High-temperature corrosion prediction model of water-cooled wall for boiler peak regulation
With large-scale renewable power integrated into the grid,the status of traditional thermal power units as energy allocation has been significantly enhanced.The safety and stability of boiler peak-shaving operation become more and more important.This work coupled the heat absorption with the hydrodynamic characteristics and forms the temperature calculation model of water-cooled wall.Meanwhile,a SOx generation model was developed to determine the process of the fuel sulfur release in a reducing atmosphere and the mutual transformation of sulfur components.Based on the numerical simulation of furnace,the temperature calculation model of water-cooled wall and the tube wall high-temperature corrosion model with time dimension,a high-temperature corrosion prediction model of water-cooled wall for boiler peak-shaving operation was proposed.The corresponding software was also developed using the Matlab GUI platform.A supercritical 600MW tangentially coal-fired boiler was selected as the research object.The results showed that the accuracies of the wall temperature distribution and H2S concentration distribution near the wall obtained by coupling calculation of wall temperature and SOx generation model were high,which provided a good basis for accurate prediction of high-temperature corrosion.The high-temperature corrosion characteristics of the water-cooled wall under different loads were different.The corrosion degree of the water-cooled wall decreases with the decrease of the boiler loaded as a whole.The area of front wall between the burner zone and SOFA zone was the most severely corroded under 100％ BMCR and 75％THA load,with maximum corrosion depths of 276μm and 233μm per year,respectively.The high-temperature corrosion depths under 50％ THA and 35％ BMCR load rapidly increased to a maximum in the top of the burner zone,which were 224μm and 256μm per year,respectively.The high-temperature corrosion state of the water-cooled wall under multiple working operation was manifested as the spatio-temporal superposition of the corrosion state of each working condition.The spatio-temporal distribution of the high-temperature corrosion state of water-cooled wall could be predicted by boiler operation parameters and operation time through the prediction software.
peak-shaving operationwater-cooled wallhigh-temperature corrosionnumerical simulationwall temperature calculation
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