CAPITALCOSTESTIMATION

Dr.M.Fadhil A.Wahab

Dr.MuhammadAbbas AhmadZaini

SKF4153 PLANTDESIGN

=

baseIICostBaseCost

CostIndexes

9 Equipmentcostisobtainedfromcharts,equationsorquotesfromvendors,andonlyvalidforacertainperiodoftime.

9 Thecostchanges(increases)fromyeartoyearprimarilyduetoinflation.

9 ToestimatepurchaseCost,CP atalaterdate,9 TheChemicalEngineering(CE)PlantCostIndex,TheMarshall&Swift

(MS)EquipmentCostIndex,TheNelsonFarrar(NF)Refinery

ConstructionCostIndex,TheEngineeringNewsRecord(ENR)

ConstructionCostIndex.

9 Onetimeexpensefordesign,constructionandstartupforneworarevampofanexistingplant.

9 Grassrootsplantsvs.Plantexpansions.9 ComponentsofTCI: CTBM:TotalBareModuleCost CDPI:DirectPermanentInvestment CTDC:TotalDepreciableCapital CTPI:TotalPermanentInvestment CW:WorkingCapitalInvestment

TotalCapitalInvestment(TCI)

Methods(Levelsofaccuracy), Orderofmagnitudeestimate( 50%) basedonproductionrateand

majorequipmentsasdeterminefrombenchscalelaboratorydata.

Studyestimate( 35%) basedonapreliminaryprocessdesign. Preliminaryestimate( 20%) basedondetailedprocessdesign

studiesleadingtoanoptimizedprocessdesign.

Definitiveestimate basedonadetailedplantdesign,includingdetaileddrawingsandcostestimates,sufficienttoapplycostaccounting.

EstimationofTCI

Toknowwhetheraprocessisworthpursuingornot? Suitableforlowpressureprocess(

UsingsixtenthsrulecomputeproductionratefactorFPR:

FPR =Capacity2Capacityb

m

= Main product flowrate,lb / yr10,000,000

0.6

Step1ofMETHOD1

Step2ofMETHOD1

CalculateindividualmodulecostCMforcompressors,blowers,separators(distillation,absorber,etc.),reactor,butnotforpump,flash,refluxdrumandheatexchanger.

160000$100

100,, 25.0

>= psiaifpsiapressuredesignFFC MPRM

FMismaterialfactor;Carbonsteel(FM=1.0),Copper(FM=1.2),Stainlesssteel(FM=2.0),NickelAlloy(FM=2.5),Titaniumclad(FM=3.0).

CalculatetotalbaremoduleinvestmentCTBMforcurrentyear,

FPIisfactortoaccountforpiping,instrumentation,automaticcontrolaswellasindirectcosts.Forsolidhandling(FPI=1.85),solid&fluids(FPI=2.0)andforfluidshandling(FPI=2.15).

= M

baseMS

MSPITBM CI

IFC,

Step3ofMETHOD1

Step4ofMETHOD1 CalculatedirectpermanentinvestmentCDPI

( ) TBMDPI CFFC 211 ++=F1 andF2 arefactorstoaccountsitepreparation,servicefacilities,utilityplants.Foroutdoorconstruction(F1=0.15),Indoor&outdoor(F1=0.4)andindooronly(F1=0.8).Forminoradditiontoexistingfacilities(F2=0.10),majoradditiontoexistingfacilities(F2=0.3)andforgrassrootsplant(F2=0.8).

CalculatetotalpermanentinvestmentCTPI Add40%tocoverforcontingenciesandanother10%forland,

royaltiesandstartup(totalof50%,thusmultiplyby1.5).

DPITPI CC 5.1= CalculatetotalcapitalinvestmentCTCI Add15%tothetotalpermanentinvestmentCTPI

TPITCI CC 15.1 =

Step5ofMETHOD1

HerethemethodisbasedonoverallfactormethodofLang(1947,1948).

ReferTable22.16forLangfactorsofTPIandCPI,fL,TPI andfL,TCI,respectively.

Purchasecost,CP foraparticularbaseyear(Ib,i) shouldalreadybeknown.

Thepurchasecostofequipmentwasbasedonyear1977,andthecorrespondingMSindexforthatyearis514.

METHOD2:StudyEstimate

Prepareanequipmentlistincludingtheirpurchasecostforaparticularbaseyear.

Updatetothecurrentcostindex(II)andsumtheupdatedpurchasecost.

Multiplyby1.05toaccountfordeliverycosttotheplantsite.

SummaryofstepsinMethod2

CTPI

= 1.05 fL , TPI

II

Ib, i

i CP, i

CTCI

= 1.05 fL , TCI

II

Ib, i

i CP, i

9 BasedonIndividualFactorsMethodofGuthrie (1969,1974).9 Bestcarriedoutafter; Optimalprocessdesign, CompleteM&Ebalances,Equipmentsizinganddecisionon

materialsofconstruction,

ProcesscontrolconfigurationdevelopedasinP&ID.

METHOD3:PreliminaryEstimate

Prepareanequipmentlistincludingtheirpurchasecostforaparticularbaseyear.

