Pre-Combustion Carbon Dioxide Capture by a
New Dual-Phase Ceramic-Carbonate
Membrane Reactor
Jerry Y.S. Lin (Principal Investigator)
School for Engineering of Matter, Transport and Energy
Arizona State University
Tempe, AZ 85287
DoE Project: DE-FE0000470
DoE Project Managers: Elaine Everitt
Arun Bose
Project Closeout Presentation
December 5, 2014
Project Background and Objectives
2
3
Project Overview
DOE Fund: $656,316 ASU Cost-Share: $164,088
PI’s summer
salary: $129K
Equipment: $35K Personnel &
etc: $586K
Equipment:
$70K
Funding:
Project Performance Dates:
Oct.1, 2009-Sept.31, 2014
Project Participants:
Arizona State University
Gasifier
Cryogenic
ASU
Coal
Oxygen
Cooler
Particulate
removal
Sulfur
removal
Steam
HT WGS
Reactor
Cooler LT WGS
Reactor
Amine
adsorber
Amine
CO2
Compressor
H2
GT Combustor
Electricity Power
Air
Compressor
Steam
𝑪𝑶 + 𝑯𝟐𝑶 𝑪𝑶𝟐+𝑯𝟐
→
→
CO2-Permeable Membrane Reactor for IGCC
with CO2 Capture
Gasifier
Syngas
CO2
Steam
𝑪𝑶 + 𝑯𝟐𝑶 → 𝑪𝑶𝟐+𝑯𝟐
WGS
H2
4
5
• Dry-reform of methane with CO2 separation
CHx+H2O High pressure H2
CO2
Applications of CO2 Perm-Selective Membranes
Hot flue gas
Steam or CH4 CO2/steam or syngas
CO2
“Clean” flue gas
CO+H2O
• Steam-reform of methane (SRM)
• Water gas shift reaction
CO2
0 100 200 300 400 500 600 700
1
10
100
1000
C
O2/N
2
Temperature (oC)
Silica Membranes
Carbon Membranes
Zeolite Membranes
• Microporous membranes made from silicas, carbons and zeolites are capable of separating CO2 from N2 at low temperature
• Ultrathin, ion exchanged Y-type zeolites are best candidates for low temperature separation
• CO2/N2 selectivity decreases with increasing temperatures
CO2 Perm-Selective Inorganic Membranes
7
Diffusion-Controlled Permeation
Diffusion
Dominating
(non-adsorbing, or
high temperature)
F = [Solubility][Diffusivity]
2
12/1
D
D
F = [1][Diffusivity]
At high temperature (>300oC) solubility difference diminishes:
1.1~
2
22
2
2/2
N
CO
N
CO
NCOD
D
F
F
M Kanezashi & YS Lin, J. Chem. Phys. C, 113, 3767(2009)
8
CO2+N2
CO3=
MOLTEN CARBONATE PHASE
DUAL-PHASE
MEMBRANE
CO2 + O= => CO3=
Upstream
High Pco2
Downstream
Low Pco2
O= O=
Metal Oxide Phase
CO2
Concept of Ceramic-Carbonate Dual-Phase Membrane
CO3= => CO2 + O=
M Anderson & YS Lin, Proc. ICIM2006, pp. 678-681 (2006)
9
1. Synthesize chemically/thermally stable dual-phase
ceramic-carbonate membranes with CO2 permeance and
CO2 selectivity (with respect to H2, CO or H2O) larger
than 5x10-7 mol/m2.s.Pa and 500;
1. Fabricate tubular dual-phase membranes and membrane
reactor modules suitable for WGS membrane reactor
applications;
2. Identify experimental conditions for WGS in the dual-
phase membrane reactor that will produce the hydrogen
stream with at least 93% purity and CO2 stream with at
least 95% purity.
