Changes in viscosity of single coals and their blends upon heating

Jun Ichiro Hayashi, Masato Morita, Koichi Matsuoka, Tadatoshi Chiba

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Thermoplasticity of two different coals and their blends was investigated upon isothermal and non-isothermal heating at temperatures of 600-800 K. Changes in viscosity (η) and the fraction of liquid (φL; defined as that of mobile hydrogen) of softening coal in a form of disk were successfully measured by means of a variable-force-loading needle penetrometry coupled with a volumetric dilatometry and a proton nuclear magnetic resonance, respectively. η and φL changed with the temperature and time over ranges of 104-1010 Pa s and 0.03-0.53, respectively, depending upon the blending ratio and also the heating mode. For every single-coal/blend, a single linear relationship between log η and φL, i.e., log η = a - bφL, was confirmed over the temperature range and regardless of the heating mode, which indicated that the softening coal behaved as a mixture of liquid and "deformable" solid. It was found that both the parameters a and b were linear functions of the blending ratio, and the log η-φL relationships for the blends were thus predictable from those for the single coals. Furthermore, log η of the blends was reasonably approximated over the temperature/viscosity ranges only from those of the single coals by assuming additivity of log η.

Original languageEnglish
Pages (from-to)405-412
Number of pages8
JournalEnergy and Fuels
Issue number2
Publication statusPublished - Mar 2007
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology


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