Optimization of Coal-Fired Power Plant Exhaust Air Ducts
NIPSCO Bailly Generating Station had a problem with a coal fired boiler. After completing the installation of pollution control equipment, the exhaust air ducts, through which exhaust gas from coal combustion is discharged to pollution control units, were operating at just 85 to 90 percent of maximum capacity. The reduced operating capacity diminishes overall energy production and revenue. Computational Fluid Dynamics (CFD) has been recognized as a cost-effective tool for the troubleshooting and optimization of the system.
CFD models were used to analyze detailed flow patterns of the air ducts for troubleshooting. The CFD simulation results were validated using measurement data and visualized on a Virtual Reality (VR) system. After identifying the cause of the problem, a series of parametric studies were conducted with the introduction of multiple turning vanes in order to provide an optimized solution. The effect of different turning vane configurations was investigated and visualized in an immersive environment. The optimized design was recommended and implemented based on CFD simulations and VR visualization.
Flow restrictions were identified as the cause of the problem. An optimized design of the exhaust duct using multiple turning vanes was generated and installed, which resulted in operation at full capacity. According to Tim Wright at NIPSCO, “When the vanes were installed, the derate went away. Using rather rough estimates, the result is an estimated $1.9 million in annual savings if the unit continues to operate in this manner.”
“The CFD study initially conducted by the students showed recirculation in the duct downstream of the “Y” where the output of the two units is combined. Further CFD study resulted in an optimized arrangement of turning vanes, thereby improving flow in the ducts. Those vanes were installed and the derate went away. Using rather rough estimates of a 20 MW derate, 10 months per year of operation of Unit 7 and Unit 8, combined with 14 hours per day of full load operation of both units, we used a cost/benefit model to estimate the benefits coming from resolving that derate. The result is an estimated $1.9 million annual savings.”
Bailly Generating Station
Click the movie below to see the Power Plant Components Duct in detail.
Faculty Collaborator: Dr. Chenn Q. Zhou