1996 Volume 82 Issue 9 Pages 731-736
A one-dimensional mathematical model of pulverized coal combustion in a blast furnace considering particle dispersion has been newly developed. On the basis of the model, the combustion efficiency was precisely estimated by setting the dispersion parameters properly for the lance structure. Evaluation of the effect of lance structure on the combustion behavior using this mathematical model suggested that the combustion efficiency in the raceway was greatly improved by intensifying the dispersion of particles. It was estimated that this phenomenon was resulted from the increase of the gasification rate of char particles caused by heating-up and the pyrolysis of the coal particles followed by the combustion of the volatile matter with peripheral oxygen. Moreover a simulation using an oxy-coal lance was carried out. The oxygen supplied from the lance tip was rapidly mixed with the hot blast as coal particles were dispersed, and concentration of oxygen that contributes to coal combustion decreased soon after injection. Therefore, injection of pulverized coal with the oxy-coal lance showed little improvement in combustibility compared with a normal single lance.
In conclusion, taking the particle dispersion into account in the one-dimensional model, it became possible to make a quantitative approach to evaluate the effect of lance structure, lance arrangement and the manners of oxygen enrichment in an actual blast furnace.
