NUMERICAL MODELING OF THE TEMPERATURE DISTRIBUTION IN A COMMERCIAL HAZARDOUS-WASTE SLAGGING ROTARY KILN

The gas, wall, and bed temperatures in a hazardous waste incineration kiln were studied using a commercially available, CFD-based, reacting flow code, which included radiation heat tra nsf er. The mod el was co mpared to field measurements made on a co-current flow, 35 MW slagging rotary kiln. Cases were run to determine the sensitivity of the predi ctions to changes in the model assumptions and to simulate the normal variation in combustion inputs. The model predictions of the peak bed temperature, of the axial temperature profile, and of the gas temperat ure at the exit-plane were consistent with the measurements at a full- scale waste incinerator during normal operation. The model and the fie ld observations both indicate that the peak bed temperature occurs nea r the middle of the kiln and that the difference between the peak bed temperature and the exit-plane gas temperature depends on the inlet fl ows. The geometry of the transition between the kiln and the secondary combustion chamber and the fuel-to-air equivalence ratio have the gre atest effect on the calculated temperature distribution. Modeling stud ies provide useful information such as the relationship between availa ble measurements and the temperature at inaccessible lo cations inside a full-scale kiln.