Open AccessA distributed activation energy model of heterogeneous coal ignition. Technical progress report, January 1--March 31, 1995
Author(s) -
J.C. Chen
Publication year - 1995
Language(s) - English
Resource type - Reports
DOI - 10.2172/113914
Subject(s) - ignition system , thermodynamics , kinetic energy , particle (ecology) , presumption , minimum ignition energy , autoignition temperature , reactivity (psychology) , chemistry , materials science , statistical physics , physics , classical mechanics , pathology , political science , law , geology , medicine , oceanography , alternative medicine
Experiments designed to measure kinetic rate constants of ignition of pulverized coals showed clearly that, for single particles or dilute suspensions, particle-to-particle variations due to reactivity and/or thermophysical properties are important. There exists ample evidence that the most important factor in interpreting these data is the existence of a variation in chemical reactivity in the sample. It is surprising, therefore, to note that all previous studies presumed that a single (average) activation energy is adequate to describe the ignition process. The equations formulated using this presumption are then correlated to the experimental measurements to infer the kinetic rate constants of ignition. The major objectives are to develop a model of heterogeneous ignition which allows for a distribution of activation energies, and to implement this model to interpret previously published data. It is the authors hypothesis that variations in chemical reactivity account for the experimental trends observed. Another objective of this project is to examine the effects of variations in thermodynamic and physical properties (e.g. specific heat, particle diameter, density) on data interpretation from previous ignition experiments