05_Pulsed Column Liquid - Liquid Extraction 2014

7/22/2019 05_Pulsed Column Liquid - Liquid Extraction 2014

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Experiment 4

Pulsed Column Liquid Liquid Extraction Unit.

1. Objective:

The students should be able to:

o Operate a Liquid Liquid Extraction Experiment using a Pulsed Column Liquid Liquid

Extraction Unit.

o To determine the tie lines connecting the bimodal curves in the toluene!ateracetone

s"stem.

o To determine the height equivalent theoretical plates #$ETP% &or column b" using

equilateral triangular diagram.

o To investigate the e&&ect o& the pulsation stro'e on the $ETP.

2. Introduction.

Extractionis a unit operation used to separate components based on their Chemical (i&&erences

instead o& di&&erences in Ph"sical Properties. )hen separation o& components o& a Liquid

*ixture becomes ine&&ective or ver" di&&icult b" means o& (istillation+ and then Liquid

Extractionis one o& the main alternatives to consider.

, !idel" used terminolog" describes the s"stem in terms o& :

o F : Feed.

o S : Solvent


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o S : Solvent

has the same components as the Feed+ though the proportions are di&&erent. On the other hand+

the Extract Streamconsists o& the required component

#SoluteorExracted Component% and Solvent#Extracting SolventorExtractant%. Thedi&&erence bet!een the Extracted !om"onent#Solute% and the Extractin% Solventor

Extractantshould be made clear at all times.

ince the Feedis a t!o component s"stem+ b" convention+ the material to be Extracted is

commonl" re&erred to as the Solute!hile the other component is generall" re&erred to as the

&iluent.

The Raffinatehas the same components as the Feed+ though hope&ull" it is much less

concentrated in Solutei.e.+ it is said to be leaner. ,n ideal unit !ith per&ect Extractiongives aRaffinate!hich has one component onl"+ that being 'ure &iluent.

The liquid used to strip the Solute&rom the Feedis re&erred to as the Solvent. $o!ever+ Solventis a general term and can sometimes be con&using as &or example b" describing the &iluentas the

Feed Solvent. The term Feed Solventshould then be avoided. The Solventa&ter becoming

enriched in solute leaves the s"stem as the Extract.

The 'ulsed !olumn Liquid # Liquid Extraction (nit #*odel: P!"% has been designed to

demonstrate the )asic 'rinci"les of a Liquid # Liquid Extraction 'rocess.

The /ormal *ode o& Operation is that the Light Phase and $eav" Phase Liquids are pumped

Counter Currentl" into the Pac'ed Extraction Column. The $eav" Phase !ill enter the top o& the

column and &lo! do!n!ards+ !hile the Light Phase !ill enter the bottom o& the column and &lo!

up!ards due to (ensit" (i&&erences. Counter Current 0lo! among the pac'ings in the column

and pulsation o& the t!o phases !ill cause the trans&er o& olute Component &rom one phase #Raffinate% to the other # Extract %. The 1a&&inate !ill emerge at the bottom !hile the Extract

!ill emerge at the top o& the Extraction Column. This Liquid # Liquid Extraction 'rocessis

carried out among the Column Pac'ings to give a higher degree o& separation.


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-. !emicals and ncillar$ Equi"ments Required:

a.% Chemicals 1equired.

o ,cetone #olute%.

o (iioni>ed)ater# (iluent%

o Toluene #olvent%.

b.% ,ncillar" Equipments 1equired:

T!o 6ml ?ug and t!o 67ml bea'ers.

eparating &unnels#0or settling and separating the mixtures%

Conical &las's

*easuring C"linder and standard laborator" apparatus

1e&ractometer .

+. O"eratin% Instructions.

+.1 /eneral Start0u" 'rocedures.

-. Prepare the &ollo!ing chemicals :

a% 0eed #$eav"'ase%: *ixture ocetone $ %ater &olution. Prepare 6 litres o&

7!t @ mixture o& #cetone in )ater b" mixing appropriate quantities o& the

#cetonein (istilled )ater.

b% Prepare 6 litres o& Solvent#Light'ase%:Pure 'oluene.

6 Ensure that all valves are closed


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-. Once the liquid starts to over&lo! at the top o& the column+ stop Pump P6.

--. The unit is no! read" &or experiment.

+.2 /eneral Sut # &own 'rocedures.

-. !itch o&& pumps P-+ P6 and P=.

6. Close valves 5= and 5;.

=. Open valves 57+ 5A and 5 to drain all liquid &rom the experiment.

;. Open valves 5-= and 5-; to drain all liquid &rom the 1eceiving 5essels 3= and 3;.

7. Turn o&& the po!er &or the control panel.

'R

+.- &etermination of Equilibrium Solute &istribution 3ie lines4

'RO!E&(RES

-. Prepare A heterogeneous mixtures o& !ater+ acetone and toluene in A di&&erent conical&las's according to the compositions recommended in the table in appendix 0.

6. ,gitate the mixtures prepared in step - &or about ; minutes.

