Design and Development Report

1. ICCBPE/ SOMChE2OO5
NITE-20
ProcessModellingofA PVCProaluctionPlant
ChanJunHoar DominicC.Y. Foo'? SivakumarKumaresanl
Ram]an Abdul Azizr Mohal Adffin Abu [Iassan3
) Cheni.al EngineerinE Pilot Plant, UniversiiTeknalogi Mdlatsid
81314 Sktulai, lohor, Malarsia
Tel: +60'7-i 53 1662,Fax: +6a-7-55697A6,E'moil: ]'ti[t@kop. tri ,tt: ntnltrt@ cepDutn
"N
1
Schaolof Cheflicdl and EnvnonnentaL Enginee n8, Uniwtsitt of NottinqhM (MdLalsiLt CMPU)
Jdian Btagd $5aA Sedenrih selahgar Darut Ehsan Matqtsia
TeI: +60-3-3921 8130,Fat: +60 3 8924'8A17,E tuail: Dottiri. l-oa@nnni'pharLetd n
3Chehi.dl Eneineenng Dep4nnen. Uniretsiti Tekhaloei Malayia
8131ASkadai,JohoL Malallia
Tel: +60-7553-5485,FN: +60-7-5581,163,E'mail: narifln@fl*kla utnfitr
Abstract
This pap.r presents the modellihs of a Polrtinrl Chbn b
lPvC) ftsins nanuJdctarins ptucess vith batch Process
sinutat r, SuperPrc DesiSner v6 0 The sihulatiot m.4.1
has been dedaped bued a. the oPentiag condnion of a
locdl PVC ntanuldc nns pkttt. As the PoLrme4dtion
prcces b cdftied out in bdtch apetatioh nade, effons har.
beeh hade to dncunent the scheduliry .tetails oJedch unrt
operdtian abd. rcsuht are prcsented in the Gantt .hart
a l" .ia? to, a .ompaP Datta'tt anoh Pra.?' i
detemined to be 11.28 hou^. The nodel also rcreak thdt
apprcriMtel, 17 batch.s ol polJmerkatioh rcactia4 con be
plocesed per .1d!, which taUies the rcaL aPelation of the
PvC nan uJdctutits plant.
Keywords: ModelLing, optinisation, batch poces,
scheduling,lVC poduciion.
Introduction
The Conrlurq Aided Proce$ DesiSn (CAPD) atd
simulationLoolshavebeenwidely usedin the buLtand
peircchedicalitdust.iessincetheerly 1960's It inv.lve-s
$e useoi conpute$to pedom steady-staleheatandm$s
balancingasveu d sizjng add costingctrcuhilons for a
processlll. However,the use of dese CA?D ud
slmulatiodt@ls has only emerged in the batcb
nanufact.ingin thelast decade[2_7] Conpded !o the
rcxdily alaildle comercial processsiDuiato^ in the bulk
chenicai industnes,there are only a limited nunber of
commecial simulatos available lor batch Proces
modellingin thema.ket,wbichincludeBarchesby Baich
ProcesTechnologies.BatchPlusby Aslen Technology,
Sup€rPrcDesignerby Inielli8enasweu asBatchDesigr
Kir by Hyprotech.This siNarionis mainlydue ro rhe
complexiryassoclatedwitb batch Procesestba! de
tequenrlyoperatedin cyclicalmode.Dueto itsreLatively
nevemergence,nuch workneedstobedonein thissector.
