Moetaz Attalla, Merched Azzi, Phil Jackson and Dennys Angove29th September 2009

Energy Transformed Flagship

Environmental Impacts of Atmospheric Emissions from Amine-based Post-Combustion CO2 Capture

CSIRO Energy Centre

CSIRO’s Energy Research At Newcastle

• Renewable Energy Systems• Solar Thermal• Vibration Energy Harvesting• Organic Photovoltaics

• Improving Energy End Use• Distributed Energy• Self Learning Smart Agent Technologies• Energy Storage

• Carbon Capture and Storage• Geosequestration (ECBM,..)

• Post Combustion Capture Technologies

The Scientific Challenges…….

Column height & diameter –CAPEX & footprint

Atmospheric emissions –environmental impacts

Heat for desorption –power station energy penalty

Flue gas impurities –solvent degradation

Corrosion –plant downtime

and repair

Identifying potential impacts when solvent-based carbon capture is deployed….

• Solvent-based carbon capture plants using amines can mitigate stationary-source CO2 emissions, BUT……

• What happens when there is amine “slip” from the capture plant?

• What is the atmospheric fate of the lost amine molecules?• Are they deposited close to the emission source, or does

atmospheric chemistry convert them into deleterious molecules, harmful to people and the environment?

• How can we develop safe levels or environmental thresholds for amines?

• What are safe levels of exposure to amines?

• How much amine can be “released” to the environmentbefore authorities need to act?

• Most, but not all, capture amines have large dipole moments and are strongly hydrophilic eg ammonia

• Ammonia undergoes atmospheric chemical reactions, and other highly polar molecules, tend to promote aggregation and particulate formation (SOA) that impact on climate change

• The degradation products of larger capture amines in the capture plant include amides and aldehydes –volatiles implicated in photochemical smog formation!

• Secondary and tertiary amines form stable nitrosamines (potent mammalian carcinogens)

Identifying potential impacts when solvent-based carbon capture is deployed….

Reference: J.J. Renard et al. J. Harzardous Mater. 2004, B108, 29

• Program currently being undertaken at the Energy Centre, Newcastle includes:

1. Oxidative/ thermal mechanisms of amine degradation in the capture plant and under controlled realistic laboratory conditions

2. the fate of ‘slipped’ amine and amine degradation products in the troposphere

3. Under what atmospheric conditions amine catalysed smog-inducing photochemistry and photo-oxidation.

4. whether secondary or tertiary amines form nitrosamines in the atmosphere

5. Develop new screening methods for assessing atmospheric amine impacts

6. Develop dispersive models with a clearer understanding of amine atmospheric chemistry taken into account

7. The environmental impact of amine slip

Key Research Program Emissions

Secondary products:ozone, aerosols, other air toxics

Fate and impacts of atmospheric amine emissions

Chemical transformationChemical reactions

ImpactsHuman health

Ecosystem healthIndustry Transport Natural

Dry and wetdeposition

MeteorologyTransport/diffusion

• What would be the impact of changing emissions profiles ?

Primary emissionse.g. alkanolamines,VOC

degradation products, NOx, SOx,

Packed absorber column for solvent degradation studies

Attalla, Jackson, Sexton

• Packing height = 25 cm• 8 mm Rasching rings

• Column diameter = 6 cm• Absorber sump: 3-L capacity• L: 1 L/min, recirculating flow• G: 3.5 SLPM, once-through

• 10% O2, 2% CO2 baseline• T = 40oC• Baseline: MEA, plastic packing,

metal salts• Future Work:

• CS, SS packings (no metal salts)• Effects of NOx/SOx

• Novel solvents

The CSIRO Smog Chamber Facility

The smog chamber is an 8 m3 teflon lined environment with UV lamps at one end to simulate sunlight.

The chamber is filled with clean air and dosed with NOx and VOC to stimulate ozone and secondary aerosol formation in the atmosphere.

