catalyst design based on catalyst descriptors and ......exp exp + + ... j. a. martens et al. appl....

Subprogram P2 and P3

Catalyst Design based on CatalystDescriptors and Adsorption by

Nanoporous Materials

Joris W. Thybaut and Pascal Van der Voort

1

Methusalem Advisory board meeting, Ghent, August 18th, 2009

LaboratoryLaboratoryLaboratoryLaboratory forforforfor

Chemical Chemical Chemical Chemical TechnologyTechnologyTechnologyTechnology

model based catalyst designMethusalem Advisory board meeting, Ghent, August 18th, 2009

synthesis performancenew conceptindustrialappllication

synthesis performance

design

new conceptindustrialapplication

catalyst library

activity/selectivity librarycatalytic chemistry ruleskinetic descritpors

catalyst descriptorsstructure activity relation

synthesis performance

design

new conceptindustrialapplication

catalyst library

activity/selectivity librarycatalytic chemistry ruleselementary steps

kinetic descriptorscatalyst descriptorsstructure activity relation

industrialapplication

2

outline

• hydrocracking: model development and catalyst design– history: (US)Y, ZSM-22, ZSM-5– shape selectivity on ZSM-22– diffusion effects on ZSM-5

• Fischer-Tropsch synthesis• current and future activities

3


fluid phase

physisorption

(de)-hydrogenation

(de)-protonation

alkyl shift

PCP-branching

ß-scission

catalyst

metal sites

acid sites

+

*

*

*

*

*

Ideal hydroconversion : (de)hydrogenation equilibrated

hydrocracking: bifunctional catalysis

4


single-event = accounting for symmetry

• reaction family of s,s methylshift

• rate coefficient

• writing symmetry explicitly

5

∆−

∆=RT

H

R

S

h

Tkk b

#,0#,0

expexp

+ +

∆−

∆=RT

H

R

S

h

Tkk b

global

reactantglobal

#,0#,0

#exp

~exp

σσ ( )ssknk MSe ;

~=

SS global

~ln +−= σ


6


( )+ 1

+ 1

rate equation: model parameters

determined by NH3-TPDcatalyst descriptor

satC

LK

LKtC protKk dehK=r 1

HP 2p p −

Pp

determined by physisorption experimentscatalyst descriptor

calculated via thermodynamic data

parameters to be estimated :kinetic descriptorcatalyst descriptor

protK

k

satC LKprotK dehK 1HP 2

p p −

LK+ 1 Pp

kinetic and catalyst descriptors

0 20 40 60 800

10

20

30

40

Mono

Di

Tri

Cr

• non shape selectivecatalysis

• free carbenium ion chemistry

• 1 type of active sites

7


SEMK development history: USYP

rodu

ct Y

ield

(%

)

Conversion (%)

• extreme shape-selective catalysis

• 3 types of activesites

8


SEMK development history: ZSM-22

Bulk of fluid phase

MicroporePore mouth

+

Bridge

• shape selectivity• diffusion limitations• 3 types of sites:α βs βw

9


SEMK development history: ZSM-5

10


physisorption on ZSM-22

fluid phasefluid phasefluid phasefluid phase microporemicroporemicroporemicroporepore mouthpore mouthpore mouthpore mouth

bridgebridgebridgebridge

11


physisorption on ZSM-22

Low interaction

mode

High interaction mode

(2 pore mouths)

High interaction

mode

(1 pore mouth)

Laxmi Narasimhan et al. J.Catal.,218, 135-147 (2003)

(1)

(3)

(2)

(1)

(3)

(2)

(3)

(2)

(3)

(2)

(3)

(1)(2)

(3)

(2)(1)

(2)(3)

(1)

(2)(3)

(1)

(2)(3)

(1)

(2)(3)

12


pore mouth catalysisproduct shape selectivity: • methyl shifts excluded

• tertiary carbenium ions cannot be stabilized

+ ++++

+

J. A. Martens et al. Appl. Catal. 1991

13


shape selectivity in SEMK• reaction network

– exclusion of tertiary carbenium ions– no alkyl shifts at pore mouth sites– cracking to primary carbenium ions in pore

mouths

• physisorption– various physisorption modes– pronounced differences between isomers

