bench-scale development and testing of rapid psa for co2
TRANSCRIPT
Bench-Scale Development and Testing of Rapid PSA for CO2 Capture
James A. Ritter & The Team
2013 NETL CO2 Capture Technology Meeting Pittsburgh, PA, July 8, 2013
Overall Project Objectives design, develop and demonstrate a bench-scale process
for the efficient and cost effective separation of CO2 from flue gas using Pressure Swing Adsorption (PSA)
goal to reduce energy consumption, capital costs, and environmental burdens with novel PSA cycle/flow sheet designs
applicable to both large (500-1000 MW) and small (5-50 MW) capacity power plants, and industries with 10 to 100 times less CO2 production
Process simulations and experiments; structured adsorbent material development, CFDs and
experiments; and complete flow sheet analyses being used for demonstrating and validating the concepts.
Grace (Hoefer)
Catacel (Cirjak)
USC (Ritter & Ebner)
Battelle (Saunders & Swickrath)
materials characterization,
and process modeling and
experimentation
technology development and
process integration
thin film materials
development and characterization
The Team investigation
specification
validation
PSA Technology Advantages established, very large scale technology for other
applications needs no steam or water; only electricity tolerant to trace contaminants; possibly with use
of guard or layered beds zeolite adsorbent commercial and widely
available increase in COE lower than other capture
technologies beds can be installed under a parking lot
PSA Technology Challenges energy intensive, but better than today’s amines;
possibly overcome by novel designs today, very large beds required implies large
pressure drop more power; possibly overcome by structured adsorbents and faster cycling
large footprint; possibly overcome by underground installation and faster cycling smaller beds
high capitol cost; possibly overcome by faster cycling smaller beds
Key PSA Technology Project Challenge although a commercial tri-sieve zeolite could be
used today in an efficient PSA cycle, it would only minimize to some extent the pressure drop issues, but not the adsorbent attrition and mass transfer issues
key challenge is to develop a structured adsorbent around an efficient PSA cycle that exhibits a high enough packing density to allow the fastest possible cycling rate ( smallest possible beds), while improving pressure drop and mass transfer issues and eliminating attrition issues
Where are we going?
• increase working capacity 10 fold (herculean) • operate at 1/10th cycle time (achievable) • known as rapid PSA
Scale of PSA System for CO2 Capture from 500 MW Power Plant
Is it possible to achieve a 1/10th volume reduction?
although rapid PSA offers potential for a low-cost solution for CO2 capture, the extent of size
reduction achievable is, at the moment, unknown
QuestAir H-6200 Rapid PSA-Installed at ExxonMobil Facility
H2 Production Rapid PSA ~ 12,000 Nm3/h/module
H2 Production Conventional PSA ~ 20,000 Nm3/h
Two of Questair’s modules do 20% better than this 6-bed PSA system
and are much smaller.
A 500 MW plant produces ~ 33,000 Nm3/h at > 30 times
lower pressure!
Where are we now after completing first year?
Preliminary Technical and Economic Feasibility Study
Overall Outcome
Significant Outcomes from Year 1 developed PSA cycle and process flow sheet with less than 35%
LCOE increase; based on completed preliminary technical and economic feasibility study
demonstrated zeolite crystals can be coated onto basic metal structure with at least 50 mm thick coating; suggests it may be possible to achieve even 100 to 150 mm coatings, if needed
demonstrated Catacel core structures can be made with up to 400 cells per square inch (cpsi); makes goal of achieving 600 cpsi, possibly even 800 cpsi, within reach
demonstrated needed limit of < 20 kPa/m pressure drop through 400 cpsi core at very high velocities up to 25 m/s; pressure drop limit utilized in preliminary technical and economic feasibility study
Significant Outcomes from Year 1 Predicted pressure drop through Catacel core nearly
quantitatively using CFD model with no adjustable parameters; paves way to fabricate even more optimum core structures using computational tools
Demonstrated, via PSA process simulation, possibly lowest energy, highest feed throughput PSA cycle for CO2 capture; amazing when considering bulk density reduced from 710 kg/m3 (typical for packed bed of zeolite beads) to 400 kg/m3 (entirely feasible with Catacel core)
PSA cycle boasts feed throughput of around 3,000 L(STP)/hr/kg and separations energy < 18 kJ/mol CO2 captured
How did we get to this point?
