Industrial Catalytic Reactor Simulation from Lab-Scale ... · Industrial Catalytic Reactor ... Kinetics Joris W. Thybaut Methusalem Advisory Board Meeting, Ghent, Belgium, 19 June

Laboratory for Chemical Technology, Ghent University

http://www.lct.UGent.be

Industrial Catalytic Reactor Simulation from Lab-Scale Intrinsic

Kinetics

Joris W. Thybaut

Methusalem Advisory Board Meeting, Ghent, Belgium, 19 June 2014

1

chemical kinetics in reaction engineering

from atom (nm) to full process (m)


2

intrinsic vs ‘industrial’ catalytic kinetics


bulk catalyst

CRb

CRs CRi

CPb

CPs CPi

exte

rnal

sur

face

CPb = CPs = CPi

CRb = CRs = CRi

3

intrinsic kinetics measurement

• well defined flow pattern

• isothermicity• no or well controlled

concentrationgradients

• gas/three-phaseconditions

• 1 to 10g of catalyst• high p and T


4

methodology

5


– validation of data available from industrial / pilot plant studies

– operatingconditions

– reaction pathway– detailed kinetics – model

construction– evaluation

estimated parameters

– phase effects– formation of

new compounds– solvent

adsorption– assessment of

liquid phase non ideality

extended set of gas phase

experimentation

limited liquid phase

experimentation

three-phase industrial reactor

simulation

Berty Reactor

Robinson Mahoney Reactor

industrial trickle bed

reactor

outline

• introduction• gas-to-liquid phase kinetics

– methodology/concepts– pyridine HDN

• multiphase catalytic reaction engineering– isomerization synergy in hydroconversion– complex mixture and phase effects

• multi-scale reactor modeling– ethylene oligomerization

• conclusions6


gas versus liquid phase thermodynamics

• ideal gas phase– identical molecular interactions– partial pressures as activity measure

• non ideal liquid phase– molecule dependent interactions– liquid hydrocarbon mixtures with

dissolved light gases– Peng-Robinson equation of state– fugacties as activity measure

7


�� ,

��

rate equations

• gas phase

• liquid phase– substitution of pi by fi according to

– phase effects in the adsorption step– gas-liquid equilibrium 8


��→�� ,��∗� ��

1

�"#$�

��%&��

��

��→�' � ��%&��∗�

� � 1 (�� ( ��%&�� ( ��)��)

� � �� ( ��*��*

∗ � ∗,�+� / � ( �*�-

*�-�.

��

��/ ��

0 1 � 1, …, 3

4� � 4∗�� 4∗��

4� � 4∗��

gas and liquid phase experimentation

9


gas phasea liquid phaseb

Reactor type Berty type (CSTR) Robinson Mahoney (CSTR)Temperature range (K) 573 – 633 543-613Pressure (MPa) 1.5 – 4.0 6.0 – 8.0

H2/pyridine (mol/mol) 80 – 600 10 – 15Space time (kgcat.s/mmol) 0.36 – 1.8 0.65 – 3

Solvent/pyridine (mol/mol) 40 20 – 40

Solvent n-hexane Halpasol© C11-C13 n-alkanes

a R. Pille and G. Froment, Stud. Surf. Sci. Catal. 106 (1997) 403-413.b C. Raghuveer et al. Fuel 125 (2014) 206-218

N

NH

NH2

NH2 SH

SH

+3H2

+H2

-H2S+H2

+H2-NH3-H2S+H2

+H2S

+H2S

-NH3

gas phase reaction network

N

NH

additional reactions at

liquid phase conditions

NH

+

NH

+

-NH3

-NH3

gas and liquid phase parameters

10


Parameter A a / Ka Ea / -∆H

kp⇄pp 33 ± 7 41 ± 10

kpp→pa 4148 ± 802 185 ± 19

kratio 1x10-3 d 100 ± 46

kPentylPP->PP+C5 1x104 d 67.8 ± 16.2

Kp 61 ± 15 110b

Ksolvent 0.02c 39.8 ± 3.0

K1-pentylpiperidine 135c 81.8 ± 3.64

Kpp 85c 117 ± 3

KNH3 30c 76 ± 2

KH2 0.2c 104 ± 3

KH2S 21c 129 ±3Units : k [mol/hr-kgcat], Ea [kJ/mol), K [bar-1] and ∆H [kJ/mol]a at average temperature, i.e., 599 Kb Calculated, assuming similar loss of mobility as piperidinec Calculated from estimated adsorption enthalpy and best fitting adsorption entropy.d (s-1 bar -1 ) Value of pre-exponential factor (Dumesic 1993, The microkinetics of heterogenous catalysis)

