Utilization of computational fluid dynamics technique in low NO_x burner/furnace retrofits

摘要

A computational fluid dynamics (CFD) technique has been utilized to provide design guidance for retrofitting low NO_x combustion systems and incorporating associated furnace modifications into existing utility boilers. The CFD program utilized is FW-FIRES (Fossil fuel, Water-walled Furnace Integrated Reaction and Emission Simulation) which simulates furnace combustion, heat transfer and pollutant formation based on fundamental principles of mass, momentum and energy conservations. The program models the gas flow field as a three-dimensional turbulent reacting continuum and the particle flow as a series of discrete particle trajectories through the gas continuum. Chemical reaction, heat transfer, and pollutant formation mechanisms are incorporated in the program. FW-FIRES furnace simulation of low NO_x combustion system retrofits has been performed for various furnace configurations including front wall-fired, front and real wall-fired, and tangentially-fired furnaces, to determine the effects of burner/furnace modifications on the NO_x emission, furnace exit gas temperature, furnace heat absorption, unburned carbon, and furnace wall corrosion.