8/3/2019 Progress on Axial Dispersion in Pulse Sieve Plate Column

1/12

Studies in Hydrodynamic aspects ofPulse sieve plate extraction column

Inderdip P Shere

M. Chem. Engg. -II

VKR

8/3/2019 Progress on Axial Dispersion in Pulse Sieve Plate Column

2/12

Contents

Preview of project

Work procedure

Current progress

Conclusion

Future plans

References

8/3/2019 Progress on Axial Dispersion in Pulse Sieve Plate Column

3/12

Carry out scale up experimental setup on 30 cm (12) column.

Study hydrodynamic studies on the column.

Utilize best fit model for axial dispersion coefficient.

Develop fundamental correlation to predict axial dispersion

coefficient based on the model selected.

Check for the validity of correlation for different systems.

Preview of project

3

8/3/2019 Progress on Axial Dispersion in Pulse Sieve Plate Column

4/12

Correlating axial dispersion

Power law

Modification in Power law

Parameters

Pulse velocity

Continuous phase velocity

Dispersed phase velocity

Pore diameter

Plate spacing

Fractional free area

Coefficient Values

A0 73.29933

a1 0.7625

a2 0.6216

a3 0.0193

a4 0.2287

a5 -0.2627

a6 1.2903

Regression coefficient ,r is 0.594

Simple Power law poorly fits to the systemAxial dispersion coefficient greater that 60 cm2/sec have been

eliminate. Gives regression coefficient,r value of 0.672.

Parameter Vd was removed to check the dependency of dispersion

coefficient. Gives reduced value of regression coefficient, r of 0.631

4

8/3/2019 Progress on Axial Dispersion in Pulse Sieve Plate Column

5/12

Correlating axial dispersion

Dimension less Parameters

Following dimensionless entities were formed

Other dimensionless entities for physical parameters

The coefficient, a0 is dimension less.The regression coefficient,r is 0.92.

Effects of dispersed and continuous phase velocity are directly seen on axial

dispersion coefficient. Since we have not studied other physical systems.

Dimension less Parameters

5

8/3/2019 Progress on Axial Dispersion in Pulse Sieve Plate Column

6/12

Models

Axial Dispersion Model

Axial dispersion model is based on following equation

We use C curve to calculate the value of dispersion coefficient

6

8/3/2019 Progress on Axial Dispersion in Pulse Sieve Plate Column

7/12

Models

Tank-in-Series Model

It gives number of tank in series to encompass axial dispersion.Advantage over axial dispersion modelPeclet-Bodenstein number, Bo

n is non dimensional variable, (number of tank in series)

Tank-in-Series Model

7

8/3/2019 Progress on Axial Dispersion in Pulse Sieve Plate Column

8/12

Correlations with non dimensional analysis proved to be more

accurate to predict axial dispersion coefficient

Fundamental correlation requires study of different systems

Tank in series model have potential benefits for dispersion

coefficient

.

Conclusions

8

8/3/2019 Progress on Axial Dispersion in Pulse Sieve Plate Column

9/12

Procedure for further investigation

Setup 12 diameter column as scale up studies.

Study hydrodynamic aspect of the column

Perform RTD analysis and develop C curve

Develop the correlation using axial model and tank in series model

Predict the axial dispersion coefficient and validate the data. 9

8/3/2019 Progress on Axial Dispersion in Pulse Sieve Plate Column

10/12

Columndimensions

Diameter : 0.3 m

Height: 1 m

Plate spacing:5E-2 m

Fraction freearea: 0.25

Hole diameter:1.5E-3 m

Number ofplates: 20

System

Light phase:Kerosene

Heavy phase:Water

RTD analysis

Tracer: KCl (aq)solution

Method ofinjection: Pulse

Method ofdetection:conductivity

Detectinginstrument:

Conductivitymeter

Frequency ofdetection: 1E3Hz

Evaluation ofAxial mixing

parameter

Use ofdispersion andtank in seriesmodel

Curve fitting

Evaluation ofaxial dispersioncoefficient

Specifications

10

8/3/2019 Progress on Axial Dispersion in Pulse Sieve Plate Column

11/12

8/3/2019 Progress on Axial Dispersion in Pulse Sieve Plate Column

12/12

Dispersion model

(Levenspiel O. and Smith W. K. 1957)

12