Cocombustion of coal and solid recovered fuels SRF in pulverized coalfired plants

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Co-combustion of coal and solid recovered fuels
(SRF) in pulverized coal-fired plants

• PhD student Hao Wu
• Supervisors Peter Glarborg, Kim Dam-Johansen
• Flemming J. Frandsen

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Outline

• Background
• Project objective and contents
• Full-scale aerosol measurement
• Conclusion

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Solid recovered fuels (SRF)

• Definition-Solid recovered fuels (SRF) are
  non-hazardous wastes usable for energy recovery
  in waste incineration or co-incineration plants
• Characteristics of SRF
• Heterogeneous
• High alkali, earth alkaline, and chlorine
  contents
• High trace element contents
• High volatile content

Typical SRF produced from MSW (Hilber et al.)
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Potential advantages of co-combustion of coal and
SRF in pulverized coal-fired plants

• Fast and cheap method to treat the increasing
  amount of waste
• Increase the electrical efficiency for utilizing
  waste energy
• Decrease the CO2 emission from a pulverized
  coal-fired power plant
• NO or SO2 emissions may be reduced
• Fly ashes from co-combustion may be usable in
  cement or concrete production

Typical electrical efficiency 25 Typical
capacity 50MW
Waste incineration plant
Typical electrical efficiency 40 Typical
capacity 500MW
Pulverized coal-fired plant
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Potential problems for co-combustion of coal and
SRF
Typical Cu, Pb and Zn contents in coal and SRF
Typical Cl and Alkali contents in coal and SRF

• More severe ash deposition and corrosion problems
  in the boiler
• Increased trace element emissions
• Lower qualities of fly ashes that may not be used
  in cement or concrete production

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Objective and contents of the project

• Objective-to investigate and understand the ash
  related problems in co-combustion of coal and
  SRF, and to optimize the process
• Contents
• Co-combustion experiments in an entrained flow
  reactor
• Full-scale aerosol measurements
• Lab-scale experiments on characterization of coal
  and SRF
• Use/develop thermodynamic models to study the
  partition of major inorganic/trace elements

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Full-scale aerosol measurement in Esbjerg Power
Station (ESV)

• Full-scale tests on co-combustion of coal and SRF
  were carried out by DONG Energy at ESV during DEC
  2008 and Jan 2009
• Aerosol measurements were performed by using an
  low-pressure cascade impactor
• The mass-based concentrations of the aerosols
  from different tests are analyzed
• The chemical composition and morphology of the
  aerosols are analyzed by SEM-EDX

Schematic drawing of the setup (Jacob Zeuthen et
al)
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Aerosol emissions from co-combustion of coal and
SRF
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Typical composition of aerosols from
co-combustion of coal and SRF (10)
Si, Al, and K increase with particle size
Ca, P and S decrease with particle size
Cl contents are very low
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Conclusion

• Co-combustion of coal and SRF may not cause
  severe ash deposition and corrosion problems in
  the boilers
• Co-combustion of coal and SRF increases the
  emissions of fine aerosols
• Trace element emissions may be increased in
  co-combustion both due to the fuel properties and
  increased fine aerosol emissions
• Ca, S, and P are important for the formation of
  fine aerosols in co-combustion of coal and SRF

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Tak for opmærksomheden/ Thanks for the Attention !