5ote To prevent emulsi&ication+ do not agitate the mixture too vigorousl".

=. top the agitator. Pour each o& the mixtures into a separating &unnel. Let the mixture

settle into t!o distinct clear la"ers !ith a sharp inter&ace.

;. )ithdra! a sample o& each phase and measure the re&ractive index o& each phase. ,gain+

ta'e an average o& three readings &or each phase. The !ater rich phase #ra&&inate% !ouldbe the heav" phase and toluene rich phase !ould be the light phase #extract%.

7. 1epeat the experiment #step 6 to =% &or all mixtures.


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'RO!E&(RES

-. Per&orm the general start up procedures #ection ;.-%

6. Turn on the both pumps P- and P6 and set the desired 0eed and olvent &lo! rates b"

adDusting the pumps &requencies and displacements.

=. 8eep the pulsator pump P= turned o&&.

;. ,llo! both liquids to &lo! into the collection vessels 3= and 3; respectivel". The

bottom product contains the )ater 1ich Phase #1a&&inate % !hile the top product contains

the Toluene 1ich Phase # Extract %.

7. *onitor the 2nter&ace Level. *aintain it at about 6= cm above the olvent inlet b"

adDusting the height o& the Over&lo! Tube.

A. Turn on the Pulsator Pump P= and set the Pulsation tro'e Length.

B. Let the experiment run &or a !hile to attain stead" state.

9. Open valve 5- to !ithdra! a - ml sample o& 1a&&inate and open valve 5-6 to collect a- ml sample o& Extract .

5ote Ta'e samples at suitable time intervals and measure their 1e&ractive

2ndices. )hen the readings are consistent over time+ stead" state has been

reached.

. 1ecord the 1e&ractive 2ndex o& both samples and use the given Calibration Curves

#,ppendix 3% to determine the ,cetone #olute% composition in each phase.

-. 1ecord all data in the given ample Table in appendix ,.

--. 1epeat the experiment #steps = to -% b" turning on the pulsator pump P= and changing


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6% (etermine the required theoretical extraction stage &rom the pulsed column liquid

liquid extraction experiment results. 1e&er to ""endix ! &or a step b" step

calculation guide.

=% Calculate the height equivalent theoretical plates #$ETP% o& the extraction column &or

di&&erent pulsation stro'e.

9E' : Effective column ei%t * 5o of teoretical "lates

;% 0rom the available data+ do a mass balance calculation around the extraction column and

obtain the extract and ra&&inate &lo! rates.

7% (iscuss the various &actors that !ould help to increase the rate o& trans&er o& solute to

solvent phase.

A% Explain ho! pulsation &requenc" increases the trans&er rate in pulsed columns.

;.< REFERE5!ES

-. *cCabe and mith+ #67%+ $nit 'perations of Chemical Engineering+ BthEdition+ *c4ra!

$ill.

6. 1obert E.Tre"bal.+ #-9-%+(ass Transfer 'perations+ =rdEdition+ *c4ra!$ill.


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''E5&I=

'R +.+ &etermination of Equilibrium Solute &istribution 3ie lines4

5o

mount in mixture 3mL4 6ater ric "ase oluene Ric 'ase

cetone 6ater olueneRefractive

Index

cetone

!om"osition

3wt>4

Refractive

Index

cetone

!om"osition

3wt>4- 6

6 ; 9 9

= A B B

; 9 A A

7 - 7 7

A -6 ; ;


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''E5&I= )

'R )+.+ Ex"eriment Extraction of cetone from 6ater (sin% oluene.

Results

0eed 12

0eed Composition

0eed

&lo!rat

e

#L


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''E5&I= !1


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""endix &

SE' )7 SE' !L!(LIO5 /(I&E

-. Obtain the equilibrium data &rom ,ppendix E or &rom literature. Plot the

binodal


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""endix &

;. Locate the point F1+!here all operating lines should meet.

7. (ra! a tie line &rom point E to its equilibrium point on the bimodal plot. Connect an

operating line &rom that equilibrium end o& the tie line to point F1. Extend that operating

line so that it intersects !ith the bimodal plot at the other end. (ra! another tie line &rom

that ne! intersection and continue until a tie line has passed the operating line connecting

1 and .


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""endix E

Equilibrium data )inodal* Solubilit$ &ata for cetone0oluene06ater S$stem

oluene Ric "ase 6ater Ric "ase

cetone 3wt

>4 6ater3wt>4

oluene3wt

>4

cetone 3wt

>4 6ater3wt>4 oluene3wt>4.B 6.;6 9B.B9 A=.= 6-.A9 -;.=

-.;9 6.6 BB.A A=.-; 6;.99 --.9

;-.A- =.B 7;.;6 79.9; =;.6B A.7

76.= 7.6B ;6.;= 7-.66 ;7.A9 =.-

A.AB B.6 =6.-; =.A7 79.B -.=9

A=.79 66.7; -=.9 -.; B9.9A -.6


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*4/Jan 14-A

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05_Pulsed Column Liquid - Liquid Extraction 2014

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