Tbis !a!e. desc.ibesthe use of tbe comeicial b.tch
processsimulatorSulerPlo Designe!v6.0 t8l in the
nodelljns of a locrl lndusbial production of pobnlnyl
chloride (PVC), which is operrred in mixed barh and
PVCManufacturingCaseStudy
I igue Lhow. ,h" proce flowdr,gjd ot LhePvc re.r
manufacluring. h consists of 10 ptuallel batcb
polymedsationrcactos, blow'down ve$el, dd two
pdallel hainsof downstrcamprocesing equipment.Ercb
downstreamproce$ing !.ail consistsof a stri?per,two
decotes dd afluid beddryer. Thephnt is op*ated ln a
semlbatchmodewhereulsLrm rclctoF ue scheduledto
nalch thedowrsr]em processingrrainslhatde operatedf
The baLchreacrorfeed consistof a mixture of f.esh vilyl
chlodde monome. (VCM) md recycied vCM from the
proce$, mainly f.om btowdowneesel ad s(ipper. At the
polynerlsing or rcacdon secdon of rbe pLant, the
polydensingproces i! caried out subsequentlyn ien
parallel barch re@to!s, Rdw ddtenab ibr the
polymerisationprocesincluded€minemlisedwarer,vcM,
idtiaio.s ard suspendingagents. Theseraw matenale
chargedjito the re&roi in sequerce. The pH of tne
deionisedeareris keptberween6.6 9.0. Thesuspelding
agentis diluted to aplroximalelr 4.0vt% ald is chrged
inro rhereactortogethervith denlneralisedwater. This is
mrinly ddeto lhe highviscosityof the suspendingagent
Jpor .hecomplefono'"u petd:ngagen.!h.rge.p,'ma^
andsecondal-alnitiatos a.eaddedinto thereactormanLially
vla the ve$el man hole. Mdual chugi!8 of initiator is

2. ICCBPE/ SOMChE2OO5
requned 3 flucluations resuked froh the autohated
chargrngsysrer nay leadIo severesafetyproblemjs not
tolerable Two rypes of inidatos a.e us€d jn thN
vcM
vcM
PVC
polymerisation p.ocess, with the prlndl initiltor in
powderfom while the secondaryiniriab. in flat<esfom.
F/8r.a / Pro.e." tloq dhgrxn ofa PV. reufnudng olMr
After rhe chdging of watei conpletes. the reactor is prrged
by nilJogen ard then vacuumed befo.e charging of VCM is
chdged. This is to ensure tbat no oxygen is pftsent in the
reactor as reactior between VCM dd oxygen dd might
Fsult in extlosioo.
Upon ihe compledon of VCM chdge, heatins is comence
to nise the reacto. temperature to the optimal rcachon
temperature of 57oC ud a workirg pessure of 8-9 bd.
Exothefri. polymensddonptuces next comnences,for a
duEnon of 7.5 hours. Contiruous cooling is needed ro
remove excess heat ud to maintain the re@tor tempentm
at57"C. PvC polyme. is the main produd arthe endof the
polymerisdtionprocess. Other bl-products of the reaction
ale the unrcacted vcMi iniiiato$, susFndhg agenr and
some kace amount of contamindt. The reaclor conrent is
dow presert in slunf fom (a mixture of PVC and wated
andis ready!o besentto tbeblowdown syst.m.
The blo$dowr vesselreceivesbatchesof slu!ry wbich ee
inremitterrly dischdged fom rhe reactors. The blowdown
lessel acts dr bdffer stonge so thar sturry cb be
-ond ,uou.lyIeJ .o ,he,wo pdallel doqnstfrd prcce..in8
tnins. As s1urryis discheged fronr the reelor, ldge lunps
which could bldk downstrem equtlnent m €noled by
sfiainen. As the slury entersihe blowdown vessel.the
najor pornon of lhe unreacted vCM trapted in the PvC
particles flshes of md is vefted to the gasloldtr for
rccolery. The vcM vapoor ls lext codpressed Dd
condensed into liquid lom before it is reused in the
pol)merisatioD prcce$.
As the effluent Aom the blowdown v€sseL entels the
doMsrrem pro.esing Lairs, lhe shlpper colum tuitrer
Th€ batch reacloi feed consjst oi a ni{tue of freslt vinyl
chloride monome. (VCM) and recycled VCM f.on tbe
p.ocess,naidly fron blovdown vesseladdsripper. At the
polymedsing or reaction seclion of lhe p1dr, the
polymerislng proces is caried ou! subsequertly io ten
pdallel batch reacto6. Raw materials fo! the
polymensationproce$ irclude denineralisedwater,VCM,
initiato$ dd suspendirg agenrs. Tbese raw matenal ue
charged inio the reactor in se4uence. The !H of the
deiorisedwate.is kept belween6.6 - 9.0. The suspending
agent is diluted to approxinately 4.0wt7o and is chdged
inio the reacror together with denineralised water. This is
mainly due to the high viscosity of fie susPendingaged
'
I o- l e co. oleoo, ol ..p_, d -e a8Fn'ft r8e. primcr)
addsecondaryinitiatos ae addedinto lhe .edctormdually
via lhe vesel mm hole. Manuai chtuSlngof initiator is
requiEd s tlucrDadons resulted lrom the autonated
chdgins system my lead to severe safely problen is not
tolefable. Two types of initialors de used in ltus
pol.TFr1non poc+i. u,rh rLr p,ma,l inilinor in
powder fom while the secordary initiator in flakes fom.
