Modeling Soot in Coal Systems

摘要

The formation of soot in power-boiler systems can have a significant impact on boiler performance due to direct effects on local flame temperatures and wall heat flux. In this work, a soot model was developed for coal systems that accommodates differences between solid fuel systems and gaseous systems, for which most traditional soot models are developed. The developed soot model contains terms for: particle nucleation based on tar evolution in a coal system, a nucleation mechanism based on the formation of PAH from gaseous species, gaseous interactions with particles (including: surface growth through HACA, particle oxidation/gasification), coagulation, and aggregation of existing particles. A monodispersed-particle size distribution form of this model can be used for cost-effective simulations, or for simulations with higher fidelity, the method of moments is used to transport higher moments of the particle size distribution. Validation work is presented, comparing numerically-derived soot values from the proposed model against measured soot concentrations in a flat-flame burner.