UnitOps5

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Experiment No. 5

Plate and Frame Filtration

Submitted by:

Alaras, Lorelie L.

Chan, Bea Jasmine V.

Chano, Shermaine !enia S.

"ason, Ann Claudette A.

#lan$a, !oris An$elia B.

Submitted to:

En$r. %u$i %ubi

&ebruary '(, '()5

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Abstract

*he plate and +rame +ilter press are usually used to separate the solids +rom the liuids o+

a slurry solution. *he solids produed +rom this +iltration tehniue are alled the +ilter a-e. &or

this experiment, aolin/0ater suspension 1)(20t3 0as employed. *hi-ness o+ the +ilter a-e

0as used to determine its relationships 0ith +iltration time, 4olume and pressure. *he resultssho0ed as the +iltration proess preedes the a-e thi-ness 0as o+ ourse inreases 0ith time,

thus lo0erin$ the +iltration rate. Li-e0ise the +ull apaity o+ the +ilter press olleted 0as

alulated and ahie4ed an experimental 4alue o+ .5x)(/5L6s'.

I. Introduction

&iltration is a ommon operation +or

the separation o+ suspended solids +rom a

liuid 1the ori$inal mixture is re+erred to as aslurry3. *here are numerous types o+ +ilters

+or ontinuous and bath operations 1Luyben

and 7en8el, )93. *he partiular type that

0e 0ill examine, a plate/and/+rame +ilter

press, is used +or bath operations.

&ilter press operates under pressure

usin$ the proess o+ a-e +iltration. *hisin4ol4es sendin$ a slurry throu$h the press,

0hih is euipped 0ith +ilter loths. *he

loths pi- up the partiles in the slurry and

allo0 0ater to pass throu$h it. As more

slurry mo4es throu$h the press, the a-e

builds up and assists the +iltration proess.

;o0e4er, as more and more solid builds up

in the +rame, +iltration beomes slo0er and

slo0er. 7hen a su++iient thi-ness o+ solids

or a-e has built up in the +rames, +iltration

is stopped, the press is dismantled and the

a-e is remo4ed +rom the +rames.

At any instant in time, the rate o+

+iltration, 1< dV6dt3, depends upon the

pressure drop aross, and the resistane o+,the a-e and +ilter. =r loo-in$ at it

>ba-0ards>, the pressure drop aross the

+ilter is a +untion o+ the +iltration rate and

the resistane to +lo0, as $i4en by loth1Bennett and ?eyers, )9'3:

(1)

*he +iltration onstants ) and ' are

lumped parameters 0hih re+let the

resistane to the +lo0 o+ +iltrate aused bythe a-e and +ilter, respeti4ely. *he

+iltration onstants an be estimated +rom:

(2)

and

(3)

*he resistane o+ the a-e inreases

0ith time as the a-e builds up in the +rame

1i.e. it beomes harder to +ore the +iltrate

throu$h the a-e, as the a-e beomes

thi-er3. At any time, this resistane to the

+lo0 o+ +iltrate is proportional to the 4olume

o+ +iltrate that has passed throu$h the a-eand is represented by the term )V. *he rate

o+ +iltration is dV6dt and the rate expression

$i4en by Euation 1)3 may be inte$rated +or

4arious modes o+ operation 1either onstant

pressure drop aross the +ilter or onstant

4olumetri +lo0 rate o+ the +iltrate3.

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II. Theoretical background

*he +lo0 rate o+ the slurry throu$h

the +ilter press system dereases 0ith time.

*his is due to the a-e build/up on the plates, as 0ell as lo$$in$ in the plates that

may our. *he -ey uantities o+ interest arethe +lo0 rate, resistane, and pressure drop.

*he pressure drop rises or the +lo0 rate

dereases 0ith time. 7hen the pressure is

held onstant, the +lo0 rate 0ill derease.*here is a onstant/pressure +iltration

euation that 0as +ound in ?Cabe, 0hih

states the +ollo0in$:

=r expandin$ the total %esistane % into its

omponents

7here:

III. Procedure

&or the preparation o+ ra0 materials,

the ra0 materials 0ere pul4eri8ed and pass

throu$h a ball mill by a @(/mesh sreen. )(

20t slurry o+ lay and 0ater 0as then

prepared. !isperse partiles 0ere stirred and

dissol4ed to homo$eni8e the slurry.

&or the preparation o+ the +ilter press,

slurry 0as ontained in a +eed tan-. t 0as

ontinuously stirred to a4oid settlin$ o+ the

lay to the bottom. *he lay slurry 0as then

pumped into the +ilter press. &eed inlet

pressure 0as then reorded. &iltrates 0ere

olleted +or spei+i time ran$es and

4olume 0as determined. A+ter the +iltration

period, plates 0ere dismantled and partiles

0ere 0ashed o++ by 0ater. A+ter dryin$ the

materials, it 0ill be assembled ba- to the

+ilter press.

