Three-dimensional numerical modeling of a field scale rotary kiln incinerator

A steady-state numerical model for the rotary kiln segment of a hazardous waste incinerator is presented. This model builds on work previously conducted at Louisiana State University by including radiation and soot in the heat transfer analysis, by switching to an adiabatic kiln wall boundary condition, and by including a more accurate geometry and better fitting grid. These changes improve agreement with data taken from a field-scale rotary kiln, operating with a natural gas support flame but no waste processing, by up to 2 orders of magnitude compared to previously developed models at LSU, In most instances, prediction is within repeatability limits of the experiments. Grid dependency is demonstrated, especially at the upper front of the kiln where gradients are very steep. Near the exit of the kiln, however, where the limited experimental data are available, both coarse and refined grids produced very similar results. Parametric and sensitivity studies using the developed model are reported.