Microkinetics assisted design and optimization of catalytic reactions
Transcription
Microkinetics assisted design and optimization of catalytic reactions
Microkinetics assisted design and optimization of catalytic reactions and reactors Joris W. Thybaut Laboratory for Chemical Technology, Ghent University http://www.lct.UGent.be 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) 1 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) microkinetic modelling multi-scale modelling • detailed • global • synergy between various scales 2 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) industrial scale transformation of chemicals 3 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) Single-Event MicroKinetics (SEMK) complex mixtures • reaction families entropy energy - enthalpy – reaction types • alkyl shift, protonated cyclopropane branching, β-scission,… • H-addition/elimination,… – intermediate stability • carbon atom type • next nearest neighbour effects σreactant S0,# kb T global k # exp σ global h R H0,# exp RT J.W. Thybaut and G.B. Marin, J. Catal. 50th anniversary, submitted 4 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) rational catalyst design performance testing 2 catalyst library activity library modelling synthesis 3 1 industrial application new concept optimized descriptors kinetic and catalyst descriptors H 3 H H 6 H k(1,2) H k(2,2) 1 k(0,2) H 2 k(2,2) k(2,2) k(1,2) H 4 H k(0,2) 7 k(1,2) * * design H * k(1,2) H H k(1,2) k(2,2) 4 9 H * H * H H k(2,2) * 12 * H k(0,2) H k(1,2) H H 10 k(1,2) H k(2,2) * H H H 13 H k(0,2) H H H H H H k(0,2) H k(1,2) H * H H k(0,2) H 8 5 11 * H * * H * H H J.W. Thybaut et al. Topics Catal. 52 (2009) 1251-1260 5 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) outline • introduction • methanol-to-olefins conversion – reaction network – kinetic and catalyst descriptors – reaction pathway analysis – assessment of zeolite framework effects • alternative cases • conclusions 6 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) methanol to olefins MTO process provides an alternative route to produce olefins/gasoline. Coal Synthesis Gas Production Methanol/ Oxygenates synthesis Natural gas MTO/MTH and higher olefins Biomass 7 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) OCMOL project CO, H2 Oxygenate synthesis Oxygenate to liquids Liquid fuels RM reactor Step 3 Autothermal coupling CH4 OCM reactor Separation O2 C2H4 Step 1 Step 2 Ethylene oligomerization reactor Liquid fuels Step 4 OCM (Oxidative Coupling of Methane) and RM (Reforming of Methane) • alternative production route for liquid hydrocarbons and fuels • exploitation of small gas reservoirs – stranded natural gas – biogas – landfill gas http://www.ocmol.eu 8 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) methanol to olefins catalysts CHA structure SAPO-34 C2H4 MFI topology ZSM-5 C3H6 MTT topology ZSM-23 C3H6 C3H6 C2H4 C2H4 Aromatics Aromatics Aromatics Teketel et al. ACS Catalysis 2 (2012) 26-37 9 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) global MTO reaction scheme DME Formation Higher Olefins Formation Primary Hydrocarbons Formation CH3OH2 + CH4 + HCHO + H+ DMO+ H+ + DME C3= (*) formation of hydrocarbon pool species is not considered. C5 Olefins isomerization C6 Olefins isomerization β-scission CH3OH HYDROCARBON POOL* Methylation & Alkylation CH3+ C4 Olefins isomerization C2= C7 Olefins isomerization 10 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) challenges addressed • identification of reaction mechanism in elementary steps for – DME – light olefin – higher olefins Trimethyl benzene Aromatic hydrocarbon pool Toluene MeOH/DME Cyclization and hydride transfers Ethene/Propene and aromatics Alkanes Higher • quantification of reaction alkenes Ethene and Alkene pathways on ZSM-5 and higher alkenes homologation cycle ZSM-23 Ethene • simulation of industrial reactor behaviour Bjorgen et al., J. Catal. 249 (2007) 195-207 11 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) aromatic hydrocarbon pool (exocyclic methylation route) Z-CH3 + Z-H + + + Z- + Z- + + Z- Z-CH3 + + Z-H + Z- ZCH3 + Z-H Aromatic hydrocarbon pool acts as active center for light olefins and get regenerated. T. Mole et al. J. Catal. 