2003 Volume 82 Issue 11 Pages 856-865
A model called “FC-CBK” is developed to predict the coal burnout profiles in a lot of furnaces. “FC-CBK” combines FLASHCHAIN, one of the network depolymerization devolatilization models, with CBK8, a mechanism for char oxidation that quantitatively represents the latest stages of burnout. Whereas these mechanisms involve numerous reaction rate constants and physical properties, all the parameters in “FC-CBK” may be specified from the coal's proximate and ultimate analyses.
In this study, an evaluation of “FC-CBK” was carried out to compare the predictions with the experimental data in an electrically heated drop-tube furnace. Firstly, the particle temperature histories in this furnace under various conditions were calculated by using a computational fluid dynamic code. Next, the obtained temperature histories were given to “FC-CBK” as the input data of the furnace conditions. Finally, the coal burnout profiles of eight coals were predicted by “FC-CBK” with the above-mentioned procedure. As a result of these verifications, we found “FC-CBK” can predict the accurate coal burnout profiles with giving the particle temperature histories.
The advanced features describing the late stages of burnout are hereby validated in conceptual terms, while the estimation of initial char reactivities still represents a major hurdle to any predictive capabilities based on only the basic coal analyses.