Coal pyrolysis in a rotary kiln: Part I. Model of the pyrolysis of a single grainReport as inadecuate

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1 Labex DAMAS 2 IJL - Institut Jean Lamour 3 GEOMAR - GEOMAR - Helmholtz Centre for Ocean Research Kiel 4 ArcelorMittal 5 LSG2M - Laboratoire de Science et Génie des Matériaux et de Métallurgie 6 LRGP - Laboratoire Réactions et Génie des Procédés

Abstract : A mathematical model is presented describing the pyrolysis of a single grain of coal and designed to be incorporated in an overall model simulating the rotary kiln coal pyrolysis process. The grain model takes into account the principal physical phenomena occurring during the conversion of coal to coke, namely heat transfer towards and within the grain, drying of the coal, and the evolution of volatile species. Particular care has been taken in the determination of the thermophysical and kinetic parameters necessary for the model. Thus, the drying kinetics for Lorraine coal were measured by thermogravimetry. The kinetics of pyrolysis were determined by both thermogravimetry and gas phase chromatography in order to separately monitor the evolution of the 9 gaseous species considered. The true specific heat and the thermal conductivity of the solid were also mesured as a function of temperature. The numerical model, based on the finite volume method, calculates the temperature, the composition and the mass flowrates for the different gases evolved at each point in the grain at any instant of time. The model was finally validated by comparing the calculated and measured values of the overall conversion of the pyrolysis reaction and the temperature at the center of the grain.

Keywords : grain model kinetics coke coal pyrolysis

Author: Fabrice Patisson - Etienne Lebas - François Hanrot - Denis Ablitzer - Jean-Leon Houzelot -



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