Study on Characteristics of Oxygen-rich Combustion and Nitrogen Emissions of Blast Furnace Gas and Pulverized Coal Blended Combustion Boiler

Take a 300 MW blast furnace gas (BFG)/pulverized coal boiler for example, numerical simulations of the combustion process are carried out at three different oxygen-rich conditions of 02 concentration (30%,35%,40%) in the combustion gas (O2/CO2) and conventional air condition by the FLUENT software. The simulation results show: In theoxygen-enriched conditions, the flue gas temperature increases with the growth O2 concentration in the bottom of the furnace and the burner zone, but in the area above the burner, showing an opposite trend, when O2 concentration exceed 35%, the flue gas temperature level has been lower than that in the conventional air condition; The NO concentration increases with the growth of O2 concentration, when the O2 concentration is 40%, NO concentration has exceeded that in the conventional air condition. The growth of NO concentration is hecause of the increasing of O2 concentration in furnace. The export CO2 concentration in three oxygen-rich conditions reached a higher level, which favors CO2 liquefaction separation. In summary, for the BFG/Pulverized Coal Blended Combustion Boiler to use oxygen-rich combustion technology, the initial oxygen concentration should not exceed 35%.