effect of mixing in stirred tank reactor

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EFFECT OF MIXING IN A STIRRED

TANK REACTOR

UNDER THE ESTEEMED GUIDANCE OF

B.DHANANJANEYULU M.Tech&RAMESH.S.BHANDE M.Tech(Ph.D)

R.SURENDRA KIRAN

M.S.RAVI TEJA G.GANESHT.SRIHARSHAVARDHAN


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ESSENSE OF THE PROJECT

To study the performance of a Stirred Tank Reactor

using different parameters.

To design a better and a controlled mixing process

that utilizes raw materials and avoids pollution.

To cut down the mixing expenditure.


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PARAMETERS CONSIDERED

Type of mixing process

Lateral mixing

Axial mixing

Type of flowLaminar Flow

Turbulent Flow

Type of reactor

Batch reactor

Type of mixers to be used

Mechanical Agitators


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KEY PROCESS VARIABLES

Residence time ()

Volume (V)

Temperature (T) Pressure (P)

Concentrations of chemical species (C1, C2.)


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Three blade marinetypeDouble flight ribbon

type:.

A high efficiency turbulent flowimpeller used on our smallestturbine agitators at direct drivemotor speeds.

The high solidity permitsoperation nearer the boilingpoint without cavitations.

It is the most efficient blender ofall existing close clearanceagitators

. Generally used for applicationswhere viscosities are ordinarilygreater than 30,000 MPa.

TYPES OF IMPELLERS


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Axial impeller :Straight BladeImpeller :

A reasonably cost effective impellerin both turbulent and laminar flow.

Good impeller for applicationswhere the viscosity changes over awide range causing the flow regimeto vary between turbulent and

laminar flow. A reasonably cost effective impeller

for solids suspension.

A cost effective impellerfor operation very near thefloor of a tank for agitatingthe heel in solidssuspension applications.

TYPES OF IMPELLERS


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PROCEDURE

1. Fill the overhead tanks with NaOH and EthylAcetate.

2. Adjust the flow rates of NaOH and Ethyl Acetateuntil the flow reaches steady state.

3. Switch on the stirrer.

4. Add 10 ml of Glacial Acetic Acid to the reactor

5. Collect the samples from outlet for every 30 seconds

of time interval.6. Take 10ml from each sample and transfer it to the

conical flask which contains 10ml HCl.

7. Titrate the sample with NaOH by adding

phenolphthalein indicator, till colorless solution


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FORMULAE

QNaOH * NNaOH

CAO =

QNaOH + QETHYL ACETATE

VETHYL ACETATE *

SETHYL ACETATE =

M.W.(1+VETHYL ACETATE )


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CBO = QETHYL ACETATE *SETHYL ACETATE


M = CBOCAO

CA = GNaOH

VSAMPLE

XA = 1 - CA

CAO

= V



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OBSERVATIONS AND CALCULATIONS


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EFFECT OF MIXING WITHOUT STIRRER

S.NO QNaOH (LPH)

QETHYLACETATE

(LPH)

V NaOHRUNDOWN

ml

1 12.5 15 6.5

2 10 12.5 4.7

3 7.5 10 3.3

4 5 7.5 3.0

5 2.5 5 2.0


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S NO sec

XA

1 0.03709 0.0001

2 0.0453 0.010

3 0.0582 0.0109

4 0.0816 0.112

5 0.136 0.119


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RESIDENCE TIME Vs CONVERSION


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CONVERSION BY VARYING RPMs

S.No XA AT 400RPM

XA AT 600RPM

XA AT 1000RPM

sec

1 0.0512 0.0841 0.112 0.03709

2 0.0740 0.099 0.344 0.045

3 0.0911 0.156 0.499 0.058

4 0.202 0.331 0.546 0.0816

5 0.335 0.584 0.844 0.136


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CONVERSION WITH A THREE blade marine TYPEimpeller

S.No QNaOH(LPH)

QETHYLACETATE (LPH)

Volume of NaOHrundown

ml

1 12.5 15 6.9

2 10 12.5 6.5

3 7.5 10 6.3

4 5 7.5 6.1

5 2.5 5 6.0


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S.No XA Sec

1 O.O114

0.037

2 0.02021 0.045

3 0.02117 0.058

4 0.19905 0.0816

5 0.20704 0.136


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S NO XA Sec

1 0.0321 0.0370

2 0.05705 0.045

3 0.06774 0.058

4 0.18905 0.0816

5 0.33903 0.136


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CONVERSION WITH AN AXIAL HIGH EFFICIENCYIMPELLER

S NO QNaOH(LPH)

QETHYL ACETATE(LPH)

VNaOH RUNDOWNml

1 12.5 15 9.0

2 10 12.5 8.5

3 7.5 10 7.0

4 5 7.5 6.9

5 2.5 5 6.5


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S NO XA Sec

1 0.045 0.037

2 0.101 0.045

3 0.194 0.058

4 0.310 0.0816

5 0.381 0.136


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CONVERSION WITH A DOUBLE flight ribbon impeller

S NO QNaOH(LPH)

QETHYL ACETATE(LPH)

VOLUME OF NaOHRUNDOWN

ml

1 12.5 15 8.4

2 10 12.5 7.5

3 7.5 10 6.7

4 5 7.5 6.5

5 2.5 5 6.4


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S NO XA Sec

1 0.0421 0.037

2 0.0631 0.045

3 0.082 0.058

4 0.210 0.0816

5 0.348 0.136


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COMPARISION OF VARIOUS TYPES OF IMPELLERS BYTAKING CONVERSION AS FACTOR


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APPLICATIONS

Stirred tank reactors are frequently used in thechemical and biochemical industry to accomplishmixing tasks.

Stirred tank reactors are used for the mixing ofvarious types of polymerizations, precipitations andfermentations.

A better designed and controlled mixing process leadsto significant pollution prevention, better usage of rawmaterials and avoids expensive separation costsdownstream in the process.

CONCLUSION


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CONCLUSION

From our project we were able to study the following: Inefficient mixing has large negative effects on the yield and

selectivity of a broad range of chemical reactions, because slowmixing can retard desired reactions.

The speed of the agitators and its involvement in the effect ofmixing using a Tachometer and a Dimmerstat.

We have taken different stirrers and achieved maximumconversion and studied the effect of mixing varying RPM andfound out the properties of different impellers and their rate ofmixing using different liquids.

The best conversion we have achieved for axial impellerbecause of the twisted blade structure when compared withother three impellers.


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SCOPE FOR FUTURE WORK

This study can be extended by varying differentreactors , agitators and solutions

The study can be done in closed type vessels wheredifferent fluids can be taken.


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REFERENCES

Schmidt, Lanny, The Engineering Of ChemicalReactions. NY Oxford Press, 1998.

Octave Levenspiel, The Chemical Omnibook,OregonSt Univ Bookstores 1993.

Effect Of Mixing in a Stirred Tank Reactor- ChemicalEngineering Journal.

Warren L.McCabe, Julian Smith, Peter Harriot. Unit

Operations Of Chemical Engineering-2005.Bakker R A, Micro mixing in Chemical Reactors

Thesis ,Delft University,1996.


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THANK YOU

effect of mixing in stirred tank reactor

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