Updatetothecurrentcostindex(I). Thepurchasecostisbasedonnearambientdesignpressure,

carbonsteelmaterialandabasedesign.

Steps1&2ofMETHOD3

Step3ofMETHOD3

Foreachpieceofequipment,determinebaremodulecost(CBM)usingbaremodulefactors(FBM)andapplyappropriate

factorsfordesign(Fd),pressure(FP)andmaterial(Fm).

CBM

= CP, b

II

b

FBM + FdFPFM 1( )[ ]

ObtainedthetotalbaremodulecostCTBM.

CTBM

= CBM

CalculatetotalpermanentinvestmentCTPI,(note:notincludingstartupandroyalties)

CTPI

= 1.18(CTBM

+ Csite

+ Cbuilding

+ Coffsite facilities

)

AddworkingcapitaltocalculatetotalcapitalinvestmentCTCI

CTCI

= CTPI

+ CWC

Steps4&5ofMETHOD3

Table22.19givessourcesofwidelyusedequipmentcostdataandthecorrespondingbasecostindex.

Usuallypresentedintheformofgraphsand/orequations. CouldbegeneratedusingAspenIcarus ProcessEvaluator(Aspen

IPE).

AspenIPE:moreaccurate,consistentandperiodicallyupdated.

PurchaseCost,Cp

9 Determinesizefactor,S=Q(H)0.5

9 QisflowrateingpmandHisthepumpheadinft

9 Calculatebasef.o.b.purchasecost,

CB=exp{9.71710.6019[ln(S)]+0.0519[ln(S)]2}

9 Purchasecost(CB hasalreadytakenintoaccount)ofasinglestage,3600rpm,verticalsplitcase(VSC),andmadeofcast

ironcentrifugalpumpforSbetween400and100000canbe

estimatedfromFigure22.3.

Cp ofCentrifugalPump

9 Forotherspecifications,purchasecostofcentrifugalpump,

Cp=FTFMCB

9 FM ismaterialfactor fromTable22.21.

9 FT ispumptypefactor fromTable22.20.

9 Thispricedoesnotincludeelectricmotor.

9 Basef.o.b.purchasecostdataofHEXarecorrelatedintermsofsurfacearea.

9 Fig.22.10isonlyvalidforcarbonsteeltubes, in.or1in.OD,wallthicknessoftubeis16BWG(BirminghamWireGage),20ftlong,

squareortriangularpitch,carbonsteelwithshellsidepressureup

to100psig,andsurfaceareabetween150to12000ft2.

9 Forotherspecifications,useEquation22.43,andCB ofparticulardesignfromEquations22.3922.42.

Cp ofShell&TubeHEX

9 Equation22.43;

Cp=FPFMFLCB

9 FL istubelengthcorrectionfactor (seepage571)9 FM ismaterialfactor (Equation22.44andTable22.25)9 FP ispressurefactor (Equation22.45),Pinpsig.9 Readalso onpurchasecostsfordoublepipeHEXandfired

heater.

Sizefactor=Weight(lb) Forotherspecifications,useEquation22.52.

Cp=FMCV+CPL

Obtaincostofemptyvessels,CV;inEquations22.53(horizontal),22.54(vertical)and22.57(towers).

Additionalcostforplatformandladder,CPL;inEquations22.55(Horizontal),22.56(Vertical)and22.58(towers).

Useappropriateunitsfortheequations ValuesofFM aregiveninTable22.26.

Cp ofPressurevesselandTowers

W=(Di+tS)(L+0.8Di)tS

isdensityofcarbonsteel. tS isthicknessofshellandellipticalheads.

9 Athighinternalpressure(operatingpressure);useEquation22.60,wheretS =tP.

9Minimumwallthicknessatlowpressuresaregivenatpage575.

Effectofwindandearthquakeonaverticalvessel/tower,useEquations22.60and22.62.tS =tV =tP+tW

Atlowinternalpressure(vacuum),useEquations22.6322.65.tS =tV =tE+tEC.

Addcostofinstalledtrays(inclusivealldowncomers),CT tocostofvessel.

Cp=FMCV+CPL+CT

CT=NTFNTFTTFTMCBT

Basecost,CBT(CE394,year2000)isgivenbyEquation22.67. NT istraynumber,FNT isgivenbyEquation22.68,FTT istraytype

factor,FTM istraymaterialfactor,seepage577.

ForPackedcolumn,selflearnfrompage578.

Cp ofTrayandPackedTower

References

G.D.Ulrich,ProcessPlantDesignandEconomics,JohnWiley,1984. L.T.Biegler,I.E.Grossman,A.W.Westerberg,SystematicMethodsof

ChemicalProcessDesign,PrenticeHall,1997. Monograph,ProcessDesignandSynthesis,Universiti Teknologi Malaysia,

2006/07 W.D.Seider,J.D.Seider,D.R.Lewin,ProductandProcessDesign

Principles:Synthesis,AnalysisandEvaluation,JohnWileyandSons,Inc.,2010.