Engineered Coal Fuels
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Engineered coal fuel technologies


Currently U.S. energy policy and the public debate over clean coal technologies primarily focus on next generation power plants and transportation fuels. They focus on the effect that energy production, generation, and use will have on greenhouse gases. While these are important considerations, there are also opportunities that exist to generate economically viable and environmentally attractive electricity from coal, using engineered coal fuels technologies.

There are a number of processes either in operation or under development, which treat coal prior to combustion making it a cleaner, more efficient fuel. These engineered clean coal fuel technologies produce enhanced fuels that result in lower sulfur dioxide (SO2), nitrogen oxides (NOX), mercury (Hg) and carbon dioxide (CO2) air emissions at plants that burn them.

The environmental benefits of pre-combustion technologies can be enhanced if other combustion (oxy-coal combustion) or post-combustion technologies (fabric filters, electrostatic precipitation, scrubbers, etc.) are also used. 

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The Environmental Big 4

NOX - Nitrogen Oxides

  • Ground level ozone/smog
  • Gas phase precursor
  • Formation depends on combustion conditions

SO2 – Sulfur Dioxide

  • Acid Rain
  • Solid phase precursor
  • Mechanical removal indicated

CO2 – Carbon Dioxide

  • Climate Change
  • A defining issue for the future of fossil power generation

Hg – Mercury

  • Bio-accumulation risks
  • Solid phase precursor
  • Mechanical removal indicated

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There are three coal preparation technologies used to improve coal prior to combustion

  • Wet Cleaning
  • Dry Cleaning
  • Chemical or Microbial Cleaning
Coal preparation is the most widely used engineered coal fuels technology. It involves cleaning the coal, to remove ash, before combustion. Lower ash levels result in decreased SO2 and Hg emissions. Washing also allows coal-fueled boilers to operate more efficiently as there are fewer impurities and other chemicals that can decrease heat and combustion rates. More efficient combustion reduces NOX and CO2 emissions.

Cleaning technologies also encourage the use and recycling of other "waste” coals that might have been previously abandoned because of lower Btu values and higher levels of impurities, rock, or dirt.

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Coal upgrading technologies increase the Btu content of lower-ranked coals by removing water (dewatering or drying). Dewatering uses four different technologies – three thermal and one non-thermal.

Dewatering and upgrading help to reduce emissions. Sulfur and Hg are reduced with water removal. NOX emissions are reduced as higher Btu values result in more complete combustion. Increased fuel and boiler efficiency leads to lower CO2 emissions per kilowatt hour generated.

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 Coal treatment technologies use additives to alter the coal’s combustion characteristics. These technologies generally use latex, metallic or mineral reagents or sorbents to change the way the coal burns. These technologies can capture sulfur and Hg in solid byproducts from the generating process rather than allowing them to be emitted in power plant exhaust gases. In addition, combustion efficiency improvements result in lower NOX and CO2 emissions per kilowatt hour generated.

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Benefits of using engineered coal fuels technologies

Recent studies conducted by EPRI (Electric Power Research Institute) and CURC (Coal Utilization Research Council) indicate that for each 1% increase in combustion efficiency there is a 2.5% reduction in CO2 emissions from power plants. By applying these technologies other emissions can also be reduced. Depending on the specific technology employed and the coal being used, emissions of mercury can be reduced from 15-90%; nitrogen oxides (NOX) can be reduced from 10-50%, and sulfur dioxide (SO2) can be reduced 10-80%.

When improvements in efficiency and reductions in emissions from engineered coal fuels technologies are combined with other clean coal technologies (combustion and postcombustion), the environmental and cost benefits are manifold.

Engineered coal fuels technologies represent an excellent opportunity to use coal – our most abundant/secure and affordable energy resource – in an environmentally sound manner. By applying these technologies along with combustion and post-combustion stage technologies our coal use will help to power us well into the future.

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Coal 2.0 AllianceCoal 2.0 Alliance

Join the Coal 2.0 Alliance

Objective: The ACC’s Coal 2.0 Alliance is focused on advancing the development and utilization of engineered coal fuels technologies and coal preparation technologies through enhancing awareness of their environmental and efficiency performance benefits.


  • Development of fact sheets.
  • Agenda participation in ACC and other industry conference programs.
  • Development of new ACC-hosted conference programs, seminar and/or webinars devoted to pre-combustion and coal preparation technology utilization.
  • Establishment of an information clearinghouse on the ACC web site of relevant reports and studies. Development of a distinct web site devoted to pre-combustion and coal preparation technologies linked and branded as an ACC adjunct site.
  • Development of original data and/or reports as deemed necessary and appropriate.
  • Promotion of the environmental and efficiency benefits of pre-combustion and coal preparation technologies through various communications and advocacy channels, including but not limited to:
    • Preparation and placement of industry trade publication and mainstream media articles.
    • Meetings with public policy makers.

Download our Engineered Coal Fuels Technologies fact sheet (pdf format) for information on pre-combustion technologies and a list of the Coal 2.0 member companies.

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Bibliography & Links

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