Study on multiphase CO2 capture with immobilised activator ... cap network web files/N -...

Xiaohui Zhang & David W. Agar: Study on Multiphase CO2 Capture withImmobilised Activator

Study on Multiphase CO2 Capture with Immobilised Activator

Xiaohui Zhang*

David W. AgarUniversity of Dortmund

24th May 2005, Lyon

* Shell Global Solutions international B.V.

Gas/Liquid Treating & Sulphur Processes

Badhuisweg 3, 1031 CM [email protected]


�Conclusions & Outlook

Contents

�Experimental Results

- G/L/S

- G/S

- L/S

- G/S – S/L

�Introduction

- Motivation

- CO2-capture technologies


Theoretical Background

CO2 absorption in amine mixtures (conventional process)A

BS

OR

BE

R

DE

SO

RB

ER

FL

AS

H

Sweet Gas

Sour

Feed

Gas

Lean Amine

Rich Amine

Acid Gas

CO2 loading

pa

rtia

l p

ressu

re

MDEA

MEA

305Capacity (vol CO2/vol solution)

2.74700Kinetics (l mol-1 s-1)

MDEAMEA

Advantages

�High absorption rate

�High capacity

Advantages

�High absorption rate

�High capacity

corrosion

high energydemand



AB

SO

RB

ER

DE

SO

RB

ER

FL

AS

H

Sweet Gas

Sour

Feed

Gas

Lean Amine

Rich Amine

Acid Gas

Idea: Immobilisation of activators



AB

SO

RB

ER

DE

SO

RB

ER

FL

AS

H

Sweet Gas

Sour

Feed

Gas

Lean Amine

Rich Amine

Acid Gas

�CorrosionCorrosionCorrosionCorrosion




AB

SO

RB

ER

DE

SO

RB

ER

FL

AS

H

Sweet Gas

Sour

Feed

Gas

Lean Amine

Rich Amine

Acid Gas


�CorrosionCorrosionCorrosionCorrosion

�EnergyEnergyEnergyEnergy demanddemanddemanddemand


polystyrene, macroporous

diameter: 0.5 – 1.0 mm

density: 1.092 g/ml

active group:C

H

H

N

H

H

Immobilised Amine

Immobilisation of Primary Amine


Mechanisms for gas-liquid-solid system

gas �� liquid �� solid �� liquid gas �� solid �� liquid



solidliquidgas

H

H

N

H

H

N

H

H

N

CO2

MDEAH+ HCO3-

CO2

MDEA -OOC




CO2 CO2

H

H

N

H

H

N

H

H

N

-OOC

MDEAH+

MDEA

liquidgas

HCO3-



solidgas

H

R1

N

H

R1

N

H

R1

N

-OOCCO2

liquid

H

H

N

H

H

N

solid

H

H

N

-OOC

HCO3-MDEAH+

H2O

MDEA H


Experiments

aerated stirred tank

gas-solid fixed-bed

liquid-solid fixed-bed

Significant effect No effect

Periodic-operated fixed-bed


Gas inlet

Gas outletBaffle

Solution./

Suspension

Experiments in a Aerated Stirred Tank Reactor

� Diameter 15 cm

� Liquid height 15 cm

� Gas flow 2 l/min

� CO2 – Concn. 50 vol%

� Amine–Concn.0.25 M

� Solid fraction 8...10 vol%

� Stirrer speed 1000 rpm


0

0,2

0,4

0,6

0,8

1

0 20 40 60 80 100

time [min]

ou

tle

t/ i

nle

t c

on

ce

ntr

ati

on

[-

]

water

0

0,2

0,4

0,6

0,8

1

0 10 20 30 40 50 60 70 80 90 100

time [min]

ou

tlet/

in

let

co

nc

en

tra

tion

[-

]

water

Lewatit (400ml)

0

0,2

0,4

0,6

0,8

1

0 10 20 30 40 50 60 70 80 90 100

time [min]

ou

tle

t/ i

nle

t c

on

ce

ntr

ati

on

[-

]

water

Lewatit (400ml)

MDEA (0.25 M)

0

0,2

0,4

0,6

0,8

1

0 10 20 30 40 50 60 70 80 90 100

time [min]

ou

tle

t/ i

nle

t c

on

ce

ntr

ati

on

[-

]

water

Lewatit (400ml)

MDEA (0.25 M)

DEA (0.25 M)

0

0,2

0,4

0,6

0,8

1

0 10 20 30 40 50 60 70 80 90 100

time [min]

ou

tlet/

in

let

co

nc

en

tra

tion

[-

]

water

Lewatit (400ml)

MDEA (0.25 M)

MDEA (0.2 M) + DEA (0.05 M)

0

0,2

0,4

0,6

0,8

1

0 10 20 30 40 50 60 70 80 90 100

time [min]

ou

tlet/

in

let

co

nc

en

tra

tion

[-

]

water

Lewatit (400ml)

MDEA (0.25 M)

MDEA (0.2 M) + DEA (0.05 M)

