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Characterization of Ash Deposit Structure from Planar Sections: Results and Challenges

  • Everett R. Ramer
  • Donald V. Martello

Abstract

Three-dimensional structural parameters were measured for fouling ash deposits from two Powder River Basin subbituminous coals using direct microscopical methods on planar sections through the deposits. These parameters included solid and pore volume fractions; specific surface area; particle contiguity; and mean solid, particle, and pore chord lengths. Spatial trends in the results for the two deposits indicated that the solid volume fraction remained relatively constant from the tube side to the flame side, but the solid phase coarsened in this direction. An increase in the contiguity between ash particles indicated that the coarsening mechanism was sintering, both via increased particle agglomeration and encapsulation of particles by a glassy phase. The bulk averages of the results were identical for both deposits, with a solid volume fraction of 0.23, a specific surface area of 0.6 x 106 m−1, a contiguity of 0.23, a mean solid chord length of 16 pm, a mean particle chord length of 12 µm, and a mean pore chord length of 53 µm. In addition, a two-dimensional structural parameter, the density-density correlation function, was measured for one of the deposits. This result indicated that the cross-sectional profiles of the solid regions with diameters less than 20 µm were isotropically oriented, and that the larger solid region profiles were preferentially oriented in the direction of the incoming particle trajectories.

Keywords

Planar Section Chord Length Tube Surface Solid Volume Fraction Spatial Profile 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 1996

Authors and Affiliations

  • Everett R. Ramer
    • 1
  • Donald V. Martello
    • 1
  1. 1.Pittsburgh Energy Technology CenterU. S. Department of EnergyPittsburghUSA

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