l, . 1lo oe ,o p,ping conJTil
donine$riled water can only be chdged inlo the reaclos
one at a lim€ Demineralised water chdgine in each reactor
rekes approximatell 20 minutes !o comPlete. chargug
procedu.e in e&h of the reactor wlll only slart after the end
of chdging in an eelier reactor. The sme situationoccurs
to rhe cheging ot vCM dd the biowdown opention after
882

3. ICCBPE/ SOMChE200s
remores lhe unreacted vcM from the Pvc slurry. srem
is iniroduced ar the bse of the stipping colum dd the
VCM is moved as a. overhead lroducr to the gdholder.
The stipped slurry is then djlected to rwo p{allel decarters
lbr water remolrl. Approrihately 797a of wate. is
.emoved by rhese<lecante$lrom the PVC slurry
Wet cake fron lbe decMtes is rcxt se to the fluidised
bed dryer ro be dried by hor an dd hor water (in tubs
whjch a.e heatedby stean). Direcr usageof steamm tne
dryer is not pGciical as the PvC resinshave a low Gla$
limsitio! Temperatlre (TJ of 78'C. Exposureof PvC
rsins unde.the stem of 10ffC will causethe siructw of
the resins to collapse. This softens the PVC resins and
resulh in poorqurlity of resjns.
D.ied PvC rcsins are transpoded by cool pldt air to the
shifter. Thc use of cool plrnt air avoids rhe e]€ctrostatic
force that may cause the resins to flocculat.. Flne .e$ns
thatpdssrhroushrheshilter (60 mesb)&e sold asproduct
while the couse .esinsde gnnded and sold as Low-gdde
BaseCaseProcessSimulation
Flgurc2 sbowsthebasecaseprocesssimulationmodelthat
basbeeddeveloledb6edontheoperathgconditiotrol tbe
PVCnanufacturingprocessusingSule.Pro DesignerV6.0
(Inteilesen,2005). The dnual operatingtine of de
Prcce$modelistak€na57920bous.
ln themodellingenvilonmentof Supe.ProDsigne., a lew
operarionr rnke place sequertially ln r single d't'
prccedure (.ret1eg.r. 2005). For instance, vesser
procednreP-l tu Fisure 2 is used ro model rhe oacr
poi)me.isai.ionpro.essthatconsisrof sequeftialolentions
ol .aw marerial chdges, vacuum, maleriai heatjng,
polynerisationproces d well asprcductblowdown. Au
tbeseindividualoperationirake plee in ve$et K207
(wheieyesselFocedureP I takesplace).Themodellinsof
thesesingleopemtiolsis desc.ibednexr.
The raw material chtugedinto K20? during rbe srari of
proce{lureP-] includesdemitrenljsedvarer (CHARGE-
H2O), slspendins agent (CEARGE-PVA), prjme.y
initiator (CHARCE-CATI) Dd secondary idrialor
(CHARCE-CAT2). P.opertiesof rhetuw materidlsusedtn
themodelde summdisedln Table I. Noreihatsuspending
rgent, pnmary and secondaryinidaron e user defined
componeDtswhere then proledies havebeetrchangedu
the model. Note that the model has iNluded rhe acual
opendng condition of the PVC moufacturing procss,
wherethechtuglngotdemineElised warerfor a subsequenl
Eactoris scheduledto srui afterthe warerchugjng ot tbe
precedingreactore!ds. Suspendirgagent,primary and
secondaryinitiatod m cheged into thereactordudngthe
The vrcum operrlions (VACWM) in prccedureP I
inciudea vacuun air purgefrom lhe reacto!to 0.226ara
(gaugepEssue = -0 8 kg/6') lbuowed by ! nimgen sas
purgeto 1.194atm (gaugepresure
- 0.2 kChnl dd
anothe-rvacuun porgeto 0.226atm(gaugepE$ule = 0.8
kg/cn"). The vacuun operationswerecdied out before
thechdgog of VCM (CHARGEVCM). Thisis to avoid
rr-n .inBol.M si.har.whch uAhr.eadroeplonon
tJ.