• protonation– depends on the number of carbon atoms

inside the pore mouth

n-alkanes

monobranchedalkanes

cracked products

dibranchedalkanes

tribranchedalkanes

7

92

pore mouths

bridge

micropores

8

12

285

69

12

1

5

C10 Hydroconversion: Analysis performed with initial rates of disappearance of individual components as feed

1

16

95

4

ZSM-22: reaction path analysis

14


Effect of acid site concentration

0

20

40

60

80

100

423 473 523 573

Isom

er Y

ield

, mol

%

Temperature, K

2 fold decrease in micropore acid sites

2 fold decrease in pore mouth acid sites

ZSM-22 design: pore mouth and micropores

15


Hayasaka et al, Chemistry- A Eur. J., 13, 10070 (2007)

nanorod assembled ZSM-22Methusalem Advisory board meeting, Ghent, August 18th, 2009

16

nC10 hydroconversion on Pt-H/ZSM-22 [Si/Al = 30] catalyst, C-IE / 2IEP=4.5 bar, W/F = 2522 kg-smol-1, H2/HC = 375

0

20

40

60

80

100

423 473 523 573

Isom

er Y

ield

/ m

ol%

Temperature / K

hydroconversion on Pt/H-ZSM-22

17


ZSM-5: diffusion in a zeolite crystal

18


Flow Balance (Fαβ = Fβα) ⇒ θα, θβs, θβw

Coppens et al, Chem. Eng. Sc, 54, 3455 (1999)

3 types of sites : α, βs, βw

)θ(1p̂θnτ

1F βαβαα

ααβ −=

]2)1[(

)1]()1([]2)[0(D)(D

swi

wis

iii,s

αββ

αββ

θ+ϕθ+θϕ−λθ−θϕ−λ+ϕθ

ϕ−+ϕλ→θ=θ

θ=θ+θϕ−+ϕθ αββ 4)1(22 ws

ϕ = Ct / Cint = f (Si/Al ratio)

λ i = (τs/ τw )i = exp[- (∆Haphys,i - ∆Hphys,i)]

Ds(θ): in presence of acid sites Methusalem Advisory board meeting, Ghent, August 18th, 2009

19

experimental dataMethusalem Advisory board meeting, Ghent, August 18th, 2009

Operating Conditions

483 - 543 K, 1.0 - 3.0 MPa

Inlet H2/n-C6 50 – 100 mol/mol

W/F0C6 90 - 400 kg-s mol-1

1

1.2

1.4

1.6

1.8

2

0 20 40 60 80

2MP

/ 3M

P m

olar

rat

io

nC6 conversion, mol%

Pt/H-ZSM-5

Pt/H-USY

0

20

40

60

80

0 20 40 60 80

Isom

er y

ield

s, m

ol%

nC6 conversion, mol%

20

model parametersMethusalem Advisory board meeting, Ghent, August 18th, 2009

Activation energy

(kJmol-1)

Alkyl shift (s,s) 76.4

Reference USY

catalyst : CBV-720

Alkyl shift (s,t) 72.2

Alkyl shift (t,t) 101.5

PCP (s,s) 104.7

PCP (s,t) 95.6

PCP (t,t) 127.3

β scission (s,s) 139.8

β scission (s,t) 127.3

β scission (t,s) 148.6

β scission (t,t) 128.6

n-C6 2.2 10-11

(Koriabkina et al, 2003, 2005; Schuring et al, 2001)

2MP 4.5 10-12

3MP 4.0 10-12

n-C3 5.9 10-09

2,2 DMB 2.3 10-15 Cavalcanteand Ruthven, 1995 2,3 DMB 2.3 10-15

Kinetic descriptors

Catalyst descriptors

Diffusion coefficients, m2s-1 (503 K)

