Development of Chemical Additives for Reducing CO2 Capture ...€¦ · Developing a novel aqueous...
Transcript of Development of Chemical Additives for Reducing CO2 Capture ...€¦ · Developing a novel aqueous...
Development of Chemical Additives forReducing CO2 Capture Costs
Yang LiLawrence Berkeley National Laboratory
Presented at 2013 NETL CO2 Capture Technology MeetingJuly 8-11, 2013
Lawrence Berkeley National Laboratory
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Research areasClimate Change and Environmental SciencesEnergy Efficiency and Sustainable EnergyBiological Sciences for Energy Research and HealthComputational Science and NetworkingMatter and Force in the UniverseSoft X-Ray Science for Discovery
Project Status
• Funding: DOE $ 1,250 K
• Project period: 6/1/08 - 5/31/13
• Participants: Ted Chang - PIParticipants: Y. Li - Chemist Project Scientist/EngrParticipants: C. Y. Liao - Graduate student
• DOE/NETL Manager: Elaine Everitt/Dave Lang
• Objectives:Developing a novel aqueous solvent system that willintegrate amine, potassium carbonate, and ammonia toattain high CO2 capture rates, reduce energy demandsand capital costs.
Concepts
• CO2 captured is transferred from one solvent to another by chemical methodsbefore the final solvent is thermally regenerated
STEP PURPOSE
1: Amine
2: K2CO3
3: KHCO3/Ammonia
12−15% CO2
CO2
CO2
~100% CO2
High CO2 capture rate
Precipitate KHCO3 as a solid =much less water than amine solution
Enhancement of CO2 production kinetics;low heat capacity
Process Description
RichAmine
LeanAmine
KHCO3
HotK2CO3
Steam
Flue Gas to Stack
Flue Gas12−14 Vol.
% CO2
CO2Absorption
Column
K2CO3
RegenerationColumnwithammoniumcatalyst
Pressurized CO2
Amine Loop Carbonate Loop
RecirculationTank(Amine regeneration,
KHCO3 precipitation,
Phase separation,
Heat exchange)
Amine−CO2 + K2CO3 Amine + KHCO3
Amine Flow
Gas Flow
• Amine Loop:Capturing CO2 by amine aqueoussolution, increasing absorptionkinetics.
• Recirculation tank:Connecting Amine Loop andCarbonate Loop, transferring CO2from amine to carbonate toprecipitate bicarbonate.
• Carbonate Loop:Transferring CO2 frombicarbonate to ammoniumcatalysts, increasing kinetics &producing pressurized CO2.
Benefits
• Enhancement of CO2 absorption kinetics, reducingabsorber capital costs,
• reduction of processing water, reducing solventregeneration energy demands,
• employment of stable and low heat capacity KHCO3,reducing emissions of harmful products and sensible heatdemands,
• reduction of reagent loss and equipment corrosion,reducing operation costs.
Challenges and Mitigation
Challenges
• Could precipitate in absorberabsorber
• Solid/slurry handling
Mitigation
• Control L/G and/or amine composition
• Engineering system analysis
Performance Schedule
Task June 2008 − May 2009 June 2009 − May 2010 June 2010 − May 2011 June 2011 − May 2012 June 2012 − May 2013
1. Project management and planning
2. Install walk−in fumehoods
Acquire system components
3. Set−up CO2 capture system
Determine Raman efficiencies
4. Absorption of CO2
5. Chemical transformation
6. Reagent regeneration and CO2
production
7. Process assessment and
technology transfer
100%
100%
100%
100%
100%
100%
100%
Integration of Absorption and Chemical Regeneration
Absorber
Recirculationtank
Solvent pump
Stirrer
• Long-term multi-cycle run (14 cycles ofabsorption and chemical regeneration, and theabsorption lasted at least 15min per cycle.)
• L/G: ∼120 gallon/1000ft3
0 2 4 6 8 10 12 14Absorption/regeneration (cycle)
0
20
40
60
80
100
Aver
age
CO
2 rem
oval
effi
cien
cy (%
)
90%
• Sustainable 90% removal efficiency indicatesthe efficient chemical regeneration of amine.
Thermal Regeneration Tests
• Semi-continuous stripping operation:make-up water in, and K2CO3 solutionout
• Sufficient KHCO3 solid was preloadedin the stripper
Stripper
Reboiler
Calorimeter
Steamer
0 5 10 15 20T (min)
0.0000
0.0005
0.0010
0.0015
0.0020
0.0025
CO
2 stri
ppin
g ra
te (k
g/m
in)
w/ ammonium catalystw/o ammonium catalyst
Short-term strippingw/ catalyst - higher CO2 stripping rate
w/o catalyst - lower CO2 stripping rate
0 20 40 60 80 100T (min)
0.0000
0.0005
0.0010
0.0015
0.0020
0.0025
0.0030
CO
2 stri
ppin
g ra
te (k
g/m
in)
w/ ammonium catalyst
Long-term stripping
w/ catalyst - after 40min,the CO2 stripping rate decreased
indicating the lose of catalyst
• The addition of ammonium catalyst increased the CO2 stripping rate under the same energy input• Ammonium catalyst has potential, but more work is needed to overcome the volatilizing problem
Raman of Regenerated K2CO3 from the Stripper
• Long-term semi-continuous stripping operation: make-upwater in, and K2CO3 solution out, with ammonium catalyst
• Sufficient KHCO3 solid was preloaded in the stripper
980 990 1000 1010 1020 1030
10min 20min 30min 40min 50min 60min 70min 80min 90min
HCO3
-NH
2COO-
950 1000 1050 1100 1150
Raman shift (cm-1)
Raman shift (cm-1)
SO2−4 internal standard
CO2−3
This area was zoomed in
• The ammoniumcarbamatepeaks wereundetectable.
