Dijkmans, Thomas

Ghent University Academic Bibliography

Laboratory for Chemical Technology, Ghent Universityhttp://www.lct.UGent.beSteam Cracking:from Feedstock Analysis to Plant OptimizationStoomkraken:van voedingsanalyse tot fabrieksoptimalisatieThomas DijkmansPublic defence, Ghent, Belgium, 26/09/20141The heart of a petrochemical plant2Public defence, Ghent, Belgium, 26/09/2014Steam crackerRaw natural gasCrude oilPetroleum refiningNatural gas processingEthanePropaneButaneMethaneCondensateNaphthaKeroseneGas oilOther productsThe heart of a petrochemical plant3Public defence, Ghent, Belgium, 26/09/2014Steam crackerRaw natural gasCrude oilPetroleum refiningNatural gas processingEthanePropaneButaneMethaneCondensateNaphthaKeroseneGas oilOther productsThe heart of a petrochemical plant4Public defence, Ghent, Belgium, 26/09/2014EthylenePropyleneButadieneBenzeneSteam crackerPolyolefin plants,…Crash course hydrocarbon chemistry5Public defence, Ghent, Belgium, 26/09/2014Hydrocarbons is a chain of carbon atoms linked to hydrogenCarbon HydrogenCarbon number = Number of carbons in the chainElemental composition =  Relative amount of H, C, … on a 100% scale (weight based or mole base)Branched hydrocarbons = Carbons with branches instead of a straight chainCracking = Breaking of those chains to form smaller unsaturated hydrocarbonsNew bonds can off course also be formed during the processCrash course hydrocarbon chemistry6Public defence, Ghent, Belgium, 26/09/2014Unsaturated hydrocarbons have a double bond between two carbon atomsEthylene PropyleneIt is this double bond that provides the reactivity needed for the downstream processes and makes these molecules specialCrash course hydrocarbon chemistry7Public defence, Ghent, Belgium, 26/09/2014Radical are species that have a missing bondThis missing bond makes them very reactive and unstableThese are important intermediate species for steam crackingDeveloping of a  model for steam cracking8Public defence, Ghent, Belgium, 26/09/2014Simulation modelGoal Reactor geometryOperating conditionsFeedstock propertiesProduct specsModeling Microkinetic modelReactor modelFundamental reactor modelDetailedfeedstock compositionDetailedproduct compositionPlug flow reactor model9Public defence, Ghent, Belgium, 26/09/2014Molecules and radicals move as a plug through the reactor and each individual plug does not influences other plugsMass balances (Nspecies) = 	Ω ,=  + Ω	 . (−Δ), = 	−2"# − 2$ +%&	' ()* − ())Momentum balance (1)Energy balance (1)Energy (heat) can go in or out of the reactorFeed ProductsheatDeveloping of a  model for steam cracking10Public defence, Ghent, Belgium, 26/09/2014Simulation modelGoal Reactor geometryOperating conditionsFeedstock propertiesProduct specsModeling Microkinetic modelReactor modelFundamental reactor modelDetailedfeedstock compositionDetailedproduct compositionMain reaction familiesBond dissociation and radical recombination11Public defence, Ghent, Belgium, 26/09/2014R1 R2 R1 R2• •+Hydrogen abstraction (inter- and intramolecular)R1 H R1R2•• R2 H++Radical addition and β-scission (inter- and intramolecular)R1 R2 R3R1• R2 R3•+Reaction Families:Need to limit the reaction sizeR1 H R1R2•• R2 H++R2-R1 H•R2-R1H•intramolecular)(inter- andR1 R2 R1 R2• •+R1 R2 R3R1• R2 R3•+Radical addition and β-scissionµ radical hypothesis12Public defence, Ghent, Belgium, 26/09/2014µ hypothesis  = Monomolecular reactions dominate for long chain radicals (#C>5)Bond dissociation Hydrogen abstractionR1R2R3•R1-R2 R3 •and radical recombinationintramolecular)(inter- andDecomposition scheme: hexane13Public defence, Ghent, Belgium, 26/09/2014RHβ moleculesQSSA speciesDecomposition scheme: hexane (2)14Public defence, Ghent, Belgium, 26/09/2014( ) ( ) RHR ++→+ ∑∑∑∑ββradoln1=l31=iipseudojn1j=31=iijpseudo146kkOkOkHCn .Applying QSSA reduces this reaction scheme to:• Drastic reduction of the number of species to need to be considered  in the final ODE’s• Drastic reduction of the number of reactionsMicrokinetic network15Public defence, Ghent, Belgium, 26/09/2014β network µ networkCRACKSIMBi- and monomolecularreactions for β radicalsMonomolecular reactionsfor µ radicalsR1 R2 R1 R2• •+R1 H