Abstract
In Pulverized coal (PC) power plants, PC particles are injected to the burner through an injection nozzle. These nozzles are eroded and replaced frequently as a result. In this work, a scaled down model of a pulverized coal pneumatic transport system was developed and used to investigate erosion patterns inside the injection nozzle that were impacted by the particles. Since the purpose of the study was to obtain qualitative wear trends and not quantitative results, for safety and availability reasons sand particles were used as a substitute for pulverized coal. The geometry of the experimental setup is a simplification of commercially available coal ducts and injection nozzles. Flow visualization and paint erosion studies were performed to determine the areas with erosion hot spots. CFD simulations were also carried for similar geometry and conditions and are compared with the experimental results. The experiments as well as CFD showed that erosion rate was not uniform across different flow paths in the nozzle, nor did hotspots correspond with highest air exit velocity. Qualitative comparison between CFD predicted and observed wear hotspots showed an agreement between the results. The findings of this study will be used in the future to model the erosion of PC particles in coal injection nozzles.
