Development of Novel CO2-Selective Membrane for H2 ...
Transcript of Development of Novel CO2-Selective Membrane for H2 ...
Development of Novel CO2-SelectiveMembrane for H2 Purification
W.S. Winston Ho
The Ohio State University, Columbus, OH
DOE Program Manager: Nancy L. Garland
ANL Technical Advisor: Thomas G. Benjamin
2004 Program Review, Philadelphia, May 24 - 27, 2004
This presentation does not contain any proprietary or confidential information.
Objectives
• Produce Enhanced H2 Product with <10ppm CO at High Pressure Used forReforming
• Overcome Fuel-Flexible Fuel ProcessorsBarrier L: H2 Purification/CO Clean-up
• Achieve Target: <10 ppm CO in ProductStream
Budget
• Total Funding for the Project
- $880,000 (10/01/01 – 09/30/04)
- DOE Share = $704,000
- Contractor Share = $176,000
• Funding for FY04 = $346,250
- DOE Share = $277,000
- Contractor Share = $69,250
Technical Barrier and Target
• DOE Technical Barrier for Fuel-FlexibleFuel Processors
- L: H2 Purification/CO Clean-up
• DOE Technical Target for Fuel-FlexibleFuel Processors for 2010
- < 10 ppm CO in Product Stream
Use CO2-Selective Membrane to:
• Remove CO2 for H2 Enhancement
• Drive Water-Gas-Shift (WGS) Reaction toProduct Side
CO + H2O H2 + CO2
• Decrease CO to <10 ppm via CO2 Removal
Approach
Fuel Processing with CO2-SelectiveMembranes for Fuel Cells
• Low Temperature CO2-Selective Membrane
• High Temperature CO2-Selective Membrane
Reformer
WaterGas
Shifter
Membrane Process
FuelCell
Hydrocarbon
H2
CO2
COH2O
H2
CO2
CO (Low)H2O
H2
CO2 (Trace)CO (Trace)
ReformerWGS
MembraneReactor
FuelCell
H2
CO2 (Trace)CO (Trace) Hydrocarbon
H2
CO2
COH2O
CO + H2O H2 + CO2
CO2-Selective Membranes by Incorporating Aminesin Polymer Networks … Facilitated Transport
Example: Polyvinylalcohol-Containing Amine Membrane
C
H
H
C
H
OH
C
H
H
C
H
OH
C
H
H
C
OH
H
C
H
H
C
OH
H
R3N
R3N
Membrane
R3N
CO2
R3N CO2CO2
+
H2
Project Safety
• CO Monitor / Alarm Installed Next to Membrane Unitsfor Personnel Safety
- Alarm Never Sounded So Far for >2.5 Years of Membrane Operations (MOs), Indicating Safe MOs
• N2 Purging Used in Ovens to Prevent CO / H2
Accumulation from Any System Leakage
- Ovens Provide Precise Temperatures for
Membrane Units for Accurate Exp. Measurements
- Locking Device Installed to Prevent N2 Purging
from Accidental Shutdown
• Membrane Units Housed in a Hood
- Locking Device Installed to Prevent Hood from
Accidental Shutdown
• Safety Vulnerability Techniques Used (HAZOP, FMEA)
Project Timeline 2001 2002 2003 2004 Task 4Q 1Q 2Q 3Q 4Q 1Q 2Q 3Q 4Q 1Q 2Q 3QPhase 1 1. Modeling Study to Show <10 ppm CO Feasible ___________
2. Synthesis of Novel Membranes ___________
Phase 2 3. Characterization of Membranes ____________ 4. Set-up of Lab Reactor ______ 5. Membrane Fabrication ____________ 6. Proof-of-Concept Demo ______
Phase 3 7. Set-up of Membr. Reactor _____ 8. Fabrication of Membrane Module/Device ___________ 9. Membrane Reactor Demo ____
Technical Accomplishments
• WGS Membrane Reactor Experiments Showed
< 10 ppm CO – Project Milestone Achieved
- Small Cell: Circular (Laboratory Membrane Cell)
- Big Cell: Rectangular with Well-defined Flow (7.5X Small Cell)
+ Data in Line with Model
• CO2 Removed Effectively to ~30 ppm
- In Line with CO2 Model Developed
• Membranes with High CO2/H2 & CO2/COSelectivities & High CO2 Flux Synthesized
• <10 ppb H2S Achieved Experimentally (Outside Project Scope)
- H2S Model Developed Shows This H2S
Achievable in Entrance Section
0
5
10
15
20
25
30
10 20 30 40 50 60 70 80
W t C t ti i F d (%)
Ex
it D
ry C
O C
on
c.
