LAB Plug Flow

TABL E OF CONTE NT

TI TLE

Abs t r ac t / Summar y

PAGES

2

I nt r oduc t i on Obj e c t i ve s

3 5

The or y

6

Appar at us

8

Pr oc e dur e s

9

Re s ul t s

11

Sampl e c al c ul at i on

14

Di s c us s i on

17

Conc l us i on

19

Re c omme ndat i on

20

Re f e r e nc e

21

Appe ndi x

22

ABSTRACT

React ors ear use d i n t he chem i cal i ndus t r y f ort he mi l l i on s o f p r oces s es . One of many di ffer en tt ypes of r eact ors i s p l ug flow r eac t or ( PFR) . A pl ug flow r eac t or si a i p p e1

shap edt an k wher e a em ch i cal r eact i on t ak es ace pl i t h w wal l s o c at edwi t h a cat al ys t an d an i nl etflow of pur e eact r an t . The p l ug flow r eact or P ( FR) i s u sd ei n t hi s exp er i men t . Ther e ar e af ew of ob j ec t i veshat t ar e n eed edt o achi eved i n t hi s exp er i men ts uchas otfind ou t t he cal i brat i on curve of on cver s i on of od si um hy dr oxi de,NaO H ver s us con duct i vi t y,t o c ar r y ou ta a sp on i fic at i onr eac t i onbet wee n NaO H an d Et ( Ac )i na P FR , an d t o det er mi ne t he r at e of r eact i on, r at el aw , an d t he react i on r at e co nst an t . Besi des hat t, t hi s ex peri men t al s o wan t s o t det er mi ne h t e con ver s i onofNaO H i nt he eact r or an d t he eff ect ofr es i den ce t i me o nt he con vers i on i na P FR. Ther e are ewf ofgr ap h bei ng pl ot t edwi t ht he es rul t s h t at ar e g otf r om t he exp er i men t . One o ft hem i s h t e g r ap h con duct i vi t y ver s us on cver s i onf or exp er i men t 1.Thi s g r ap h t hat had bei ng pl ot t edi s n i ver sel y pr opor t i onal . Next ap gr h i s pl ot t edbet ween con vers i on s ofaO N H i n r eact or ver sus i res den ce i me t d i s t r i but i on. Thi s sho ws h t att he es ri den ce i me t s in i cr ease d as he t con vers i on of NaO H i ncr eased . The at re of eac rt i on an d r at e c on s t an t a cn be cal cul at ed af t er n k ow t he val ues f oo cn ver s i on s . How ever ,t he v au l e o f conv er s i on i n t hi s exp er i men ti s exc eed 100% an d t hi s aff ec tt he val ue o fr atef react o i on.

I NTRO DUCTI ON

React or s are sed ui n t he ch em i cal i ndus t r y f or h t e m i l l i ons o f pr oces ses . Ther e a r e 2

manydi ffer entyp es t f o eac rt or s due t o manydi ffer entac t f or s h t at an c c on t r ol he t f or mat i on of pr od uctdur i ng t he eact r i on. One o f man y di ffer en tt ypes of r eact or s s i p l ug flow r eact or ( PFR) .

A pl ug flow r eac t or si api pes hap edt ankwher e ac hem i c alr eac t i on t akes l ac e p 1

wi t h wal l s o c at edwi t h a cat al ys t an d ani nl etflow of p . ur T eheeact rp l u an gt fl ow r eac t or has an i nl etflow com posed of he t re act an t s . The re act an t flow i nt ot he re act or an d i s h t e c on ver t ed i nt o t he pr od uctby c er t ai n c hem i c alr eac t i on . The pr od uc t fl ow s o ut ofhet r eact or h t r ough t he out l etflow .I n man y sc en ari os,a cat al ys ti s n i vo l ve d i n t he r eact i on. Fi gur e bel ow sho ws t hathow t he en zy me coat st he n i t er i or oft he w al l .