Dedicated instruments track the concentrations of;•Ozone•NOx•Particles•VOCs

Smog Chamber Facility

• Study of the chemical basis for O3, NO2 ,aerosol and other oxidants formation

• Provide necessary data to develop and test chemical mechanisms for different ranges of conditions

• Evaluation of atmospheric impacts of using different types of scenarios on photochemical smog oxidants formation

• Identification of the appropriate chemical reaction pathsfor ozone and SOA formation using explicit mechanisms

• The data obtained are used to update and develop advanced techniques that can be embedded into our air quality tools for air quality modelling and assessment.

♣ Chemistry is non-linear and changes in concentrations and ratios can have significant impacts on photochemistry

♣ Two photochemical smog regimes

♣ O3 production depends on available sunlight, temperature and the concentrations of VOC and NOx and their ratio

♣ NOx determines the maximum ozone potential

♣ Real air parcels are also subject to fresh emissions

Mechanisms of photochemical smog formation

VOC + NOx + hv O3 + SOA + other smog products

Smog Chamber used to elucidate the detailed photochemistry

NO NO2

O3

VOC

Hours

Con

cent

ratio

n

2 4 6MorningPeak

Modelling power station emissions

Inter-regional transport of pollutants

Amine emissions

• With the exception of ammonia, the majority of alkanolamine capture solvents have boiling points > 100 °C

• This does not mean that amine losses will be small…..for a 1 million tonne CO2/p.a. capture plant, this means amine losses of ~ 40-160 tonnes/p.a.*

• Amine oxidation within the capture plant produces aldehydes and small organic acids (see next slide)

• The small organic acids react with primary or secondary capture amines to produce amides

• Solution-based MEA oxidation:

*NILU OR 77/2008

Absorber side

Thermaldegradation

Oxidative degradation

[O2] > 240 °C

OH

NH2

2-aminoethanol, MEA

Molecules that should be monitored close to PCC plants

O CH3

NH3

OH

O CH3

ammonia

acetaldehyde

acetic acid

OH

OH

Ohydroxyacetic acid

O

OH

Ooxoacetic acid

OH

O

OH

Oethanedioic acid

OH

NH

NH2

2-[(2-aminoethyl)amino]ethanol

NH

OH 2-(pyrrolidin-2-yl)ethanol

NH

NHpiperazine

O

NH

N

OH

4-(2-hydroxyethyl)piperazin-2-one

OH

NH

O

CH3

N-(2-hydroxyethyl)acetamide

1.2.3 1.2.4.5

2

1.2.3 1.2.4.5

1.2.4.5

1.2.4.5

1.2.4.5

1. assists particle aggregation

2. undergoes photochemical reactions

3. undergoes acid rain forming reactions

4. can form nitrosamines

5. ultimate fate is unknown

1.2.3.5

1.2.3.5

1.2.3.5

Ozone and NOx profiles for ULP (grey) and ULP+MEA (colours) experiments

0 100 200 3000

50

100

150

200

C

once

ntra

tion

(ppb

)

Time (min.)

Ozone NO NOy-NO NOy

0 100 200 3000.01

0.1

1

10

100

ULP + MEAULP

SOA

Mas

s con

c. (µ

g/m

3 )

Time (min.)

SOA mass conc. profiles for ULP (red) and ULP+ MEA (black) experiments

Realistic lab based data and analytical procedures:Oxidation and thermal degradation experiments carried out under controlled

conditions Low level analytical procedures

Pilot plant samples from exhaust and liquor Long term operational data

Smog chamber simulations will be carried out to:Identify the major pollutants produced by the photo-decomposition of the flue gas compounds of the absorber under selected ambient conditions Identify the major chemical reactions pathways responsible for the MEA oxidationDevelop the appropriate chemical mechanism required to simulate the oxidation of MEA

Airshed modelling to determine the potential environmental impact of using amine solution for CO2 capture

Embedded the modified chemical mechanism into the airshed modelSimulate different atmospheric scenarios to assess the potential impact of the new CO2 capture processDetermine the trade off between CO2 capture and local and regional air quality

Current and future work at CSIRO

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Contact UsPhone: 1300 363 400 or +61 3 9545 2176Email: enquiries@csiro.au Web: www.csiro.au

CSIRO Division of Energy TechnologyMoetaz Attalla

Phone: +61 2 4960 6083Email: moetaz.attalla@csiro.auWeb: www.csiro.au/org/ET