Fisutp 2 s'nLta a"llo|.heqat PvC aonuta' t"tnc
333

4. ICCBPE / SOMChE 2OO5
Tabte t - Feed Stean SpeciJication
ChilledHrO 100USgal
(1135.62ks)
1.7kg
MW = 571.00
07kg MW=398.70
Nomdl boiling point=
461"C
I55kg
MeLdngpoint= 228'C
vcM
10500ke
ln the heating operation, hot water (inlet temlerature of
90'C and outlet temperature of 70"C) is defined s a new
heat transfei agent to heat the redctor to 57 aC where
polrmerisationprccess(REACT-1) occus. ln the re@tion
operaiion, duradon of the polynerisadon !rccess rakes 7.5
hou.s and tbe @action extent is sei ar 90%. Stoichiometric
reacdoonodel is used and the reaction stoichiomefic is
defidedto convertonemss ofVCM to onema$ of PVC,
,(vcM)) (Pvc)" (l)
The ldsr operadon in the veseL procedu.e is to dis.hdge
(TRANS OLIT) ihe slury reactor contenr to the blowdown
procedureP 14 (in vesel V-101). Simild to the caseor
deminerdlisationwater chdge, bLowdownoperation of a
subsequent reactor is also scheduled to start afte. the
completjon a preceding reactor, due to the pipfg constran
in the actual process. Tbe specification ol the prccess
!e$€Lsis showdin Table2.
Tdble 2 - Equipneflt Specifcatiot Table
Equipment Equipmcntt.g volme (mrl
identical deceters dd a fluid-bed dryer rhat opeErein
continuousmode. Thus,no scheduljng;qeededin lhese
processes. The dodelling s!@ificaiions ol eeh unir
procedurein tlresedownstreamp.oce$ing L2ins re next
descdbed.
Stripperprocedures(P-16and P-17){e usedfor VCM
lemoval. Thedesigr componentof thescippersis selected
tobevcM. 2880kg of steaaat i loqcisinfoducedtorbe
stripler to achievea VCM remova1of 99.9%. In the
sinularion node1.rhecondenserar rhestrippertop which
coldensesthestem is onitied sincevCM recoveryfaciliry
id dol modelled. Hence,the srem leavesN enx$,u!
togeder wirh VCM- Tbis teadsto d slight de{eue in dE
totalamountol w$tew er dischdgedtrcm rhedecdte.,
which howeverco be omitteddue to ils insignilicer
Theslury thL (P-l?ddP'18) served tehpor:trystorase
for tbe PVC s1u.rybefore it entes into tbe two p@llel
identicrldecanieB(P-20md P-21;notshownid Fig 3.2).
Solidremovalin thedecant€Bis sp€ciliedu 997dfor PvC,
witb water los! of 21% (includecbiled water lost).
E,Il.en "mrs ho{ rhesedecr.pr uri,r , rhr d..1
wasrewaterof the processiwhile the wet lilter cakeis sert
tofluidised-beddryersfor noistu€ rnolal.
In thefluidised-beddrye6 (P'22 andP-23),hot air ar95"C
is usedto dry lbe wet fllter cake. EvapomrionEte of water
andthefinal solidtenperatlre de setai 916ke H:O /h ed
60'C.espectively-As a resDlt,99.8%of thenoisture(the
comlonentofwaterandchilledwrtet iscmoved,
From the simulationmodel,the cycle time fo. a comliete
batchpotymerisationprocessis 14.28hous. This nodel
also reveals that approxlEately 17 batchs of
polymensrtion reaciioncar be proce$ed per day. which
nllies the real ope.ationof |he PVC mduhctding plant.