• Ammoniumspecies won’tcontaminate thesolvent in theabsorber.
Energy Penalty Determination
Two different methods:
With an autoclave With a stripper
Energy Penalty Determination with Autoclave
• High-pressure autoclave with functions of in-situRaman
• Water and KHCO3 were in the autoclave
010
0020
0030
0040
00
Ene
rgy
pena
lty (
kJ/k
g C
O2)
30wt% MEA
This approach
Sensible heatLatent heatEnthalpy
• Under 1.6bar, the stripping energy was preliminarilydetermined to be 2130kJ/kg CO2
Energy Penalty Determination with Stripper
• Long-term continuous stripping test
• The input energy by steam was measured
• From CO2 stripping rate (left), and assuming the sensible heatrecovery, the stripping energy was estimated (right)
0 20 40 60 80 100 120T (min)
0.0000
0.0005
0.0010
0.0015
0.0020
0.0025
0.0030
0.0035
0.0040
CO
2 stri
ppin
g ra
te (k
g/m
in)
0 20 40 60 80 100 120T (min)
0
2000
4000
6000
8000
Strip
ping
ene
rgy
(kJ/
kg C
O2)
Preheatingphase
Steady state
Preheatingphase
Steady state
• The stripping energy was preliminarily determined to be 2079kJ/kgCO2 on average at steady state.
• Further parametric optimization and energy penalty demonstrationare needed.
Process Chemistry
CO2 Absorption and Chemical Regeneration of Amine
• 1st absorption:Fresh BL aqueous solution
• 2nd absorption:The solution in which K2CO3 wasreplenished after the KHCO3 solid wasfiltrated
• 3rd absorption:The solution in which K2CO3 wasreplenished for the second time after theKHCO3 solid was filtrated
Samples were collected and analyzed by NMR.
Process Chemistry
CO2 Absorption and Chemical Regeneration of Amine
R1 C
H
N
R2 R3
C
O
O−
(RNCOO−)
R1 C
H
N
R2 R3
H
H
(RNH2)+
N
R2 R3
H
(RNH)
R1 C
H
and
+
0 5 10 15 20 25T (min)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Con
c. (M
)
BLH,1st
BLH2+ ,1st
BLCOO− ,1st
BLH,2nd
BLH2+ ,2nd
BLCOO− ,2nd
BLH,3rd
BLH2+ ,3rd
BLCOO− ,3rd
δ(ppm) ∝RNH+
2
RNH + RNH+2
• The concentration of carbamate
increased, and then decreased during
2nd and 3rd absorption processes
Degradation and EH&S Impact• Ammonium species were undetectable in the absorber;
• only trace amount of amine exists in the high-temperature stripper;
• amine doesn’t have to undergo huge temperature swing.
• Mitigating ammonia emission problems
• Mitigating thermal degradation problems of amine
• Mitigating the formation of nitrosamine in high temperature zone
Thermal Degradation Nitrosamine Formation
0 200 400 600 800
T (hrs)
0.2
0.3
0.4
0.5
0.60.70.80.91.0
[Am
ine]
/[A
min
e 0]
8M Pz, α=0.4, t=165 ◦ C, Freeman et al., Ind. Eng. Chem. Res. 2012, 51, 7719.
30wt% MEA, α=0.4, t=135 ◦ C, da Silva et al., Ind. Eng. Chem. Res. 2012, 51, 13329.
4.28M MDEA, PCO2=2.59MPa, t=140 ◦ C, Chakma, et al., Can. J. Chem. Eng. 1997, 75, 861.
3M DEA, PCO2=4.137MPa, t=162 ◦ C, Kennard et al., Ind. Eng. Chem. Fundam. 1985, 24, 129.
0.0025 0.0027 0.0029 0.0031
1/T (K−1 )
102
103
104
105
k3
(dm
6m
ole−
2s−
1)
135 ◦ C, 0.1mol/dm3 PZ with phosphate buffer
100 ◦ C, 5, 1.7, 0.5 mol/dm3 PZ
80 ◦ C, 5 mol/dm3 PZ
50 ◦ C, 5 mol/dm3 PZ
• Nitrosamine’s formation rate constant:
about 103 less at 50◦C than 135◦C.
Goldman et al. Environ. Sci. Technol. 2013, 47, 3528-3534.
Conceptual Process Configuration
SOLID−LIQUIDSEPARATION UNIT
FLUE GAS
BLOWER
ABSORBER STRIPPER COMPLEX
FLUE GAS TO EXISTING STACK
RICH AMINE
LEAN AMINE
CO2
RECIRCULATION
TANK
KHCO3
KHCO3
W/ AMMONIUMCATALYSTS
K2CO3
REBOILER
SOLVENT SOLVENTPUMP PUMP
Technology transfer
• Berkeley Lab has licensed a worldwide patent to Jiantawn LLC• Jiantawn LLC is teaming with Nexant, Alstom, IHI, and UCB to push the technology forward
Plans for Future Development
After this project - team approach:
• Scale-up demonstration, a proposal was submitted inresponse to DE-FOA-0000785
• Techno-economic analysis
• EH&S implications
Acknowledgment
• The project was accomplished by Shih-Ger (Ted) Chang (PI),Yang Li (Chemist Project Scientist/Engr), and Chang-yu Liao(graduate student)NMR instrument support: Chris Canlas, College of Chemistry, U.C. Berkeley
• Special thanks to DOE/NETL project managers: Elaine Everittand David Lang for their guidance and management
• This work was supported by DOE under ContractDE-AC02-05CH11231 through the NETL