CO2 Isotherm on Adsorbent and Dual Process Langmuir Fit
0.0
1.0
2.0
3.0
4.0
5.0
6.0
0 20 40 60 80 100 120
CO
2 Loa
ding
[mol
/kg]
Pressure [kPa]
T = 25 oC T = 50 oC T = 75 oC
0.010
0.100
1.000
10.000
0.001 0.010 0.100 1.000 10.000 100.000 1000.000
CO
2 Loa
ding
[mol
/kg]
Pressure [kPa]
T = 25 oC T = 50 oC T = 75 oC
Dual Process Langmuir (DPL) Isotherm
1, 1, 2, 2,
1, 2,1 20
, , ,
,0, ,
1 1
exp
s si i i i i i
ii i i isite site
s s stj i j i j i
j ij i j i
n Py b n Py bn
Py b Py b
n n n T
Bb b
T
− −
= + + + = +
=
N2 Isotherm on Adsorbent and Dual Process Langmuir Fit
0.00
0.10
0.20
0.30
0.40
0 20 40 60 80 100 120
N2 L
oadi
ng [m
ol/k
g]
Pressure [kPa]
T = 25 oC T = 50 oC T = 75 oC
0.0001
0.0010
0.0100
0.1000
1.0000
0.01 0.10 1.00 10.00 100.00 1000.00
N2 L
oadi
ng [m
ol/k
g]
Pressure [kPa]
T = 25 oC T = 50 oC T = 75 oC
1, 1, 2, 2,
1, 2,1 20
, , ,
,0, ,
1 1
exp
s si i i i i i
ii i i isite site
s s stj i j i j i
j ij i j i
n Py b n Py bn
Py b Py b
n n n T
Bb b
T
− −
= + + + = +
=
Dual Process Langmuir (DPL) Isotherm
O2 Isotherm on Adsorbent and Dual Process Langmuir Fit
0.00
0.05
0.10
0.15
0 20 40 60 80 100 120
O2 L
oadi
ng [m
ol/k
g]
Pressure [kPa]
T = 25 oC T = 50 oC T = 75 oC
0.0000
0.0001
0.0010
0.0100
0.1000
1.0000
0.01 0.10 1.00 10.00 100.00 1000.00
O2 L
oadi
ng [m
ol/k
g]
Pressure [kPa]
T = 25 oC T = 50 oC T = 75 oC
1, 1, 2, 2,
1, 2,1 20
, , ,
,0, ,
1 1
exp
s si i i i i i
ii i i isite site
s s stj i j i j i
j ij i j i
n Py b n Py bn
Py b Py b
n n n T
Bb b
T
− −
= + + + = +
=
Dual Process Langmuir (DPL) Isotherm
Zeolite Coated Metal Foil preliminary fabrication coated on flat foil coupon at 30 mg/in2
coating passed Catacel adhesion test goal: to make coating 100 – 150 µm thick
50 µm
50 µm
20 µm
19
Rapid Adsorbent Characterization
commercial zeolites – activation at 350 oC
overnight in N2 – cycling at 90 oC
• 2 min adsorption in 15% CO2-N2
• 2 min desorption in 100% N2
– PT = 1 atm
BalanceBalance
Perkin-Elmer TGA-7
To ExhaustTo Exhaust
TGA Controller
Timer
Flow meters Sample plate
Balance wireGlass tube
Furnace w/thermocouple
Syringe Pump(H20 Injection)
Feed
Balance Gas
BalanceBalance
Perkin-Elmer TGA-7Perkin-Elmer TGA-7
To ExhaustTo Exhaust
TGA ControllerTGA Controller
Timer
Flow meters Sample plate
Balance wireGlass tube
Furnace w/thermocouple
Syringe Pump(H20 Injection)
Feed
Balance Gas
TGA Runs at 70 oC Cycle: 100 s Stream with CO2 /100 s Pure N2
0 1 2 3 4 5 6 7Time (min)
PowderWashcoatBead
-0.4-0.20.00.20.40.60.81.01.21.4
0 1 2 3 4 5 6 7
Rel
ativ
e L
oadi
ng (m
ol/k
g)
Time (min)
PowderWashcoatBead
15% CO2 in N2/100 % N2 100% CO2 /100 % N2
Working Capacities of washcoat between 50 and 100% higher than commercial beads!
