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Outline
• Background
• Capture technologies & status
– Post-combustion
– Pre-combustion
– Oxy-fuel
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Capture ready plants
• Not well defined! Place & performance!
• Post-combustion most suitable for
future “capture ready” plants
• Large steam extractions needed for
regeneration
• Minimum pre-investment for steam
turbine
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Amine Scrubbing
Advantages
• Proven technology
• Known chemical process
• Ability to predict performance and solvent consumption
Limitations
• High energy consumption for solvent regeneration
• High rate of process equipment corrosion
• High solvent losses due to fast evaporation
• High degradation in presence of oxygen
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Status
• No full scale plants in operation yet
• More research and development needed
• Scaleable, flexible pilot plants for
validation & verification
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Chilled Ammonia (1.6 C)
• Advantages
• Lower regeneration energy with HP regeneration
• Low-temp. CO2 absorption min. NH3 emissions.
• High CO2 absorption efficiency in bubbler absorber.
• Applicable for new plants and for retrofit
• Carbonates are stable over a wide range of
temperatures & do not degrade during absorption-
regeneration
• The process uses low-grade waste heat
• Potential to capture 90% of CO2 emissions
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Chilled Ammonia
Limitations
• Ammonia volatility can be an issue.
• The pH of the ammonia solvent does not allow for
much carbonate formation.
• Slower absorption rate than MEA. Requires three
times more packing to achieve the same CO2
removal performance. A number of absorber
vessels are required, increasing capital cost and
affecting plant layout.
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Status
• 2 MWe field pilot to be operated at the
Pleasant Prairie Power Plant, Wisconsin, US
• Pilot plant under construction at
Karlshamnsverket, Sweden
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Oxy-fuel
Advantages
• Exhaust gases consist of CO2 & H2O. Separation by condensation.
• Very low NOx emissions
• Efficient O2 separation reduces efficiency penalty (AZEP, membrane)
Limitations
• Expensive air separation process with high energy demand (Cryogenic)
• New development of gas turbines needed
• CO2 recirculation for temp. control
• Condensation process needs new equipment