Si/Al = 137

0.12Ct ,mol kgcat-1

14

0.09

6.0

-30,7

-65,4 ± 2.3 Ref USY

λ

L, µm

ϕ, Ct / Cint

,kJmol-1

,kJmol-1

o

prottH∆

oprots

∆H

21

oprots

∆H

0

10

20

30

50 100 150 200 250

nC6co

nver

sion

, mol

%

W/F0C6 kg-s mol -1

Conversion at 20 bar

0

10

20

30

50 100 150 200 250

nC6

conv

ersi

on, m

ol%

W/F0C6 kg-s mol -1

Conversion at 30 bar

�� Experimental Data

Model Calculations

model calculationsMethusalem Advisory board meeting, Ghent, August 18th, 2009

22

23

Importance of incorporation of diffusion

0

10

20

30

0 10 20 30 40

Isom

er y

ield

s, m

ol%

n-C6 conversion, mol %

2,2 DMB

2 MP

0

10

20

30

0 10 20 30 40

Isom

er y

ield

s, m

ol%


2 MP

2,2 DMB

model calculationsMethusalem Advisory board meeting, Ghent, August 18th, 2009

T = 503 K, P = 2.0 Mpa, inlet H2/nC6 molar ratio = 50; : 134 kg-s mol-106/ CFW

0

0.2

0.4

0.6

0.8

0 0.2 0.4 0.6 0.8 1

Fra

ctio

nal

spec

ies

occ

upan

cy,

θθ θθ

Dimensionless length, ξξξξ

nC6

2MP

2,2 DMB

24

internal concentration profileMethusalem Advisory board meeting, Ghent, August 18th, 2009

Components

Di (θ→θ→θ→θ→0) (m2s-1)

503 K 523 K Literature value

n-C6 (4.2 ± 0.6) 10-11 (5.6 ± 0.5) 10-11 2.2 10-11

2MP (1.2 ± 0.7) 10-11 (1.8 ± 0.9) 10-11 4.5 10-12

3MP (1.6 ± 0.3) 10-12 (2.3 ± 0.8) 10-12 4.0 10-12

0

10

20

30

0 10 20 30 40

Isom

er y

ield

s, m

ol%


2 MP

3 MP

Estimation of diffusion coefficientsMethusalem Advisory board meeting, Ghent, August 18th, 2009

25

outline

• hydrocracking: model development and catalyst design

• Fischer-Tropsch synthesis– model development for Fe based catalyst– model application for Co based catalyst– industrial reactor modelling

• future activities

26


27


reaction network

MMOMMMCMMMCO

MMCOMCO

MHMH

+↔+↔+↔+

3

2

222

MOHMHMOH

MMOHMHMMO

2

2

2 +↔++↔+

MMCHMHMMCH

MMMCHMHMMMCH

MMMMCHMHMMMC

2

2

32

2

+↔++↔+

+↔+Chain initiation

Chemisorption/dissociation

Formation building blocks

Formation of water

Chain growth and termination• Mechanistic details still unknown

• Chain growth on surface through

stepwise addition of carbon

monomers

• Anderson-Schulz-Flory product

distribution → chain growth

probability independent of cn

M M

M

M

M

MM

M

28


validation Fe and Co catalyst• Water-Gas Shift (formate

mechanism, iron oxide phase,

6 additional elementary reactions)

• Range of experimental conditions:

• Adjustable parameters:

– QC,QH,QO on iron carbide phase (3)

– QH on iron oxide phase (1)

– Ea,for of kinetically relevant reaction

families (10)

T (K) H2/CO ptot (bar) Nobs

523-623 2-6 6-21 90Lox, Ph.D. Thesis, Ghent University (1987)

Lozano-Blanco et al., OGST – Rev. IFP, Vol. 61 (2006), No. 4

• Primary-alcohols (CO insertion

mechanism, 3 additional elementary

reactions)

• Range of experimental conditions:

• Adjustable parameters:

– QC,QH,QO on cobalt metallic phase (3)

– Ea,for of kinetically relevant reaction

families (12)

T (K) H2/CO ptot (bar) Nobs

493 1.6-2 20 22Fiore et al., Studies in Surf. Sci. and Cat. (2004)

Iron Cobalt

29


Reaction family/

elem. reaction(bar-1s-1

or s-1)

UBI/QEPEstimatedUBI/QEPEstimated

Fe Co

3.1 108 0.0 - 0.0 -

2.2 107 0.0 - 0.0 -

1.3 1013 139.5 56.8±0.5 155.1 52.8±6.2

8.8 1014 127.6 77.7±0.7 122.3 74.3±10.3

5.7 1011 67.6 11.9±0.1 58.3 12.2±2.0

2.3 1011 38.1 61.9±0.5 27.2 71.9±3.1

1.3 1012 118.6 103.8±1.0 110.8 107.0±6.6

2.4 1011 78.0 86.2±0.6 51.8 91.6±24.3

M-C - - 639.5±2.1 - 611.2±2.7

M-H - - 249.2±0.6 - 243.3±3.2

M-O - - 578.8±0.9 - 553.7±6.0

Validation Fe and Co catalyst

MHMH 222 ↔+MMCOMCO ↔+ 2

MMOMMMCMMMCO +↔+ 3

MMMMCHMHMMMC +↔+MMMCHMHMMMCH 22 +↔+

MMCHMHMMCH 232 +↔+MMOHMHMMO 2+↔+MOHMHMOH 22 +↔+

forA~ (kJ/mol) QE fora /,

30


Reaction family/

elem. reaction(bar-1s-1

or s-1)

