THE MAIN NATURAL LOWS OF HIGH-RATE COAL PYROLYSIS

Abstract

The importance of coal pyrolysis studies for the development of energy technologies is evident, since pyrolysis is the first stage of any process of coal thermal conversion. In combustion, pyrolysis deter mines conditions of coal ignition and the rate of char after-burning; in gasification, pyrolysis determines total yield of gasification products. It must be noted that in modern energy technologies pyrolysis occurs at high rate of coal particle heating (approx. 103 K/s for different fluidized bed, or FB-technologies) or super-high-rate (≥105 K/s for entrained-flow gasification), and in some of them at high pressure. In CETI during last 12 years the detailed study of pyrolysis in FB laboratory-scale PYROLYSIS-D plant and entrained-flow pilot-scale GSP-01 plant, was carried out. In this paper main results of mentioned investigations are given. Kinetic constants for bituminous coals and anthracite high heating rates in entrained flow for high temperatures (≥1500 C and ≥1900 C), and in fluidized bed conditions in temperature range 972-1273 K. In order to describe data obtained in fluidized bed conditions, G-model-based method of calculation of devolatilization dynamics was suited to FB heating conditions. Calculated and experimental kinetic data are in good agreement. The result proves that at FB-pyrolysis conditions intrinsic mass-transfer limitations are negligible and devolatilization is really kinetic-controlled.

Keywords

Dates

  • Submission Date2003-06-02
  • Revision Date2003-09-12
  • Acceptance Date2003-10-11

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Volume 7, Issue 2, Pages77 -87