E8 - BFD PFD P&ID

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BFD, PFD, P&ID

DavideManca

Lab5 ofProcessSystemsEngineering MasterDegreeinChemicalEngineering PolitecnicodiMilano

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Therearethreemaindiagramsusedbychemicalengineerstodesignanddescribetheprocesses

BlockFlowDiagramBFD Startingfromaninputoutputdiagramoftheprocesswedivideitintoitsmain

functionalblockssuchas:thereactionsection,theseparationsection,etc

Thenweaddtherecyclestreamsandthepreliminarymaterialbalances.

ProcessFlowDiagramPFD Thenextstepistoevaluateandquantifyefficientlythematerialandenergy

balancesforalltheprocessstreams.Thenweaddthepreliminarydesign

specificationsoftheequipment.

PipingandInstrumentationDiagramP&ID Weintroducethespecificdetailsdescribingthemechanicsandtheprocess

instrumentation.

Diagrams in process engineering

DavideManca ProcessSystemsEngineering MasterDegreeinChemEng PolitecnicodiMilano 2

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Themostefficientwaytocommunicateinformationrelatedtoachemical

processistouseflowcharts.Visual informationisthebestwaytopresent

designdataanditavoidsmisunderstandingsandambiguities.

WhenpossibleitshallbeadoptedtheEnglishterminologyandsymbologysince

inmostcasesthedocumentationproducedbyanengineeringcompanyisfor

foreignorders.

Werefertosymbolsanddiagramsfromthetext:

R.Turton,R.Bailie,W.Whiting,J.Shaeiwitz

Analysis,SynthesisandDesignofChemicalProcesses

PrenticeHall,NewJersey,1998

Diagrams in process engineering


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Reaction:C7H8+H2=C6H6+CH4

InternationalconventionsandrecommendedformatsfortherealizationofBFDs Theunitoperationsareindicatedbyblocks

Themainstreamsareidentifiedbylineswitharrowsindicatingtheflowdirection

Whenpossible,thedirectionofthestreamsisfromlefttoright

Lightcurrents(gas)upwards,heavycurrents(liquidsandsolids)downwardsoftheblocksrepresentingthesingleportionsoftheplant

Providebasicandmostimportantinformationoftheprocess

Iftheprocesslinesintersect,thehorizontalonesareheldwhilsttheverticalonearebroken

Providesimplifiedmaterialbalancesandmainreactions

BDF: Block Flow Diagram


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ThePFDisgreatlyenhancedcomparedtotheBFD.Itisthemostimportantanduseddiagramtodescribewithanadequatelevelofdetailthestructureoftheprocess.

Thereisnotauniversallyacceptednomenclature.Ingeneral,aPFDcontainsthefollowinginformation:

1. Theimportantequipmentisshowntogetherwithashortdescription.Eachdeviceis

identifiedbyacode.

2. Thestreamsareshownandidentifiedwithanumber.Everystreamshowstheprocess

conditionsandcomposition.ThesedatacanbeentereddirectlyonthePFDorina

summaryattachedtable.

3. Theutilities oftheequipmentareshownanddescribed

4. Themaincontrolloopsareshown

TheinformationprovidedbyaPFDcanbesummarizedasfollows:

Topologyoftheprocess

Informationonstreams

Informationonequipment

PFD: Process Flow Diagram


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PFDfortheproductionofbenzenebythehydrodealkylationoftoluene(HDA)



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Wedefineastopologyoftheprocessthepositionandtheinteractionamongtheunitsandthestreamsoftheprocess.

Theequipmentisrepresentedbyicons.TheASME (AmericanSocietyofMechanicalEngineers)periodicallypublishesalistofsymbolstobeusedintheproductionofthePFD.Nevertheless,engineeringcompaniesareusedatadoptingcustom symbolsinordertomaketheirownPFDrecognizableanddistinguishablefromthoseoftheircompetitors.

EachpieceofequipmentisidentifiedbyanumberonthePFD.Forexample,thetoluenepumpP101A/B providesthefollowinginformation:

P101A/Bmeansthattheequipmentasapump P101A/Bmeansthatthepumpislocatedinthearea100 oftheplant P101A/Bmeansthatthespecificpumpisnumber01 ofthearea100 P101A/Bmeansthattherearetwopumps:P101A andP101B.Thesecondone

isasparepartthatworksasabackup(i.e. normallyisnotworkingbutitstartsrunningwhentheformerbreaksorneedstobeserviced).

ThewordToluenepumpisthecolloquialnamethatidentifiesP101andisusedindiscussionsabouttheprocess.



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LibraryofequipmentsymbolsforaPFD



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Conventionsusedtoidentifytheequipmentoftheprocess

Generalformat:XXYZZ A/B XX aretheidentificationlettersfortheclassificationoftheequipment

C Compressor,turbine E HeatExchanger H FiredHeater P Pump R Reactor T Tower TK StorageTank V Vessel

Y showstheareaoftheplantwheretheequipmentisplaced ZZ reportsthesequentialnumberofthespecificprocessunit A/Bmeansaparallel/spare/backupequipment



