The effect of fuel pyrolysis on the coal particle combustion: An analytical investigation

Abstract

The aim of this work is to analytically investigate the symmetrical combustion of an isolated coal particle with the fuel pyrolysis effect. The modelling concept of coal particles is similar to that of the liquid droplet combustion but in the case of coal devolatilization, the particles do not shrink like droplet does due to evaporation of liquid fuel. The rate of devolatilization of volatiles can be calculated using the equation that is similar to Arrhenius equation. This model is based on an assumption of combined quasi-steady and transient behaviour of the process and especially focuses on predicting the variations of temperature profile, radius of pyrolysis and transfer number. It is revealed that the entrance of pyrolysis effect into the governing equations leads to the reduction in the film radius and consequently a reduction in the stand-off ratio and transfer number.

Combustion of lycopodium particles in random media: Analytical model and predicting the effect of heat loss and Lewis number

“…Solid particles that are lycopodium which more than 80% of it formed by CH 4 which is inside of it. Therefore, the mass of particles are negligible in compare with the gases mass: From definition in (9)- (11), it can be find:…”

“…It was found that when the Lewis number is less than unity, the flame velocities in ducts with an isothermal wall may exceed those in ducts with an adiabatic wall of the same diameter. Baghsheikhi et al [11] investigate the symmetrical combustion of an isolated coal particle with the fuel pyrolysis effect. It is revealed that the entrance of pyrolysis effect into the governing equations leads to the reduction in the film radius and consequently a reduction in transfer number.…”