Pulverized coal combustion and its interaction with moisture

摘要

A mathematical model for combustion of wet pulverized coal in fluidized bed was developed. The equations for species concentration, energy, devolatilization, ash release to the gaseous ambient, burning of carbon and drying of the particles are solved numerically. The rate of mass consumption is kinetically controlled and simultaneous devolatilization and char combustion was considered. All chemical formulae were established for all species present in the reacting flow. Several tests were performed taken into account the reciprocal influence between wet sub-bituminous coal particles and gaseous phase. The influence of moisture in coal combustion was also analyzed. A slight reduction in combustion time was found with the increasing of the wetness in the particle and a catalytic effect of the water was detected in the conversion of CO to CO{sub}2. Concerning the gas phase (CO), it was observed that the presence of moisture causes the displacement of the combustion zone. It was found good agreement with the experimental data available in the literature.