Component ∆Sadsorption(J/mol-K)

ammonia -98

solvent -98

1-pentylpiperidine -130

piperidine -158

hydrogen -187

hydrogen sulphide

-190

Decreasing mobilityon catalyst surface

gas and liquid phase simulation

11


Symbols: experimentally obtained values, ♦ : Pyridine, ■ : Piperidine, •: 1-Pentylpiperidine,▲: C5 hydrocarbons

▬▬ : Pyridine, ▬▬ : Piperidine, -- : 1-Pentylpiperidine, ••• : C5 hydrocarbons

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1,0

550 575 600 625 650

Co

nv

ers

ion

(-)

sele

ctiv

ity

(-)

Temperature (K)

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0

0,2

0,4

0,6

0,8

1

560 570 580 590 600

Co

nv

ers

ion

(-)

sele

ctiv

ity

(-)

Temperature (K)

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

1 1,5 2 2,5 3 3,5

Co

nv

ers

ion

(-)

Yie

ld (

-)

Total Pressure (MPa)

0

0,1

0,2

0,3

0,4

0,5

0,6

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

1,5 2 2,5 3 3,5 4

Co

nv

ers

ion

(-)

Yie

ld (

-)

Total Pressure (MPa)

gas

phas

e

liqui

d ph

ase

outline





• conclusions12


hydroisomerization yields

13


+

+

Pt

+

isomerization

Pt

+PtPt

Consecutive reaction mechanism1. physisorption2. dehydrogenation3. protonation4. isomerization/cracking

max isomer. yield ≈ 60% in idealn-decane hydroconversion

0

10

20

30

40

50

60

70

80

0 20 40 60 80 100

pro

du

ct y

ield

(%

)

n-decane conversion (%)

C10 isomers

Cracking products

0

10

20

30

40

50

60

70

80

0 20 40 60 80 100

pro

du

ct y

ield

(%

)


C10 isomers

Cracking products

Unidirectional medium-pore zeolites:� diffusion of branched species in

micropores restricted� reaction nearly exclusively at pore

mouths USY

ZSM-22

synergy effect between ZSM22 and Y

14


physical mixtures of ZSM22 and Y with tailored activity → enhanced isomerization yield in gas phase model component conversion

reaction pathway1. monobranching on ZSM222. dibranching on Y

while avoiding excessive cracking on Y→ Y should only be mildly active

ZSM22

Y

tridimononormal

ZSM22 + Y

tridimononormal

tridimononormal

30

40

50

60

70

80

60 70 80 90 100

tota

l iso

mer

izat

ion

yiel

d (%

)

total nC10 conversion (%)

ZSM22

25-75

50-50

75-25

Y

gas phase, feed mixture

15


component Molar composition (%)

n-decane 17

n-undecane 43

n-dodecane 28

n-tridecane 12

0

20

40

60

80

0 20 40 60 80 100

isom

er y

ield

(%

)

total parapur conversion (%)

total

C13

C12

C11

commercial n-alkane mixture ‘parapur’

syne

rgy

disa

ppea

rs

preferential physisorption and reactionof heaviest compounds

Y

C13

C12

C10

C11

30

40

50

60

70

80

40 50 60 70 80 90 100

tota

l iso

mer

izat

ion

yiel

d (%

)

total parapur conversion (%)

