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Title: Diode laser absorption measurement and analysis of HCN in atmospheric-pressure, fuel-rich premixed methane/air flames

Measurements of HCN in flat, fuel-rich premixed methane/air flames at atmospheric pressure are reported. Quartz-microprobe sampling followed by wavelength modulation absorption spectroscopy with second harmonic detection was used to obtain an overall measurement uncertainty of better than 20% for mole fractions HCN on the order of 10 ppm. The equivalence ratio, {phi}, was varied between 1.3 and 1.5, while the flame temperature was varied independently by changing the mass flux through the burner surface at constant equivalence ratio. Under the conditions of the experiments, the peak mole fractions vary little, in the range of 10-15 ppm. Increasing the flame temperature by increasing the mass flux had little influence on the peak mole fraction, but accelerated HCN burnout substantially. At high equivalence ratio and low flame temperature, HCN burnout is very slow: at {phi}=1.5, {proportional_to}10ppm HCN is still present 7 mm above the burner surface. Substantial quantitative disagreement is observed between the experimental profiles and those obtained from calculations using GRI-Mech 3.0, with the calculations generally overpredicting the results significantly. Changing the rates of key formation and consumption reactions for HCN can improve the agreement, but only by making unreasonable changes in these rates. Inclusion of reactions describing NCN formation andmore » consumption in the calculations improves the agreement with the measurements considerably. (author)« less
Authors:
;  [1] ;  [1] ;  [2]
  1. Laboratory for Fuel and Combustion Science, University of Groningen (Netherlands)
  2. (Netherlands)
Publication Date:
OSTI Identifier:
21116110
Resource Type:
Journal Article
Resource Relation:
Journal Name: Combustion and Flame; Journal Volume: 155; Journal Issue: 1-2; Other Information: Elsevier Ltd. All rights reserved
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; HYDROCYANIC ACID; NITRIC OXIDE; METHANE; LAMINAR FLAMES; AIR; ATMOSPHERIC PRESSURE; COMBUSTION PROPERTIES; TEMPERATURE DEPENDENCE; BURNERS; BURNOUT; MASS; MATHEMATICAL MODELS; ACCURACY; NITROGEN COMPOUNDS; CYANIDES Diode laser absorption spectroscopy