Project Objectives
10
Technical Tasks
Task A Synthesis of Dual-Phase Membrane Disks
Task B Studying Permeation and Separation Properties
of Disk Membranes
Task C Synthesis of Tubular Dual-Phase Membranes
Task D Gas Separation and Stability Study on Tubular
Membranes
Task E Synthesis and WGS Reaction Kinetic Study of
High Temperature Catalyst
Task F Modeling and Analysis of Dual-Phase Membrane
Reactor for WGS
Task G Experimental Studies on WGS in Dual-Phase
Membrane Reactors
Task H Integration to IGCC and Economic Analysis
Task A
Synthesis of Dual-Phase Membrane Disks
11
12
Molten Carbonates
Li/Na/K Carbonate
Li/K Carbonate
Li/Na Carbonate
Na/K Carbonate
Composition (mol%)
43.5/31.5/25 62/38 52/48 56/44
Melting Point (oC)
397 488 501 710
CO3=
Conductivity (S/cm)
1.24 1.15 1.75 1.17
13
Oxygen Ionic Conducting Metal Oxide Supports
Material Abbreviation Structure
O= conduct-
ivity i
(600oC)
(S/cm)
Transfer
-ence
number
ti
LaCeGaFeAlO3 LCGFA Perovskite ~ 0.001 ~ 0.02
LaSrCoFeO3 LSCF Perovskite ~ 0.003 ~ 0.01
YZrO2 YSZ Fluorite ~ 0.004 ~ 1.0
CeSmO2 SDC Fluorite ~ 0.005 ~ 1.0
BiYSmO2 BYS Fluorite ~ 0.08 ~ 0.9
CO3= ~ 1.2 S/cm for molten carbonate at 600oC
Desired characteristics - High ionic conductivity - Long-term chemical stability
- Compatible with molten carbonate - Controllable pore size, porosity
14
Synthesis of Porous Ceramic Disks
Mix metal nitrate precursors in desired ratio in
water
Add excess citric acid and heat the covered
solution
Uncover solution and heat until a brick-red gel
remains; dry remnants
Self ignite remnants at 400C in an oxygen-rich
environment to remove the organics
Grind the powder and pre-sinter it
at 600C
Mix pre-sinterred metal oxide powder with PVA
solution
Place the metal-oxide and PVA mixture into a 30.0
mm stainless steel die-mold
Press the powder at 30 MPa for 1 minute, and
then 160 MPa for 4 minutes
Remove the disk from the die and dried at 40C
and 40% RH for 1 day
Sinter the support at about 900C
for 1 day
La0.6Sr0.4Co0.8Fe0.2O3-δ La0.85Ce0.1Ga0.3Fe0.6Al0.1O3-δ Ce0.8Sm0.2O2-δ
(LSCF) (LCGFA) (SDC)
powder disk
Carbonate Infiltration Method
Metal support pore
Molten carbonate
Capillary rise
Carbonate wettability on support surface
Buy SmartDraw!- purchased copies print this
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]1
[cosp
lvCr
P Capillary force drives carbonate to support during preparation or holds it in operation
Support pore size
16
Dual-Phase Membrane Characteristics
He permeance of support:
~ 10-6 mol/m2∙s∙Pa
XRD
After infiltration of carbonate:
- 25% weight increase
- He permeance: <10-10 mol/m2∙s∙Pa
(Li/Na/K)2CO3(43/32/25) LSCF- La0.6Sr0.4Co0.8Fe0.2O3-
The base support
- non-wettable to molten carbonate
- ionic-conducting 17
Thin Dual-Phase Membrane – the Concept
BYS or BYS-SDC
Asymmetric Porous Membranes
BYSYSZ BYS LSCF BYS40SDC60SDC
BYS = Bi-Y-Sm-O2
YSZ = Y-Zr-O2
SDC = Sm-Ce-O2
LSCF = La-Sr-Ce-Fe-O3
18
19
Carbonate Infiltration on Asymmetric Supports
BYS
YSZ
ALU
LSCF top layer peeled after infiltration
Carbonate penetrates to YSZ and ALU
supports
Only YSZ on BYS or SDC on BYS-SDC
work
0 20 40 60 80 100 1080 1140 1200
0
5
10
15
20
25
30
35
40
45
Weig
ht
ga
in a
fter i
nfi
ltrati
on
(%
)
Time (seconds)
d-YSZ/YSZ
d-YSZ/ALU
d-YSZ/BYS
Before Infiltration After Infiltration Weight gain infiltration contact time
20
High Temperature Permeation Schematic
• Membrane is sealed to alumina tube
– Pyrex™, LSCF6482, Al2O3∙Na2O
• System is heated to 900C at 1C/min
• Gases fed:
– Feed: CO2, Ar (50 mL/min each)
– Sweep gas: Helium (100 mL/min)
• Measure the composition of the permeate using a GC (TCD)
High Temperature
Permeation Apparatus
1
2
3
5
4
4
4
7
1. CO2, 2. Ar, 3. He, 4. Mass Flow Controller, 5. Purge tube, 6. Feed tube, 7. Outer Tube,
8. Inner tube, 9. Membrane,10. Furnace, 11. Permeate out, 12. Retentate out, 13. GC
6
9
8
10
11
12
13
21
Carbon Dioxide Permeance
500 600 700 800 900