MDEA (0.2 M) + Lewatit (400 ml)

Results of the Aerated Stirred Tank Reactor



gas-solid fixed-bed




Experiments


Experiments in a Gas-Solid Fixed-Bed Reactor

� Diameter: 4 mm

� Length: 1.1 m

� Porosity: 0.78 � Temperature: 25 - 55 °C

� Gas flow rate: 0.01~0.07 m/s

� CO2- Concentration: 4~20 vol%

Helium, CO2

Lewatit


Results of the Gas-Solid Fixed-Bed Reactor

0

2

4

6

8

10

12

0 60 120 180 240 300Time [min]

Con

ce

ntr

atio

n C

O2 [

vo

l%]

25 °C

40 °C

55 °C

0

2

4

6

8

10

12

0 60 120 180 240 300Time [min]

Con

ce

ntr

atio

n C

O2 [

vo

l%]

25 °C

40 °C

55 °C

CO2 and Lewatit react

almost

instantly



gas-solid fixed-bed




Experiments


Experimental Setup W

ate

r

MD

EA

Sample collector

CO2

Fix

ed

-bed

Dete

cto

r1

Detector2

T : 20 / 25 / 30 °CV : 1.2 L T1 :15 / 20 / 25 °C

V : 34.5 mlL : 11 cmD : 2 cm

Input signal

output signal

Experiments in a Liquid-Solid Fixed-Bed Reactor


Results of the Liquid-Solid Fixed-Bed ‘Adsorption’

0

0.2

0.4

0.6

0.8

1

0 50 100 150 200 250 300

time [min]

rati

o o

f o

utl

et

to i

nle

t co

ncn

. [-

]

0

0.2

0.4

0.6

0.8

1

100% CO2

70% CO2

50% CO2

SimulationSimulationSimulation

25 °C

Influence of Concentration



gas-solid fixed-bed




Experiments


Evaluation

Measured kinetic parameters at 298 K

2.3

6.2

1458

instantaneous

Keff a(10-4 1/s)

Rate-limiting5.6Desorption/regenerationSolid-liquid

Rate-limiting15.4AdsorptionLiquid-solid

Slow3600AbsorptionGas-liquid

InstantaneousinstantaneousAdsorptionGas-solid

assessmentkeff

(10-8 m/s)Mass transfer process

2.3

6.2

1458

instantaneous

Keff a(10-4 1/s)

Rate-limiting5.6Desorption/regenerationSolid-liquid

Rate-limiting15.4AdsorptionLiquid-solid

Slow3600AbsorptionGas-liquid

InstantaneousinstantaneousAdsorptionGas-solid

assessmentkeff

(10-8 m/s)Mass transfer process



CO2 CO2

H

H

N

H

H

N

H

H

N

-OOC

MDEAH+

MDEA

liquidgas

HCO3-

CO2

H

H

N

H

H

N

H

H

N

-OOC

MDEAH+

MDEA

liquid

gas

-OOC

solid

HCO3-

HHHH2222OOOOHHHH2222OOOO


CO2 CO2

H

H

N

H

H

N

H

H

N

-OOC

MDEAH+

MDEA

liquidgas

HCO3-

CO2CO2 CO2

H

H

NH

H

N

H

H

NH

H

N

H

H

NH

H

N

-OOC-OOC

MDEAH+MDEAH+

MDEAMDEA

liquidgas

HCO3-HCO3-

CO2

H

H

N

H

H

N

H

H

N

-OOC

MDEAH+

MDEA

liquid

gas

-OOC

solid

HCO3-

CO2CO2

H

H

NH

H

N

H

H

NH

H

N

H

H

NH

H

N

-OOC-OOC

MDEAH+MDEAH+

MDEAMDEA

liquid

gas

-OOC-OOC

solid

HCO3-HCO3-

HHHH2222OOOOHHHH2222OOOO

Mechanism

SlowerSlower FasterFaster

New absorber concept

slow

limiting

limiting limiting

instantaneous

Comparision of the two mechanisms


Periodic Trickle Bed

� Periodic operation of trickle bed

H

H

N

H

H

N

H

H

N

gas solid

CO2

-OOC

Sour feed gas

Sweet gasLean amine

Rich amine

H

H

N

H

N

H

H

N

liquid solid

-OOC

MDEAH+ HCO3-

MDEA

Immobilised

Amine

time

Flo

w ra

te time

Flo

w ra

teH


Results of the Periodic-Operated Fixed-Bed Reactor

0 5 10 15 20 25 30 35 40 45

0.0

0.2

0.4

0.6

0.8

1.0

uG= 0,06 ms

-1, u

L= 31,4 m

3m

-2h

-1

p = 2,5 bar (Lewatit), ε = 0,60

p = 2,0 bar (Glass), ε = 0,45

T = 25 °C

Ou

tpu

t/in

pu

t co

ncen

trati

on

[-]

Time [min]

Lewatit dP= 0,7-1,0 mm

Inert glass dP= 1,0 mm

the natural pulsing flow

regime —

marginal effect



gas-solid fixed-bed




Experiments

Why ?