UBI/QEPEstimatedUBI/QEPEstimated

Fe Co

8.9 109 8.0 44.8±0.4 0.0 43.5±2.0

2.1 1010 15.5 117.8±0.7 6.4 103.6±2.0

1.1 1010 26.2 96.3±0.5 24.1 86.1±1.4

1.3 1013 62.1 - 57.0 -

MHMC

MMCHHMC

nn

nn

2321

212

+↔+

++

+

MHCMHHMC nnnn 22212 +↔+ ++MHHMCMHMC nnnn +↔++ 212

MHCHMC nnnn +↔ 22

Validation Fe and Co catalyst

forA~ (kJ/mol) QE fora /,

• most significant changes in atomic chemisorption enthalpies and

in elementary steps determining the product distribution

31


Results - Nonisothermal

T=553K;ptot=21bar;H2/CO=3

0

0,4

0,8

1,2

1,6

0 20 40

yi(m

ol i/

mol

CO

ini)

W/FCO ini (kgcat s/mol)

■ H2

�� CO

▲ H2O

� CO2

● CH4

0

0,4

0,8

1,2

0 20 40 60 80

yi(m

ol i/

mol

CO

ini)


0

0,2

0,4

0,6

0,8

1

0 20 40

yi(m

ol i/

mol

CO

ini)


0

0,2

0,4

0,6

0,8

0 20 40 60

yi(m

ol i/

mol

CO

ini)


T=523K;ptot=21bar;H2/CO=3

T=623K;ptot=21bar;H2/CO=3 T=573K;ptot=11bar;H2/CO=3

Slurry Bubble Column Reactor

200-350°C

10-60 bar

Cocurrent flow mode

Heterogeneous flow

5-8m diameter

Up to 30m height

32


Gas products

Slurry

Freshslurry

Syngas

reactor model

2-bubble class heterogeneous model withaxial effective diffusion

– Axial mass and heat transfer: convection and axial diffusion(exc. LB)

– Gas-liquid mass transfer resistance: liquid phase

– External and internal liquid-solidmass transfer resistance: negligible

– Superficial gas velocity: linearfunction of the syngas conversion

– Constant slurry velocity– Catalyst concentration profile

described with a sedimentation-dispersion model

UG,LB UG,SB

USL

UG

USL

33


model equations

34


( ) ( )jLjLBG

jLBjLBG

LBjLB

LBG

LBjLBLB CCStC

U

U

d

d

d

dC

Ped

dC

d

d,,,,

0

,

,, −−

ξ−

ξε

ξ=ε

τ

( ) ( )jLjSBG

jSBjSBG

SBjSB

SBG

SBjSBSB CCStC

U

U

d

d

d

dC

Ped

dC

d

d,,,,

0,

,

,, −−

ξ−

ξε

ξ=ε

τ

( ) ( )

( ) ( )∑=

θηυ−−

+−+

ξ−

ξε

ξ=ε

τnr

isurfjLiiijCjLjLB

LjLB

jLjSBL

jSBjLG

SLjL

L

LjLL

CCRCCCSt

CCStCU

U

d

d

d

dC

Ped

d C

d

d

1,,,,

,,,,0,

,,

...,,~

( ) ( ) ( )∑=

θη+−θ−

θ

ξ−

ξθε

ξ=θε

τ

nr

isurfjLiiiCH

G

SL

H

LL CCRBeCSt

U

U

d

d

d

d

Ped

d

d

d

0,

0,...,,

~1

( )...,,,, θ=

τ surfjLksurf

CCfnd

dC

calculation strategyGas

products

Slurry

Freshslurry

Syngas

1ξ∆2ξ∆

( )jLjSBjLBksurf CCC

d

d

d

dC,,,

, ,,ττ

⟨⟨

• Discretization of axial position variable:

