Numerical Investigation of the Influence of Furnace Wall Temperature on Pulverized Coal Combustion and NOx Emissions in a Supercritical CO2 Boiler

Abstract

A study on the combustion process and NOx emission of pulverized coal in a supercritical CO2 boiler was carried out by using the method of numerical simulation. Using a comprehensive combustion model and a post-treatment NOx formation model, the influence of wall temperature on the characteristics of combustion and NOx emissions of a 300 MW tangential coal-fired boiler were studied. The temperature field and the concentration distribution of waste flue gas at the furnace outlet are analysed and studied. It was found that the furnace wall temperature seriously affected both the distribution of the temperature field and the emission of NOx. The supercritical CO2 boiler’s partial flow strategy led to further increases in temperature and NOx near the tail. According to the results of the calculations, the supercritical CO2 boiler might raise the exhaust gas temperature, making the difficulty of extracting energy from waste gas increased dramatically. The increased NOx emissions will lead to higher cost for implementation of after treatment of NOx emissions. The work’s findings can be used to improve the design of coal-fired supercritical CO2 boilers as well as gain a deeper comprehension of the formation of NOx.