(pp
m)
40 cc/min
Feed
60 cc/min
Feed
6 cc/min
Feed
20 cc/min Feed
30 cc/min Feed
WGS Membrane Reactor Experiments
Showed < 10 ppm CO: Small Cell
Feed: 1% CO, 17% CO 2, 45% H 2, 37% N 2 (on dry basis)
150oC, 2.1 atm
CO2-Selective Membrane Reactor:Experiments and Modeling
H2 Feed CO2High H2 Product
Air, N2 or SteamAir with CO2
z = 0 7.8 in. (19.8 cm)
Big Cell
• Well-defined Gas Flow and Velocity• Suitable for Modeling and Scale-up
0
2
4
6
8
10
12
14
0 10 20 30 40 50 60 70
F d Fl R t ( / i )
Exit
Dry
CO
Co
nc. (p
pm
)
Model
Feed: 1% CO, 17% CO 2, 45% H2, 37% N2 (on dry basis)
150oC, 2 atm
WGS Membr. Reactor Experiments Showed
< 10 ppm CO in Line with Model: Big Cell
0
2
4
6
8
10
12
14
0 1000 2000 3000 4000 5000 6000 7000
C l l t d S V l it (GHSV h-1)
Exit
Dry
CO
Co
nc. (p
pm
)
150oC, 2 atm
Model
Calculated Space Velocity Based on
Experimental Data: Big Cell
1
10
100
1000
10000
0 10 20 30 40 50 60 70
Feed Flow Rates (cc/min)
Ex
it D
ry C
O2 C
on
c.
(pp
m)
CO2 Removed Effectively --
CO2 Concentration in Retentate
Feed: 1% CO, 19% CO 2, 43% H2, 37% N2 (on dry basis)
120oC, 1.6 atm, Big Cell
Sweep/Feed Molar Ratio = 1
Sweep: N2 or Steam
Model
Methanation Readily ConvertsCarbon Oxides to Methane
• Methanation (at ~160 – 180oC)
CO + 3 H2 CH4 + H2O
CO2 + 4 H2 CH4 + 2 H2O
• Important to Remove CO2 as Much asPossible before Methanation
• Exit CO Concentration < 5 ppm
H2S Removal Rate Expected to beFaster than CO2 Rate(Outside the Project Scope)
• CO2 Reaction via Mainly Carbamate Formation
2 R-NH2 + CO2 R-NH-COO- + R-NH3+
• H2S Reaction via Small Proton Transfer
… Very High Rate
H H + N NH+ + HS-
S
H2S
0
5000
10000
15000
20000
25000
30000
100 110 120 130 140 150
T t (oC)
Pe
rme
ab
ilit
y (
Ba
rre
rs)
CO2
H2S Has Higher Permeability than CO 2
2 atm
Feed: 50 ppm H2S, 1% CO, 17% CO2,
45% H2, 37% N2 (on dry basis)
(Outside the Project Scope)
1 Barrer = 10-10 cm3(STP)-cm/cm2-s-cmHg
H2S/H2 Selectivity Higher than
CO2/H2 Selectivity
0
200
400
600
800
1000
100 110 120 130 140 150
Temperat re (oC)
Se
lec
tiv
ity
vs
. H
2
2 atm
H2S
CO2
(Outside the Project Scope)
1.0E-24
1.0E-21
1.0E-18
1.0E-15
1.0E-12
1.0E-09
1.0E-06
1.0E-03
1.0E+00
1.0E+03
0 10 20 30 40 50 60 70
M d l L th ( )
Ex
it D
ry H
2S
Co
nc
. (p
pm
) 50 ppm Feed
2 ppm
Feed
5 ppm Feed
10 ppb
Modeling Shows <10 ppb H 2S
Achievable in Entrance Section (Outside the Project Scope)
0.01
0.1
1
10
100
5 10 15 20 25 30 35
F d Fl R t ( / i )
Exit
Dry
H2S
Co
nc. (p
pm
)
Feed with 1% CO, 17% CO2, 45% H2, 37% N2 (on dry basis)
120oC, 2 atm
Small Cell
H2S Removed Effectively: 50 ppm H2S Feed
(Outside Project Scope)
0
2
4
6
8
10
12
14
5 10 15 20 25 30 35
Ex
it D
ry H
2S
Co
nc
. (p
pb
)H2S Removed Effectively: 100 ppb H2S Feed
120oC, 2 atm
Small Cell
(Outside the Project Scope)
0.01
0.1
1
10
100
5000 10000 15000 20000 25000 30000
C l l t d S V l it (GHSV h-1
)
Exit
Dry
H2S
Co
nc. (p
pm
) 120 oC, 2 atm
Small Cell
Calculated Space Velocity Based on Exp. Data 50 ppm H2S Feed (Outdise the Project Scope)
Significant Interactions/Collaborations
• Work with Unitel Technologies / H2fuel onMembrane Scale-up
- Discussions with Auto Companies
• Collaboration with H2 Supplier for FuelCell Applications
• Presentations / Publications on
CO2-Selective Membranes
- 2 at AIChE 2003 Annual Meeting
- 6 Seminars at Universities / Companies
Responses to Reviewers’ Comments
• Recommend to Identify High-Temp Membrane
- Continued to Synthesize / Characterize
Membranes with Improved Thermal Stability
• Investigate Membrane Reactor Scale-up
- Built a Big Cell (7.5X Small Cell) with Well-
defined Flow Suitable for Modeling/Scale-up
- Showed Data in Line with Model Developed
• Generate a Detailed Model (Experimental)
- Developed WGS / CO2 Removal Models
- Showed Good Agreements between the
Models and Experiments
Future Plans
• Continue to Synthesize / CharacterizeMembranes with Improved Properties
• Investigate Membrane Stability
• Complete Membrane ReactorDemonstration
• Demonstrate <10 ppm CO via CO2
Removal and Methanation for Fuel Cells
• Look into More Active WGS Catalysts