Sastrawinata, T
1993
Properties of Soot from Coal Tar
Ma, J.; Dean, M.; Rossman, J.; Sastrawinata, T.; Webb, B.W. and Fletcher, T.H.
Meeting of the Western States Section of the Combustion Institute, October 1993, Menlo Park, CA. Funded by ACERC.
Soot properties and formation mechanisms have been extensively studied in gas flames such as acetylene and propane. However, relatively little information is known concerning soot properties in coal combustion. Coal tar is the precursor to soot in coal combustion, so that the aromatic ring structures are already present. Experiments are presented to show the size of soot particles generated from coal tar at high temperature. A flat flame burner is used to provide the high temperature environment. Coal particles are entrained along the centerline of the reactor, and release pyrolysis products into the hot surrounding gas. The tar/soot cloud diffuses radially away from the centerline as it is convected axially in the flow reactor. The soot sampling system inserts a carbon-coated microscope grid radially into the soot cloud at different residence times, and the soot particle deposit thermophoretically. Soot particles are then analyzed using transmission electron microscopy (TEM) at magnifications as high as 150,000. Distinct soot particles with approximate diameters of 25 nm were observed along with particle agglomerates consisting of multiple primary particles. The observed agglomerate size increases with residence time in the reactor. Liquid-like unstable deposits (believed to be condensed tar) were also observed. These qualitative observations are important for descriptions of soot radiation from coal flames.
Sastrawinata, T
1993
Properties of Soot from Coal Tar
Ma, J.; Dean, M.; Rossman, J.; Sastrawinata, T.; Webb, B.W. and Fletcher, T.H.
Meeting of the Western States Section of the Combustion Institute, October 1993, Menlo Park, CA. Funded by ACERC.
Soot properties and formation mechanisms have been extensively studied in gas flames such as acetylene and propane. However, relatively little information is known concerning soot properties in coal combustion. Coal tar is the precursor to soot in coal combustion, so that the aromatic ring structures are already present. Experiments are presented to show the size of soot particles generated from coal tar at high temperature. A flat flame burner is used to provide the high temperature environment. Coal particles are entrained along the centerline of the reactor, and release pyrolysis products into the hot surrounding gas. The tar/soot cloud diffuses radially away from the centerline as it is convected axially in the flow reactor. The soot sampling system inserts a carbon-coated microscope grid radially into the soot cloud at different residence times, and the soot particle deposit thermophoretically. Soot particles are then analyzed using transmission electron microscopy (TEM) at magnifications as high as 150,000. Distinct soot particles with approximate diameters of 25 nm were observed along with particle agglomerates consisting of multiple primary particles. The observed agglomerate size increases with residence time in the reactor. Liquid-like unstable deposits (believed to be condensed tar) were also observed. These qualitative observations are important for descriptions of soot radiation from coal flames.