Soot, organics, and ultrafine ash from air- and oxy-fired coal combustion

Description

Pulverized bituminous coal was burned in a 10W externally heated entrained flow furnace under air-combustion and three oxy-combustion inlet oxygen conditions (28, 32, and 36%). Experiments were designed to produce flames with practically relevant stoichiometric ratios (SR=1.2-1.4) and constant residence times (2.3s). Size-classified fly ash samples were collected, and measurements focused on the soot, elemental carbon (EC), and organic carbon (OC) composition of the total and ultrafine (<0.6µm) fly ash. Results indicate that although the total fly ash carbon, as measured by loss on ignition, was always acceptably low (<2%) with all three oxy-combustion conditions lower than air-combustion, the ultrafine fly ash for both air-fired and oxy-fired combustion conditions consists primarily of carbonaceous material (50-95%). Carbonaceous components on particles <0.6µm measured by a thermal optical method showed that large fractions (52-93%) consisted of OC rather than EC, as expected. This observation was supported by thermogravimetric analysis indicating that for the air, 28% oxy, and 32% oxy conditions, 14-71% of this material may be OC volatilizing between 100 and 550°C with the remaining 29-86% being EC/soot. However, for the 36% oxy condition, OC may comprise over 90% of the ultrafine carbon with a much smaller EC/soot contribution. These data were interpreted by considering the effects of oxy-combustion on flame attachment, ignition delay, and soot oxidation of a bituminous coal, and the effects of these processes on OC and EC emissions. Flame aerodynamics and inlet oxidant composition may influence emissions of organic hazardous air pollutants (HAPs) from a bituminous coal. During oxy-coal combustion, judicious control of inlet oxygen concentration and placement may be used to minimize organic HAP and soot emissions. This dataset is associated with the following publication: Andersen, M., N. Modak, C. Winterrowd, C.W. Lee , W. Roberts, J. Wendt, and B. Linak. Soot, organics and ultrafine ash from air- and oxy-fired coal combustion. Proceedings of the Combustion Institute. Elsevier B.V., Amsterdam, NETHERLANDS, 36(3): 4029-4037, (2017).

Resources

Name Format Description Link
10 Table%201%20of%204.docx https://pasteur.epa.gov/uploads/10.23719/1372478/Table%201%20of%204.docx
10 Table%202%20of%204.docx https://pasteur.epa.gov/uploads/10.23719/1372478/Table%202%20of%204.docx
10 Table%204%20of%204.docx https://pasteur.epa.gov/uploads/10.23719/1372478/Table%204%20of%204.docx
53 Fig%202rev.xlsx https://pasteur.epa.gov/uploads/10.23719/1372478/Fig%202rev.xlsx
33 Fig%201%20of%203.pdf https://pasteur.epa.gov/uploads/10.23719/1372478/Fig%201%20of%203.pdf
53 Fig%203_20160509_Possible_Edits.xlsx https://pasteur.epa.gov/uploads/10.23719/1372478/Fig%203_20160509_Possible_Edits.xlsx
10 Table%203%20of%204.docx https://pasteur.epa.gov/uploads/10.23719/1372478/Table%203%20of%204.docx

Tags

  • oxy-coal-combustion
  • elemental-carbon
  • loss-on-ignition
  • ultrafine-fly-ash
  • organic-carbon

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