Modeling of swelling behavior of single coal particle during carbonization

The swelling behavior of a softening coal particle during carbonization was investigated both experimentally and numerically. In the numerical simulation, since the swelling of a coal particle was caused by the growth of bubbles in the particle, the bubble growth due to the inflow of volatile matters to the bubbles was calculated involving nucleation, coalescence in the particle and release of bubbles from the particle during the softening stage. The production of volatile matters was evaluated by a FLASHCHAIN model. The calculated swelling ratio was qualitatively consistent with the experimental results. In addition, the effect of viscosity on the swelling ratio was also investigated. As the viscosity became high, the swelling ratio increased and leveled off.