Fu r t her mor e,pl ug flow r eac t or s ar e an i deal i zeds c enar i o wher e i s no mi xi ng i nvol vedi n t he react or . Si nce F P R i s an i dea l i ze d r ea co t r ,i t does ot nt ru l y ex i sti n t he rea l wor l d. I ti s mp i oss i bl e o t haveon mi xi ng atal l dur i ng a eact r i on, but t he am ount of mi xi ng i nt he eact r or can mi ni mi ze.

Pl ug flow r eac t or s ar e f r equ ent l y us edi n t he c hem i c ali ndus t r y due t o t he non mi xi ng pr op er t y of he t r eac t or s . Pl ug flow r eact ors ear f r equ en t l y us ed i n bi ol og i cal r eac t i on s w hent he s ubst r at e flow s n i t o t he r eact or an d i s con ver t edt o pr od uctwi t h t he us e o f anen zy me.Bes i des hat t, pl ug flow r eac t or are s ef ul uf or con t i nuou s p r od uct i on be c aus et he yha veani nl e tandout l e ts t r e am.I nac onc l us i on,pl ugflow r e ac t or sar emos t usef ul f or co nt i nuous r pd ouct i on, l ar gescal e rea ct i ons, or f ast reac t i ons.

( * 1 ‘Plug Flow Reactor’, Product Description by Matthew Grisewoodhttp!!www"scribd"co#!doc!2$1$%&'!Plug)Flow)Reactor

&

OBJ EC TI VE

+

Exper i ment 1:

1.Tofind t he cal i br at i on cu r veof con vers i on vers us o c nduct i vi t y.

Exper i ment 2 and 3:

1.Tocar r y ou ta s apon i fic at i onr ea c t i onbet wee n NaO H andEt ( Ac )i n a pl ug flow r eact or ( PFR) . erm i ne h t e at re f o react i on, r at e aw l, an d r act i on r at e co nst an t . 2.To det er mi ne h t e con ver s i onofNaO H i nt he eac rt or . 3.Todet 4.Todet er mi ne h t e eff ec t ofr es i den ce i me t on t he con ver s i oni n a p l ug flow r eac t or ( PFR) .

THEORY %

Con ver s i on

The c onv es r i on ,AX i s h t e number of ol es m of eac t r anthat t haveeac r t ed per ol me of r eact an tf edt ot he sy st em . XA =

moles of reactant reacted moles of reactant fed

Resi den ce i m t e,τ

The r esi den ce i me t di s t r i but i on ( RTD) of a r eact or s i ach aact r er i s t i c o ft he mi xi ng t hat occu r s n it he ch em i cal react or . V PFR

Res i den cei me, t τ =V 0 wher e :

V PFR V0

=r eac t or vol ume =t ot alf eed flow r at es

Rat e O f Rea c t i onAnd Rat e Law

The r eact i on r at e( r at e of r eact i on) or s peedof r eact reactant i on o f r orproduct a i na part i cu l ar reaction i s n i t ui t i vel y defi nedas ow h f as t orow sl a r eact i on2.t ak Fo e rs l ace p si mpl e defi ni t i on, t he r at e of eact r i o , n, i srh t e number ofol es m f or eact an tr eact i ng A 3 3 ( di s ap pear an c) eperuni tt i me p eruni t vo l ume mol ( . s )/ .dm

The r eact i on r at e eq uat i on ( or h t er at el aw )i s essen t i al l y anal geb r ai c eq uat i on i nvol vi ng con ce nt r at i on .The com mongen er alf orm s of t he at re aw l equ at i oni s h s ow n, α β r A =k AC A C A

wher e AC andC hetn i di vi dualr eact an t s’co ncen t r at i ons,each r ai sed t o t he p owers α Bare an d β,whi l eAi s kh t e reacti on r at e co nst an t . The or der of he t r eact i on r ef er s o tt he p ow er s o t whi chcon cent r at i on s are ai se d r i n t he 2 http!!en"wiipedia"org!wii!Plug-.low-reactor-#odel th

