MODELLING OF SLURRY ABSORBER FOR BIOMIMETIC CO2...
Transcript of MODELLING OF SLURRY ABSORBER FOR BIOMIMETIC CO2...
MODELLING OF SLURRY ABSORBER
FOR BIOMIMETIC CO2 CAPTURE
Maria Elena Russo, Piero Bareschino, Giuseppe Diglio, Giuseppe
Olivieri, Riccardo Chirone, Piero Salatino, Antonio Marzocchella
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
Introduction: biomimetic CO2 capture
The biomimetic approach is the adoption of Carbonic anhydrase as industrial biocatalyst for the
enhancement of CO2 absorption rate in aq. solutions
2 2
2 2
2 2
2 2
[ ] [ ]* [ ]
[ ]* [ ]
[ ] [ ]* [ ]
e e
H O H O
OH OH
r k CA CO CO
r k CO CO
r k OH CO CO
- -
2 3CO + OH HCO
- +
2 2 3CO + H O HCO + H
Parallel reactions in aq. phase
Catalysed by
carbonic anhydrase
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
Introduction: bioreactor design
Technical solutions for the adoption of CA as industrial biocatalyst (Russo
et al. 2013, Sep Pur Technol)
•Random and structured packing columns (Fradette and Ceperkovic, 2008 Patent
n° US2008/0148939)
•Spray columns (Fradette, 2004 Patent n°WO2004/056455A1, Bhattacharya, et al.
2004 Biotechnol Bioeng)
•Membrane systems (Trachtenberg et al. 2001 Energy Proc.)
•Monolith in Taylor regime (Iliuta and Larachi, 2012 Sep Pur Technol)
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
Main issues related with selection of a reactor configuration
Counter-current gas-liquid flows
Maximization gas-liquid interface
Enzyme immobilization/entrapment on/in solid phase
Optimization of heterogeneous catalysis in chemical absorption:
Enzyme catalysis close to the g-l interface
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
Introduction: bioreactor design
Aim of the work
Development of a theoretical model for the assessment of performances of
heterogeneous biocatalyst based on immobilized CA in the enhancement
of CO2 absorption under typical CCS operating conditions
Development of a mathematical model of slurry absorber for biomimetic
CO2 capture
Selection of reactor configuration: staged bubble column
Model computation
Comparison of different reactor configurations and biocatalyst types
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
Model assumptions and equations
Staged Counter-current gas-liquid flows
Bubble
Column
Slurry
Zahradnik, J. (2001) in Multiphase Bioreactor Design. Ed.
Cabrai, J. M. S., Mota, M., Tramper J. CRC Press 1-23
ID= 0.29 m
H=2m
6 stages
(perforated plates)
Stage height 0.3 m
Enzyme immobilization/entrapment
on/in solid fine particles
Optimization of heterogeneous
catalysis in chemical absorption
Maximization gas-liquid interface
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
Model assumptions and equations
Gas IN
yIN
Gas OUT
yOUT
Liq IN
Liq OUT ith stage
Sta
ge
d S
lurr
y B
ub
ble
Co
lum
n
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
Model assumptions and equations
Liquid phase
KHCO3/K2CO3 sol
(K2CO3 20%wt)
L=2.6 10-4 m3/s
Gas phase
CO2 10%vol
N2 90%vol
G=1.7 10-3 m3/s
Isothermal operation @ 25°C
Total volume V=1.32 10-2 m3
Homogeneous catalysis by
free carbonic anhydrase
Heterogeneous catalysis by slurry
immobilized carbonic anhydrase
Sta
ge
d S
lurr
y B
ub
ble
Co
lum
n
Stable and uniform gas distribution for the particular plate geometry
kL= 5.1 – 4.6 m/s a= 194 – 108 m-1 eg= 0.28 – 0.16
Bubble diameter 0.7 10-3<db<1.1 10-2 m Zahradnik, J. (2001)
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
Overall stoichiometry 2
2 3 2 32CO CO H O HCO
Chemical reactions occurring in liquid phase
2 2 3CO H O HCO H
2 3CO OH HCO
Spontaneous CO2 hydration
and catalysed by
free enzyme
slurry immobilized enzyme
CO2 hydroxylation
Bicarbonate dissociation
