Utilization of computational fluid dynamics technique in low NOx burner/furnace retrofits
A computational fluid dynamics (CFD) technique has been utilized to provide design guidance for retrofitting low NOx 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 principals 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 NOx 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 NOx emission, furnace exit gas temperature, furnace heat absorption, unburned carbon, and furnace wall corrosion. For front wall-fired, and front and real wall-fired furnaces, the NOx emission requirement is met by the use of Foster Wheeler lox NOx burners and overfire air (OFA) staging. Studies of burner and OFA quantify and spacing are conducted to limit NOx emission and unburned carbon to acceptable levels. A major concern in once-through supercritical units with OFA is furnace wall corrosion which is caused by high furnace wall metal temperature and corrosive hydrogen sulfide (H{sub 2}S) created in a reducing atmosphere from part of coal sulfur. The FW-FIRES code is used to minimize this corrosion potential by selecting the proper location and quantity of boundary air. A simulation of tangentially-fired unit, which has been retrofitted with low NOx burners, is used to study the effect of the burner tilt on the furnace exit gas temperature. This paper details the basis and results of several CFD analyses conducted for potential retrofit programs.
- Research Organization:
- Foster Wheeler Development Corp., Livingston, NJ (US)
- OSTI ID:
- 20013457
- Resource Relation:
- Conference: 24th International Technical Conference on Coal Utilization and Fuel Systems, Clearwater, FL (US), 03/08/1999--03/11/1999; Other Information: PBD: [1999]; Related Information: In: The proceedings of the 24th international technical conference on coal utilization and fuel systems, by Sakkestad, B.A. [ed.], 1091 pages.
- Country of Publication:
- United States
- Language:
- English
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