Jerimiah C. Forsythe

April 23, 2012

Amine-Functionalized Ceramic Materials for Enhanced Gas Absorption

Oil1%

Base Case 2009

Coal45%

Other0%

Natural Gas23%

Renewable11%

Nuclear20%

Nuclear18%

Renewable14%

Other0%

Coal44%

Natural Gas23%

Reference Case 2030

Oil1%

DOE/NETL CO2 Capture Update, May 2011http://www.eia.gov/tools/faqs, Accessed April 2012

1

Introduction: The CO2 Problem

Power generation by fuel type in the United States:

Coal34% Oil

43%

Natural Gas23%

2009 CO2 emissions by fuel type: Overall power requirements for the US:

313 GW of power produced

600 coal-fired power plants in the US

~ 850 million tons of coal burned annually

~ 4 million L of CO2 produced annually

Introduction: The CO2 Problem

2http://www.eia.gov/tools/faqs, Accessed April 2012http://www.esrl.noaa.gov/gmd/ccgg/trends/, Accessed April 2012

280 ppm CO2 from pre-industrial ages (1832)

1.9 ppm CO2 average increase per year

Projected CO2 for 2030: 420 ppm

Clearly, we will be producing CO2 for the long-term to meet our energy demands

We need systems in place to assist in addressing the overall CO2 concentrations in the immediate future

Flue Gas Composition and Regulations

3

Component

N2 70%

CO2 13-16 %

H2O 5-7 %

O2 3-4 %

HCl 10-100 ppm

SO2 100-1200 ppm

SO3 1-40 ppm

NOx 300-1000 ppm

Hg 1 ppb

Fly Ash 10%

Lu, D. Y.; Granatstein, D. L.; Rose, D. J. Ind. Eng. Chem. Res. 2004, 43, 5400-5404Granite, E. J., personal communication

Already removed before entering exhaust stack

EPA issued ruling for removal in 4 years

25 years for EPA to regulate Hg emissions from power plants, expected to increase price by 0.1 ¢ per KWh

EPA just issued regulations for CO2 emissions, final announcements on December 2012Expected to double overall cost of electricity with current carbon capture technology

Outstanding issue of cost and corrosive nature of amines

Current CO2 Removal Systems

4

Post-combustion capture systems with aqueous solvent absorption

http://www.co2crc.com.au/aboutccs/cap_absorption.html, Accessed April 2012

Comment solvents:amines, carbonates, or bicarbonates

Monoethanolamine (MEA)

Diglycolamine (DGA) Diethanolamine (DEA)

pKa = 9.6 pKa = 9.0pKa = 8.6

High heat (> 100 °C) required for unloadingCorrosive at 0.4 mol CO2 per 1 mol amine

Rapid reaction rate with CO2

Low reaction ratesCorrosive at 0.4 mol CO2 per 1 mol amine

Low volatilityRapid reaction rate with CO2

Corrosive at 0.4 mol CO2 per 1 mol amineVolatile, loss in absorber overhead

Current amine standard:Fluor’s Econamine using MEA

Post-Combustion CO2 Capture Systems

DOE/NETL CO2 Capture Update, May 2011http://www.mhi.co.jp/en/products/detail/km-cdr_process.html, Accessed April 2012http://www.eia.gov/tools/faqs, Accessed April 2012

Performer LocationCapture

TechnologyCapture Rate

Ton/yrStart Date

NRG EnergyThompsons,

TXAmine 550,000 2015

American Electric Power

New Haven, WV

Chilled Ammonia

1,650,000 2015

5

Mitsubishi Heavy Industries has been operating several carbon capture facilities on natural gas using Kansai Mitsubishi Carbon Dioxide Recovery (KM-CDR) technology with KS-1™

Test operations on 25 MW coal-fired plant in Al since 2011

Additional efforts in pre-combustion capture and oxy-combustion capture, coming on-line between 2014-2016

CO2 Absorption in Aqueous Systems

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CO2 + H2O

Carbonic acid formation and equilibria

H2CO3pKa at 25 °C = 6.352

Gibbons, B. H. J. Biol. Chem. 1963, 238, 3502McCann, N. J. Phys. Chem. A 2009, 113, 5022-5029

or above pH = 7 and 25 °C

CO2 + HO– HCO3– pKa at 25 °C =

10.329

So, overall:

H2CO3 + B HCO3– + HB

pKH2CO3 at 25 °C = 3.7

Predominate species in solution will be HCO3– at any pH ≥ 6

H2CO3 + RNH2

Two feasible pathways for amine with carbonic acid:

RNHCO2H + H2O

HCO3– + RNH2 RNHCO2

– + H2O

Or...we can have direct interactions with CO2 (aq)

CO2 Absorption in Aqueous Systems

7

Three proposed interactions with amines:

1. Carbamate Intermediate1

2. Zwitterion Intermediate2

3. Single-Step3

Arstad, B. J. Phys. Chem. A 2007, 111, 1222-1228McCann, N. J. Phys. Chem. A 2009, 113, 5022-5029

CO2 + R1R2NH

R1R2NHCOOHR1R2NHCOOH + B

R1R2NHCOO– + BH+

CO2 + R1R2NH

R1R2NH+CO2–

R1R2NH+CO2– + B

R1R2NCO2– +

BH+

R1R2NCO2– +

BH+

2nd order reactionCarbamic acid formation rate determingRapid proton transfer assumed

Assumed rapid deprotonationMechanistically favored from kinetic data

Termolecular reaction for carbamate formationB = base acting as proton acceptor/donor (water or amine)

Reaction rates are very rapid with unstable intermediatesDifficult to determine exact reaction mechanismCarbamate product stable and easily detected

Project Aims and GoalsPrimary Goal: To functionalize alumina foams with amines to enhance the absorption of CO2 by

solution based-amines

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Specific Aim: What effect does calcinated α-alumina (Al2O3) have on our test system?Specific Aim: What effect does APTES functionalized calcinated α-alumina (Al2O3) have on our test

system?

Ultimate Goal: To insert functionalized alumina foams into the absorber for enhanced CO2 removal

Project Aims and Goals

9

Tower packing to increase gas-liquid surface area and gas absorption

Current use of either trays or packing material (e.g. Raschig Rings)

Type and design depends on application and solution viscosity, operating temperature, and pressure conditionsHowever, if we can select a material that can accept functionalization by chemical groups, we can enhance the surface properties and make the absorption process more effective

Alumina foam (Al2O3)

50-25 mL Amine/Water solution

Gas dispersion tube Gas collection tube

Mass Flow Controller #1

13% CO2/N2 Tank

“simulated flue gas”

LinePurge

N2 TankN2 Purge

Purge

Rotameter

Purge

IR Detector

N2 D

ilutio

n

0.2 L min-1

0.8 L min-1

0.2 L min-1

1.0

L min

-1

Mass Flow Controller #2

Instrumental Set-up

10

30% (w/w) DGA in waterWater “blank”

Bubbler System Trials

25 mL of 30% (w/w) DGA in water with 220 mL min-1 “simulated flue gas”

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Bubbler System Trials

50 mL of 30% (w/w) DGA in water with 220 mL min-1 “simulated flue gas”

30% (w/w) DGA in water+ 5 g alumina+10 g alumina

Alumina itself has an effect on the total loading of CO2

Competition with amines for acid/base chemistry

α-alumina (Al2O3), calcinated, 125-350 meshpKa measured to be 5.5

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(3-aminopropyl)triethoxysilane

(APTES)

3% H2O in EtOH (v/v)pH = 5.0, 5 min, RT

Hydrolysis

+H-bondformation

Silanolcondensation

H-bondformation with surface -OH groups

2 hour contact time with 1.0 g of Al2O3 powder

Condensation

- H2O

EtOH wash, cure at 110 °C for 30 min.

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Surface Functionalization with APTES

TGA Analysis

CO2 Loss:0.04 mg

CO2 Loss:0.02 mg

APTES Loss:0.02 mg

APTES Loss:0.04 mg

Functionalized AluminaPost-bubbler Alumina

Ramp rate: 10 °C min-1 from 250 to 650 °C under Ar

Amine and water catalysis removing APTES from surface

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30% (w/w) DGA in water+ 1 g APTES Alumina+ 1 g alumina

APTES Functionalized Alumina

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Conclusions

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Acidic alumina lowers the CO2 loading capacity of the DGA solutions due to acid/base equilibria competition

APTES functionalization of alumina is ineffective for generating significant surface coverages

APTES is easily removed from alumina surface by catalysis via water and amines

Increase surface coverage of surface-bound amines while minimizing bond catalysis by surrounding water/amine solution

Future Work

Demonstrate effectiveness of surface amines in CO2 capture when coupled with circulating amine solutions

Acknowledgments

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Funding:

US Department of Energy (DOE)

Schlumberger

Prof. George Hirasaki

Prof. Michael Wong

Prof. Ed Billups

Sumedh Warudkar