Basedon the dnual operatingtime ol 7920hous, lbis
ranslatesinto554batchevyed,
It shouldalsobenoiedtba! all veselprocedurcs(P'1toP'
10) m obsefled to havedifferent cycle time (seeGarti
Chadin Fig!re3). Thisis maidy dueto theschedullngol
me TRANSFEROUTI op.Etions in eachof the le&tor
procetures(P-L to P-10). SinceTRANSFEROUT'1
opelatlonin eachof Oe tacior is scheduledto smnafter
fie TRANSFER-OUT-I olection of ihe peceding reaclo.
ends,this crealesalagtimefo. theprcductto bedlch&ged
from the sDbsequentreacto!befo.e the pfecedingredctor
compleiesiis TRANSFEROUTI olemtiotr. A good
exmple is shown in Figure 3. As sbo*n, tbe
polynerisation .eactionin P-ZK-?078 coftpieted at 9.62
hr. However, due ro the TRANSFER-OUT-I of Pl/K-
207,4is in opeEtion,TR-{NSFEROUT I operationir P-
2/K 2078 cannot si.n until the TRANSFER-oUT-1
operationin P'1/K-20?Aendsar9-78hr. Hence,lhisleads
to alagtine of 0.16br.
!olytneisahon reactos K2O7AK2O7J
v 101
V'l?mdV 13
2)
94
100
As the polyme.isarionprocessis cmied out in batch
operahonmode,efforts havebeenmadero documelt the
scbedutingdetailsforeachof thebatchvesellrocedure(P'
I !o P-ro). Thisincludestheretup ine ISU'|),prccess
tihe (W), Md srirt dn (S'l) ol eachindilidual opeEtion
in lhe ves$elprocedup. The dellils of tbis scheduling
summa.r,4e shorn in Table3, wirh lheprccessGtntt chalr
Fromtheblowdo{n vessel,theslurrypioductenresdro
L*o luallel idendcaldownstreamprccessingtmi$ which
indivrduallyconsistoi a stripper,slury tank.two pdallel

5. ICCBPE/ SOMChE2005
'tdble3 SchedrlinsStntury lor B6e CaseSin atot
P-1/K207Ato
P r]/K2Ut
Chdge in SUT= 0min CHARCE-iI2O for seconddd
Ff=20mln subsequenrreactorstarcafterthe
endof CHARGE-H2Oin
ST= Beclnningof batch
(CHARGEPVA)
SUT=0mn
ST= 5mir afterCHARGE-H2O
(CHARCE-CATl)
SUT= 0 sin
Pr=2min
Starttime= l0 mlnafterCHARCE-
H2Oslans
(CHARGECAT2)
SUT=0min
St&ttiBe= 10nin afterCHARCE-
H2Ostafis
(vAcwM)
SUT= 0 mid :lJsl Vacuumto 0,226a6n
lurce$ith N, to L194rrn
ST= After CHARGE-Ii2Oends SecondV(uun ro0.226xtn
chugeinvCM
(CHARGE-VCM)
SUT= 5f,in
ST= afterVACUUM e.ds
Heat
(HEAT,1)
SUT=0min
Usehotwate.(90- ?fC) as
FhalheatingT= 57"C
ST= aier CHARCE-VCMends
(REACT-1)
SUT= 0nin
PT=.+50min Emisior = 20%of YCM (off vent
ST- Alier HEAT-I ends :ooli.g agent= coolirg wate.dr
Chdgei! Chilled
ICHILLEDH2O)
Sln =0min
ST=?h afterREACT-Istarts
GRANSFER,OUT-1)
SUT=0tun Scheduledto stanafterrhe
transferoutol'previousreactor
ST=rfter RE-ACT-I ends

6. TCCBPEi SOMChE2OO5
Figute 3 Prccess Ganlt Chan for Bde CaseSimulation
Conclusion
A linulatlon model based on the optratilg condition of a
PVC manuferuring process has be€n developed on ! batch
lroces sinulation softwtue. The developed model rilhes
the real operadotrwherc 17 batch€s of polymerisation
prccessare caried ou per day. This trdslates into 554
batchesof product per a.num.
AcknolYledgement
The technicalsupporlofMr YoeDgCheeNyok of hdushar
ResinlMalaysia)Berhadis srarenrlLyacknowledged
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