Published 6 issues per year
ISSN Print: 2150-766X
ISSN Online: 2150-7678
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THE MODEL OF POROUS CARBONIZED PARTICLE COMBUSTION
ABSTRACT
The theoretical model of porous carbonized particle combustion in air is discussed. The model considers equations of heat and mass transfer in the gas phase and inside porous particles. The heat flux from the particles surface to the wall of the furnace is taken into account. The different regimes of particle combustion are investigated. It is shown that the gas-phase regime of particles combustion, in which the heterogeneous chemical reaction of carbon interaction with oxygen is absent and the homogeneous chemical reaction occurs above particle surface, is realized when the furnace walls temperature is rather high. In this regime of the particle combustion the heterogeneous chemical reaction of carbon interaction with carbon dioxide takes place inside particle, because the oxygen is almost totally supplied in homogeneous chemical reaction above the particle surface. For lower furnace wall temperature the kinetic regime of particle combustion, in which the heterogeneous chemical reaction of carbon interaction with oxygen as well as with carbon dioxide takes place inside porous particle, is observed. In the kinetic regime of the particle combustion the rate of the particle burning out is increased with furnace wall temperature increasing and that practically achieves the maximum particle burning out rate in the diffusing regime of particle combustion. In the gas-phase regime of the particle combustion the rate of the particle burning out is smoothly increased achieving the maximum rate of the particle combustion at the very high furnace wall temperature. Thus, there is some crisis of the particle burning out rate, when the rate of the particle burning out is very sharply fallen down in the narrow range of the furnace wall temperature (from 1300 K to 1400 K for particle having size about 100 μm and burning out in air).