Mass Transport Resistance of Liquid Film

CO2

A

CO2 A

A

A

A

CO2

CO2

1

CO2

2a

CO2

3

CO2

2b

CO2

A

Aquous CO2

Activator

Liquid

Liquid film

Liquid in pore

Solid

1 External mass transfer

2a

2a Internal mass transfer (pore diffusion)

3 “Adsorption”

2b Internal mass transfer (surface diffusion)

ChallengesChallengesChallengesChallenges

� three-phase system (gas-liquid-solid)

� higher mass transport resistance lies

in the liquid phase

ChallengesChallengesChallengesChallenges

� three-phase system (gas-liquid-solid)

� higher mass transport resistance lies

in the liquid phase


R

Film-pore diffusion model

Shrinking Core model

or Unreacted-core model

Yagi, S., and Kunii, D.

Chem. Eng. Sci., 16,364, 372, 380 (1961)

Levenspiel O.

Chemical Reaction Engineering, Wiley, New York, (1972)

dN/dt

Dpadsorbed region

liquid film

CO2

free region

concentration-front

kf

Cs

Cb

( )qCGr

CDr

rrt

Cppp ,

1 2

2ρε −

∂

∂

∂

∂=

∂

∂

( )qCGt

q,=

∂

∂

Mass balance in the particle:

R

p

p

pbb

bb

bb

r

CD

m

Rz

CV

z

CD

t

C

∂

∂

−

∂

∂−

∂

∂=

∂

∂

ρεε

32

2

Mass balance in the fixed bed:

;Rr = ( )R

pbfr

CDCCk

∂

∂=−

Boundary condition:


Results of Calculation

Measured kinetic parameters at 298 K

39.6

25.0

16.0

CO2 Conc. [mol/m3]

1.125

0.870

0.900

D_pore[10-9 m2/s]

5.5

6.0

4.0

k_film [10-5 m/s] 2D_pore

k_film.d

18.3

25.9

16.7

Bi =

Pore diffusion is more limiting than film mass transfer


gasgas

Centrifugal Absorber

Gas Flush

Centrifuge

Vacuum

� reactor diameter 20 mm

� reactor height 200 mm

� solid volume 35 ml

� adsorber temp. 25°C

� Gas flow rate 300 ml/min

� CO2 conc. 10-60 vol %


0 20 40 60 80 100 1200.0

0.2

0.4

0.6

0.8

1.0

Rati

o o

f o

utl

et

an

d i

nle

t C

on

c.

Time [min]

Flush

Centrifugal Reactor

Liquid phase on the surface and in the pore is rate-limiting step

Centrifuge can only make the liquid on the surface away

After vacuum the particle is totally free of liquid and reaction is much faster0 20 40 60 80 100 120

0.0

0.2

0.4

0.6

0.8

1.0

Ra

tio

of

ou

tle

t a

nd

in

let

Co

nc.

Time [min]

Flush

Centri.

0 20 40 60 80 100 1200.0

0.2

0.4

0.6

0.8

1.0

Rati

o o

f o

utl

et

an

d i

nle

t C

on

c.

Time [min]

Flush

Centri.

Vacuum


Summary

Summary

� Absorption can be accelerated by immobilised activators

� Centrifuge Reactor can only remove the surface liquid

� Idea : Hydrophobic Immobilised Sterically Hindered Amines

� Higher mass transfer resistance in the liquid phaseLiquid

gas

Liquid

gasgas

bubble columnbubble column


PI

double chamber mixed-cell

gas-solid fixed-bed



periodically operated fixed-bed


PI


gas-solid fixed-bed



periodically operated fixed-bed

aerated stirred tankaerated stirred tank

PI


PIPI


gas-solid fixed-bedgas-solid fixed-bed

liquid-solid fixed-bedliquid-solid fixed-bed


periodically operated fixed-bedperiodically operated fixed-bed

� Chemical ‚shuttle‘ mechanism via carbamate formation

� Enhancement of carbamate hydrolysis necesssary

� Wettability Modification of Immobilised Amine


Diplom- & Masterstudenten:

Jan MackowiakNuthakki Seshagiri Rao

Yozi Bastian

Acknowledgement

Techniker:

Micheal Schlüter

Julian Gies Max-Buchner Stiftungen

Research group:

Prof. Dr. Agar

Dr. M. Grünenwald

Dr. SchubertM.Sci. Yudy Tan


EndEndEndEndThanks for your attention!Thanks for your attention!Thanks for your attention!Thanks for your attention!

Thanks!

[email protected]@[email protected]@Shell.com


Energy Map in the IA System

2~ 60 /kJ mol CO

2CO

Exothermic

22RNH

m o lkJ /85HR

≈∆ Endothermic

3RNH RNHCOO

+ -

MDEA

3MDEAH HCO

+ -+

2CO

Heat

Endothermic2CO

Study on multiphase CO2 capture with immobilised activator ... cap network web files/N -...

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