& /" 0cott Fogler, le#ents o. 3he#ical Reaction ngineering, +dition4, Pearson 5nternational dition (266* 

r eact i on r at e aw l. Fr om eq uat i on ab ov e,t he o ver al l or der of he t react i on, n i s, n = α + β Fo r h t i s exp er i men t ,t hi s r eac t i on i s a s ec on d or der eq ui mol ar i w t h t he s am e i ni t i al react an t co ncen t r at i on A ( C ,t he at re aw l sho wn t o be: o=CBo)

whe r e :

X

=e xt e ntofc onve r s i on

CA

= exi t con ce nt r at i onofr eac t an t NaO H [ M]

VO

=t ot ali nl etflow r at e o f sol ut i ons mL ( /mi n)

CAo

=i nl etcon cent r at i on of r eact an t NaO H i nt he eact r or M] [

The eact r i on r at e con s t an t can be d eer tmi nedby : Vo

k

= V PFR C Ao

( ) X

1− X

7

APPARATU S AND MATE RI ALS

APPARATUS: •

Beaker

•

Coni cal flask

•

Bur et t e

•

Pl ug fl ow r eac t or( Mod el :BP 101)

•

Con duc t i vi t y met er

•

Meas ur i ng y ci l nder

MATERI AL: •

Sod i um hyd r oxi de o su l t i on ,NaO H ( 0. 1M )

•

So di um acet at e o s l ut i on,Na A (c)( 0. 1M )

•

Dei oni sed wat er ,2H O

•

Hydr ochl or i c ac i ds ol ut i on, HCl ( 0. 25M )

'

PROCE DURE S

EXPE RI MENT 1

Pr ep arat i on of cal i br at i on cu rveorfcon vers i on vers us o c nduct i vi t y

1.The ol fl ow i ng s ol ut i on s wer e p r epare d: •

1 i l t erofs od i um hy dr oxi de, NaO H ( 0. 1M )

•

1 i l t er of sod i um acet at e,Na( Ac)( 0. 1M )

•

1 i l t er fodei oni sed water ,H 2O

2.The c ond uc t i vi t y andNaO H

c once nt r at i on f or ea c h c onver s i on val ue s was

det er mi nedbymi xi ng t he o f l l ow i ng s ol ut i ons i nt o 100 lm of dei oni se d wat er : •

0% c onve r s i on

:100 mlNaOH

•

25% c onve r s i on

:75 mlNaOH + 2 5 mlNa( Ac )

•

50% c onve r s i on

:50 mlNaOH + 5 0 mlNa( Ac )

•

75% c onve r s i on

:25 mlNaOH + 7 5 mlNa( Ac )

•

100% c on vr e s i on :100 mlNa( Ac )

3.Al l dat a w er e ec rod red.

$

4.The cal i br at i on cu r ve f ocon duct i vi t y vers us o c nvers i onwas l ot pt ed . The sl ope an d yax i si nt er cep t was et d erm i ned .

EXPE RI MENT 2

Effect of esi rden ce i m t e o nt he eact r i on i na T FR

1.The gener als t ar t up pr oced ur eswer e p ef r or med . 2.Val ve s V9 and 11 V we r e opene d. 3.Bot ht he N aO H an d Et ( Ac )s ol ut i on s wer e al l ow edt o en t ert he p l ug re ac t orR1 an d em pt yi nt ot he w as t e an tk B3. 4.P1 an d P2 w er e ad j us t edt o gi ve a cons t ant flow r at e of abou t 300 l / m mi n atflow met er s FI 01 an d FI 02. Make r e suh t atbo t h flow r at esar e h t e a sm e.The fl ow r at es wer e ec rod red . 5.The i nl et Q( I 01) d an ou t l et Q( I 02)on cuct d i vi t y val ues er we s t ar t ed mon i t ore d unt i lt heydo not han cgeov er i me. t Thi s s io t en sure hat tt he r eact or h as each r ed st ea dy st at e. 6.Bot h i nl et and ou t l et t eady s s t at e c on duc t i vi t y val ues wer e r ec od red. he T c on c ent r at i on of aO N H exi t i ng t he r eac t oran d ext ent of on vc er s i on f r om t he cal i br at i on cu r vewer e o f und. 7.Sam pl i ng val ve 15 V as w op ened and a 50m ls am pl e w as ol c l ec t ed. A bac kt i t r at i on pr ocedu r e w as ar c r i edou tt o man ual l y det er mi ne h t e con ce nt r at i onofNaO H i nt he r eact or an d ext en t of con vers i on. 8.St ep4 t o 7 wer e e rp eat edf or i ff der entes i r dence i mes t by r ed uc i ng t he eed f flow r at esofNaO H an d Et ( Ac)t o ab ou t 250, 200, 150, 100 and 50 l m /mi n.make e sur h t at bot hflow r at e sar et hes ame .

