STEAM-CRACKING: FROM MOLECULE TO INDUSTRIAL PROCESS · steam-cracking: from molecule to industrial process kevin m. van geem and guy b. marin (keynote) 8th asian-pacific chemical

STEAM-CRACKING: FROM MOLECULE TO INDUSTRIAL PROCESS

Kevin M. Van Geem and Guy B. Marin (keynote)

8TH ASIAN-PACIFIC CHEMICAL REACTION ENGINEERING (APCRE 2017) SYMPOSIUM EAST CHINA UNIVERSITY OF SCIENCE AND TECHNOLOGY, SHANGHAI, CHINA, NOV. 12-15, 2017

Laboratory for Chemical Technology

Ghent University History13-Nov-17

2/172

2017

Furnace revamp

8th Asian-Pacific Chemical Reaction Engineering (APCRE 2017) Symposium

East China University of Science and Technology, Shanghai, China, Nov. 12-15, 2017

COILSIM1D13-Nov-17

3/1728th Asian-Pacific Chemical Reaction Engineering (APCRE 2017) Symposium


Steam cracking: hot section

D

A

C

A: Radiation section

B: TLE

C: Steam drum

D: Convection section

Endothermic process 1050–1150 K

Preheat feed and other utility streams

Rapidly

quenching

of reactor

effluent

B

45%

50%800K

700K

1050–1150 K

5%

1450 K

FPH

Saturated steam

BFWECO

Feed

Dilution steam

SSH

HTC

Steam

13-Nov-17



Developing of a model for steam cracking

Simulation

model

Goal Reactor geometry

Operating conditions

Feedstock

properties

Product

specs

Modeling Microkinetic

model

Reactor

model

Fundamental

reactor model

Detailed

feedstock

composition

Detailed

product

composition

13-Nov-17



Outline

• Introduction

• Feedstock

• Kinetics

• Reactor

• Process

• Conclusions

13-Nov-17



Outline

• Introduction

• Feedstock: characterization

• Kinetics

• Reactor

• Process

• Conclusions

13-Nov-17



1st dimension retention time (min)

0 4020

2n

d d

ime

nsio

n r

ete

ntio

n tim

e (

s)

0

5

8060

indene

naphthalene

acenapthylene

phenanthrene

pyrenetoluene

benzeneethyl-Bz

(b)

xylenes

1st dimension retention time (min)(a)

styrene

methyl-naphthalenesvinyltoluene

anthracene

biphenyl

tri-methyl-Bz

methyl-indenes

acenapthene

mono-

aromatics

di-

aromatics

naphtheno-

aromatics

naphtheno-

di-aromatics

tri-aromatics

tretra-aromatics

GCGC chromatogram: 2 parts

Conventional 1D part C4-

Comprehensive 2D part C5+

3D view

methane

propene

1.3-butadiene

ethene

ethane propane1-butene

propadiene

8

Pyl, S.P. et al.,Journal of Chromatography A, 1218, 3217-3223, 2011On-line GC × GC

13-Nov-17



• Average molecular

weight

• Elemental composition

• Specific density

• Global PINA analysis

• Boiling point data

(e.g. D2887 simdist)

• Aromatic Sulfur

SIMCO: Maximization of Shannon Entropy

Feedstock properties Detailed composition

• Species identity

Feedstock

reconstruction

± 20 properties More than 100 unknown

mole fractions

Shannon

entropy

maximization

MM N

i

i

N

i

iii yyyyS11

1 with ln MAX

Constraints from mixing rules (example):

MN

i iii

ii

y

y

1exp Mwd

Mw

d

1

MN

i

iiy1

exp MwMw

• Mole or mass fractions

S.P. Pyl et al., AIChE Journal, 56, 12, 3174-3188, 2010

13-Nov-17



SIMCO results: Hydrocarbonsn-paraffins i-paraffins

Naphthenes Aromatics

13-Nov-17



Outline

• Introduction

• Feedstock

• Kinetics

• Reactor

• Process

• Conclusions

13-Nov-17



CRACKSIM: steam cracking kinetics

Simulation

model

Goal Reactor geometry

Operating conditions

Feedstock

properties

Product

specs

Modeling Microkinetic

model:CRACKSIMReactor

model

Fundamental

reactor model

Detailed

feedstock

composition

Detailed

product

composition

13-Nov-17



Outline

• Introduction

• Feedstock

• Kinetics: reaction network

• Reactor

• Process

• Conclusions

13-Nov-17



Network generators

●●

●●

●●●

●

●

●

●

●

●

●

●

●

●

RING

Daoutidis

Minneapolis

Genesys

PRIM(-O)

