Institut für Chemie - Max Planck Societyw0.rz-berlin.mpg.de/imprs-cs/download/Schomaecker_Reactors.pdf · Institut für Chemie Select the reactor from selectivity discussion 1) More

Institut für Chemie

Reactor design- A Primer

Reinhard Schomäcker

Dept. of Chemistry

TU Berlin

- A selection of reactors

- Kinetic studies

- Up-Scaling of a reactor

- Simulation of a PFTR


How to select a reactor for an industrial scale synthesis ?

“Something went wrong when we scaled-up the recipe”


L

G

G

L

Packed Bubble Column

Tray collumn

Gas-Liquid-Reactors Fixed Bed Reactors Three Phase Reactors

Single Bed Reactor

Katalysator

GL

L G

G

Trickle Bed Reactor

G

Multi Tube Reactor

GK+L

K+L

Tank Reactor


Multi tube reactor (MSA, EO)

Fixed bed reactor (SO3)


Expanded fluidized bed reactor (PE, PP)


Select the reactor from selectivity discussion

1) More suitable chemistry (different reactants)2) Better Catalyst or reaction medium3) Better temperature4) Reaction engineering

( Type of reactor, mode of operation).

Parallel reactionsExample 1:

A + B CA + B D

BAcckr

11=

BAcckr

22=

21

1

21

1

kk

k

rr

r

Aconsumed

CproducedS

C +=

+==

S

X

A

C

D


BAcckr

11=

r k cA2 22=

Sgebil es C

umgesetztes Ar

r r k ck c

CA

B

= =+

=+

det 1

1 2 2

1

21

1 2

A + B C2 A D

Example 2:

Example 3: consecutive reaction

A + B C

C + B D

r k c cA B1 1=

r k c cC B2 2=

A

C

C ck

ck

r

r

r

rr

Aconsumed

CproducedS

1

2

1

2

1

21 11 −=−=−==

S

X

A B C

∫=CA

CAAC

dCSS0


z

cA

0 Lz

qnA

.

M

CSTR

cAV

0

•

cAV•

.

V

V R=τVR

Coordinate z

Zulauf Ablauf

cA

PFTR


0 Lz

qnA

.

M

CSTR

cAV

0

• cAV•

.

V

V R=τVR

PFTR

Residence time in reactors

Institut für ChemieInstitut für Chemie

CH3OH + H2O 3H2 + CO2

Cu-Kat.

150 km/h450 km

Motivation


Experimental Set-up


Kinetics of steam reforming of methanol at diff. temperatures230°C

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 0.2 0.4 0.6 0.8 1Verweilzeit [s]

Par

tiald

ruck

[atm

]

250°C

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 0.1 0.2 0.3 0.4 0.5 0.6

Verweilzeit [s]

Par

tiald

ruck

[atm

]

300°C

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 0.1 0.2 0.3 0.4 0.5 0.6

Verweilzeit [s]

Par

tiald

ruck

[atm

]

MeOHH2OCOCO2

H2

Simulation


Reaktion mechanism from literature

CH3OH CO + 2H2CO + H2O H2 + CO2

2 CH3OH 2 HCHO + 2 H2HCHO + HCHO HCOOCH3HCOOCH3 CO + CH3OHCO + H2O CO2 + H2

2 CH3OH HOOCH3 + 2 H2HCOOCH3 + H2O HCOOH + CH3OHHCOOH CO2 + H2

B.A. Peppley, J.C. Amplett

Su, Rei, Kobayashi, Idem, Bakhshi

Takahashi, Takezawa

1.

2.3.


Reaktion network and kinetic parameter

Ea1h= 70 kJ/mol k01h= 2,1 1012 Pa0,4/sEa1r= 120 kJ/mol k01r= 7,7 1015 Pa-3/s Ea2h= 88 kJ/mol k02h= 1,3 1013 Pa-1/s Ea2r= 47 kJ/mol k02r= 2,0 1011 Pa-1/s

m= 0,3 n= 0,3

r1h= k1h PmMeOHPn

H2O

r2h= k2h PCO2 PH2

k1h

k2h

k2r

k1r


Pore diffusion and reaction in porous catalyst

φ = L k Ci

n-1

D

k > D k < D

particleCatalyst

ofLength ticCharakteri :L

orderReaction :n

iComponent ofion Concentrat :Ci

tcoefficienDiffusion :D

constant rate :k

Modul Thiele :φ


Determination of reactor size

Rdz

dCu

dtdC AA −−=

∫ −=

A

A

C

C

A

RdC

0

τ

)1(0

XCCAA

−=

Material balance

dXCdCAA 0

−= ∫Φ=

eXAO

X

dX

RC

00 )(τ

)(0

XRR Φ=

Reaction time

Introduction of Conversion 0

0

A

AA

C

CCX

−=

Rd

dCA −=τ

VR

jA

RPFTR


.

V

Vt R== τ

∫Φ=

eXAO

X

dX

RC

00 )(τ

∫Φ=

eXAO

R X

dX

R

CVV

00

.

)(

∫Φ=

eX

AO

X

dX

R

C0

0)(

τ

Calculation of Reactor Volume (PFTR)

Time required to reach conversion X

Residence time

Reactor Volume

nP=V CAo X.



)()( XeDadz

dX XRT

E

Φ=−

∞τ

Heat removal from PFTR:

)()(K

RT

E

adTTStXeDaT

dz

dT −−Φ∆=−

∞τ

pR

WW

p

WW

cV

Fk

cV

FkSt

ρτ

ρ==

&

)(

)(0

pA

A

ad c

cHT

ρν−∆−=∆

0

0)(

Ac

kDa

τυ−=∞

0AC

R

dz

dX=τ

Zeit

Tem

pera

tur

adiabatischer Reaktor

gekühlter Reaktor

TT

aK

z


r

TK

Radial temperature profile with tube reactor

rtube< rcrit.

rtube> rcrit.


Catalysis and mass transport in pores

reactants

activemembrane

fixed bed reactor

reactants

product

A + B C D

A + B

C

pelletproducts


Preparation and characterisation

MOCVD 27MOCVD 27--capillary bundlecapillary bundle

• Pores- ∅: 1,9 µm

•MOCVD: about 89 mg Pd


Set-up Experimental

• 0,5-4 mg Pd/Membrane• AMS or COD in n-Heptane or Cumene

(CAMS= 1.4 mol/l; CCOD=0.4 mol/l)• 1 - 40 bar• T= 40-50 °C• VGemisch= 110 ml• Flow rate = 60-500 ml/min

MIC

FIC

TI

TI

PI

PI

T °

T °

H2

GC

PIC


Microstructured reactors

Documents

Institut für Chemie - Max Planck Societyw0.rz-berlin.mpg.de/imprs-cs/download/Schomaecker_Reactors.pdf · Institut für Chemie Select the reactor from selectivity discussion 1) More