A study of NO{sub x} reduction by fuel injection recirculation. Final report, January 1995--June 1996

Technical Report · Thu Aug 01 04:00:00 EDT 1996

DOI:https://doi.org/10.2172/441734· OSTI ID:441734

Feese, J J; Turns, S R

Flue-gas recirculation (FGR) is a well-known method used to control oxides of nitrogen (NO{sub x}) in industrial burner applications. Recent small- and large-scale experiments in natural-gas fired boilers have shown that introducing the recirculated flue gases with the fuel results in a much greater reduction in NO{sub x}, per unit mass of gas recirculated, in comparison to introducing the flue gases with the combustion air. That fuel injection recirculation (FIR) is more effective than windbox FGR is quite remarkable. At present, however, there is no definitive understanding of why FIR is more effective than conventional FGR. The objective of the present investigation is to ascertain whether or not chemical and/or molecular transport effects alone can explain the differences in NO{sub x} reduction observed between FIR and FGR by studying laminar diffusion flames. The purpose of studying laminar flames is to isolate chemical effects from the effects of turbulent mixing and heat transfer, which are inherent in practical boilers. The results of both the numerical simulations and the experiments suggest that, although molecular transport and chemical kinetic phenomena are affected by the location of diluent addition depending on flow conditions, the greater effectiveness of FIR over FGR in practical applications may result from differences in turbulent mixing and heat transfer. Further research is required to understand how differences in diluent-addition location affect NO{sub x} production in turbulent flames. The present study, however, provides an underlying basis for understanding how flow conditions can affect flame chemistry. 51 figs., 7 tabs.

• Research Organization: Pennsylvania State Univ., University Park, PA (United States)
• Sponsoring Organization: USDOE Assistant Secretary for Energy Efficiency and Renewable Energy, Washington, DC (United States)
• DOE Contract Number: FG04-95AL87310
• OSTI ID: 441734
• Report Number(s): DOE/AL/87310--3; ON: DE97003462
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
AIR POLLUTION CONTROL
BOILERS
COCOMBUSTION
COMBUSTION KINETICS
EXHAUST RECIRCULATION SYSTEMS
FLUE GAS
FUEL INJECTION SYSTEMS
INDUSTRIAL PLANTS
NATURAL GAS
NITROGEN OXIDES
PROGRESS REPORT
RECYCLING