A Quasisteady Analysis of Oxy-Fuel Combustion of a Wood Char Particle

A quasisteady model for single char particle combusting at oxy-fuel conditions is presented. The model is validated against predictions of a detailed numerical model and experimental data reported in the literature. The main idea is to study burning characteristics of small char particles obtained from wood pyrolysis at the conditions corresponding to those found in industrial biomass furnaces (high heating conditions, larger and less dense particles compared to coal char particles). The results indicate that the particle temperature is considerably lower in O2/CO2 mixtures (due to the endothermicity of the gasification reactions) than that in an O2/N2 environment. For an O2 mass fraction of 0.3, the burnout time is found to be the same in both gasifying environments. However, at lower O2 mass fractions, the burnout time of a particle burning in the oxy-fuel conditions is shorter than that in an O2/N2 mixture.