82 (1983) 261 and J.F. Haw et al. Acc. Chem. Res. 36 (2003) 31712 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) alkene homologation cycle ZSM-5 ZSM-23 Methylation Alkylation /β-scission Protonation /Deprotonation Hydride shift Two additional pathways related to secondary to primary and tertiary to primary cracking Methyl shift PCP branching 13 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) reaction network on H-ZSM-5 catalyst Reaction network in terms of elementary steps for ZSM-5 catalyst: Number of Species (Cyclic) Olefins/DME/H2O Carbenium ions Aromatics Total Number of elementary steps Protonation Deprotonation Hydride shift Methyl shift PCP branching Methylation Demethylation Alkylation Dealkylation β-scission hydration dehydration Total DME formation 3 3 Higher olefins formation 50 41 6 Primary olefins formation 4 5 1 10 3 3 3 3 71 71 40 15 54 22 3 3 2 2 91 15 6 1 1 8 16 294 Surface methoxy and DME formation: 2 quasi-equilibrium reactions (protonation of MeOH and DME) 2 reversible reactions 6 adjustable parameters Methane formation: Irreversible reaction 1 adjustable parameters Primary olefins formation: 8 reversible reactions 10 adjustable parameters 1 total concentration of hydrocarbon pool Higher olefins formation: 1 Irreversible reaction (methylation) 1 reversible reaction (alkylation) 12 adjustable parameters - 6 activation energies based on stability of carbenium ions -6 olefin protonation enthalpies depending on number of carbon atoms from O2 to O7 14 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) activation energies and protonation enthalpies on ZSM5 (T = 360 - 480 0C, Pt = 1.04 bar and W/FMeOH = 0.5 - 6.5 kgcat.s mol-1) Activation energy Forward Reverse (kinetic descriptors) (kJ/mol) (kJ/mol) Protonation enthalpy (kJ/mol) (catalyst descriptors) Surface methoxy, and DME formation Dehydration 222.7 ± 8.1 170.4 ± 15.6 Methanol -61.8 ± 3.8 Protonation with MeOH 138.6 ± 7.5 163.7 ± 14.8 DME -42.8 ± 8.1 Methane formation Methane formation 121.1 ± 18.4 Hydrocarbon pool species formation Methylation of p-xylene 101.5 ± 1.1 123.2 ± 17.1 Deprotonation of TMeB+ and DMeEtB+ 156.7 ± 9.6 123.1 ± 16.8 Methylation of DMeMCHDE and DMeEtCHDE 75.5 ± 16.9 151.8 ± 17.4 Dealkylation of DMeEtB+ and PDMeB+ 84.2 ± 8.2 Deprotonation of PX+ 143.4 ± 20.8 123.9 ± 16.8 14.1 ± 2.4 P. Kumar et al. Ind. Eng. Chem. Res. 52 (2013) 1491-1507 15 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) model parameters Activation energy (kJ/mol) (kinetic descriptors) Protonation enthalpy/ CHP (kJ/mol)/(mol/ kgcat) Methylation (p-p) 131.9 ± 28.2 (catalyst descriptors) Ethene Methylation (p-s) 92.8 ± 10.9 Propene -42.5 ± 7.6 Methylation (p-t) 54.9 ± 9.2 Butene -53.9 ± 9.0 Alkylation (s-s) 138.0 ± 9.4 Pentene -61.6 ± 15.1 Alkylation (s-t) 119.7 ± 17.6 Hexene -67.7 ± 2.1 Alkylation (t-s) 167.6 ± 28.6 Heptene -70.3 ± 12.4 CHP 3.47 × 10-2 -11.1 ± 0.16 • activation energies in line with reactant and product stability • stable intermediates have more negative protonation enthalpies P. Kumar et al. Ind. Eng. Chem. Res. 52 (2013) 1491-1507 16 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) simulation results Parity diagram of experimental vs calculated outlet MTO products flow rates at T = 360 - 480 0C, Pt = 1.04 bar and W/FMeOH = 0.5 - 6.5 kgcat.s mol-1. line: experimental; : obtained from model regression 17 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) performance curves Experimental and model calculated yield of MTO products at T = 400 0C and Pt = 1.04 bar. Symbols: experimentally observed values, ethene (), propene (▲), butene (■); lines: calculated Experimental and model calculated yield of MTO products at T = 400 0C and Pt = 1.04 bar. Symbols: experimentally observed values, pentene (), hexene (▲), heptene (■), methane (); lines: calculated Experimental and model calculated yield of primary olefins at methanol conversion = ~65% and Pt = 1.04 bar. Symbols: experimentally observed values, ethene (), propene (▲); lines: calculated Experimental and model calculated yield of olefinic products at T=360 0C, Pt = 1.04 bar and W/FMeOH = 4.28 kgcat.s mol-1. 