Solvent dissociation
Model assumptions and equations
Kinetic models
1 1
1
d i i
i i i i
w hr c w h k c
K
, ,
2
3
3
i
i
i
i
i
CO c
HCO w
CO z
H h
OH oh
2
2 2
1
H Od
i i i i i i
Kr c w oh k c oh w
K
, ,
equilibrium
1
d i i
e i i i e i
w hr c w h k CA c
K
, ,
1
d i i
e imm i i i s s e iimm
w hr c w h k CA c
Ke
_
, ,
ith stage
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
2
3 3CO H HCO
2H O OH H
Model assumptions and equations
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
1 1 1 10
i i i i i i i i
PGY Y L C C L W W L Z Z
RT
Overall carbon balance
Equations at each column stage
Liq
uid
(slu
rry)
bulk
L
iqu
id (
slu
rry)
bo
un
da
ry la
ye
r
2
2
1 220, , , , , ,i
CO i i i i i i e i i i
d cD r c w h r c w oh r c w h
dx
23 3
2 2
1 22 20, , , , , ,i i
i i i i i i e i i iHCO CO
d w d zD D r c w h r c w oh r c w h
dx dx
0 0 1
ii i
i
YPx c x c C
He Y
( ) ( )
2[ ]i i i i
h K w z oh
2i i
i
z hK
w
2H O i iK oh h
2 1 1 2
0, , , , , ,iCO i i SL i i i i i i e i i i
x
dcVaD L C C Va r C W H r C W OH r C W H
dx
e
23 3
1 1 1 2 0, , , , , ,i ii i i i SL i i i i i i e i i iHCO CO
x x
dw dzVaD L W W VaD L Z Z Va r C W H r C W OH r C W H
dx dx
e
2[ ]i i i i
H K W Z OH
2i i
i
Z HK
W
2H O i iK OH H
CO2 mass balances
3
0
0 ii iHCO
x
dwD w W
dx
( )
HCO3/CO3 mass balances Electroneutrality condition Chemical equilibrium
conditions
The system of algebraic/differential equation
was computed using the commercial software
package Comsol Multiphisycs®
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
Fink, D. J (1973). Biotechnology & Bioengineering
Model results
i) pure solvent 20% wt K2CO3;
ii) solvent 20% wt K2CO3 plus free CA;
iii) solvent 20% wt K2CO3 plus immobilized CA.
CA solubility limit 100 mg/L
Wide spectrum of immobilized CA
• non-porous solid particles
• porous solid particles
• cross-linked enzyme aggregates
Preliminary assessment of
effectiveness factor for
heterogeneous biocatalyst
Cases
iii
CO2
concentration
mol/m3
ked=kcat/KM
m3/mol s
[CA]imm
mg/g es
s
kg/m3
rp
m DCO2/Deff
A
5 10-2
105 80 0.08
1200 10-6 10
0.2
B 50 0.02
0.4
C 5 104 50 0.5
D
104
80 0.08 0.4
E 50 0.02
0.8
F 1 0.9
Porous solid particles 10-6m
Irreversible M&M kinetics
Biocatalyst properties according to
Russo et al 2013 Chem Eng Transact
Model results
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
Concentration profiles in the Slurry Staged Bubble column
Case free CA
% captured CO2
73% 86%
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
Model results Concentration profiles in the Slurry Staged Bubble column
Case slurry biocatalyst
% captured CO2
51% 87%
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
Model results Concentration profiles in liquid boundary layer
Stage 1
Stage 6
Inert slurry Slurry biocatalyst
13TH INTERNATIONAL CONFERENCE MULTIPHASE FLOW IN INDUSTRIAL
PLANTS SESTRI LEVANTE (GENOVA), ITALY - 17-19 SEPTEMBER 2014
Conclusion and …
Theoretical results confirmed the beneficial effect of free CA catalysis on CO2
absorption in staged bubble column at CA concentration consistent with enzyme
solubility limit (100 mg/L).
The slurry biocatalyst considered provided the same CO2 capture %
obtained with homogeneous free enzyme catalysis
Detailed modelling of chemical absorption catalysed by free or immobilized
CA is required since the process can be classified as moderately fast chemical
absorption(2>Ha>4)
… next steps
Study of different reactor configurations (changing kL and gas hold-up)
Development of single particle model to assess effectiveness factor:
non linear enzyme kinetics, porous/non porous biocatalyst
Design of operating conditions of 60 L staged bubble column (national research
project PON 03 PE 00157 ‘Smart Generation’ )