Corrugated Catacel Cores 1” x 6” x 400 cells/in2
goal: to increase corrugation to 800 cpsi
0
5
10
15
20
25
30
35
40
0 5 10 15 20 25 30 35
dP/d
l (KP
a/m
)
Interstitial Velocity (m/s)
One 1.0" 289 CPSI coreOne 1.0" 400 CPSI coreTwo 1.0" 289 CPSI coresTwo 1.0" 400 CPSI coresOne 1.5" 289 CPSI coreCFDErgun Eq., pelletized bed349.4 g, 4.32 mm GB in 3.934" L, 1.524" D bed
Structured and Beaded Media Pressure Drop
Pressure Drop Apparatus Qmax = 1000 SLPM
∆Pmax = 30, 70 or 140 in H20
goal: ∆Pmax < 20 kPa/m at design velocity of 20 m/s
Volumetric Frequency Response Apparatus
5x10-5 to 10 Hz 100 g adsorbent
80 oC and 0.2 atm
V3 V4 Gas Inlet
To Vacuum
V2 Pressure
Transducer
Differential Pressure
Transducer
Thermocouple
Bellows
Linear Volumetric Displacement Transducer
Water Jacket
Constant Temperature
Bath
Acentric Cam
Sample Chamber
Volumetric Frequency Response Schematic
0
5
10
15
20
25
30
35
Inte
nsity
744 Torr185 Torr102 TorrMacropore DiffusionMicropore DiffusionMacropore Convection
0
10
20
30
40
1.0E-05 1.0E-03 1.0E-01 1.0E+01
Phas
elag
Frequency, Hz
744 Torr185 Torr102 TorrMacropore DiffusionMicropore DiffusionMacropore Convection
Volumetric Frequency Response Results
Mass Transfer Models Macropore Diffusion Macropore Convection Micropore Diffusion
System and Conditions CO2-commercial zeolite beads T = 25 oC P = 102, 185, or 744 torr f = 5x10-5 to 10 Hz
Correlation of Mass Transfer Models with Experimental Data
only macropore diffusion model unequivocally fits the data over the
pressure range investigated
1-Bed Rapid PSA Apparatus 0.1 to 2 Hz
100 g adsorbent 80 oC and 0.1 atm
TV-15
PT-LP
LP
FM-HP
TV-17
HP PT-HP
PT-VAC
HP CnD
VAC
TV-16
PT-LPP
PT-LR
PT-EQ3
PT-EQ2
PT-EQ1
PT-HR
PT-HE EQ
PT-F
PT-BED
BED
FM-F
FM-HR
FM-LPP
FM-LP
FM-LR
TV-6 SV-6
TV-1 SV-1
TV-2 SV-2 TV-3 SV-3
TV-4 SV-4
TV-5 SV-5 HE EQ
HR
F
HP LR
HP CnD
TV-12 SV-12
TV-7 SV-7
TV-8 SV-8 TV-9 SV-9
TV-10 SV-10
TV-11 SV-11
LE EQ 1
LR
LP F
LP HR
LP CoD LPP
TV-13 SV-13
LE EQ 2
TV-14 SV-14
LE EQ 3
1-Bed Rapid PSA Schematic
Two-Step CO2 and N2 Cycling Experiments
PH ↑ PL
PH ↓ PL
Pure CO2 or N2 Effluent
Counter-Current Blowdown Pressurization
Pure CO2 or N2 Feed
Information Obtained a) Determination of Valve Cv
b) Determination of excluded volume
c) Validation of Single Component Isotherms
d) Validation Adsorption/Desorption Mass Transfer Coefficients
Pure Gas Cycling in 1-Bed Rapid PSA System CO2 on Beaded Zeolite at 22 oC
0
25
50
75
100
125
150
0 10 20 30
Pres
sure
[kPa
]
Time [sec]
Feed Tank
Model Bed
Vacuum Tank
ts = 3 s
0
25
50
75
100
125
150
0 5 10 15 20
Pres
sure
[kPa
]
Time [sec]
0
25
50
75
100
125
150
0 10 20 30
Pres
sure
[kPa
]
Time [sec]
0
25
50
75
100
125
150
0 2 4 6 8 10
Pres
sure
[kPa
]
Time [sec]
0
25
50
75
100
125
150
0 1 2 3 4 5
Pres
sure
[kPa
]
Time [sec]
ts = 3 s ts = 2 s
ts = 1 s ts = 0.5 s
Pure Gas Cycling in 1-Bed Rapid PSA System CO2 on Beaded Zeolite at 22 oC
kLDF = 1.87 s-1
P(Torr)
hA(kJ/K/s)
Dp/Rp2
(s-1)kLDF
(s-1)
744 1.7e-4 3.32 1.94
185 1.7e-4 3.32 0.38
102 1.7e-4 3.32 0.18
Comparison of Mass Transfer Coefficients CO2 on Beaded Zeolite
Volumetric Frequency Response Apparatus (25 oC)
1-Bed Rapid PSA System (22 oC)
Snapshot of Multi-Bed PSA System
Typical Cycle Steps for PSA Operation
PH
T
PH PH ↓
PI1
PI2 ↓
PL
PL PL ↓
PI1
PI1 ↓
PH
T CO2 Feed Gas CO2 Rich Product
CO2 Depleted Product
Feed Heavy Reflux
Equalization Counter- Current
Depressurization
Light Reflux
Equalization Light Product
Pressurization