16

EXPE RI MENT 3

Back t i t r at i on pr oced ur es or fman ualcon vers i on det er mi nat i on

1.A bu r e t t e w asfil l e d upwi t h 0. 1M NaO H s ol ut i on. 2.10mlof0. 25 M HClwasme as ue r di n a as flk. 3.50 l ms am pl e w asobt ai ned f r om t he exper i ment and t he sa mpl e w asadd e dt ot he HCl i mmed i at el yi nt he fl ak st o quen ch he t a sp on i ficat i onr eac t i on . 4.A f ew dr op s ofpH i ndi c at orwer e d aded nt i o h t e m i xt ur e. 5.The m i xt ur e w as i t r t at edwi t h NaO H s ol ut i onf r om t he b ur et t e u nt i lt he m i xt ur e s i neu t r al i zed .The am ou nt ofNaO H t i t r at edwas ec r od red .

RESU LTS

Exp er i ment 1:

SOL UTI ON MI XTURES 0 . 1M 0. 1M H2O NaOH 10 mL 0 75 mL 50 mL 25 mL -

Na ( Ac ) 25 mL 50 mL 75 mL 10 mL 0

10 mL 0 100 mL 100 mL 100 mL 10mL 0

CONV ERSI ON ( %)

0 25 50 75 100

CONDUCTI VI TY ( mS)

12. 46 10. 46 8. 72 6. 50 4. 66

11

CONDUCTIVITY versus CONVERSION 14 12

f(x) = - 0.08x + 12.47

10 8 CONDUCTIVITY (mS)

6 4 2 0 0

20

40

60

80

100

120

CONVERSION (%)

12

Exp er i ment 2:

Re ac t or vol ume

Conc e nt r at i on f oNaOH i n h tef e e d a t nk

= 0. 1M

Conc ent r at i on of Et ( Ac )i n h te ee f d a tnk

= 0. 1 M

FLO W NO

=0. 4 L

FLO W

TOTAL LOW F

RATE OFRATE OF

RATE OF

RESI DENC E

OUTLE T CONDUCTI VI TY CONVERS I ON, ( mS/ c m) s t

1 2 3 4 5 6

NaOH Et ( Ac) SO LUTI ON TI ME ( mi n) 1 ( mL/ mi n)( mL/ mi n) V0( mL/ mi n) i nl et 313 331 644 0. 621 7. 2 256 253 509 0. 786 7. 1 206 204 410 0. 976 6. 9 152 154 306 1. 307 6. 5 101 103 204 1. 961 6. 1 53 51 104 3. 846 5. 3

X

REAC TI ON RATE

RATE OF REAC TI ON

nd

2 out l et 6. 6 5. 8 5. 6 5. 1 4. 8 4. 2

( %)

101. 8 103. 0 102. 6 103. 2 106. 2 108. 2

CONSTANT ( mol / L. mi n) ( L/ mol . mi n)

910. 54 436. 89 404. 48 246. 71 87. 36 0. 20

2. 95 x 10 3. 93 x 10 2. 73 x 10 2. 53 x 10 3. 36 x 10 1. 34 x 10

1&

3 3 3 3 3 5

CONVERSION vs RESIDENCE TIME 110 108

f(x) = 1.97x + 101.05

106

Conversion,  (%)