ZSM22

25-75

50-50

75-25

Y

ZSM-22

liquid phase, model compound

16


Attenuated synergy effect

micropore saturation at liquid phaseconditions→ ZSM22 micropores saturated with

linear species→ enhanced cracking at the expense of

isomerization50

60

70

80

90

100

0 20 40 60 80

ZS

M2

2 m

icro

po

re o

ccu

pa

ncy

(%

)


gas phase

liquid phase

gas ↔ liquid: ZSM22 micropores

30

40

50

60

70

80

60 70 80 90 100

tota

l iso

mer

izat

ion

yiel

d (%

)

total nC10 conversion (%)

ZSM22

25-75

50-50

75-25

Y

liquid phase, feed mixture

17


0

20

40

60

80

0 20 40 60 80 100

isom

er y

ield

(%

)

conversion (%)

total

C13

C12

C11

synergy preserved for high ZSM-22 content

more pronounced physisorptioncompetition

catalyst mixture compositionoptimization viaSEMK model simulation

Y

ZSM22

30

40

50

60

70

80

60 70 80 90 100

tota

l iso

mer

izat

ion

yiel

d (%

)

total papapur conversion (%)

ZSM22

25-75

50-50

75-25

Y

outline





• conclusions18


multi-scale reactor model

19


REACTOR SCALEmass balance:

energy balance:

impulse balance:

compii niR

dW

dF...1==

( )rr

ncomp

iiifBpfs TT

d

URH

dz

dTCu −−∆= ∑

=

41

,ρρ

p

sg

d

uf

dz

dp 2ρ=−

≠==

=2

022

for00

CiF

FFW

i

CC

0at0 == WTT

0at0 == Wpp

10, <≤→> ϕipi Vp

( ) li

gii RWERWER +−= 1

1...)(Re0 ≤=≤ lfWE

PELLET DIAMETER

liquid formation:CRYSTALLITE SCALEintra particle transfer:

∂∂+

∂∂

∂∂+

∂∂−=

∂∂

2

2

2

,,

4

ξθ

ξθ

ξξθ

ξθ iiii

ic

isati

iisat

DD

s

L

CR

tC

∂∂+

∂∂

∂∂+

∂∂−∆=

∂∂

∑=

2

2

21

,

4

ξξξλ

ξλ

ξTTTs

LRH

t

T

ci

n

iif

comp

0at0

1at

==∂∂

==

ξξθ

ξθθ

i

sii

for all t, except t = 0 for t = 0

1at0

1at

≠===

ξθξθθ

i

sii

0at0

1at

==∂∂

==

ξξ

ξT

TT sfor all t, except t = 0 for t = 0

1at

1at

≠=

==

ξξ

s

s

TT

TT

NANO SCALE

∑=

−=rxnn

jjjii rR

1,ν

( )...,,,, DTyxpfRi =

intrinsic kinetics:

industrial reactor design

20

0

2

4

6

8

10

12

14

16

18

0 5 10 15 20 25

Yie

ld (

%)

Conversion (%)

Butene

Hexene

Ni+

Ni+ Ni

+

Ni+

C2H4C2H4

C2H4

C2H4

C2H4C4H8

Ni+

C2H4

C4H8

...

C2H4

met

al-i

on a

ctiv

ity

termination

insertion

chemisorptionchemisorptioninitiation

SEMK simulation net production ratesdesign criteria

100 kT/y CH4 and 30% yield to C2H4→ 30 kT/y C2H4 = 37.2 mol s-1

design variables� dimensions (Lr, Lr/dr)� heating regime (isothermal, adiabatic, heat exchanging, …)� number of catalytic beds� inlet conditions (T0

max = 573 K, p0max = 3.5 MPa, …)

� catalyst properties (size …)

catalyst: Ni-Si/Al (no strong acid sites)absence of acid catalysis

mainly dimerizationreaction conditions independent selectivity

→ maximization of XC2 (and YC4)


0

20

40

60

80

100

0 1 2 3 4 5 6

Co

nv

ers

ion

(%

)

Wcat (ton)

570

590

610

630

0 1 2 3 4 5 6

Te

mp

era

ture

(K

)

Wcat (ton)

reactor scale: heating regime

21

95%

1. difference between single bed heat exchanging and multibed is negligible

2. economic analysis needed (cfr. cooling utilities)

