POWER GENERATION FROM COAL USING

SUPERCRITICAL CO2

D R Q I A N Z H U

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BACKGROUND

• The 2016 IEA Outlook concluded that coal would remain the second-largest energy source worldwide until 2030. World coal consumption is projected to increase by more than 20% by 2040

• Coal-fired power plants are a major source of CO2 emissions

• The Paris agreement aimed to cap global warming at well below 2oC (1.5oC if possible)

• CCS will have a major role to play in reducing CO2 emissions in order to meet the goal

• Advanced coal technologies are required to increase efficiencies, to reduce CO2 emissions from coal power plants and to facilitate CCS

• CO2 as a working fluid

• Non-explosive, non-flammable, non-toxic and readily available at low cost

• Reaches a supercritical state at moderate conditions — 7.4 MPa and 31°C

• Large fluid density (and low pressure ratio) keeps turbomachinery small

SCO 2 POWER CYCLE

INDIRECTLY-HEATED, CLOSED SCO 2 CYCLE

A recuperated, recompression closed sCO2 cycle

DIRECTLY-FIRED, SEMI-CLOSED OXY-COMBUSTION SCO 2 CYCLE

Nuclear Fossil fuel

Solar power Geothermal and waste heat Ship-board propulsion

MAIN BENEFITS AND APPLICATIONS

RECENT DEVELOPMENTS

Integrated System Test (IST) facility at Bettis Atomic Power Laboratory

10 MWe high-pressure, high-temperature turbine rotor design

— small scale testing sCO2 turbine design

RECENT DEVELOPMENTS

Materials testing

— compact heat exchangers and materials

Recuperator design

RECENT DEVELOPMENTS

— Echogen heat engine EPS100• First commercial 8 MWe prototype heat engine

• Use recuperated closed sCO2 Brayton cycle

• Turns waste heat to electricity

• Lower costs

RECENT DEVELOPMENTS

50 MWt Demo plant in La Porte, TX, USA• Natural gas fuelled, oxy-combustion with

combustion product CO2 ready for storage• Mirrors design of commercial plant to ensure

scalability• Includes all components of the Allam Cycle• Plant will undergo full performance evaluation

— Allam Cycle

A gas-fuelled 300 MWe commercial plant under development• Pre-FEED study completed on full-scale plant;

FEED and early development work has begun• Toshiba undertakes commercial turbine design

COAL-BASED ALLAM CYCLE POWER GENERATION

• Integrate core Allam Cycle with existing gasification systems

• Simple power cycle• Highly efficient and flexible, lower costs• Additional R&D needs include syngas

clean-up process, handling of corrosion from impurities, and syngas combustor for low-CV fuels

• The sCO2 cycles hold great potential for providing alternative power generation systems that can achieve higher plant efficiency and full carbon capture at lower costs

• Two pathways have been identified and investigated for power generation from fossil fuels using sCO2 cycles:

– indirectly-heated closed sCO2 cycle (coal based PC, CFB boiler/furnace)

– directly-fired semi-closed oxy-combustion sCO2 cycle (coal derived syngas and natural gas)

• Some outstanding technical issues need to be addressed

• Significant progress has been made recently in developing sCO2 cycle power systems. The sCO2 power cycles, could revolutionise the future power generation from coal in a carbon constrained world, provided solutions can be found to meet all the technical challenges in developing the cycles.

KEY MESSAGES

THANK YOU FOR YOUR ATTENTION

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