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Carbon Capture Readiness for CCGTs
Michael Rolls18 May 2010
2 18 May 2010 Energy Sector
Copyright © Siemens AG 2010. All rights reserved.
Post-Combustion for Combined CyclesDrivers and Development Challenges
Post-2020 targets drive capture readiness
Siemens pursues within the Statkraft CCS Study the developmentof a dedicated capture process for combined cycle power plants
• Compared with average emissions from installed global steam power plant capacity:specific CO2 reduction of 66%
• Compared with state of the art steam power plant emissions: specific CO2 reduction of more than 50%
• EU legislation calls for capture ready feature for new plants with an output > 300 MWe
Post-Combustion Development Challenges
• Low CO2 concentration in flue gas• High oxygen content in flue gas• Operation with frequent load changes• Fewer integration options for low temperature heat
from the capture plant
3 18 May 2010 Energy Sector
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Steam from steam cycle
40-45°C 90-105°C
CO2 concentration 99% pressure 200 bar
approx. 120°C
Siemens post-combustion capture processCurrent development status
• Heating up solvent
• Desorption of CO2• Evaporation of
reflux water
High absorption rate
Stringent environmental requirements are easily met
Low degradation (O2)
Solvent slip nearly zeroSiemens CO2 compressorsolutions
Low energy demand
4 18 May 2010 Energy Sector
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Ammonia
MEA
Amino acid Amino acid salt
CH
NCH
R
R’O
O
K+ -
NH
HH
CH
NCH
R
R’OH
O
Salts have no vapor pressure
Negative ion is less sensitive to O2
Amino acids are naturally present
• No thermodynamic solvent emissions
• Not inflammable• Not explosive• Odorless• No inhalation risk
• Low degradation• Biodegradable• Nontoxic• Environmentally
friendly
CH
2
NHOCH2
H
H
Amino acid salt is the basis of our solvent
Solvents based on amino acid salts are economic, have low environmental impact and are easy to handle.
No vapor pressure
Chemically stable
Naturally present
5 18 May 2010 Energy Sector
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Further process improvements in several development fields are ongoing
Re-optimization of CCS plant for CCGT is showing good results
Improved design∆ η -9.2%pts.
2.7 GJ/ton CO2 for coal plants
Equipment Optimization
Efficiency
Investment CostsScale-Up
• Pressure drop• Type of equipment (e.g. packing)
• Size• Material
• Large distributors• Train concept • Heat integration
• Split loop configuration
Process ConfigurationProcess
Optimization
Power Plant Integration
Process Conditions
• Low temperature heat integration• Adaption of turbine operating characteristics
• Pump around• Desorber pressure• Process temp.
Solvent Optimization
Corrosiveness Chemical Stability
Kinetics
• Additives• Equipment material
• Additives• Structure of solvent
• Activation• Enhanced mass transfer
Capacity
• Concentration of AAS• Solubility• New functional AAS
Lab-proven
6 18 May 2010 Energy Sector
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Carbon capture plantsComparison for different fuels
Coal/Steam Power Plant Gas/Combined Cycle Power Plant
Large power plant footprint
Low excess oxygen
High CO2 concentration
Small power plant footprint
High excess oxygen
Low CO2 concentration
7 18 May 2010 Energy Sector
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Capture ready requirementsSiemens reference steam power plant
Steam turbines• extraction of approx. 40 % of LP
cross over steam• options for modification of turbines
depend on operation modes(part load, full load capability w/o CO2 capture, other plant and site conditions)
Steam turbine buildingsufficient space/foundation for:• modification of turbines• steam and condensate pipes• installation of heat exchangers
Our offer proposal:Our offer proposal:Integration of carbon capture unit into theIntegration of carbon capture unit into thepower plantpower plant““Capture Ready / Retrofit SolutionsCapture Ready / Retrofit Solutions””
FGD• either consider capacity
extension in column design• or provide space for
enlarged FGD unit
Air heatingOptional: space for installation of heat exchanger(s) for lowest grade heat utilization
Exhaust ducts• consider Δp from CO2
absorption unit • later flue gas connection to
capture unit (T-branch)
Flue gas fan• upgradeable design• or additional space for
installation of second fan downstream of FGD
Electrical auxiliary loadsufficient space for:• additional auxiliary transformer(s)• switchyard• cable routes
Condensate system,sufficient space for:• heat exchangers for low grade
heat utilization• additional piping routes with
supporting structure / racks
Cooling systemsufficient space for:• additional circulation pumps• service water system• sufficient cooling capacity of
cooling tower
Raw water & cooling water supply / Waste water treatment• sufficient space for enlargement• secure water utilization rights
8 18 May 2010 Energy Sector
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Exhaust gas
Life steam
Condensate
4
98
10
Cooling tower
Coolingair
6 5 1 2 3
Air Fuel
Gas turbine plant:
11
12
7
9
Fresh water
1 Air intake2 Compressor3 Gas turbine4 Heat recovery
steam generator5 Generator6 Transformer
Steam turbine plant:7 Steam turbine8 Condenser9 Feeding pump
10 Generator11 Transformer12 Circulating pump
Capture ready requirementsSiemens reference CCGT design (2 + 1)
Steam turbines / Reheating adaptability for steam extraction, options for modification of turbines depend on required operating modes
Turbine building,sufficient space/foundation for modification of turbines, steam extraction and installation of additional equipment
Electrical auxiliary load,sufficient space for additional auxiliary transfomer(s), switchyard and cable routes
Cooling systemsufficient space for additionalcirculation pumps and service water system, sufficient cooling capacity of cooling tower
Condensate system,sufficient space for additional piping routes with supporting structure /racks
Raw water supply / Waste water treatment,sufficient space for enlargement, secure water utilization rights
Exhaust duct,consider laterflue gas connection to capture unit (T-branch)
Definition of capture ready measures requires insight into an appropriate capture process
9 18 May 2010 Energy Sector
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TurbineHall area
Capture Ready RequirementsSteam supply options for single shaft SST-5000
LP Main Steam
Cold ReheatHot Reheat
Re-boiler CarbonCapture Plant
Steam extraction at low pressurelevel from the crossoverpipe possible
Extraction line routingmight require adaptationsin the turbine hall concept
Requires throttle flapin the crossover pipe
10 18 May 2010 Energy Sector
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Steam turbines for combined cyclesSST-3000 SST-5000
Combined IP/LP turbine; axial exhaust Combined HP/IP turbine; lateral exhaust
Steam turbine concept influences optionsfor later capture plant retrofit.
Cooling and
module
concept
determine
ST design
11 18 May 2010 Energy Sector
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Capture Ready RequirementsSteam supply options for single shaft SST-3000 & SST-5000
TurbineHall area
Re-boiler (carbon capture plant)
Optional Back Pressure Turbine
Not affected by capture ready /retrofitmeasures for process steam extraction
from steam cycle extraction
12 18 May 2010 Energy Sector
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Conclusions
capture ready CCGT designs are ready now
no compromise is required to base plant performance
any additional plant costs for CCR are trivial (eg space provision)
future conversion requires ST blade path changes for lower flow
actual conversion impact depends on CCS technology status at thetime
Siemens amino acid salt solution applies for coal and gas plants
the CCS process is being optimised for CCGT flue gases