30 kT/y C2H4 | p0C2H4 = 3.5 MPa | T0 = 573 K

single vs. multi fixed bed operation:

single bed, adiabaticsingle bed, heat exchangingmulti bed (3), adiabatic


570

580

590

600

610

0 1 2 3 4 5 6

Te

mp

era

ture

(K

)

Wcat (ton)

0.001

0.01

0.1

1

10

0.0001 0.001 0.01

Δp

(%

)

dp (m)

30 kT/y C2H4 | p0C2H4 = 3.5 MPa | T0 = 573 K

single fixed bed operation:

heat exchanging (573 K)

Lr/dr = 5 – 10 – 15

Lr/dr↓ → heat exchanging surface area↓→ higher temperature and later occurrence of hot spot in the reactor

Lr/dr > 10: ∆T < 20 K

∆p is negligible(<<1%)

reactor scale: dimensions and pressure drop

22

Lr/dr↓


particle diameter

0.0

0.2

0.4

0.6

0.8

1.0

0 2 4 6 8 10

fra

ctio

n o

f w

ett

ed

ca

taly

st

surf

ace

are

a (

-)

Wcat (kton)

0

20

40

60

80

100

0 2 4 6 8 10

Co

nv

ers

ion

(%

)

Wcat (kton)

pellet scale: liquid formation

23

• liquid formation can enhance ethene conversion

• future prospective: including acid catalysis

→ liquids to branched olefines

30 kT/y C2H4 | p0C2H4 = 3.5 MPa | T0 = 303 K

single fixed bed operation, isothermal� C4+ (liquids) are inert on Ni(+)

� micropores are filled with liquids� ‘decelerating’ and ‘accelerating’ effect→ reduced surface slows the rate down→ product condensation keeps ethylene

partial pressure high � axial gas phase composition: ± constant�RC2: ± constant at available sites

no liquids cat. 1 cat.2 Amacro > Amicro Amacro < Amicro

better performance worse performance


crystallite scale: mass transfer limitations

24

under current conditions (D/Lc²>103 s-1):no mass transfer limitations

future prospect: heavy componentse.g.: D/Lc² = 0.1 ms-1

effect of shape factor of the catalyst particles = 2 (sphere) → η = 75%s = 1 (cylinder) → η = 62%s = 0 (slab) → η = 39%

0

0.1

0.2

0.3

0.4

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

θC

2(-

)

ξ (-)

Burghardt et al. Chem. Eng. Proc. 35 (1996) 65-74


570

575

580

585

590

595

600

0

10

20

30

40

50

60

70

80

90

100

0 0.5 1 1.5 2 2.5 3 3.5

Te

mp

era

ture

(K

)

Co

nv

ers

ion

(%

)

Wcat (ton)

ultimate industrial reactor design

25

30 kT/y C2H4 (≈37.2 molC2H4 s-1)95% conversion of C2H4

p0C2H4 = 3.5 MPa

T0 = 573 Kmulti (3) fixed bed adiabatic operation

Lr = 8.1 mdr = 0.81 m mcat = 3.75 ton

no liquid formationnegligible pressure dropno intraparticle mass and

heat transfer limitations

95%


conclusions

• starting from ‘intrinsic’ catalytic kinetics– phase effects where accounted for– adequate thermodynamics description

• multiphase reaction engineering– optimization of synergy in isomerization yield

• multi-scale industrial reactor modeling– ethylene oligomerization– reactor, pellet and crystallite scale

• variety of model reactions– HDN, hydroisomerization, ethylene

oligomerization


26

future work

i-CaD

fossil

resources

carbon

hydrogen

biomass

carbon

hydrogen

oxygen


27

innovative catalyst design for large-scale sustainable processes (i-CaD)

acknowledgements

prof. Guy B. MarinBart VandegehuchteKenneth TochChetan Raghuveer

28


29


Documents

Industrial Catalytic Reactor Simulation from Lab-Scale ... · Industrial Catalytic Reactor ... Kinetics Joris W. Thybaut Methusalem Advisory Board Meeting, Ghent, Belgium, 19 June