Inhibition of premixed carbon monoxide-hydrogen-oxygen-nitrogen flames by iron pentacarbonyl

Journal Article · Wed Mar 01 04:00:00 EST 2000 · Combustion and Flame

DOI:https://doi.org/10.1016/S0010-2180(99)00114-5· OSTI ID:20019023

Rumminger, M D; Linteris, G T

This paper presents measurements of the burning velocity of premixed CO-H{sub 2}-O{sub 2}-N{sub 2} flames with and without the inhibitor Fe(CO){sub 5} over a range of initial H{sub 2} and O{sub 2} mole fractions. A numerical model is used to simulate the flame inhibition using a gas-phase chemical mechanism. For the uninhibited flames, predictions of burning velocity are excellent and for the inhibited flames, the qualitative agreement is good. The agreement depends strongly on the rate of the CO + OH {leftrightarrow} CO{sub 2} + H reaction and the rates of several key iron reactions in catalytic H- and O-atom scavenging cycles. Most of the chemical inhibition occurs through a catalytic cycle that converts O atoms into O{sub 2} molecules. This O-atom cycle is not important in methane flames. The H-atom cycle that causes most of the radical scavenging in the methane flames is also active in CO-H{sub 2} flames, but is of secondary importance. To vary the role of the H- and O-atom radical pools, the experiments and calculations are performed over a range of oxygen and hydrogen mole fraction. The degree of inhibition is shown to be related to the fraction of the net H- and O-atom destruction through the iron species catalytic cycles. The O-atom cycle saturates at a relatively low inhibitor mole fraction ({approximately}100 ppm), whereas the H-atom cycle saturates at a much higher inhibitor mole fraction ({approximately}400 ppm). The calculations reinforce the previously suggested idea that catalytic cycle saturation effects may limit the achievable degree of chemical inhibition.

• Research Organization: National Inst. of Standards and Technology, Gaithersburg, MD (US)
• OSTI ID: 20019023
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 4 Vol. 120; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
08 HYDROGEN
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
CARBON MONOXIDE
CARBONYLS
COMBUSTION KINETICS
FIRE EXTINGUISHERS
FLAMES
HYDROGEN
INHIBITION
IRON COMPOUNDS
MATHEMATICAL MODELS
METHANE