The importance of the nitrous oxide pathway to NO{sub x} in lean-premixed combustion

Journal Article · Sun Jan 01 04:00:00 EST 1995 · Journal of Engineering for Gas Turbines and Power

DOI:https://doi.org/10.1115/1.2812756· OSTI ID:28051

Nicol, D G; Steele, R C; Marinov, N M; Malte, P C ^[1]

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1. Univ. of Washington, Seattle, WA (United States)

This study addresses the different chemical pathways responsible for NOx formation in lean-premixed combustion, and especially the role of the nitrous oxide pathway relative to the traditional Zeldovich pathway. NOx formation is modeled and computed over a range of operating conditions for the lean-premixed primary zone of gas turbine engine combustors. The fuel is methane. The fuel-air equivalence ratio is varied from 0.5 to 0.7. The chemical reactor model permits study of the three pathways by which NOx forms, which are the Zeldovich, nitrous oxide, and prompt pathways. Modeling is also performed for the well-stirred reactor alone. Three recently published, complete chemical kinetic mechanisms for the C1-C2 hydrocarbon oxidation and the NOx formation are applied and compared. Verification of the model is based on the comparison of its NOx output to experimental results. For lean-premixed combustion at gas turbine engine conditions, the nitrous oxide pathway is found to be important, though the Zeldovich pathway cannot be neglected. The prompt pathway, however, contributes small-to-negligible NOx. Whenever the NOx emission is in the 15 to 30 ppmv range, the nitrous oxide pathway is predicted to contribute 40--45% of the NOx for high-pressure engines (30 atm), and 20--35% of the NOx for intermediate pressure engines (10 atm). For conditions producing NOx of less than 10 ppmv, the nitrous oxide contribution increases steeply and approaches 100%. For lean-premixed combustion in the atmospheric pressure jet-stirred reactors, different behavior is found. All three pathways contribute; none can be dismissed. No universal behavior is found for the pressure dependence of the NOx.

• Sponsoring Organization: USDOE
• OSTI ID: 28051
• Report Number(s): CONF-930502--
• Journal Information: Journal of Engineering for Gas Turbines and Power, Journal Name: Journal of Engineering for Gas Turbines and Power Journal Issue: 1 Vol. 117; ISSN 0742-4795; ISSN JETPEZ
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
CHEMICAL REACTION YIELD
COMBUSTION KINETICS
FUEL-AIR RATIO
GAS TURBINE ENGINES
MATHEMATICAL MODELS
NATURAL GAS
NITROGEN OXIDES
NITROUS OXIDE
REACTION INTERMEDIATES