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Conventionsusedtoidentifythestreamsoftheprocess Eachprocessstreamisidentifiedbyanumberinadiamondaboveit.Thedirectionis

definedbyoneormorearrows. Theutilitiesinclude:electricity,compressedair,coolingwater,chilledwater,steam,

condensate,inertgas,chemicalsewer,watertreatmentandflares.Weusethefollowingsymbols: lps lowpressuresteam35barg(sat) mps mediumpressuresteam1015barg(sat) hps highpressuresteam4050barg(sat) htm heattransfermedium(organic):to400C cw coolingwater:fromcoolingtower30Creturnedatlessthan45C wr riverwater:fromriver25Creturnedatlessthan35C rw refrigeratedwater:inat5Creturnedatlessthan15C rb refrigeratedbrine:inat45Creturnedatlessthan0C cs chemicalwastewaterwithhighCOD ss sanitarywastewaterwithhighBOD el electricenergy(specify220,380,440,660Vservice) ng naturalgas fg fuelgas fo fueloil fw firewater



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Asalreadystated,eachstreamisidentifiedbyanumber.Asummarytable whichaccompaniesthePFDprovidesthedataontheprocessstreams. Essentialinformation

Streamnumber Temperature[C] Pressure[bar] VaporFraction TotalMassFlowRate[kg/h] TotalMoleFlowRate[kmol/h] IndividualComponentFlowRates[kmol/h]

Optionalinformation ComponentMoleFractions ComponentMassFractions IndividualComponentFlowRates[kg/h] VolumetricFlowRates[m3/h] SignificantPhysicalProperties:Density,Viscosity, ThermodynamicData:HeatCapacity,Enthalpy,Kvalues, Streamname



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ThelastelementofthePFDisasummaryoftheequipmentwhichallowsestimatingthecostsandprovidesthestartingpointtocarryoutadetaileddesign.

Equipment type Description of the equipment

Towers Size (height and diameter), Pressure, Temperature, Number and type of trays, Height and type of packing, Materials of construction

Heat Exchangers Type: gas-gas, gas-liquid, liquid-liquid, Condenser, VaporizerProcess: Duty, Area, Temperature and Pressure for both streamsNumber of shell and tube passesMaterials of construction: shell and tubes

Tanks, Vessels Height, Diameter, Orientation, Pressure, Temperature, Materials of construction

Pumps Flow, Discharge, Pressure, Temperature, P, Driver type, Shaft power, Materials of construction

Compressors Actual inlet flow rate, Pressure, Temperature, Driver type, Shaft power, Materials of construction

Heaters (fired) Type, Tube pressure, Tube temperature, Duty, Fuel, Materials of construction

Others Provide critical information



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The PFD can include explicit information of the process streams by means of special flags. Theseflags are attached to the streams which they refer to, with text boxes in different shapes to indicatethe value of measures such as:

STREAMID

TEMPERATURE

PRESSURE

LIQUIDFLOWRATE

GASFLOWRATE

MOLARFLOWRATE

MASSFLOWRATE



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AsynonymousofP&ID isMFD,MechanicalFlowDiagram.Itcontainsthedataneededtostartplanningtheconstructionoftheplant.Mechanicalandfunctionaldataaregivenforeachpieceofequipment.Exceptionsare:

1. Operatingconditions:TandP2. Streamvalues3. Equipmentpositioning4. Piping:lengthsandfillings5. Supports,FoundationsandStructures

Thefollowingbitsofinformationmustbereported:

For Equipment show every piece including: Spare units, Parallel units, Summary detail on each unit

For piping show all lines including Drains, and specify:

Size (standard), Thickness, Materials of construction, Insulation (thickness and type)

For instruments Identify: Indicators, Recorders, Controllers, Show instrument lines

For utilities Identify: Inlet and outlet utilities, Waste treatment facilities


P&ID: Piping & Instrumentation Diagram

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Positioningoftheinstrumentation:

Fieldinstrumentation

InstrumentationonthefronofControlPanelinthecontrolroom

InstrumentationonthebackofControlPanelinthecontrolroom

XYYMeaningofidentifyingletters

First letter: X Second and third letters: YA Analysis A Alarm

B Burner flame B

C Conductivity C Control

D Density or specific gravity D

E Voltage E Element

F Flowrate F

H Hand (manually initiated) H High

I Current I Indicator

J Power J

K Time or time schedule K Control station

L Level L Light or low

M Moisture or humidity M Middle or intermediate

O O Orifice


P&ID

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First letter: X Second and third letters: YP Pressure or vacuum P Point

Q Quantity or event Q

R Radioactivity or ratio R Record or print

S Speed or frequency S Switch

T Temperature T Transmit

V Viscosity V Valve, damper or louver

W Weight W Well

Y Y Relay or compute

Z Position Z Drive

XYYMeaningofidentifyingletters

Identificationofinstrumentalconnections

Capillary

Pneumatic

Electric


P&ID

E5DavideManca ProcessSystemsEngineering MasterDegreeinChemEng PolitecnicodiMilano 17

P&ID

E5

LoopcontrolstructureforthetanklevelV102 LE levelsensorpositionedonthetankV102 LT leveltransmitterpositionedonthetankV102 Transferthesignalviaanelectricline tothecontrolroom LIC levelindicatorandcontrollerinthecontrolroom Transferanelectricalsignal totheinstrumentLY LY instrumentabletocalculatetheexactvalveopening Transferapneumaticsignal(solidline)tothecontrolvalveLCV LAH toohighlevelalarminthecontrolroom(frontpanel) LAL toolowlevelalarminthecontrolroom(frontpanel)


P&ID

E5DavideManca ProcessSystemsEngineering MasterDegreeinChemEng PolitecnicodiMilano 19

E5

R.Turton,R.Bailie,W.Whiting,J.Shaeiwitz,Analysis,SynthesisandDesignofChemicalProcesses,Prentice

Hall,NewJersey,1998

DavideManca ProcessSystemsEngineering MasterDegreeinChemEng PolitecnicodiMilano

References

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E8 - BFD PFD P&ID

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