Using numerical simulation methods to predict the effects of balancing coal and primary air flow rates on furnace emissions
This paper presents the technical results of a computer modeling exercise to quantify the impacts of balanced and unbalanced coal flows on NO{sub x} emissions and other boiler performance indicators. Using Airflow Sciences Corporation`s proprietary codes, separate computational fluid dynamics models of the furnace region and coal nozzles of a 200 MW{sub e} tangentially-fired boiler equipped with an ABB C-E Services Low NO{sub x} Concentric Firing System (Level II) were constructed. In modeling the coal combustion process, the numerical simulation of gas conditions within the furnace is accomplished by coupling the fluid dynamics relationships with sub-models that predict heat transfer (conduction, convection and radiation), turbulence, coal particle trajectories and temperatures, coal devolatilization, char combustion and equilibrium (mixing limited) chemistry. The equilibrium chemistry sub-model defines concentrations of the products of combustion at all locations within the furnace, with the exception of NO{sub x} concentrations. The generation of NO{sub x} is decoupled from the CFD simulation and is determined using finite-rate chemistry. The model was validated using test results from a recently completed US Department of Energy-sponsored Clean Coal Project at Gulf Power Company`s Plant Lansing Smith Unit 2. Validation was accomplished through comparison of the model results with experimental data including NO{sub x} emissions, unburned carbon, furnace exit gas temperatures, carbon monoxide levels, and excess oxygen values. Following validation, additional simulations were run to quantify the effect of balanced and unbalanced coal flows. Conditions simulated included the as-found condition, a fully balanced condition, a mill-by-mill fully balanced condition, and a {+-}10 percent balanced condition. The results showed that NO{sub x} emissions were not significantly affected by improving the distributions of primary air and coal between the burners.
- OSTI ID:
- 427860
- Report Number(s):
- CONF-961006-; ISBN 0-7918-1795-4; TRN: IM9708%%187
- Resource Relation:
- Conference: 1996 international joint power generation conference, Houston, TX (United States), 13-17 Oct 1996; Other Information: PBD: 1996; Related Information: Is Part Of Proceedings of the 1996 international joint power generation conference -- Volume 1: Environmental control/fuels and combustion technologies. EC-Volume 4; FACT-Volume 21; Smouse, S.M. [ed.] [Dept. of Energy, Pittsburgh, PA (United States). Pittsburgh Energy Technology Center]; Gupta, A. [ed.] [Univ. of Maryland, College Park, MD (United States)]; PB: 516 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Advanced tangentially fired low-NO{sub x} combustion demonstration. Phase 2, LNCFS Level 2 tests
Innovative Clean Coal Technology (ICCT): 180 MW demonstration of advanced tangentially-fired combustion techniques for the reduction of nitrogen oxide (NO{sub x}) emissions from coal-fired boilers. Topical report, LNCFS Levels 1 and 3 test results