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
CO
2 F
lux (
mL
. cm
-2. m
in-1)
Temperature (oC)
SDC
LSCF
LCGFA
YSZ
BYS
Thin Film Membrane
(10-20 m)
Bulk Membrane
(1-1.5 mm)
• All ceramic supports infiltrated with Li/Na/K molten carbonate
• Feed CO2 concentration of 50% (YSZ tested with 25%)
• Feed and sweep flow rates of 100 mL.min-1
Name Ceramic Phase
YSZ Zr0.92Y0.08O2
BYS Bi1.5Y0.3Sm0.2O3
SDC Ce0.8Sm0.2O1.9
LSCF La0.6Sr0.4Co0.8Fe0.2O3-δ
LCGFA La0.85Ce0.1Ga0.3Fe0.6Al0.05O3-δ
Measured CO2 Permeance = 10-8-10-7 mol/m2.s.Pa
CO2/N2 =500-3000
22
Thin SDC-Carbonate Dual-Phase Membrane
500 550 600 650 700 750
1.0
2.0
3.0
4.0
5.0
6.0
7.0
Temp. = 550-700 oC
Upstream: 50% CO2/N
2
Downstream: FHe
=100 ml/min
CO
2 flu
x (1
0-3 m
ol/s
/m2 )
Temperature (OC)
0 30 60 90 120 150 180
5.0
5.5
6.0
6.5
7.0
7.5
Temp. = 700 oC
Upstream: 50% CO2/N
2
Downstream: FHe
=100 ml/min
CO
2 f
lux (
10
-3 m
ol/
s/m
2)
Time (h)
Surface Cross
Cross
After infiltration
150 μm
Maintain stable 180 h 1 mL.cm-2.min-1
Carbon Dioxide Permeation Flux
500 600 700 800 900
1E-7
1E-6
1E-5
1E-4
1E-3
0.01
0.1
thin YSZ
thin SDC
SDC
SDC65MC35
BYS
LSCF
LCGFA
CO
2 f
lux
(m
ol/
s/m
2)
Temperature (oC)
23
Task B Studying Permeation and Separation
Properties of Disk Membranes
24
25
High Temperature CO2 Permeation Measurements
Sweep
Gas
Feed Gas
Atmospheric Feed The membrane is sealed
with silver rings or glass seal
Probostat
module
CO2 50 ml/min
N2 50 ml/min
Helium 100 ml/min
Ramping rate 1 C /min
Testing Temp. 450 ～650 C
Experimental conditions
He or Ar
N2
CO2
Permeation
cell
Data analysis
GC
vent
The membrane is sealed in
the cell with graphite gaskets
High Temperature CO2 Permeation Measurements
High Pressure Feed
26
Carbon Dioxide Permeation Flux - Theory
Total
conductance Membrane
thickness
Experimental
conditions
𝑇 =𝑝σ𝐶 𝑠𝜎𝑖
𝑝𝜎𝐶 + 𝑠𝜎𝑖
Carbonate ion
conductivity oxygen ionic
conductivity
Pore or solid fraction to tortuosity ratio for
carbonate and ceramic phase
𝐽𝐶𝑂2 = σ𝑇𝑅𝑇
4𝐹2𝐿
𝑃′𝐶𝑂2𝑃"𝐶𝑂2
𝑑𝑙𝑛𝑃𝐶𝑂2
𝐽𝐶𝑂2 =
σ𝑇𝑅𝑇
4𝐹2𝐿𝑙𝑛
𝑃′𝐶𝑂2𝑃"𝐶𝑂2
constant σT
27
Conductivity Dependence of CO2 Permeation Flux
28
SDC
LSCF
LCGFA
Feed: 50:50 CO2:N
2 (100 mL
.min
-1)
Sweep: Ar (100 mL.min
-1)
700 750 800 850 900
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
CO
2 F
lux
(m
L. c
m-2
. min
-1)
Temperature (oC)
0
2
4
6
8
10
CO
2 P
erm
ea
nc
e (
mo
l. m-2
. s-1
. Pa
-1)
CO3= conductivity for (Li/Na/K)2CO3
SDC
SDC
LSCF
LSCF LCGFA
LCGFA
Feed: 1:1 CO2;N2 (100 mL/min)
Sweep: Ar (100 mL/min)
CO2 permeation flux is mainly controlled by oxygen ionic
conductivity of ceramic phase
1.5 mm thickness
Activation Energy:
60-90 kJ/mol
CO2 Permeation Flux Conductivity
Ceramic Supports of Different Structure La0.6Sr0.4Co0.8Fe0.2O3- (LSCF)
Morphology of the supports prepared at
different sintering temperature
900oC 1000oC
1100oC 1200oC
Porosity and He permeance of the supports
prepared at different sintering temperature
29
Pore and Solid Structure of Ceramic Support
He permeation to measure pore structure Electrical conductivity of porous and
dense LSCF ceramic for solid phase
structure Intercept
Slope
988.8
2 LM w
Pore
p
i
s
Solid
S
Pore (carbonate) fraction to tortuosity ratio Solid fraction to tortuosity ratio
400 500 600 700 800 900
0
20
40
60
80
100
120
0.5
0.6
0.7
0.8
0.9
1.0
Geometric Correction Factor
Porous LSCF
Co
nd
ucti
vit
y (
S/c
m)
Temperature ( oC)
Dense LSCF
Geo
metr
ic C
orrecti
on
Fa
cto
r
30
Characteristics of Pore (Carbonate) and Solid Structure
Support
Sample
Number
Sintering
temp for
preparing
support (oC)
Solid (pore)
fraction
(ε)
Solid
fraction to
tortuosity
ratio S
Pore (carbonate)
fraction to
tortuosity ratio p
LSCF-900 900 0.47 (0.53) 0.11 0.16
LSCF-1000 1000 0.54 (0.46) 0.26 0.18
LSCF-1050 1050 0.64 (0.36) 0.59 0.041
LSCF-1100 1100 0.77 (0.23) 0.82 0.013
Used to calculate the total conductance
31
Effect of Pore Structure on CO2 Permeance
LSCF-Carbonate Membrane, 1.5 mm thick
32
How CO2 Flux Depends on Pressures?