104 102 100 98 0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Residence time, τ (min)

Exp er i ment 3: 1+

TI TRA TI ON SAMPL E

VOLUME ofNa OH ( mL) s t

1 T RI AL

( mL)

AVE RAGE VOLUME of

nd

2TR I AL

Na OH ( mL)

300

25. 00

25. 90

25. 45

250

25. 50

26. 00

25. 75

200 150

25. 90 25. 90

25. 40 26. 00

25. 65 25. 80

100

26. 10

27. 00

26. 55

50

25. 70

26. 60

27. 05

SAMPLE CA LCU LATI ON EXPER I MEN T 2and : 3

NaOH + HCl

NaCl+ H 2O

Unk now n qu ant i t y

Concent r at i on of NaO H i nt he eact r Na o ,C Or H

= 0. 1M

Know n qu ant i t i es

Vol ume of s am pl e, sV Concent r at i on of NaO H i nt he eed f vess ,C NaOel H, f

= 50 mL = 0. 1M

Vol ume of HCI f orqu enchi n g, HC I , sV

= 1 0 mL

Concent r at i on of HCI i ns t an dar d sol ut i on ,C HC I , s

= 0. 25M

Vol ume of t i t r at ed aO N H, 1 V

= 25. 45mL

Concent r at i on of NaO H us edf or t i t r at i o n , Na O H, sC

= 0. 1M 1%

Sam pl e C al c ul at i on( f or am spl e fl ow r at e of00m 3l / mi n)

Concent r at i on of NaO H en t er i ng t he eact r Na o , Or H, oC =( CNaOH,f) /2 0.1

=

2

= 0. 05 ol m/L

Vol ume of unr eac t ed u q enchi ng H C ,V 2I C NaOH ,s

=

C HCI , s

xV1

0.1

=

0.25

x 5. 2 45

= 10 . 18mL V ol ume ofHCI r ea c t ed i w t h N aO H i n a s pl e, V 3m =VHCI,s-V2 = 10 – 10. 18 = - 0. 18 L m

Mol esofHCI r ea c t ed i w t h N aO H i n sa mpl e, n 1 =CHCI,sxV3 −0.18

= 0. 25 1000 x 5 = 4. 5 x 10 mol

Mol esofunr ec a t ed aO NH i ns am p l e, n1n 2= 5 = 4. 5 x 10 mol

1

Con ce nt r at i onofunr eact edNaO H i nt he e rNaOH a cor t,C =n2/(Vs/1000 ) − 4.5 x 10−5

=

50 1000

4 = 9. 0 x 10 mol /L

Con ver s i onofNaO H i nt he eac rt or ,X C NaOH

= ( 1C NaOH ,o

)x 10 0%

−4

−9.0 × 10

=( 1 –

)x 1 00%

0.05

= 101 . 8 %

Res i den cei me, t τ V ( PFR )

=

Vo

1000 mL

0.4 L

=

/

x

644 mL min

1L

= 0. 621 i n m

Rat e co nst an t ,k Vo

=

X

V ( PFR ) CA 0

(

1− X

)

wher e Xi s ak ti ng f r om t he cal cu l at i on i n exp er i men t2 644 / 1000

=

0.4 x 0.1

1.018

( 1 −1.018

)

=910. 54 / L mol . mi n

17

Ratef react o i on, r 2

2 =k C A 0 ( 1X) 2 = ( 910. 54) ( 0. 1)2(1-1.018)

=2. 95x-310 moL/L. mi n

DI SCU SS I ON

Ther e ar e t hr eeexp er i ment s or f l u pg flow r eac t or PFR () . Thes e exp er i ment s ar e con duct ed t o ach i eve a f ew obj ect i ves, whi char e t o car r y out a sap on i ficat i on r eact i on be t we e nNaOH andEt ( Ac )i naPFR,t ode t e r mi net her at eofr e ac t i on,t hec onve r s i onof NaO H i n t he e rac t or and t o find t he eff ec t ofr es i dence i met o n t he conv er s i oni n a p l ug flow r eac t orPFR () . 1'