IV. Results

*able ): !ata +or aolin/7ater A!"I#$%AT&R

aolin

(kg)' 3.33 I(m) .2*21

%ater

(")' 3

+,eight' 1+

Feed Rate

("-min) *

Time

Range

Filtration

Pressure height

Filtration

Volume

Filtration

Rate

s sig m " "-s

'( (.()'( (.() (.(('

( (.((55 (.@@ (.()

@( (.((( (.'@( (.()

( (.((5 (.'5 (.())

)(( (.((5 (.'5 (.())

)'( (.((5 (.'5 (.())

)( (.((5 (.'5 (.())

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)@( (.((5 (.'5 (.())

)( (.((( (.'()( (.()()

'(( (.((( (.'()( (.()()

a/e rate .101

caacit .041

5akeata

Frame

#o.

5ake

Thickness

(mm)

area

co/ered /olume

) ) )@5x)@5 '''5

' ) )@5x)@5 '''5

) )@5x)@5 '''5

' )@5x)@5 55(

5 )@5x)@5 )@5

@ )@5x)@5 )@5

)@5x)@5 )@5

)@5x)@5 )@5

9 )@5x)@5 )@5

)( .5 )@5x)@5 95'.5

)) ' )@5x))( @((

)' (.5 )@5x)(( '5(

a/e cake

thickness 2.16

0 50 100 150 200 2

0

0.5

1

1.5

2

2.53

3.5

Filtration Pressure vs Filtration Ti

fltration pressure vs fltration time

&i$ure ): &iltration "ressure 4s *ime

0 50 100 150 200 250

0

0.5

1

1.5

2

2.5

3

3.5

4

Cake Thickness vs Filtration Time

cake thickness vs fltration time

&i$ure ': Ca-e *hi-ness 4s *ime

0 50 100 150 200 250

0

0.01

0.02

0.03

0.04

0.05

Filtration Volume vs Filtration Time

fltration volume vs fltration time

&i$ure : &iltration Volume 4s *ime

7amle 5omutations'

&eed %ate<Vslurry

t ( filtration)

&eed rate<

30 L

200 s∗1min

60 s

&eed rate<9L6min

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&iltration 4olume<πD2h

4

At time '(s, h< ).' m d<(.'9')m

&iltration 4olume<π ∗1.210−2

∗029212

4 <

(.(L

&iltration rate<filtration volume

time

&iltration rate<0.804 L

20s < (.( L6s

Capaity o+ +ilter press<

V ave filtrate volume

t ave filtration time 0here V

a4e<(.()5L6s

Capaity <0.015 L/ s200s <.5x)(/5L6s'

V. iscussion o8 Results

Based +rom the results alulated and

illustrated, it an be obser4ed that as the

aolin D 7ater +iltration proeeds, the

+iltration pressure 4aries diretly 0ith the

+iltration time as sho0n in &i$ure ). *his

means that no apparent han$e in pressure

0as seen durin$ the 0hole +iltrationexperiment. As +or the a-e thi-ness, it an

be notied that as +iltration time inreases,

the a-e +ormed also inreases thus 4aryin$

the resistane to the +iltration rate. 7ith

re$ards to the +iltration 4olume, it an be

seen that there is a $radual redution o+ the

4olume as the time $oes by. *he omputed

apaity o+ the +ilter press is (.()5 L per

seond.

As +or the a-e thi-ness, it an be

obser4ed that the a-es 0ere mostly +ormed

in the middle +rames. *his sho0s that it 0as

not uni+orm all throu$hout the plate and

+rame +ilter euipment. "ossible soure o+

errors +or this experiment may be the

instrument or the euipment.

VI. 5onclusion and Recommendations

Almost all o+ the obeti4es o+ the

experiment 0ere met. *he optimum+iltration time is the +irst t0enty seonds o+

+iltration 0ith a +iltration rate o+

(.(('('. t also sho0s that as the time

inreases, the +iltration rate dereases, but

0ith almost onstant rate. *he optimum

thi-ness o+ a-e is .5 millimeters 0hih is

obser4ed at +rame number )(. t is also

obser4ed that as the mesh number o+ the

+ilter inreases, the a-e thi-ness also

inreases. *he pressure is held onstant at psi $a$e.

&iltration is one o+ the ommon unit

operations used in the industry beause o+ its

inexpensi4e maintenane and basi

proedure in separatin$ materials. But, it

still has limitations. *he euipment ould

not hold bul-y suspended solids as it an

dama$e the pump. Also, orrosi4e mixture

ould not be used 0ith this separation

proess as it an dama$e the +ilterin$ plates.

&reuent maintenane should be also

obser4ed 0hen usin$ this euipment as it

an lead to orrosion and other

mal+untions. &or the +uture experimenters,

they ould use other material to be +iltered

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or other onentration o+ -aolin to

di++erentiate the e++et o+ these parameters

0ith respet to the results o+ this experiment.

Re8erences

• Luyben, 7.L. and L.A. 7en8el,

)9, Chemial "roess Analysis:

?aterial and Ener$y Balanes9

"rentie/;all, En$le0ood Cli++s,

N.J., pp. /@.

• ?Cabe, 7arren and Julian Smith,

"eter ;arriott, #nit =perations o+

Chemial En$ineerin$F ?Gra0/;ill

n.F Ne0 Hor-, 5th Edition, )99, p$ )((' / )('.

• http:66000.slideshare.net6eu+ier6plat

e/+rame/+ilter/press/+inal/report

http://www.slideshare.net/jeufier/plate-frame-filter-press-final-report




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