2nd order pde’s

1st order ode’s in time

• Concentration of surface species

in quasi-steady state

1st order ode’s

differential-algebraic equations

• Iteration routine with initial guesses

• Program running till reaching steady-state

35


0

0,05

0,1

0 5 10 15 20

C (

mol

/mol

gas

tot i

nitia

l)

Axial position (m)0

0,2

0,4

0,6

0 5 10 15 20

C (

mol

/mol

gas

tot i

nitia

l)

Axial position (m)

CO

H2 CO2

CH4

H2O

1,01

1,012

1,014

1,016

1,018

1,02

0 5 10 15 20

T/T

cool

ing

(-)

Axial position (m)

Temperature

LB

SB,SL

Height = 22mDiameter = 5mH2/CO = 2P = 30barT = 553K

Fsyngas=5m3/s

Fslurry=0.2m3/s

Ccat = 0.25

neq = 4158

simulation results

36


simulation results

37


1,E-04

1,E-02

1,E+00

1,E+02

0 2 4 6 8

Mol

ar fl

ow (m

ol/s

)

Carbon number

LB

SB

L

1,E-04

1,E-02

1,E+00

1,E+02

0 2 4 6 8

Mol

ar fl

ow (m

ol/s

)

Carbon number

LB

SB

L

alkanes alkenes

Height = 22mDiameter = 5mH2/CO = 2P = 30barT = 553K

Fsyngas=5m3/s

Fslurry=0.2m3/s

Ccat = 0.25

neq = 4158

outline

• hydrocracking: model development and catalyst design

• Fischer-Tropsch synthesis• current and future activities

– model reactions– Periodic Mesoporous Organosilicas (PMOs)– Metal Organic Frameworks (MOFs)

38


types of components

• pure hydrocarbons:hydrocracking, catalytic cracking, Fischer-Tropsch synthesis, aromatic hydrogenation, oxidative coupling of methane, ethyleneoligomerization, methane aromatization

• hetero atom containing components:– oxygen: (trans)esterification, partial oxidation,

hydroformylation– sulphur and nitrogen: hetero-atom removal

39


catalyst types• acid catalysts

catalytic cracking, (trans)esterification

• metal catalystshydrogenation of aromatics, Fischer-Tropschsynthesis, hydroformylation

• bifunctional catalysts (acid + metal)hydrocracking, methane aromatization, ethyleneoligomerization

• metal oxidesoxidative coupling of methane, partial and/or totaloxidation reactions

40


no brønsted acid sites

Post-modificationOrganic group of PMO

Grafting or co-condensation method

PMOs as novel solid acid catalysts

41


PMOs as novel solid acid catalysts

O

O

OH OH

O

+ H2O+

Acidcatalyst

0,0

20,0

40,0

60,0

80,0

100,0

0 50 100 150 200 250

Con

vers

ion

[%]

Time [min]

SO3H

42


→ Inorganic cluster (Metal Ion) + Organic Linker = Framework

MOF-5

Zn

Organic linker

Metal Organic Frameworks (MOFs)

43


Same structure, different linkers:ISORECTICULAR synthesis

Pore diameter: 8Å -20Å

variation possibilities

44


potential applications

45


Host-guest chemistry:Separation→example MIL-47Gas storage →H2, CO2, CH4,…

MOFs are ideal models for studying the important parameters in heterogeneouscatalysis. For example

MIL-47 : porous but exhibiting coordinatively SATURATED V-sitesMIL-59 : non-porous but exhibiting coordinatively UNSATURATED V-sites

MIL-59

Shape selectivity!

model reactions

46


OH OH

OH

OH

OH

oxidation

phenol catechol

hydroquinone

+

CH3OH

catalystoxidizing agent

benzaldehydetoluene

summary of future activities

• ‘application’ of existing tools to newreactions involving hydrocarbons– ethylene oligomerization– methane aromatization– …

• extension and development of new tools accounting for hetero atoms– (trans)esterification, e.g., using PMOs– (partial) oxidation, e.g., using MOFs– …

47


Discussion/feedback

Methusalem, Advisory Board Meeting, August 18, 2009

48

catalyst design based on catalyst descriptors and ......exp exp + + ... j. a. martens et al. appl....

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