new materials and process development for energy-efficient...
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New Materials and Process Development
for Energy-Efficient Carbon Capture in the
Presence of Water Vapor
Randy Snurr,1 Joe Hupp,2 Omar Farha,2 Fengqi You1
1Department of Chemical & Biological Engineering
2Department of Chemistry Northwestern University, Evanston, IL 60208
http://zeolites.cqe.northwestern.edu
Increasing Atmospheric CO2 Concentrations
http://www.esrl.noaa.gov/gmd/ccgg/trends/
Level in 1832 from
Antarctic ice cores:
284 ppm
Post-Combustion Carbon Capture
and Sequestration
World Resources Institute, www.wri.org
Goal: Remove CO2 from “flue gas” exiting a power plant with
• minimal energy usage
• minimal operating costs
• minimal capital cost
CO2 Capture
Currently, amine capture
processes would cause
~80% increase in cost of
electricity (COE).
The DOE goal is 35%.
• Flue gas is mainly
– N2
– CO2
– H2O
• Very challenging separation – Very large flow rates: A 400 MW pulverized coal power plant
produces • 1,000,000 m3/h of flue gas
• 2,200,000 tons of CO2 per year = 6000 tons per day
– Flue gas is at low pressure
• There are about 1100 coal-fired power plants in the U.S.
and 5000 worldwide.
CO2 Capture
Adsorption Separations
PSA, TSA, VSA
Adsorption separations
• are widely used in processes such as
air separation
• can be more energy efficient than
traditional distillation separations
A key issue is the choice of the adsorbent
Novel adsorbent
“Nanotechnology for Carbon Dioxide Capture,” R.R. Willis, A.I.
Benin, R.Q. Snurr, A.O. Yazaydin, in Nanotechnology for the
Energy Challenge, J. Garcia-Martinez, Ed., Wiley-VCH, 2010.
• The goal of this project is to develop new materials and new adsorption process
configurations for economical capture of 90% of CO2 from flue gas, with a particular focus
on circumventing or overcoming competitive adsorption of water.
• A critical premise of this work is that the sorbent material and the adsorption process must
be developed together.
• This synergy is critical for our project.
• New materials may allow – or even require – new process configurations. Similarly,
process design and development work may suggest new avenues, new design
criteria, and new targets for materials synthesis and application.
• Team approach:
• Joe Hupp – MOF synthesis, characterization, and testing
• Omar Farha – MOF synthesis, characterization, and testing
• Randy Snurr – molecular modeling and adsorption testing
• Fengqi You – process modeling
GCEP Project
Started July 17, 2012
Metal-Organic Frameworks
• “MOFs”
• Permanently porous,
crystalline materials
• Metal or metal oxide nodes
connected by organic “linker”
molecules
• Large surface areas (up to
7000 m2/g) and pore volumes
• Nodes and linkers can be
tuned for desired purposes
Mulfort, Farha, Stern, Sarjeant, and Hupp, J. Am. Chem. Soc., 2009.
Fahra, Yazaydin, Eryazici, Malliakas, Hauser, Kanatzidis, Nguyen, Snurr, and Hupp, Nature Chem., 2010.
“NU-100”
“DO-MOF”
Metal-Organic Frameworks
MOF-177
Diversity of MOFs
MOF-177
HKUST-1 MIL-103
MIL-53
Molecular Tinker Toys
Materials Design
?
Can tune material properties via synthesis
• pore size
• linker functionality
• open-metal sites
• extraframework cations or anions
Can also modify MOFs after their synthesis
• Combined Experimental and Computational
Screening – Identify candidate MOFs
– Obtain structure/property insights
– Model validation
• High-throughput Computational Screening
How Can We Rapidly Screen MOFs for
CO2 Capture?
Experimental CO2 uptake at 0.1 bar and 298 K
M\DOBDC MOFs perform particularly well.
MOFs with large free volume
perform the worst at low
pressure.
MOFs having coordinatively
unsaturated metal sites
(open-metal sites)
demonstrate the best
performance.
Yazaydin, Snurr, Park, Koh, Liu, LeVan, Benin, Jakubczak, Lanuza, Galloway, Low, Willis,
J. Am. Chem. Soc., 2009.
Screening MOFs for CO2 Capture
Screening MOFs for CO2 Capture
Yazaydin et al., J. Am. Chem. Soc., 2009.
No correlation
with SA
No correlation
with free volume
There is a strong correlation between CO2
uptake and heat of adsorption at low pressure.
Simulation versus Experiment
Experiment GCMC
Mg-MOF-74 1 2
Ni-MOF-74 2 3
Co-MOF-74 3 5
Zn-MOF-74 4 4
Pd(2-pymo)2 5 1
HKUST-1 6 6
UMCM-150(N2) 7 9
UMCM-150 8 8
MIL-47 9 7
ZIF-8 10 11
IRMOF-3 11 10
UMCM-1 12 12
MOF-177 13 13
IRMOF-1 14 14
This diverse set of
MOFs is a stringent
test of simulation.