18 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) contribution analysis Contribution analysis for MTH on H-ZSM-5 catalyst at space time of 2.21 kgcat.s/mol and at 400 0C, conversion=66.9% 19 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) contribution analysis: temperature effect Contribution analysis for MTH on H-ZSM-5 catalyst at space time of 2.21 kgcat.s/mol and at 400 0C, conversion=66.9% Contribution analysis MTH on H-ZSM-5 catalyst at space time of 1.40 kgcat.s/mol and at 480 conversion=73.6% 0C, 20 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) activation energies, protonation enthalpies on ZSM-23 (T=400 0C, Pt= 1.04 bar, Weff/FMeOH =15.1-50.9 kgcat.smol-1) (kJ.mol-1)/ Protonation (mol.kgcat -1) enthalpy/ CHP Activation (kJ.mol-1) energy Ethenea -11.1±0.16 -10.3 ± 1.2 Methylation(p-p) 131.9 Propeneb -42.5±7.6 -49.9 ± 5.4 Methylation(p-s) 92.8 Buteneb -53.9±9.0 -55.9 ± 12.6 Methylation(p-t) 54.9 Penteneb -61.6±15.1 -60.3 ± 8.2 Alkylation(s-s) 138.0 Hexeneb -67.7±2.1 -64.1 ± 9.4 Alkylation(s-t) 119.7 Alkylation(t-s) 167.6 Alkylation (s-p) 174.5 ± 41.2 Alkylation (t-p) 197.7 ± 46.5 ΔH(s-p) a b to primary carbenium ion, to secondary carbenium ion -31.2 ± 6.4 21 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) performance curves 30 100 25 20 % yield 60 15 10 5 propene 40 ethene 20 0 % conversion 80 oxygenates Symbols: experimentally observed values lines: calculated 0 20 26 32 38 44 effective space time (kgcat.s/mol) 50 35 pentene 30 25 C6+ % yield 14 20 butene 15 10 5 methane 0 14 20 26 32 38 44 effective space time (kgcat.s/mol) 50 22 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) contribution analysis: framework effect Contribution analysis for MTH on H-ZSM-5 catalyst at space time of 2.21 kgcat.s/mol and at 400 0C, conversion=66.9% Contribution analysis for MTO on ZSM-23 catalyst at T= 400 0C and Weff/FMeOH = 24.8 kgcat.smol-1 conversion=50.2% 23 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) MTO industrial reactor simulation ZSM-5 @ 450°C ZSM-23 @ 400°C: potential benefits of co-feeding 24 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) outline • introduction • methanol-to-olefins conversion • alternative cases – methane aromatization – xylene isomerization/ethylbenzene dealkylation – long alkane hydrocracking • conclusions 25 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) methane aromatization 973K, Mo/HZSM-5 K. Wong et al. Micro. Meso. Mater 164 (2012) 302-31226 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) from steady state to dynamic simulations 0.10 Stage 2: optimal methane aromatisation -1 Flow rate (mol s ) 0.08 Stage 1: development of active catalyst form 0.06 0.04 Stage 3: catalyst deactivation CO CO2 -1 0.6 C2H4 0.4 -2 deactivation CH4 + MoC → H2 + ‘coked’ MoC C6H6 + H+ → H2 + coked H+ Flow rate 10 (mol s ) 0.02 activation CH4 + 2MoO3 → CO2 + 2H2 + 2MoO2 3CH4 + MoO2 → 2CO + 6H2 + MoC 0.00 0.2 C2H6 0.0 0 5000 10000 Time on stream (s) 15000 27 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) zeolite framework effects Catalyst Max. sphere diameter (Å) Vmicro (cm3/g) Brønsted acidity XCH4 (%) Benzene Yield (%) ΔH Phys C6 kdeact acid sites Mo/IM-5 7.34 0.125 188 6.2 3.7 -95 2.17E-05 Mo/ZSM-5 6.36 0.120 143 9.0 5.5 -91 7.62E-06 Mo/TNU-9 8.46 0.132 83 8.0 5.6 -80 6.73E-06 Mo/MCM-22 9.69 0.156 137 9.2 7.2 -63 2.75E-06 physical adsorption and related deactivation effects 28 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) xylene isomerization: SEMK model Xylene isomerization on a bifunctional Pt/H-ZSM-5 catalyst Reaction network consists out of: • acid catalyzed reactions: (de-)protonation, alkyl shift (MS), dealkylation, (DA) transalkylation (TA) • metal catalyzed reactions: Hydrogenation (HYD) • physisorption K. Toch et al. Appl. Catal. A-Gen 425 (2012) 130-144 29 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) xylene isomerization: results Successful estimation of the kinetic parameters • small confidence interval • physically meaningful importance of the reactions HYD << TA << DA ~ MS order of activation energies: ΔS A DA >0 105 Aref Monomolecular MS 0 Aref Monomolecular TA <0 10-3 Aref Bimolecular HYD - 102 Aref Bimolecular, number of active sites Ea,DA >> Ea,MS ~ Ea,TA >> Ea,HYD Successful description of the responses 30 