R1R2•• R2 H++R1 R2 R3R1• R2 R3•+R1 R2 R1 R2• •+R2-R1 H•R2-R1H•R1 R2 R3R1• R2 R3•+R1R2R3•R1-R2 R3 •1324 reversible reactions51 molecules43 radicals13584 schemes676 moleculesValidation radiant coil16Public defence, Ghent, Belgium, 26/09/2014Ethylene PropyleneFeedstocks:Detailedfeedstock compositionSimulation modelGoal Reactor geometryOperating conditionsProduct specsModeling Microkinetic modelReactor modelFundamental reactor modelDetailedproduct compositionFeedstock propertiesFundamental modeling approach17Public defence, Ghent, Belgium, 26/09/2014GC×GCAnalytical techniques1-dimensional chromatography18Public defence, Ghent, Belgium, 26/09/2014DetectorInjectorTimeSignalGC × GC19Public defence, Ghent, Belgium, 26/09/2014DetectorModulatorInjectorTimeSignal1D to 2D chromatogram20Public defence, Ghent, Belgium, 26/09/2014Dallüge et al., J. Chrom. A 2003Raw 2D chromatogramTransformationVisualisation3D plotColor plotGC × GC – FID/TOF-MS21Public defence, Ghent, Belgium, 26/09/2014Qualitative, difficult to quantifyQuantitative but no direct identification possibleParaffinsDiaromaticsAromaticsTriaromaticsSCD22Public defence, Ghent, Belgium, 26/09/2014DiaromaticsC12 C13 C14• Roof tile structure helps identification• Overlap of sulfur containing hydrocarbons with pure hydrocarbons• Not all sulfur containing hydrocarbons can be found with TOF-MS due to high differences in concentrationC11 benzothiopheneC12 benzothiopheneGC × GC – SCD23Public defence, Ghent, Belgium, 26/09/2014Again no direct identification is possibleGC × GC – SCD (2)24Public defence, Ghent, Belgium, 26/09/2014Calibration mixtureShale oilThiolsBenzothiophenesDibenzothiophenes0 9045First dimension retention time (min)Second dimension retention time (s)07073.53.5GC × GC – NCD25Public defence, Ghent, Belgium, 26/09/2014Again no direct identification is possibleSPE -GC ×GC - TOFMS26Public defence, Ghent, Belgium, 26/09/2014HexaneDichloromethaneAcetoneShale oil sample1) Load SampleHexane flushDichloromethane flushAcetone flushPyridinesPyridinesAnilinesAnilinesIndolesQuinolinesGC × GC – NCD27Public defence, Ghent, Belgium, 26/09/2014GC × GC – FID/SCD/NCDPublic defence, Ghent, Belgium, 26/09/2014#C P I MN DN MA NA DA NDA TA Pd An Q In Ac Ca T BT NBT DBT Ph Total5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.24 0.00 0.00 0.00 0.00 0.256 1.62 2.30 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.04 0.00 0.00 0.00 0.00 0.00 0.25 0.00 0.00 0.00 0.00 4.217 2.26 1.48 0.00 0.00 0.11 0.00 0.00 0.00 0.00 0.11 0.02 0.00 0.00 0.00 0.00 0.16 0.00 0.00 0.00 0.07 4.198 2.20 1.98 0.00 0.00 0.70 0.00 0.00 0.00 0.00 0.26 0.05 0.00 0.01 0.00 0.00 0.10 0.02 0.00 0.00 0.11 5.419 2.36 2.24 0.57 0.00 1.68 0.00 0.00 0.00 0.00 0.47 0.07 0.01 0.06 0.00 0.00 0.07 0.14 0.00 0.00 0.12 7.7910 2.33 1.53 0.86 0.00 1.78 0.39 0.05 0.00 0.00 0.15 0.11 0.08 0.17 0.00 0.00 0.04 0.33 0.00 0.00 0.05 7.8711 2.33 1.18 1.09 0.00 1.36 0.33 0.40 0.01 0.00 0.18 0.11 0.17 0.28 0.00 0.00 0.03 0.33 0.00 0.00 0.00 7.7712 2.36 0.98 1.21 0.01 0.95 0.26 1.01 0.16 0.00 0.12 0.08 0.19 0.30 0.00 0.00 0.03 0.20 0.01 0.01 0.00 7.8413 2.31 1.41 1.14 0.13 0.88 0.42 1.08 0.20 0.00 0.18 0.03 0.12 0.16 0.00 0.02 0.02 0.06 0.00 0.03 0.00 8.1914 2.28 1.09 1.06 0.14 0.62 0.34 0.76 0.40 0.03 0.17 0.00 0.03 0.14 0.01 0.02 0.00 0.03 0.00 0.08 0.00 7.2015 2.24 1.06 0.91 0.26 0.81 0.26 0.41 0.33 0.17 0.13 0.00 0.00 0.00 0.02 0.00 0.00 0.01 0.00 0.04 0.00 6.6516 2.22 0.71 0.78 0.18 0.50 0.16 0.24 0.16 0.40 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5.4317 2.09 0.85 0.88 0.10 0.49 0.11 0.14 0.10 0.14 0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.9418 2.00 0.81 0.92 0.09 0.30 0.09 0.03 0.07 0.00 0.03 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.3319 1.65 0.73 0.58 0.09 0.26 0.09 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.4020 1.55 0.48 0.76 0.06 0.20 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.0321 1.37 0.38 0.58 0.07 0.18 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.5922 1.36 0.37 0.43 0.05 0.