ReNGeP

LCT, Ghent, Belgium

RMG

Green

Cambridge

NetGen

Broadbelt

Delaware

EXGAS

Battin-Leclerc

Nancy, France

RDL

Mavrovouniotis

Evanston

RDL++

Vankatasubramanian

West Lafayette

CASB

Porollo

Josjkar-Ola, Russia

MAMOX(+)(++)

Ranzi

Milan, Italy

REACTION

Blurock

Lund, Sweden

COMGEN

Truong

Salt Lake City

MECHGEN

Héberger

Budapest, Hungary

KING

Di Maio

Cosenza, Italy

RAIN

Ugi

Munich, Germany

GRACE, Yoneda

KUCRS, Miyoshi

Tokyo, Japan

RNG

Lederer

Prague, Czech RepublicMECHEM

Valdes-Perez

Pittsburgh

13-Nov-17



GENESYS : GENEration of reacting SYStems

PatternRecognition

MoleculeIdentifiers

Reactant -> product

Vandewiele, N.M. et al., Chemical Engineering Journal, 207-208, 526-538, 2012

Van de Vijver, R. et al. International Journal of Chemical Kinetics, 47 (4), 199-231, 2015

Vandewiele, N.M. et al., Journal of Computational Chemistry, 36 (3), 181-192, 2015

“Kinetics of Chemical Reactions : Decoding Complexity”

G.B. Marin and G.S. Yablonsky,Wiley-VCH Verlag, 446 pages, 2011

13-Nov-17



Families of elementary reactions

Bond dissociation and radical recombination

R1 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

•+

13-Nov-17



CRACKSIM: μ and β networks

β network μ network

CRACKSIM

Bi- and monomolecular

reactions for β radicals

Monomolecular reactions

for 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

•+

R1

R2R3

•R1-R2 R3 •

1324 reversible reactions

51 molecules

43 radicals

13584 schemes

676 molecules

13-Nov-17



Outline

Introduction

Feedstock

Kinetics: ab initio

Reactor

Process

Conclusions

66th Canadian Chemical Engineering Conference “Sustainability & Prosperity” October 16-19 (2016) Québec City (Canada) 13-Nov-17



Conventional Transition State Theory (high pressure limit)

The CBS-QB3 ab initio method is used.

Electronic barrier ΔE0

• Ideal gas approximation

• Hindered Rotor (1D-HR)

Partition functions q

• Eckart

Tunneling coefficient κ

RT

E

m

BA

B eVqq

q

h

Tk)T()T(k

0‡

‡E

A + B [AB]‡ C

Transition state

Δ‡Eelectronic

Reaction coordinate

‡

Reactants

Products

Kinetics: computational approach13-Nov-17



Objective: data base 13-Nov-17

Reactor model

Solver

Reaction network

Kinetic and thermodynamic data

Develop a consistent data set based on ab initio

calculations

Reactor simulation for hydrocarbon radical chemistry

? Larger speciesusing group additivity

Van de Vijver, R. et al., Chemical Engineering Journal, 278, 385–393, 2015



O

O

OH

2-methoxy-2-methylbut-3-enoic acid additive groups

Cd-(H)2

C-(C)( Cd)(O)(CO)

Cd-(C)(H)

O-(C)2

C-(O)(H)3

C-(C)(H)3

CO-(C)(O)

O-(CO)(H)

O

O

OH

Additivity

= + + + +

+ + + +

O

OH

Atoms in large molecules

Atoms in small molecules

with similar surroundings

Group additivity

O

From small to large species with group additivity13-Nov-17



Hydrogen abstraction (ethyl + ethenyl methylether)