𝐽𝐶𝑂2 = σ𝑇𝑅𝑇
4𝐹2𝐿
𝑃′𝐶𝑂2𝑃"𝐶𝑂2
𝑑𝑙𝑛𝑃𝐶𝑂2
PO2=PCO2q Depends on gas phase reaction
equilibrium or mass balance
σT ~σi=koPO2m
with k′=kom
mq
General Flux Equation:
constant σT
Depends on defect reaction equilibrium between gas
phase and ceramic phase
𝐽𝐶𝑂2 =𝑘′𝑅𝑇
4𝐹2𝐿[ 𝑃′𝐶𝑂2
𝑛 −(𝑃"𝐶𝑂2)n]
𝐽𝐶𝑂2 =σ𝑇𝑅𝑇
4𝐹2𝐿𝑙𝑛
𝑃′𝐶𝑂2𝑃"𝐶𝑂2
33
CO2 Permeation of Thick SDC-Carbonate Membrane
0.0 0.4 0.8 1.2 1.6
0
1
2
3
4
5
6
7
900oC, n=0.125
700oC, n=0.5
P'
CO2
n-P
"
CO2
n (atm
n)
CO
2 f
lux
(1
0-3 m
ol/
s/m
2)
SDC-carbonate disk
membrane, 1.5 mm thick;
1 mL.cm-2.min-1
34
35
0.0 0.2 0.4 0.6 0.8 1.0
0.0
2.0
4.0
6.0
8.0
10.0Temp. = 700
oC
Upstream: 10-90% CO2/N
2
Down stream: FHe
=100 ml/min
CO
2 f
lux (
10
-3 m
ol/
s/m
2)
P'
CO2
(atm)
8 10 12 14 16
6.0
7.0
8.0
CO
2 f
lux
(1
0-3
mo
l/s/m
2)
P"
CO2
(103atm)
Temp. = 700 oC
Upstream: 50% CO2/N
2
Downstream: FHe
= 75-175 ml/min
0.0 0.2 0.4 0.6 0.8 1.0
0
2
4
6
8
10
n = 0.5
Temp. = 700 oC
CO
2 f
lux
(1
0-3
mo
l/s/m
2)
(P'
CO2
n-P
"
CO2
n ) (atm
n)
FHe PCO2”
75 0.015
100 0.013
125 0.011
150 0.0098
17 5 0.0086
PCO2’ PCO2”
0.1 0.0049
0.25 0.0082
0.375 0.011
0.5 0.013
0.625 0.015
0.75 0.017
0.9 0.018
Thin 150 μm SDC-carbonate
Membrane
CO2 Permeation of Thin SDC-Carbonate Membrane
1 mL.cm-2.min-1
36
Task C
Synthesis of Tubular Dual-Phase
Membranes
37
Preparation of Tubular SDC-Carbonate Dual Phase
Membranes
Centrifugal casting method
SDC suspension
after ball milling SDC green tube
Centrifugation
Drying Stainless steel tube
High speed motor
4000-4500 RPM
38
Inner surface
Cross section
Porosity: 30-45%
Porous SDC Tubes
39
SDC-carbonate membrane
Molten carbonate
Infiltration Removal of excess
carbonate
This process was operated at 550-600 oC
Porous SDC support
Ceramic crucible
Carbonate Infiltration of Tubular SDC Supports
Morphology of tubular dual-phase membrane
SDC tubes Inner surface Outer surface
Inner surface Outer surface
a-c: porous supports; d-f: dual phase membrane
Cross-section
40
Porosity: 30-45%
41
Preparing thin SDC layer on the inner surface of carbonate-non-wettable
porous SDC-BYS tubes
Preparation of Tubular Dual-Phase Membranes wih
Thin SDC-Carbonate Layer
Membrane tube with a dense inner SDC-carbonate layer
Carbonate infiltration
42
SDC-carbonate dual phase
membrane
SDC-BYS porous support
sintered at 1120 oC
BYS powders calcined at 900oC
SDC powders calcined at 900 oC
XRD Patterns of Tubular SDC-Carbonate in Various
Stages
43
Structure of Tubular SDC-carbonate Membrane
Ccross-section Surface
Before
carbonate
infiltration
After
carbonate
infiltration
Porous SDC-BYS
base
Porous SDC inner
surface layer
Task D
Gas Separation and Stability Study on Tubular and Disk Membranes
44
45
Experimental Setup for Tubular SDC-carbonate
Membrane
or CO2
Membrane module
Or membrane module for reaction
46
CO2/N2 separation
800 825 850 875 9000.0
0.1
0.2
0.3
0.4
0.5
0.6
Temperature (oC)
CO2 Flux
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
CO
2 F
lux (
mLc
m-2m
in-1
)
CO
2 P
erm
eance (
10
-7m
olm
-2s
-1p
a-1
)
CO2 Permeance
0.84 0.86 0.88 0.90 0.92 0.94
-17.25
-17.00
-16.75
-16.50
-16.25
Ln (
CO
2 P
erm
eance)
1000/T (T in K)
Ea=81.2 KJmol-1
Feed side: CO2 flow rate 25 ml·min-1, N2 flow rate 25 ml·min-1;
Sweep side: He flow rate 50 ml·min-1
CO2 Permeation and Separation Performance
SDC tubular dual-phase membrane: membrane thickness 1.5 mm
CO2/N2 selectivity > 200
47
CO2 separation from simulated syngas
800 825 850 875 9000.0
0.1
0.2
0.3
0.4
Temperature (oC)
CO2 Flux
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
CO
2 F
lux (
mLc
m-2m
in-1
)
CO
2 P
erm
eance (
10
-7m
olm
-2s
-1p
a-1
)
CO2 Permeance
Feed side: simulated syngas (49.5% CO, 36% CO2, 10% H2 and 4.5% N2)
Thickness of the membrane is about 1.5 mm.