→ Ranking from
simulation is very
close to that from
experiment.
→ The top 5 MOFs
are correctly
identified by the
simulations.
Molecular Tinker Toys
Crystal generator for hypothetical MOFs
• Comprehensively enumerates all possible structures
from a library of building blocks
• Creates a large database of hypothetical MOFs
(over 137,000 entries and growing)
• Designed for high-throughput screening of physical
properties
Wilmer, Leaf, Lee, Farha, Hauser, Hupp, Snurr,
Nature Chem., 2012.
Virtual High-Throughput Screening
Real Hypothetical
Virtual High-Throughput Screening
Hypothetical MOF Rank
12500 Monte Carlo cycles / MOF
Top 350 MOFs
CH
4 a
dso
rptio
n (
v(S
TP
)/v)
Hypothetical MOF Rank
500 Monte Carlo cycles / MOF
All 137k MOFs
CH
4 a
dso
rptio
n (
v(S
TP
)/v)
Hypothetical MOF Rank
2500 Monte Carlo cycles / MOF
Top 7000 MOFs
CH
4 a
dso
rptio
n (
v(S
TP
)/v)
Top 5%
(7000 MOFs)
Top 5%
(350 MOFs) World record
Finding Improved Methane Storage Materials
Database restricted to MOFs with one type of node
and one or two types of linkers
Wilmer, Leaf, Lee, Farha, Hauser, Hupp, Snurr, Nature Chem., 2012.
Structure-Property Relationships
hmofs.northwestern.edu
Accessed by
researchers in over 40
countries to date.
High-throughput Screening for CO2/N2 Separations
• Used extended charge equilibration (EQeq) algorithm‡ to obtain partial charges of framework atoms for over 137,000 structures − Method avoids expensive quantum chemical calculations − Method works with full periodic MOF structures − Charges on all structures obtained in ~2 hours using 500
processors • Ran CO2 and N2 pure component GCMC simulations at pressures
relevant to VSA process for carbon capture from flue gas (as above)
‡Wilmer, Kim, Snurr, J. Phys. Chem. Lett. 2012.
Effect of Pore Size on Selectivity
Wilmer, Farha, Bae, Hupp, Snurr, Energy & Environmental Science, in press.
Effect of the Heat of Adsorption
Can the Hypothetical MOFs Be Synthesized?
Farha, Yazaydin, Eryazici, Malliakas, Hauser, Kanatzidis, Nguyen, Snurr, Hupp, Nature Chem., 2010.
• Combined Experimental and Computational
Screening (14 materials) – Identify candidate MOFs
– Obtain structure/property insights
– Model validation
• High-throughput Computational Screening
(137,000 materials)
How Can We Rapidly Screen MOFs for
CO2 Capture?
Acknowledgments
• Screening of Existing MOFs for CO2 Capture – Dr. A. Özgür Yazaydin (U. Surrey) – Dr. Krista Walton (Georgia Tech)
– Dr. Rich Willis (UOP) – Dr. John Low (Argonne)
– Annabelle Benin (UOP) – Prof. M. Doug LeVan (Vanderbilt U.)
– Prof. Stefano Bandani (U. Edinburgh) – Prof. Adam Matzger (U. Michigan)
• Rapid Assessment Criteria – Prof. Youn-Sang Bae (Yonsei University)
• High-throughput Computational Screening – Chris Wilmer
– Dr. Ki Chul Kim
– Prof. Youn-Sang Bae (Yonsei University)
– Prof. Omar Farha
– Prof. Joe Hupp
• Funding – GCEP
– Department of Energy
– Defense Threat Reduction Agency
– XSEDE Computing Resources
– NERSC Computing Resources
New Materials and Process Development for Energy-Efficient Carbon Capture in the
Presence of Water Vapor
Randy Snurr, Joe Hupp, Omar Farha, Fengqi You
20 minutes plus 5-8 minutes for discussion
Subscripts: 1 = strong adsorbate (CO2), 2 = weak adsorbate (N2)
N = uptake at partial pressure (considering the mixture condition)
(1) CO2 uptake at adsorption condition (mol/kg), N1ads
(2) Working CO2 capacity (mol/kg), ∆N1 = N1ads − N1
des
(3) Regenerability (%), R = (∆N1 / N1ads) × 100
(4) Selectivity at adsorption condition, α12 = (N1ads / N2
ads ) × (y2 / y1)
yi = gas phase mole fraction of component i
(5) Sorbent selection parameter, S = [(α12ads)2/ α12
des] × (∆N1 / ∆N2)
Five Adsorbent Evaluation Criteria for PSA or VSA Applications
None of these criteria are perfect, but the criteria are complementary.
Because only single-component isotherms of two gases at appropriate P and T
ranges are required, these criteria can be easily calculated by material chemists
to evaluate new materials.