PREDICTION OF HEAT-TRANSFER IN THE KRAFT RECOVERY BOILER SUPERHEATER REGION

Accurate prediction of tube surface temperature is important for deter mining whether accelerated superheater corrosion will occur in kraft r ecovery boilers. A heat transfer model, which combines an iterative nu merical solution scheme with a more realistic flue-gas flow field obta ined from a CFD code FLUENT, had been developed to predict the tube, s team and flue-gas temperatures in the superheater region. Results of t ests performed for a recovery boiler show that temperatures predicted by the model are in good agreement with actual temperatures measured u sing thermocouples. The presence of a large flue-gas recirculation zon e above the bullnose is shown to have an adverse effect on the heat tr ansfer in the superheater region.