0.84 0.86 0.88 0.90 0.92 0.94
-17.25
-17.00
-16.75
-16.50
-16.25
-16.00
Ln (
CO
2 P
erm
eance)
1000/T (T in K)
Ea=89.62 KJmol-1
CO2 permeation flux similar to CO2/N2 feed
CO2 Permeation and Separation Performance
Feed side: flow rate 50 ml·min-1
Sweep side: He flow rate 50 ml·min-1.
CO2/N2 and CO2/H2 selectivity is about 2200 and 65
Measured CO2/N2 Selectivity for Dual-Phase
Membranes
48
Membrane Permeation and Chemical Stability
0 10 20 30
0.0
0.2
0.4
0.6
0.8
SDC-carbonate
900oC, 1.0 mm thick
50% CO2 feed with feed and sweep flow of 100 mL
.min
-1
LSCF-carbonate
850oC, 1.5 mm thick
CO
2 F
lux
(m
L. c
m-2
. min
-1)
Days
• LSCF-carbonate membrane was tested for 4 days
• SDC-carbonate was tested for one month at 900oC
49
Membrane Stability – Permeation Flux
Feed: CO2, CO, H2 , N2, H2O
He
CO2
0 5 10 15 20 25 30 35
0.0
0.1
0.2
0.3
0.4
0.5
(b)
(a)
JC
O2 (
mL
. cm
-2. m
in-1)
Days
• SDC-carbonate membrane, 1.5 mm
• Feed and sweep flow rates: 50 mL.min-1
• Separation temperature: 700oC
Feed P(total)=5 atm, P’CO2=1.8 atm
Feed P(total)=1 atm, P’CO2=0.35 atm
20 30 40 50 60 70 80
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
(420
)
(331
)
(400
)
(222
)
(311
)
(220
)
(200
)
Re
lati
ve
In
ten
sit
y
2
Sweep
Feed
(111
)
XRD after 35 day stability test
50
Task E Synthesis and WGS Reaction Kinetic Study of High Temperature Catalyst
51
WGS Catalyst and Kinetic Study
WGS catalyst
- Testing temperature: 500oC - Pressure in the fixed bed: 101 kPa
- Total gas flow rate: 80 cc/min
52
Catalyst: Fe-Cr-Cu spinel oxide catalyst (atomic ratio of 10:1:0.25) was
prepared following the published procedures*
* Reddy GK, Gunasekera K, Boolchand P, Dong J, Smirniotis PG. J Phys Chem C 115 (2011)7586–95.
Differential Fixed-Bed Reactor for Kinetic Study :
WGS Catalyst Kinetics
)1
1()18.288
exp(
2
22053.0
2
163.0
2
33.0
2
89.0
'
OHCO
COH
e
HCOOHCOPP
PP
KPPPP
TRKR
Regressed Reaction rate (mol g-1 s-1):
Ke: Equilibrium constant of WGS reaction
)1
1()1(
2
22
OHCO
COH
e PP
PP
K
𝐾𝑒 = exp(4577.8
𝑇− 4.33)
53
WGS reaction rate
on catalyst was
obtained at
different partial
pressure of
reacting or product
gases
Task F Modeling and Analysis of Dual-Phase Membrane
Reactor for WGS
54
Modeling Dual-phase WGS Membrane Reactor
H2, H2O
CO2
CO2
CO2 CO2 CO2 CO2 CO+H2+CO2+H2O CO2
55
Z
- Packed with WGS catalyst, has to be operated at
lower temperature (<500oC); Low CO2
permeance for the membrane
- Catalyst-free, operated at high temperatures
(>800oC); High CO2 permeance for membrane #
Model to find
Ci=f(z) and then at
reactor exit
# Homogeneous high temperature WGS: F. Bustamante, R.M. Enick, R.P. Killmeyer, B.H. Howard,
K.S. Rothenberger, and A.V. Cugini, B. D. Morreale M.V. Ciocco, Uncatalyzed and wall-catalyzed
forward water–gas shift reaction kinetics, AIChE J., 51 (2005) 1440.
