Effects of volatile-char interactions on the reactivity of chars from NaCl-loaded Loy Yang brown coal

Hongwei Wu, Xiaojiang Li, Jun Ichiro Hayashi, Tadatoshi Chiba, Chun Zhu Li

研究成果: Contribution to journalArticle査読

76 被引用数 (Scopus)

抄録

In a fluidised-bed gasifier, char particles are in constant contact with the volatiles and the products from the gasification and thermal cracking of volatiles. The highly reactive nature of volatiles as well as the vulnerable structure of char from brown coal means that there are strong interactions between volatiles and char. The purpose of this study is to investigate the effects of volatile-char interactions on the reactivities of chars from a Victorian brown coal. NaCl-loaded and acid-washed Loy Yang brown coal samples were pyrolysed in a novel fluidised-bed/fixed-bed reactor at 900 °C that has been specially designed to investigate the volatile-char interactions. Char reactivity in air was measured in a thermogravimetric analyser (TGA) under conditions minimising mass transfer limitations. The oxidation of char with air in the TGA showed apparent kinetic compensation effects between the apparent activation energies and pre-exponential factors. The presence of the apparent kinetic compensation effect is a reflection of the heterogeneous structure of char having sites of a wide range of energy levels. Our results have clearly shown that volatile-char interactions can lead to drastic decreases in char reactivity due to the volatilisation of Na and the changes in char structure. The reactivities of chars from the pyrolysis of the catalyst-free H-form Loy Yang brown coal provided unequivocal evidence for the changes in char structure after volatile-char interactions. For chars from the NaCl-loaded Loy Yang brown coal, it appears that the condensation of ring structures in char as a result of volatile-char interactions could have also led to changes in the dispersion of Na catalyst.

本文言語英語
ページ(範囲)1221-1228
ページ数8
ジャーナルFuel
84
10
DOI
出版ステータス出版済み - 7 2005
外部発表はい

All Science Journal Classification (ASJC) codes

  • 化学工学(全般)
  • 燃料技術
  • エネルギー工学および電力技術
  • 有機化学

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