CH=CH2

resEEEE EYGAVXGAVCGAVCGAVTETE ,a1o

1o

2o

1o

refa,a )()()()()()(aaaa

C1 H C2

H

H

H

H

‡

• OCH3+CH2 CH3 CH3

OCH2

CH3 CH3 + CH2

OCH2

+4.7 kJmol-1 +0 kJmol-169.7 kJmol-1 -18.2 kJmol-1

Ea, ab initio= 62.0 kJmol-1Ea,GA = 62.6 kJmol-1

C1-(C)(H)2 C2-(O)(H)2CH3 + CH4

-0.866 +0.4805.268 +0

logAab initio= 5.203log(AGA /m3 mol-1s-1)= 5.095

-0.053

O-(C2)(Cd)C-(C1)(H)3 H-

+6.8 kJmol-1 -0.4 kJmol-1

C1-(C)(H)2 C2-(O)(H)2CH3 + CH4 O-(C2)(Cd)C-(C1)(H)3 H-

-0.512

Paraskevas, P. et al.,Journal of Physical Chemistry A, 119 (27), 6961-6980, 2015

Kinetics: data base of ΔGAVo13-Nov-17



Kinetics: validation of group additivity

0

2

4

6

8

10

0 2 4 6 8 10

log

kG

A

log(kAI/m³mol-1s-1;s-1)

H additions

H β scission

C addition

C β scission

H-abstraction

1000 K

Sabbe et al. ChemPhysChem 2008, 9 (1), 124-140

Sabbe et al. ChemPhysChem, 2010, 11(1), 195-210

Sabbe et al. PhysChemChemPhys, 2010, 12 (6), 1278-1298

13-Nov-17



Outline

• Introduction

• Feedstock

• Kinetics

• Reactor

• Process

• Conclusions

13-Nov-17



Steam Cracking Pilot PlantGas-Fired Furnace + Reactor

Online Analysis

Section

Control “Room”

High temperature

sampling system

HC

Feed

H2O

13-Nov-17



Pilot results: C1/C2/C3/C4Process conditions

Feed 3 wt% C1

67 wt% C2

22 wt%C3

8 wt% C4

COT 1005-1119 K

COP 0.152-0.157 MPa

Steam dilution 0 kg/kg

0

10

20

30

40

50

60

70

0 10 20 30 40 50 60 70

Ab

init

io p

red

icte

d y

ield

(w

t%)

Experimental yield (wt%)

methane

ethene

ethane

propene

propane

0

1

2

3

4

5

6

7

0 1 2 3 4 5 6 7

Ab

init

io p

red

icte

d y

ield

(w

t%)

Experimental yield (wt%)

1,3-butadiene

1-butene

n-butane

benzene

H2

without a single

adjusted parameter

13-Nov-17



Industrial ethane/propane cracker

Satisfactory agreement for all major product yields,

based on ab initio data only.

0

10

20

30

40

50

60

Pro

du

ct

yie

ld (

w%

)

experimental

simulated

CH4

13-Nov-17



Outline

• Introduction

• Feedstock

• Kinetics

• Reactor: 3D alternatives

• Process

• Conclusions

13-Nov-17



Coke formation

Optimization by

- Feed additives

- Metallurgy & surface technology

- 3D reactor technology

Deposition of a carbon layer on the reactor surface

Thermal efficiency

Product selectivity

Decoking procedures

Estimated annual cost to industry: $ 2 billion

2L. Benum, "Achieving Longer Furnace Runs at NOVA Chemicals," in AIChE Spring National Meeting, 14th Annual Ethylene Producers’ Conference, New Orleans, Louisiana, 2002.