Mathematical Model
Mass balance on the reaction (tube) side:
iiiB
i PRFRdz
dq 22
qi ( i= CO, H2O, CO2, H2, N2 ) = molar flow rate in the tube side,
vi = stoichiometry of species i in WGS reaction, vN2 = 0,
Fi = permeance for species i
Pi = transmembrane partial pressure difference of species i
= reaction rate for WGS.
Mass balance on sweep (shell) side
ii PRFdz
dQ 2i Qi = molar flow rate in the shell side.
𝐽𝐶𝑂2 = 𝑘′ ·𝑅𝑇
4𝐹2𝐿· (𝑃𝐶𝑂2
′ 𝑛− 𝑃𝐶𝑂2
′′ 𝑛) 𝐹𝐶𝑂2 =
1
𝑃′𝐶𝑂2
−𝑃"
𝐶𝑂2
σ𝑇𝑅𝑇
4𝐹2𝐿
𝑃′𝐶𝑂2𝑃"𝐶𝑂2
𝑑𝑙𝑛𝑃𝐶𝑂2
Gas permeance or flux through the membrane:
For CO2
For other gases
Fi=0
56
Mathematical Model
WGS Reaction Kinetic Equation:
- On catalyst (heterogeneous WGS) (slide 53)
- Catalyst-free WGS (homogeneous WGS)*
𝛾 = 𝐹𝑘𝑓[𝐶𝑂]
0.5[𝐻2𝑂](1 −𝐶𝑂2 [𝐻2]
𝐾𝑒𝑞[𝐶𝑂][𝐻2𝑂])
Model equation solved by Matlab to Find
CO conversion
(%)100(%)0
0
CO
COCOCOCO
q
QqqX
(%)100(%)0
0
CO
COCOCO
q
qqX
Membrane reactor (MR)
Traditional reactor (TR)
(%)100(%)
22
2
2
COCO
CO
COQq
QY
CO2 recovery or capture
57 * Modified from F. Bustamante et al., AIChE J., 51 (2005) 1440
Reactor length: 1.0 cm Weight of catalyst is 0.4 g CO flow rate: 15 ml·min-1
H2O/CO ratio is 3.0 Sweep gas flow rate: 30 ml·min-1 Feed pressure is 5 atm.
Heterogeneous WGS in Dual-Phase Membrane Reactor
– Effect of Temperature and H2O/CO ratio
58
Simulations were performed with CO2 permeance = 30 x Measured
Otherwise the results of MR are same as TR
2 4 6 8 100.5
0.6
0.7
0.8
0.9
1.0
CO
co
nve
rsio
n o
r C
O2 r
eco
ve
ry
Feed pressure (atm)
CO conversion
CO2 recovery
2 4 6 8 103.5
4.0
4.5
5.0
5.5
6.0
6.5
Feed pressure (atm)
CO
2 p
erm
ea
tio
n f
lux (
mLc
m-2m
in-1
)
CO
2 p
erm
ea
nce
(1
0-7
mo
lm-2s
-1P
a-1
)
CO2 permeance
0
2
4
6
8
CO2 permeation flux
CO conversion and CO2 recovery as a
function of feed pressure
Heterogeneous WGS in Dual-Phase
Membrane Reactor – Effect of Feed Pressure
59
CO2 permeation flux and permeance as a
function of feed pressure
500 oC.
500 oC.
Homogeneous Catalyst-Free WGS in Dual-Phase
Membrane Reactor – Effect of Temperature
The feed pressure is 1 atm, H2O/CO ratio is 3.0
60
Homogeneous Catalyst-Free WGS in Dual-Phase
Membrane Reactor – Effect of Pressure and Flow Rate
0 5 10 15 20 25 30 35 400
20
40
60
80
H2 c
on
cen
trat
ion
in
th
e re
ten
tate
(%
)Feed pressure (atm)
CO
co
nv
ersi
on
, C
O2 r
eco
ver
y (
%) CO2 recovery
CO conversion
40
50
60
70
80
90
H2 concentration
Steam to CO ratio is 3.0; syngas flow rate 25
mL·min-1; syngas space velocity 19.89 min-1;
reaction temperature is 900 oC.
10 15 20 25 30 35 400
20
40
60
80
100
H2 c
once
ntr
atio
n i
n t
he
rete
nta
te (
%)
Syngas flow rate (mL/min)
CO
conver
sion, C
O2 r
ecover
y (
%)
CO2 recovery
CO conversion
40
50
60
70
80
90
100
H2 concentration
Syngas space velocity 7.96-31.83
min-1; Steam to CO ratio is 3.0;
reaction temperature is 900 oC;
feed pressure is 20 atm.
61
Task G Experimental Studies on
WGS in Dual-Phase Membrane Reactors
62
Temperature: 800-900 oC;
Feed, Sweep side pressure: 1 atm;
Catalyst: No;
Simulated syngas: 49.5% CO, 36% CO2, 10% H2 and 4.5% N2;
Feed side: Syngas flow rate 10-30 mL·min-1, N2 flow rate 10 mL·min-1,
steam to CO molar ratio 1.0-3.0;
Sweep side: He flow rate 60 mL·min-1.