α β
Co-Current Depressurization
PH ↓
PI2
γ
0 > α, β, γ > 1
b
c d e
0 > a, b, c, d, e > 1
PI1 ↓
PH
Feed Gas
Pressurization
a
PSA Process Conditions for DAPS* Process Conditions PH = 120 kPa PL = 5 kPa TF = 75 C h = 0.0 W/m2 K (adiabatic) tc = 120 s θ = 2,600 – 3,100 L(STP)/kg/hr Structured Bed Properties Lb = 0.125 m db = 0.09848 m ρb = 400 kg/m3
εb = 0.64
Feed Composition (Dry) yCO2 = 0.1592 yN2 = 0.8029 yO2 = 0.0379
Mass Transfer Coefficients kCO2 = 10.0 s-1
kN2 = 1.0 s-1 kO2 = 1.0 s-1 * DAPS: dynamic adsorption process simulator
DAPS Results of Bench Scale PSA Process
17.35
17.40
17.45
17.50
17.55
17.60
17.65
17.70
17.75
17.80
17.85
84
86
88
90
92
94
96
98
100
2500 2700 2900 3100 3300
Ener
gy [K
J/m
ol C
O2]
CO
2 Pur
ity &
Rec
over
y [%
]
Throughput [L(STP)/hr kg ]
Purity Recovery Energy
DOE Crite ria
this is a low energy, high
feed throughput PSA cycle for CO2 capture
that meets the DOE criteria,
especially when considering the bed density is
only 400 kg/m3
Motivation to Compare Solid Amine to Zeolite sorbents for post-combustion CO2 capture zeolites have sufficient working capacity for CO2
not H2O tolerant: must be removed prior to PSA unit! solid amine sorbents commercial amines grafted or immobilized within
large pores of a high surface area support like silica gel
have sufficient working capacity for CO2 H2O tolerant: will it pass through the PSA unit with
N2?
solid amine sorbents have NOT been studied extensively for CO2 capture from flue gas by PSA
CARiACT G10 Solid Amine Sorbent* substrate: CARiACT G10 silicon
dioxide (Fuji Silysia) surface area: 300 m2/g pore volume: 1.3 ml/g particle size: 75-150 µm
polyethylenimine (PEI) (MN 423 Aldrich)
40 wt% PEI physically adsorbed (immobilized) onto G10
*Gray et al., Energy Fuels, 23 (2009) 4840.
Snapshot of Multi-Bed PSA System
Typical Cycle Steps for PSA Operation
PH
T
PH PH ↓
PI1
PI2 ↓
PL
PL PL ↓
PI1
PI1 ↓
PH
T CO2 Feed Gas CO2 Rich Product
CO2 Depleted Product
Feed Heavy Reflux
Equalization Counter- Current
Depressurization
Light Reflux
Equalization Light Product
Pressurization
α β
Co-Current Depressurization
PH ↓
PI2
γ
0 > α, β, γ > 1
b
c d e
0 > a, b, c, d, e > 1
PI1 ↓
PH
Feed Gas
Pressurization
a
Comparison of PSA Process Performance PEI vs Zeolite
for the same process performance and conditions (much different PSA cycle), zeolite beds are 10X smaller than PEI beds with PEI consuming 2X
the energy => need amine with faster desorption kinetics
PEI Zeolitetcyc (s) 300 120
Feed Throughput (L(STP)/kg/hr) 224 2870
CO2 Recovery (%) 91.0 91.8CO2 Purity (%) 95.2 95.8
Energy (kJ/mol CO2
Recovered) 34.2 17.6
Conclusions metal foil coated with commercial zeolite and corresponding
low pressure drop corrugated structure showing much promise for CO2 capture from flue gas
frequency response and 1-bed rapid cycling experiments both show very fast mass transfer rates of CO2 in beaded zeolite
very low energy, very high feed throughput PSA cycle configuration developed using validated DAPS
novel hybrid adsorption process flow sheet resulted in < 35% COE increase
shorter PSA cycle times showing potential to significantly reduce column size and thus plant footprint
PEI solid amine sorbent showing potential in PSA process; it may allow H2O to pass through bed with N2; need better kinetics to make PSA process performance more like zeolites
Acknowledgements
Thank You!
?
Funding provided by DOE/NETL and
SAGE is greatly appreciated!