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) xylene isomerization: catalyst optimization acid strength modifications: ΔHpr is varied from -60 … -110 kJ mol-1 What is of industrial relevance? maximization of PX content minimization of xylene losses 120 100 maximization of benzene yield 16 100 14 90 80 12 60 653K, 1MPa 8 673K, 1MPa 673K, 1MPa -70 -80 -90 ΔHpr (kJ mol-1 ) -100 -110 633K, 1MPa 653K, 1MPa 20 673K, 1MPa 10 0 -60 50 30 2 0 60 40 4 653K, 1MPa 20 633K, 1MPa 6 633K, 1MPa 40 70 10 YB (%) XXYL (%) ATEPX (%) 80 0 -60 → definition of profit function Ψ: -70 -80 -90 ΔHpr (kJ mol-1 ) -100 -110 -60 -80 -90 ΔHpr (kJ mol-1 ) -100 -110 7000 6000 633K, 1 MPa 653K, 1 MPa 5000 673K, 1 MPa Ψ ATEPX S B H pr max X XYL -70 4000 3000 → ΔHpr(opt) ≈ ΔHpr(est) (catalyst used = industrial catalyst) 2000 1000 0 -60 -70 -80 -90 ΔHpr (kJ mol-1 ) -100 -110 31 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) long alkane hydrocracking over BETA USY n-octane BETA n-hexadecane B. Vandegehuchte et al. Appl. Catal. A-Gen 441 (2012) 10-20 32 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) shape selectivity Transition state shape selectivity during Ethyl branch formation + rAS = kAS CR+ 1,2 alkyl shift 0 exp kAS = kAS -(Ea;AS + ∆Ea) RT + 2.5E-07 21.9 (± 1.0) kJ Ea;AS Fmod (mol s-1) Energy ∆Ea mol-1 79.8 kJ mol-1 b 2.0E-07 1.5E-07 1.0E-07 5.0E-08 0.0E+00 0.0E+00 + 5.0E-08 1.0E-07 1.5E-07 2.0E-07 2.5E-07 + Fexp (mol s-1) Reaction coordinate 33 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) adsorption saturation: size entropy Entropic effects favor the component with the lowest carbon number at saturation loadings as smaller molecules fit more easily in the gaps within the zeolite matrix. Krishna et al. Chem. Eng. J., 2002 0 Linear approximation of -∆Ssiz 80 ↗ 70 60 50 =0 ↗ 40 30 ↘ 20 10 0 4 6 8 10 12 14 CN ↗ 34 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) outline • • • • introduction methanol-to-olefins alternative cases conclusions 35 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) conclusions • versatility of the SEMK methodology has been demonstrated (MTO, aromatization, isomerisation and cracking) • contribution analyses provide unprecedented insight in reactant and product ‘flows’ – reaction path analysis – reaction mechanism elucidation – formulation of guidelines for reactor operation 36 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) conclusions • zeolite framework and acid strength effects have been quantitatively assessed – physical adsorption – protonation – deactivation 37 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) perspectives • ‘Pleiade’ of future applications – hydrocarbon chemistry • hydroisomerisation including diffusion • ethylene oligomerization – ‘renewables’ chemistry • • • • • ethanol to hydrocarbons aldol condensations glycerol hydrogenolysis stabilization/hydrodeoxygenation … • accounting for O as hetero-atom • potential stereochemistry effects • reaction families to be revisited 38 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) acknowledgements • Methusalem program/Special Research Fund (Flemish Government/Ghent University) • EC FP7 (OCMOL, NEXT-GTL) • FWO (NSF) • IAP (Belgian Science Policy) • Shell • … 39 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) acknowledgements • • • • • Prof. Guy B. Marin (director LCT) Pravesh Kumar (MTO) Kae Shin Wong (methane aromatization) Kenneth Toch (xylene isomerization) Bart Vandegehuchte (long alkane hydrocracking) CaRE 40 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) questions? 41 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) rational ZSM-22 design Bridge site: far pore mouths Pore mouth site micropores external surface (Pt clusters) Bridge site: near 100 Isomer Yield / mol% 80 60 40 20 0 423 473 523 Temperature / K 573 related patents: - US20100181229 - US20110042267 publications: - Hayasaka et al. Chem. Eur. J. (2007) - Choudhury et al. J. Catal. (2012) 42 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) μkinetic engine: background high-throughput experimentation microkinetic modeling (includes all elementary steps) 1. 