Ceramic: SDC; Carbonate: Li2CO3/Na2CO3/K2CO3
OD: 1.1cm; ID: 0.8cm; Thickness: 1.5 mm; Effective length: 2.5cm.
Membrane
Reaction conditions
Experiments on High Temperature WGS Reaction
H2, N2, H2O
CO2
CO2
CO2 CO2 CO2 CO2 CO+H2+CO2+N2+H2O CO2
Simulated syngas
63
High Temperature WGS Reaction Setup
64
800 825 850 875 9000.0
0.1
0.2
0.3
0.4
Temperature (oC)
CO
2 P
erm
eati
on
Flu
x (
mLc
m-2m
in-1
)
900 oC, CO2 permeation flux 0.36 ml·cm-2·min-1;
CO2 permeation activation energy is 90.8kJ·mol-1.
0.84 0.86 0.88 0.90 0.92 0.94
-16.25
-16.00
-15.75
-15.50
-15.25
-15.00
Ln
(C
O2 f
lux
, m
olcm
-2s
-1)
1000/T (T in K)
CO2 Permeation Flux during WGS Reaction
65
800 825 850 875 9000
5
10
15
20
25
30
CO
2 r
ecov
ery
(%
)
CO
co
nv
ersi
on
(%
)
Temperature (oC)
CO conversion-MR
CO conversion-TR
0
5
10
15
20
25
30
CO2 recovery-MR
900 oC, CO conversion and CO2 recovery are 26.1% and 18.7%, respectively, in
membrane reactor (MR); CO conversion of traditional reactor (TR) is much lower.
WGS Performance – Effect of Temperature
Traditional reactor (no
membrane) (TR)
Membrane reactor
(MR)
66
CO conversion increases with steam/CO ratio, CO2 recovery decreases.
1.0 1.5 2.0 2.5 3.0 3.5 4.00
5
10
15
20
25
30
CO
2 r
eco
ver
y (
%)
CO
co
nv
ersi
on
(%
)
H2O/CO ratio
CO conversion
0
5
10
15
20
25
30
CO2 recovery
900 oC
67
WGS Performance – Effect of H2O/CO Ratio
10 15 20 25 300
5
10
15
20
25
30
35
40
CO
2 r
ecover
y (
%)
CO
conver
sion (
%)
Syngas flow rate (mLmin-1
)
CO conversion
0
5
10
15
20
25
30
35
40
CO2 recovery
900 oC
Both CO conversion and CO2 recovery decrease with increasing syngas flow rate.
68
WGS Performance – Effect of Syngas Flow Rate
0 20 40 60 80 100 1200
5
10
15
20
25
30
CO
2 p
erm
eati
on f
lux (
mLc
m-2m
in-1
)
CO conversion
CO recovery
0.0
0.2
0.4
0.6
0.8
1.0
Time (h)
CO
conver
sion o
r re
cover
y (
%)
CO2 permeation flux
Cycle Time
1 0-30 h
2 30-58 h
3 58-84 h
4 84-112 h
900 oC, CO conversion and CO2 recovery and CO2 flux maintain at around
26.2%, 18.4% and 0.36 mL·cm-2·min-1, respectively, for more than 110h.
High Temperature WGS Reaction in Membrane
Reactor - Stability
69
Between cycles:
900oC => RT => 900oC
(a) Outer surface (sweep side) (b) Inner surface (reaction side)
The surface of sweep side is slightly eroded, 1-2 μm;
The surface of reaction side is dense and the corrosion is not obvious.
Characteristics of Membrane after WGS Reaction
70
After 120 hr WGS Operation
XRD pattern of membrane after long-term operation
(b) Sweep side
(c) Reaction side
(a) Fresh membrane
Both reaction side and sweep side maintain full fluorite structure
20 30 40 50 60 70 80
Rel
ativ
e In
ten
sity
(a.
u.)
