modelling and simulation in chemical engineering-rodrigues_e14.pdf




OUTLINEINTRODUCTIONTHE ART OF MODELLINGMODELS OF 10$, 100$ and 1000$PROCESS SIMULATIONPERFUSION CHROMATOGRAPHYSIMULATED MOVING BED (SMB)HYBRID PROCESS-SMB REACTOR

CONCLUSIONS




BSL




Ingredients for Process Innovation

Science Technology

Process




Increaseddiffusivity byconvection

Adsorbents (Materials)

Perfusion chromatography




SMB conceptModellingSimulation

Adsorbent(Materials)

Technology(rotary valve)

Sorbex processes (UOP)




ChE MethodologyLe Goff (1970)

Conservation equations (mass, energy, momentum, electric charge)

Equilibrium laws at the interface (s)Constitutive laws (e.g., ideal gas law)Kinetic laws of transport and reactionInitial and boundary conditionsOptimisation criterion




Surface diffusion

Pore diffusion External film diffusion

Axial dispersion (bulk)

Surface diffusion

Pore diffusion External film diffusion

Axial dispersion (bulk)

THE ART OF MODELLING




Scaling and dimensionless groups

constant time reactionconstant time diffusion

rate diffusionrate reactionDa

Dkc

IIe

niS ====

2

12 l

022

= niie kcdz

cdD

iSi

i

cczdzdcz

====

,

0,0

l

01

22

2=

n

ie

niSi f

Dkc

dx

fd l

lzx =

iS

ii c

cf =




Averaging

LDF

cicis

qis qis

qi(R)

=Rq

RRR

Dt

q ih

i

2

21

)(,

0,0

iiSp

i

cfqRRRq

R

====

) )(( ==== iiShiiShp

iiS

p

h

R

i

p

hi qqkqqR

DR

qqRD

Rq

RD

tq

pp2

1533




Choice of variables

00,

i

ii

i

ii q

qq

cc

c ==

i

ii cK

cKq

)1(1

+=

01 =++t

qcq

tc

zc

u iio

ioiii

KTKKTK

ci 1,1

1

=

= 11ztuT i

m




From model results to real life

eiS

obsDc

r 22 l= tanh=

0.1

1

0.1 1 10i

1

1/0

1

0.01 0.1 1 10 100

2




Obtaining useful relations between dependent variables

)()(

iiSe

es cc

HDTT =

0)(22

= iie cTkdz

cdD

0)()(22

=+ ie cTkHdz

Td

0,0 ===dzdT

dzdc

z i

siSi TTccz === ;,l

cisci(R)

cis

TsT(R)

Ts




+=++

=

+

==

+=+

2

2

2

2

2

2

2

2

2

2

2

2

)()(

;

)()(

yC

xCD

yuC

xuC

tC

yx

xv

yu

yxyv

xu

MODELS OF 10$, 100$ AND 1000$




10$ models:Equilibrium theory for adsorption columns

0)1(0 =++ tq

tc

zc

u iii

)(* iii cfqq ==

i

i

ish

cq

uu

+

=

11)(11 ' ii

cc

cf

utzu

ii

+

=

=

dispersive front compressive front




100$ models:Diffusion, convection and reaction in isothermal catalysts

reaction A B in slab catalysts

042 22

2= f

dxdf

dxfd

Sm

eS D

kl=

em D

v l0=

Thiele modulus

intraparticlePeclet number

)( 12

)12(1

)12(2 21

=

sh

esheshfxx

24 22

2,1Smm +=




21

21cothcoth

/1/1

=dc

S

Sd

tanh=

0=mwhen convection is not important

eS D

kl=




1000$ models:Computational Fluid Dynamics (CFD)

L

H

ux (y) 0.2 H

0.7 H

0.1 H

y

x




PROCESS SIMULATION




Increased diffusivity by convection



Increased diffusivity by convection



Perfusion Chromatography




Perfusion Chromatography

Old resin producer: Rohm & Haas2003 -criou Advanced Biosciences

Amberchrom chromatographic media, Amberlite XAD (biopharmaceuticals), Ambersynth CTC resin

