed column 8

6.Resulet & Computation:

DRY AND WET PRESSUR DROP IN BA CKED COLUMN

0

1

2

3

4

5

6

7

8

0 20 40 60 80 100 120 140 160 180

AIR FLOW ( L / MIN )

DRY COLUMN

WET COLUMN


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Packed bed column 9

0

10

20

30

40

50

60

0 20 40 60 80 100 120 140 160 180

PRESSURDROP(cmwater)

AIR FLOW RATE ( L / MIN )

PACKED BED PRESSUR DROP

WF= 1.5

L/MIN

WF= 2 L/MN

WF= 2.5

L/MIN

FOOLING

LOADING

7.Discussions:


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Packed bed column 10

From the graphs we see the loading point is appearing at 2 , 2.5 and 3 L/min offlow rate of water at 160 , 140 L / min of air flow rate respectively.

Also the flooding appears after the loading directly at 2.5 and 3 L / min of flow rate of

water at 160 L / min of air flow rate for each cases.

We know from results and graphs the loading is appear after that is coming the

flooding thats mean if the water flow rate and air flow rate is increase that makes

water is stopping in the column mean not dropping in down this case is called loading,

after increase the water flow rate is appear the flooding thats mean the water is

backing to top in the column.

Conclusion:

This experiment is important to studded to be educated what the meaning ofphenomena of loading and flooding to tacit as meaning in designing, and to now the

type of packs and how we can packed.


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Appendix

a. Variable Listing:

h =Height different in manometer


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= Density

error= Error in manometer

g = Graffiti

P = pressure drop

b. Result table


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A) Dry column :

hh2h1air flow ( L / min )

0-9.8-9.80

0.6-9.1-9.7200.8-9-9.840

1-8.9-9.960

1.2-8.8-1080

2.7-7.5-10.2100

4.7-7.3-12120

5.1-7-12.1140

6.7-6.2-12.9160

B) Wet column :


0-9.8-9.80

0.7-9.1-9.820

0.9-9-9.940

1-9-1060

1.3-8.9-10.280

2.2-8.4-10.6100

3.8-7.6-11.4120

5.6-6.8-12.4140

7.4-5.8-13.2160

C) Water flow rate @ 1.5 L/min :


0.1-9.7-9.80

0.2-9.2-9.420

0.4-9.2-9.640

0.9-8.9-9.860

2.6-8-10.680

5-6.9-11.9100

7.3-5.9-13.2120

11.8-3.6-15.4140

13.2-1.2-14.4160

D) Water flow rate @ 2 L/min :


0.2-9.6-9.800.6-9-9.620


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1-8.9-9.940

3.2-10.4-13.660

3.8-7.6-11.480

6.2-6.4-12.6100

10.9-4-14.912015.1-1.9-17140

25.82.8-23160

E) Water flow rate @ 2.5 L/min :


0.5-10-9.50

0.9-9-9.920

1.1-8.9-1040

2.5-8.4-10.960

4.5-6.9-11.48010-4.4-14.4100

13.41-12.4120

24.52.9-21.6140

40.611.6-29160

F) Water flow rate @ 3 L/min :

Hh2h1air flow ( L / min )

0.4-9.5-9.90

1.1-8.9-1020

1.6-8.6-10.240

2-8.4-10.460

3.6-7-10.680

9.8-4.6-14.4100

211-20120

337-26140

4915-34160

C. References:


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1(MCCAE, W.L, SMITH, J.S, HARRIOT, P Unit Operations of Chemical

Engneering 5th ED ,McGRAW-HILL,1993 P 683 -693

2(GEANKOPLIS ,C.J,Transport Processes AND Separation Process Principles 4th

ED , Prentice Hall ,2003 P 656-659.

3 (Chemical Engineering Laboratory 2 CHE 403 2001, P G1-G2.

4(FELDEE , R.M , ROUSSEAU , R.W Elementary Principles Of Chemical

Engineering 3rd ED , WILEY , 2000 P 54-56.

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Experiment on Packed Bed Column- Mass Transfer