I n exp er i men t one,t he con duct i vi t y met er si u s edt o measure he con tduct i vi t y i n t he w to s ol ut i on s w hi c h ar e o sd i um hy dr oxi de,NaO H and s od i um ac eat te,Na( Ac ) . Us i ng t he s am e c on ce nt r at i on bu t di ffer ent u vol me of eac h s ol ut i on i s con duc t ed t o ac hi eve des i r e co nv esi ron. Then ,t he co nduct i vi t y f or each new sol ut i on t hathas ei b ng mi xed i s t est edbycon duct i vi t y met er . The cal i br at i on cu rve of con duct i vi t y vers us co nvers i on i s pl ot t ed . The sl ope of t hi s g r ap h i s 0. -07 82an d yax i s n i t erc ep ti s 12 . 47 2.The co nduct i vi t y l ow er h w ent he con vers i on i s n i cr eased . Fo rt he n ext exp er i men t ,t he p l ug flow r eac t or Mod ( el : BP 101) i s u s ed . The eed f of s od i um hy dr oxi de,NaO H an d et hy l ace t at e,Et ( Ac)i s vari edt o get di ffer en t of es r i den ce t i me,

τ.heTt heor y of r es i dence t i me di s t r i bu t i on s gen er al l y beg i ns wi t h t hr ee

assu mpt i ons w hi charehet react or s i at st ead yst at e,t r an sp or t att he n i l etan d t he o ut l et 4 t ak es l ace p nl y o byad vect i on, an d t he fl ui d i si ncom .p Fo r ess ri bl each e di ffer en tr esi den ce

t i me,t he 50mL of am spl e i s col l ect edan d bei ng back t i t r at e wi t h hy dr ochl or i c aci d t o det er mi ne t he c on c ent r at i on of od si um hyd r oxi de,NaO H i n t hatam s pl e.Then, het c on ver s i onofNaO H i n t he e rac t or sia cc l ul at ed . The g r ap h ofc on ver s i onofNaO H an d r esi den ce i me t s ipl ot t ed . Thi s gr ap h sh ows h t att he con vers i on i s n i cr ease st h a e esi r den ce t i me i ncr eas e.Fo r t he r ealas e c,t he conv er s i on mus t n i cr eas e ast he r es i den cet i me 5 i ncrea se . How ever ,t he con ve r si on t hatsical cu l at edi s w ‘ei r d’ becau se he t con ve r si on i s

hi gherhan t 100% . From t he con vers i onva l ue,t he at re co ns t an t an d r at e o fr eact i on can be cal cu l at ed t oo. Al lt he r at esof eact r i on t hat are getr om f t he cal cu l at i on are neg ai t ve val ues .Thes e hap pen edbecau s e h t e on cver s i onval uesar e m ore t han100% . Ther ef or e,i t can sa yt hatt her e arer or er s occu r s d ur i ng con duct edt hi s exp er i men t . One o f t he err or s h t atcan hap pen edi nt hi s exp er i men ti s h t er e a r e mp i ur i t i esnit he co ni cal flask dur i ng t he t i t r at i on pr oces s . Thi s can aff ec tt he am ou nt of od si um hy dr oxi de s ol ut i on us ed. Next , maybe t her e was om se l ea kage atanyval vet hatdi d no t not i c ed dur i ng con ductt he exp er i men t . Ot her han t t hat ,t he col ou r o bai tneddur i ng t i t r at i on does not 4 Levenspiel, O., ‘Chemical Reaction Engineering’(3r ei!i"n). #"$n %ile& ' "ns, * (1999).

% Research 0aponi.ication o. thyl 8cetate by 0odiu# /ydro9ide in a Plug Flow Reactor4 by :indsey ;ato, 0hawna