Auto-ignition temperatures of binary mixtures of alkanes in a closed vessel: Comparisons between experimental measurements and numerical predictions

Conference · Mon Jan 01 04:00:00 EST 1990

DOI:https://doi.org/10.1016/S0082-0784(06)80452-2· OSTI ID:6909507

Griffiths, J F; Coppersthwaite, D; Phillips, C H ^[1]; Westbrook, C K; Pitz, W J ^[2]

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1. Leeds Univ. (UK). School of Chemistry
2. Lawrence Livermore National Lab., CA (USA)

Autoignition temperatures of the binary mixtures methane + ethane and methane + butane in air were measured at atmospheric pressure in a 0.56 dm{sup 3} spherical reaction vessel. The method used followed that for standard ASTM and BS tests for gaseous fuels. Fixed proportions by volume of the total fuel in air were studied, which correspond at the extreme of each composition range to the equivalence ratios for methane, ethane and butane of {phi} = 0.93, 1.63 and 3.04, respectively. Supplementary experiments were carried out on butane alone under the same conditions, in which its proportion was varied in the equivalence range 0<{phi}<3.04. The autoignition of methane was sensitized by ethane most strongly when the ethane was present at up to 10% of the total fuel. The autoignition temperature (T{sub a,cr}) was reduced by 40 K with respect to that for pure methane (T{sub a,cr} = 900 K). There was an even stronger sensitization by similar proportions of butane added to methane, such that T{sub a,cr} decreased to 810 K. in neither case were the effects linearly dependent on the proportion of additive. There was an addition sensitive region when butane was present in the proportion 0.5--0.7 of the methane/butane mixture, at which T{sub a,cr} fell sharply by 50 K over this limited composition range. Remarkably, except at the leanest mixtures ({phi}{sub butane} < 0.5), the autoignition temperatures of compositions containing butane alone matched very closely the autoignition temperatures of the equivalent methane/butane mixtures. We believe that this is a new and very important observation in relation to the understanding and interpretation of combustion hazards involving mixtures of fuels. 28 refs., 4 figs.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• Sponsoring Organization: DOE/CE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6909507
• Report Number(s): UCRL-102778; CONF-900704--8; ON: DE90007856
• Country of Publication: United States
• Language: English

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ALKANES
BUTANE
CHEMICAL ANALYSIS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMBUSTION CHAMBERS
COMBUSTION KINETICS
EFFICIENCY
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METHANE
ORGANIC COMPOUNDS
OXIDATION
PREDICTION EQUATIONS
PRESSURE EFFECTS
PURIFICATION
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THERMODYNAMICS