13-Nov-17



Coke formation: 3D reactor technologies13-Nov-17

~ 15 °C

~100 °C

Reduce convective heat resistance

Better mixingIncrease surface area

Cokes formed here

T ↑ coking rate ↑↑

~60 °C

*Borealis.com, kubota.com, Technip.com



CFD and Coking kinetics: Coke layer growth

SOR (0 hrs)

48 hrs

Fin c-Rib

SOR

10 days

13-Nov-17



Millisecond propane cracker

• Feedstock 118.5 kg/h propane

• Propane conversion 80.15 % (± 0.05%)

• Steam dilution 0.326 kg/kg

• CIT 904 °C

• COP 170 kPa

• Different geometries simulated• Same reactor volume

• Same axial length

• Same minimal wall thickness

Bare c-RibFin

13-Nov-17



Millisecond propane cracker: run length simulation

SOR 96h48h

Increasing run length

13-Nov-17



Tube Metal Temperature

Max. TMT increasesThermal resistance coke layer

Bare

c-Rib

Fin

13-Nov-17



Outline

• Introduction

• Feedstock

• Kinetics

• Reactor

• Process

• Conclusions

13-Nov-17



Outline

• Introduction

• Feedstock

• Kinetics

• Reactor

• Process: furnace

• Conclusions

13-Nov-17



Coupled reactor-furnace simulation

External coil temperature

Heat flux to reactors

Reactor(COILSIM1D)

Furnace simulationconvergenceFURNACE/

COILSIM1D

Hu, G. et al.,Industrial & Engineering Chemistry Research, 54 (9), 2453-2465, 2015

13-Nov-17



Full furnace simulation

Ultra Selective Conversion (USC)

100% floor burner Fuel composition mol%: CH4(89%)-

H2(11%) U coil Feedstock: Naphtha

Coupled modeling

3D CFD furnace model 1D reactor model (COILSIM1D) Detailed cracking kinetics (CRACKSIM)

Zhang, Y. et al.,AIChE Journal 61 (3), 936-954, 2015

13-Nov-17



Flue gas: velocity and concentration fields

Detailed case• Stronger turbulence• Faster reaction

detailed simplified

Methane mole fraction

13-Nov-17



Tube wall temperature field: local hot spots

This information is key for run length

13-Nov-17



Outline

• Introduction

• Feedstock

• Kinetics

• Reactor

• Process

• Conclusions

13-Nov-17



Conclusions

• Shannon Entropy maximization to reconstruct feedstocks in

terms required for a microkinetic model (SIMCO)

• Consistent data set for thermochemistry and kinetics of

hydrocarbon radical chemistry (CRACKSIM)

• Ab initio simulation of steam cracking of C2/C3/C4

• Emergence of 3D reactor technologies: CFD as tool

• Integration of reactor/convection section/furnace (COILSIM1D)

integration of computational chemistry methods with

engineering tools, e.g. CFD, at larger time and length

scales and experimental validation provides a

powerful tool for the optimization and/or design of

industrial units

13-Nov-17



Acknowledgments

• Profs. Marie-Françoise Reyniers,Maarten Sabbe, Feng Qian

(ECUST)

• Drs. Steven Pyl, Nick Vandewiele,Thomas Dijkmans, Paschalis

Paraskevas, Marko Djokic, Ruben Van de Vijver,David Van

Cauwenberge, Andres Munoz (AVGI),Yu Zhang (ECUST)

• PhD students Pieter Reyniers, Laurien Vandewalle, Nenad Ristic,

Florence Vermeire, Moreno Geerts, Aleksandar Bojkovic,

Muralikrishna Khandavilli

13-Nov-17



LABORATORY FOR CHEMICAL TECHNOLOGY

Technologiepark 914, 9052 Ghent, Belgium

E [email protected]

T 003293311757

https://www.lct.ugent.be

GLOSSARY

• SFT: Swirl Flow Tube, a tube with a helicoidal centerline.

The helix amplitude is smaller than or equal to the tube

radius.

• Swirl flow: a whirling or eddying flow of fluid.

• Swirl number: ratio of tangential over axial momentum

transfer

• Wall shear stress: component of stress parallel with the wall.

It is the product of the viscosity and the derivative of axial

velocity with respect to the radial coordinate.

13-Nov-17



STEAM-CRACKING: FROM MOLECULE TO INDUSTRIAL PROCESS · steam-cracking: from molecule to industrial process kevin m. van geem and guy b. marin (keynote) 8th asian-pacific chemical

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