2. optimize catalyst properties and kinetic parameters predict behavior for reactions / compounds of the same family • generic methodology for kinetic model construction • no user intervention is needed in programming • reaction network is automatically converted into rate equations 43 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) μkinetic engine: workflow Experimental data Reaction Network No. experiments Input data No. input variables Datafile No. responses Generation Reactor type Initial values Operating conditions Generate plots Model predictions Kinetic parameters Statistical analysis of results Standalone software tool 44 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) detailed flow scheme • start main program • reading section • overall information • experimental • regression • reaction network • thermochemistry • regression section • Rosenbrock • LevenbergMarquardt • adjust parameter values • perform simulation for all experiments • compare calculated and experimental outlet flow rates • writing section • simulation results • statistical interpretation no yes fit ok? • thermochemical calculations • parameter constraints • solution set of equations: • initialization • integration 45 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) calculated versus experimental values Error 𝑁𝑒𝑥𝑝 𝑁𝑟𝑒𝑠 𝑆 𝛽𝑗 = 𝑤𝑖 𝑖=1 WSSQ 𝐹𝑖𝑙𝑐𝑎𝑙𝑐 − exp 2 𝐹𝑖𝑙 𝛽𝑗 𝑚𝑖𝑛𝑖𝑚𝑢𝑚 𝑙=1 Weight to the reponse Experimental flowrates Flowrates calculated using model Parameters to be estimated 46 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) solution set of equations: reactor model • Plug Flow reactor (differential equations) • Continuous Stirred Tank Reactor (algebraic equations) 𝐹𝑖𝑖𝑛 − 𝐹𝑖𝑜𝑢𝑡 + 𝑅𝑖 𝑤𝑐𝑎𝑡 = 0 47 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) solution set of equations: kinetic model • net production rate of component i Ri i , j r j j where, αi,j is stoichiometric coefficient of component i in reaction j • reaction rate (A* + B D*, A*: intermediate, B: response) n m rs ks presponse intermediate Ctot , ks f ( j ), s 1...nelem steps j 1...nparameters • rate coefficient Ea 1 1 ks kTave exp R T Tave β 48 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) solution set of equations • Mass balance for the catalyst’s active sites Ctot C* Cintermediate • analytical solution only possible for simple reaction mechanisms • steady state approximation: • intermediates are considered as highly reactive, i.e., net rate of formation equals zero: Rintermediate 0 • DDASPK2.0 used as solver for the set of equations 49 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) graphical user interface 50 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) μkinetic engine: summary • performs microkinetic modeling adopting complex networks in heterogeneous catalysis • no programming required by the end user • incorporates differential and algebraic solvers + deterministic & stochastic optimization routines • able to provide information about quasiequillibruim steps. 51 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) μkinetic engine: summary • reaction orders can also be estimated • no rate determining step. • able to plot the agreement between model and experimental data points with residual error and save them as images • Provide statistical analysis of results: • • • • 95% confidence interval, t-value, F value etc. 52 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) transesterification • ethylacetate + methanol over Lewatit K1221 (sulphonic acid ion exchange resin) + + E. Van de Steene et al. J. Mol. Catal. A-Chem. 359 (2012) 57-68 53 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) model discrimination Simulated values (lines) exhibit a good agreement with the experimental results (temperature effect and initial reactant molar ratio effect) Kinetic model: ER_MeOH_SR: Eley-Rideal mechanism with the reaction of EtOAc from the bulk with adsorbed MeOH on the catalyst surface as rate-determining step. 1 k SR K MeOH aMeOH aEtOAc aMeOAc aEtOH K eq r 1 aMeOH K MeOH aEtOH K EtOH E. Van de Steene et al. J. Mol. Catal. A-Chem. 359 (2012) 57-68 54 6th IDECAT/ERIC-JCAT Conference on Catalysis (IEJCat-6), 3rd-6th March 2013, Brixen (Italy) model assessment: reaction mechanism E. Van de Steene et al. J. Mol. Catal. A-Chem. 359 (2012) 57-68 55