New : PerSeptive Biosystems(1990)

Now Applied Biosystems




Chromatography Pioneers

V

A

R

1

e

f

d

ba

c

M. Tswett D. T. Day




Factors governing the behaviour of an adsorptive process

IntraParticle Convection

IntraParticle Diffusion

Film Mass Transfer

Hydrodynamics (RTD)

Equilibrium Data




Concept behind Perfusion chromatography

)(1~fDD ee =

1

10

100

1 10 100

De

De~

1/f( )

Enhancement factor for diffusivity due to convection, 1/f()




HETP= A + B/u + Cu

uCfuBAHETP )(++=




How to decrease intraparticle mass transfer resistance?




Porous materials

POROSHELL (Agilent Technologies)POROS packing Silica Monolith












SimulatedSimulated MovingMoving BedBed




Simulated Moving Bed - (SMB)




SMB Technology

Old : UOP(1961)Sorbex Processes: PAREX, SAREX, MOLEX

New : NovasepFirst SMB in pharmaceutical industry

(UCB Pharma, 1999)




Old and New

ParexProductivity 120 Kg/m3 hAdsorbent capacity 200 Kg/m3

Chiral separationsProductivity 1-10 Kg/m3 hAdsorbent capacity 10 Kg/m3




UOP Parex

AC=adsorbent chamber; RV=rotary valve; EC=extract column; RC=raffinate column.Lines: 2-desorbent; 5-extract; 9-feed; 12-raffinate.




NOVASEP-chiral separation

The largest unit in operation for chiral separations has only 6 columns (Blehault et al., AIChE Meeting, Chicago, March 2001).




SMB unit at

Licosep 12-26 (Novasep)




TMB concept

Desorbent(D)

Feed (A+B)

Extract(A+D)

Raffinate (B +D)

A B

liquid circulation

Zone 1 Zone 2 Zone 3 Zone 4

solid circulation

A A B

B

regeneration of the adsorbent

regeneration of the desorbent

desorption of B adsorption of A




SMB concept

Desorbent (D) Extract (A+D)

Feed (A+B) Raffinate (B+D)

Port switching direction

Desorbent (D)

Raffinate (B+D)

Extract (A+D)

Feed (A+B)

Zone 1

Zone 3

Z

o

n

e

4

Zone 2B more strong adsorbedA more strong adsorbed

Extract (A+D)Desorbent (D)

Feed (A+B)Raffinate(B+D)

Desorbent (D)

Extract (A+D)

Feed (A+B)

Raffinate(B+D)




SMB-TMB equivalence

Solid phase Liquid phase

SMB 0 jv

TMB = tLu cs sjj uvv = *




Concentration profiles in TMB

EE XX FF RR




SMB Cyclic steady state

00.20.40.60.8

11.21.41.61.8

2

0 50 100 150 200 250

t ( min)

c

(

g

/

l

)

0

0.5

1

1.5

2

0 1 2 3 4 5 6 7 8

c

,

g

/

l

E X F R

0%

50%

100%

B

0

0.5

1

1.5

2

0 1 2 3 4 5 6 7 8

c

,

g

/

l

E X F R

0%

50%

100%

A

0

0.5

1

1.5

2

0 1 2 3 4 5 6 7 8

c

,

g

/

l

E X F RE X F R

0%

50%

100%

A

0

0.2

0.4

0.6

0.8

1

1.2

0 50 100 150 200 250

t ( min)

c

(

g

/

l

)

A

B

EXTRACT

A

B

RAFFINATE




Design of SMBSeparation constraints - equivalent TMB

1>IAS

IAIqQcQ

1>IIBS

IIBIIqQcQ

1

modelling and simulation in chemical engineering-rodrigues_e14.pdf

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