ChEn 433 Coal

Class 14

Coal Rank

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Coal Rank

Increasing coal rank…

  1. (Peat): coal precursor; soft organic partly decayed plant matter
  2. Lignite: brown coal; high moisture; low heating value
  3. Subbituminous: dull black; electricicy
  4. Bituminous: high heating value; electricity, steel
  5. Anthracite: hard, brittle, high carbon

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Coal composition

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1,2 dimethyl chickenwire

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Coal composition

Skyline coal (bituminous)

Proximate analysis (as received)

Component wt%
Moisture 9.52
Volatiles 37.83
Fixed Carbon 44.56
Ash 8.10

Ultimate analysis (dry)

Component wt%
Carbon 73.52
Hydrogen 5.19
Nitrogen 1.32
Sulfer 0.58
Oxygen 10.46
Ash 8.95

Higher Heating value = 12407 Btu/lb (dry)

(\(\text{HHV}=\Delta H_\text{comb}=-\Delta H_\text{rxn}\), water in products as liquid)

U.S. Coal Deposits

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U.S. Coal Power Plants

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US Coal Plants

  • 241 plants in 2019
  • 236 GW installed capacity
  • 23% of US electricity

U.S. plants start dates

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88% of coal capacity installed over 30 years ago

China

Chinese Coal Plants

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Wiki

  • >1000 plants
  • 184 plants under construction in 2020
  • 58% of Chinese energy in 2019
    • 80% in 2010

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Coal power plant

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Low NOx burner

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Low NOx Combustion Retrofit Options (article)

Steam drum

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Furnace types–stoker

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  • Smaller size units
  • Crushed coal, not pulverized
  • Variable fuel

Pulverized coal furnaces

PC furnaces

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(a) front-wall fired   (b) opposed-wall-fired   (c) corner-fired

Corner fired

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Cyclones

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L1500 Turbulent Coal Jet

L1500 Turbulent Coal Jet

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L1500 Turbulent Coal Jet

OFC coal flame detail