Numerical investigation of Kraft recovery furnace wall temperature

Deposits can affect the in-furnace wall surface temperature in a Kraft recovery furnace. In CFD (Computational Fluid Dynamics) models of the Kraft recovery furnace, the wall surface temperature is frequently used as the heat-transfer boundary condition. Therefore, the effect of deposits must be taken into account in CFD models. In this work, CFD simulations of a Kraft recovery furnace were performed. Three approaches were used to provide the wall surface temperature as the heat-transfer boundary condition for the CFD model: A) a char-bed burning model was applied to the wall, and the surface temperature was calculated; B) the "radical deformation temperature" T-70 was used as the surface temperature; C) a slagging wall model was used, and the surface temperature was calculated. These three approaches emphasize different aspects of Kraft recovery furnace deposits. In particular, implementation of the stand-alone slagging wall model as part of a furnace model has been accomplished in this research. The in-furnace wall surface temperature and the radiative heat fluxes to the wall from the CFD simulations have been analyzed and evaluated using measurements made in the Kraft recovery furnace.