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.3023 1.13 0.32 0.28 0.04 0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.8124 0.90 0.25 0.20 0.01 0.03 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.3825 0.78 0.07 0.16 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.0026 0.60 0.08 0.09 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.7727 0.46 0.06 0.08 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.6028 0.31 0.05 0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.4029 0.21 0.03 0.03 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.2730 0.13 0.03 0.03 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.1831 0.05 0.02 0.02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.0932 0.03 0.02 0.02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.0733 0.02 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.03Total 39.08 20.50 12.71 1.21 11.00 2.43 4.14 1.42 0.74 1.98 0.46 0.59 1.10 0.04 0.04 0.93 1.10 0.01 0.16 0.34 100.0028Fundamental modeling approach29Public defence, Ghent, Belgium, 26/09/2014Simulation modelReactor geometryOperating conditionsFeedstock propertiesProduct specsMicrokinetic modelReactor modelFundamental reactor modelDetailedfeedstock compositionDetailedproduct compositionGC×GCStandard methodsGoalAnalytical techniquesFeedstockreconstruction• Average molecular weight• Elemental composition• Specific density • Global PINA analysis• Boiling point data (e.g. D2887 simdist)• Aromatic SulfurFeedstock reconstruction30Public defence, Ghent, Belgium, 26/09/2014Feedstock properties Detailed composition• Species identityFeedstock reconstruction± 20 properties More than 100 unknown mole fractionsShannon entropy maximization( ) ( ) ∑∑===−=MM NiiNiiii yyyyS111     with          ln     MAXConstraints from mixing rules (example):∑∑==MNi iiiiiyy1exp MwdMwd1∑==MNiiiy1exp MwMwMolecular library• Mole or mass fractionsResults: Sulfur containing hydrocarbons31Public defence, Ghent, Belgium, 26/09/2014Thiols/sulfidesExperimentalOld indicesNew indicesBenzothiophenesDibenzothiophenesResults:  Hydrocarbons32Public defence, Ghent, Belgium, 26/09/2014n-paraffins i-paraffinsNaphthenes AromaticsFundamental modeling approach33Public defence, Ghent, Belgium, 26/09/2014Simulation modelReactor geometryOperating conditionsFeedstock propertiesProduct specsMicrokinetic modelReactor modelFundamental reactor modelDetailedfeedstock compositionDetailedproduct compositionGC×GCStandard methodsGoalAnalytical techniquesFeedstockreconstruction Computational efficient• Mathematical techniques– Using a different solving technique (e.g. analyticalJacobian)– Alternative calculation of functions that are difficult to evaluate• Computational techniques– Using a graphical card to perform certain calculationstical techniquesa dif erent solving technique ( .g. analyticalian)t rnative calculation of functions that are difficult to tetational techniquesa graphical card to perform certain calculationsDecreasing simulation time• Chemical techniques= simplify kinetic mechanism by network reduction34Public defence, Ghent, Belgium, 26/09/2014Total simulation time35Public defence, Ghent, Belgium, 26/09/2014500Base caseTabulationAnalytical JacobianGPUGPU +Analytical JacobianTabulation +GPU +Analytical JacobianConclusions• Development of a fundamental simulation tool requires the use of different state-of-the-art techniques such as:– Single-event microkinetic models to account for all the reactions occurring between species– GC × GC or feedstock reconstruction to obtain a detailed feedstock composition• The models are however valid over a broad range of process conditions and for different feedstocks36Public defence, Ghent, Belgium, 26/09/2014Conclusions (2)• The simulation time of such fundamental reactor models can drastically be reduced by:– Tabulation– Calculating an Analytical Jacobian instead of a finite-difference Jacobian– Using the graphical processing unit to handle part of the calculations37Public defence, Ghent, Belgium, 26/09/2014Questions38Public defence, Ghent, Belgium, 26/09/2014

Steam cracking: from feedstock analysis to plant optimization

https://biblio.ugent.be/publication/5903385/file/5903657

Steam cracking: from feedstock analysis to plant optimization

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Ghent University Academic Bibliography