Flame structure studies of neat and NH{sub 3} doped H{sub 2}/N{sub 2}O flames employing molecular beam mass spectrometry and modeling

Conference · Wed Mar 01 04:00:00 EST 1995

OSTI ID:110840

Sausa, R C; Singh, G; Lemire, G W ^[1]

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1. Army Research Lab., Aberdeen Proving Ground, MD (United States); and others

The H{sub 2}/N{sub 2}O chemical system has received much interest in recent years. Much of this interest stems from the fact that this system is fairly simple and that it has important implications in understanding NO{sub x} pollutant formation, and nitramine propellant combustion and decomposition. The elementary reactions of this system form a subset of a larger mechanism needed to understand the nitrogen chemistry of more complex combustion systems. An understanding of the way additives alter the chemical pathways in combustion systems is a prerequisite for controlling and enhancing system performance. In a recent comprehensive experimental and modeling study of a 20 Torr, burner stabilized flame, the authors reported that the burned gases of the flame contain concentrations of NO and H{sub 2} that are ten times more than that computed from equilibrium calculations. NO, a product of incomplete combustion (PIC), acts as an inhibiter and prevents full energy release of the system within or near the flame zone. This paper reports experimental and modeling studies of H{sub 2}/N{sub 2}O/NH{sub 3} flames in order to explore the conversion of NO to final products by adding trace concentrations of NH{sub 3}. NH{sub 3} was used as the additive because of its proven use in the thermal deNO{sub x} process to remove NO from effluent streams of industrial furnaces. Species profiled include H{sub 2}, N{sub 2}O, NH{sub 3}, H{sub 2}O, N{sub 2}, O{sub 2}, and NO. These profiles are compared to calculated profiles generated using PREMIX, a one dimensional premixed laminar flame code. Rate and sensitivity analyses were performed on the PREMIX results using an interactive postprocessing code the authors have written so that the details of the chemistry may be understood. The efficacy of the NH{sub 3} additive on the conversion of NO to N{sub 2}, as well as the mechanisms of NO formation from both neat NH{sub 3}-doped flames are presented and discussed.

• Research Organization: National Renewable Energy Lab., Golden, CO (United States)
• OSTI ID: 110840
• Report Number(s): NREL/CP--433-7748; CONF-9410343--; ON: DE95004052
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
AMMONIA
COMBUSTION
FLAMES
HYDROGEN
INHIBITION
MASS SPECTROSCOPY
MOLECULAR BEAMS
NITRIC OXIDE
NITROUS OXIDE