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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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