Chalmers University of Technology
2nd Post-Combustion Capture Conference Bergen, Norway
19 Sept, 2013
Henrik Jilvero Carbon Capture and Combustion Group
Department of Energy Technology Chalmers University of Technology
Avoiding ammonia slip from ammonia-based post-
combustion - Evaluation of reduction methods
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Reduce ammonia slip
2 3 4 56
7 8
19
To stack
Pure CO2
HEALTH ENVIRONMENT
• Eutropification • Soil acidification • Fertilization • Smog
• Respiratory system disease (PM2.5) • Eye/Skin/Throat irritation
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Ammonia concentrations
5000-500 ppm Prolonged exposure can lead to death 150-50 ppm Eye/Skin/Throat irritation 50-5 ppm Odor detection 25 ppm Recommended 8-hour exposure limit 7 ppm Recommended long-term exposure limit 300 ppb Recommended exposure limit urban areas
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Equilibrium partial pressure
Temp: 20°C
NH3-CO2-H2O
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Reduction Methods
Method Type
Steam stripping Secondary/Regenerative
Cooled absorption Primary
Staged absorption Primary
Acid wash Secondary/Destructive
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Steam stripping
43
1 2
Beneficial for high CO2 conc.
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Steam stripping
90% CO2 removal
CO2 Capture cycle ~2500 kJ/kg CO2
Rate-based simulations
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Cooled absorption
5
43
1 2
10% NH3
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Staged absorption
43
1c 21b1a
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Staged absorption
Flue gas
CO2-lean
CO2-Rich
Flue gas
CO2-lean
CO2-Rich
a) b)
50000ppm
3000ppm
One-absorber Two-absorber
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Acid wash
1 2
6
Capture with H2SO4
Formation of (NH4)2SO4
Reduction of SOx
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Summary
Reduction method Ammonia reduction potential
Advantage Disadvantage
Steam stripping ~ 100% Full recovery Heat req. Low CO2 conc.
Cooled absorption ~ 60-70% Low cost Chilling req.
Staged absorption ~ 80% High impact Absorber height
Acid wash ~ 100% Byproduct Ammonia destruction
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Summary
1 2
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Conclusion
• Slip is an important design aspect of the absorber
• Trade-off between capture efficiency, ammonia slip and absorber height
• Cost of destructive/regenerative methods?
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Thank you!
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Extra slide 1
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Extra slide 2
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Extra slide 3
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Extra slide 4