Simulation of Residual Ash Formation During Pulverized Coal Combustion: Bimodal Ash Particle Size Distribution

Abstract

Ash formation during pulverized coal combustion has been simulated using a Monte Carlo model to follow the ash coalescence and char fragmentation processes that govern the final particle size distribution. As a consequence of the competition between the particle breakup by fragmentation and the ash coalescence enhanced by the shrinking peripheral area with the progress of char reaction, a bimodal size distribution is obtained. A simplified two-column model is also presented in order to explain the influence of the ash redistribution scheme used in the model on the evolution of the bimodality.