Response to "Letter to the Editor: Spontaneous heating of a coal stockpile" by J.C. Jones.
J Loss Prev Process Ind 2009 Jul; 22(4):554
We think that it is necessary to consider the effect of oxygen concentration in the reaction rate formulation in our study. Although a criterion for the effect of oxygen on critical behavior is known, it can only be used for coal stockpiles in open. But in our study, we did not study a typical coal stockpile. We studied a large-scale coal bed chamber that simulates a mine-out area in an underground coal mi ne. Coal mass inside the coalbed chamber was completely sealed from the ambient surroundings. Only forced ventilation was provided through a 1.3-cm-ID copper tube in the front plenum with the exhaust gas exiting the chamber via a 25-cm-ID duct in the rear plenum. There was no oxygen diffusion from the ambient surroundings into the coalbed chamber. Therefore, the criterion for the effect of oxygen on critical behavior established by Bower P.C. for stockpiles in open cannot be applied to our coalbed chamber. Test results obtained from this coalbed chamber by Smith, Miron, and Lazzara (1991) clearly show the effect of oxygen concentration on the self-heating of coal in the coalbed chamber.
Air-flow; Analytical-processes; Biochemistry; Explosions; Explosive-gases; Explosives; Flammable-gases; Fuels; Laboratory-techniques; Laboratory-testing; Mathematical-models Statistical-analysis;
Author Keywords: LFL; UFL; LOC; Flammable; Gas; Mixture
Liming Yuan, Pittsburgh Research Laboratory, National Institute for Occupational Safety and Health, P.O. Box 18070, Cochrans Mill Road, Pittsburgh, PA 15236
Journal of Loss Prevention in the Process Industries