2-theta (degree)
S: SDC
SS
SS
SS
S
(c)
(b)
(a)
S
71
Characteristics of Membrane after WGS Reaction
Task H
Integration to IGCC and Economic
Analysis
72
Dual-phase membrane for CO2 capture
Gasifier
Syngas
CO2
Steam WGS
Use of Dual-Phase Membrane Reactor for
High Temperature WGS in IGCC
Steam
Gasifier
Cryogenic
ASU
Coal
Oxygen
Cooler
Particulate
removal
Sulfur
removal
Steam
HT WGS
Reactor
Cooler LT WGS
Reactor
Amine
absorber
Amine
CO2
Compressor
H2
GT Combustor
Electricity Power
Air
Compressor
30%H2, 40%CO,
20%H2O, 10%CO2
1450 oC, 50 bar
73
For best heat integration, the membrane reactor
might have be put closer to the gasifier
Optimizing WGS Membrane Reactor with CO2 Capture
Parameter Range Values used in the calculations
Inner diameter of membrane (cm) 0.5-0.1.5 0.8
Membrane length (cm) 50-200 100
Temperature (oC) 700-900 850
Feed coal syngas flow rate (mL·min-1) 10-1000 50-730
Feed dry composition (mol%)#
H2 10-40 29.8
CO 20-60 41.0
H2O 10-30 16.8
CO2 5-20 10.2
Feed steam to CO molar ratio (after added steam)
2-4 3
Feed pressure (atm) 10-40 10-40
Sweep flow rate (mL·min-1) 50-500 200
Sweep side pressure (atm) 1 1
Membrane
Dimension
and
WGS/CO2
Separation
Operation
Conditions
for a Single
Tube
Membrane
Reactor
# Composition of coal syngas from Texaco coal gasifier, with 0.3% CH4, 1.1% H2S, 0.8%N2 74
Multiple-Stage Membrane Reactor with CO2 Capture
75
76
Methodology for Design of Membrane Reactor and
Calculation of Membrane Area
Calculation Results
0 1 2 3 4 5 6 740
50
60
70
80
90
100
40 atm
30 atm
20 atm
10 atm
30 atm without sweep gas
Hyd
rog
en
co
nce
ntr
atio
n (
%)
Stage
93%
0 1 2 3 4 5 6 720
30
40
50
60
70
80
90
100
40 atm
30 atm
20 atm
10 atm
30 atm without sweep gas
Ca
rbo
n c
ap
ture
(%
)Stage
90%
Concentration of hydrogen (dry-based) in retentate from the final stage of the
multi-stage WGS membrane reactor and carbon capture operated under
various feed pressures at Qsyngas=300 mL/min
77
Optimized
Results
Parameter Value
Membrane
Inner diameter of membrane (cm) 0.8
Membrane length (cm) 100
Number of stages 2
Membrane area (based on average radius/inner radius) (cm2) 592/502
Operation Conditions
Operation Temperature (oC) 850
Feed syngas flow rate (mL·min-1) 205
Feed syngas composition (mol%)
H2 29.8
CO 41.0
H2O 16.8
CO2 10.2
Flow rate of total added steam to the feed (mL. min-1) 218
Feed pressure (atm) 30
Sweep steam flow rate (each stage) (mL·min-1) 200
Sweep side pressure (atm) 1
Reaction and Separation Performance
CO conversion % 90.0
Permeate total flow rate (mL·min-1) 495
CO2 concentration in the permeate (dry-based) (mol%) 100
Permeate composition (wet-based) (mol%) CO2 19.1
H2O 80.9
Carbon capture % 90.2
Retentate (product) total flow rate (mL·min-1) 323
H2 concentration in retentate (product) (dry-based) (mol %) 93
Retentate composition (wet-based) (mol%) H2 42.23
CO 2.6
H2O 54.6
CO2 0.5
Averaged CO2 permeation flux (mL.cm-2.min-1) 0.16 78
Integration with IGCC-Process I
79
80
Integration with IGCC-Process II
Cost Estimate for Membrane Reactor
Electric Powder Production Capacity 800 MW
Efficiency of IGCC 0.4
Higher Heating Value of Coal
12,774 Btu/lb
23,769.84 kJ/kg
Coal Consumption Rate (mass) 67.28 kg/s
Carbon content 60 %
Percentage of Carbon converted to CO2 85 %
Rate of CO2 produced 2,859.40 mol/s
CO2 Permeation Rate (90% Capture) 2,573.46 mol/s
Areas of Membranes (2 tube in series) 600 cm2
Membrane cost 500 $/m2
CO2 flux under optimum conditons for current membrane
0.2 cc (STP)/cm2.min
Estimate number of 2-tube-sieries 28,822,752
Total membrane area required 1,729,365 m2
Estimate membrane costs 864,682,560 $
81
82
CO2 perm-selective disk and tubular ceramic-carbonate membranes were fabricated:
- Perm-selective to CO2 (measured selectivity up to 3000)
- Chemically/thermally stable
- CO2 permeance in 0.5-5x10-7 mol/m2.s.Pa at 500-900oC
CO2 permeation mechanism and factors affecting CO2 permeation of the dual-phase membranes have been identified.
WGS reaction in the dual-phase membrane reactor was studied by modeling and experiments. Conditions to produce hydrogen of 93% purity and CO2 stream of > 95% purity, with 90% CO2 capture have been identified
Dual-phase membrane reactor can improve IGCC process efficiency but the membrane reactor is too expensive with membranes having current CO2 permeance.
Summary and Conclusions
83
Other Accomplishments
o Refereed Journals: 12 SCI Papers Published
o Presentations: 15
• Including ICIM2014 Plenary Lecture
o Patents: 1 US Patent Application Filed
o Ph.D. Students Trained: 3
• Matt Anderson
• Norton Tyler
• Bu Lu
o Post-Dr. Trained: 3
• Xueliang Dong
• Jose Ortis-Lenderos
• Zebao Rui
84
