Abstract:
In this work, an economizer model in circulating fluidized bed boiler has been developed based on computational fluid dynamics simulation in steady-state for analyzing hydrodynamics and heat transfer behavior which can help to predict risk areas of erosion and corrosion within the economizer. The outlet flue gas temperature in the base case has been compared with the data from the actual operating conditions from Integrated Research Center Co., Ltd. From the results of the prediction of corrosion risk areas due to sulfuric acid condensation, it was found that the tube surface near the feed water inlet is the area where the flue gas temperature is the lowest. To predict risk areas by chloride induced corrosion, it was found that the changes in fluid hydrodynamics and heat transfer behaviors in each case study resulted in different distributions of the ash deposition layer. To predict the risk area with the relationship between the corrosion rate and tube surface temperature, the simulation results showed that the risk areas of the tube surfaces are near the feed water outlet where the tube surface temperature is the highest. The areas at risk of fire side abrasive erosion are predicted by using the study of the maximum ash velocity around the heat exchanger tube. It was found that ash particle collisions at the highest speeds caused the erosion risk areas near the feed water inlet of the economizer.