A Lumped Approach to the Kinetic Modeling of Pyrolysis and Combustion of Biodiesel Fuels

A lumped approach to the kinetic modeling of pyrolysis and combustion of biodiesel fuels.

Chiara Saggese, Alessio Frassoldati, Alberto Cuoci, Tiziano Faravelli, Eliseo Ranzi

Supplemental Material

Figure S1. High and low temperature lumped oxidation mechanism of methyl decanoate [10].

Table S1

Lumped reactions of methyl decanoate and heavy methyl esters.

1-Comparisons of lumped and detailed model [1] predictions.

1.a Ignition delay times of stoichiometric fuel/air mixtures in a shock tubeat 13.5 atm.

Figure S2. Ignition delay times of stoichiometric fuel/air mixtures in a shock tubeat 13.5 atm. Comparison of the ignition delay times of methyl palmitate, methyl stearate, methyl oleate, linoleate, and methyl linolenate predicted with the lumped (lines with symbols) and the detailed model (lines) [1].

1.b Oxidation of stoichiometric fuel/air mixtures in a JSR at 1 atm.

Figure S3. Conversion ofmethyl stearate and methyl linolenatein stoichiometric fuel/air mixturesin a JSR.0.2% fuel with Helium diluents at 1 atm and 1.5 s. Comparison of the fuel conversion predicted with the lumped (dashed lines) and the detailed model (solid lines) [1].

There is a close agreement between predicted ignition delay times for all the methyl esters, but the methyl linolenate,possibly due to the different decomposition paths of intermediate unsaturated radicals. Lumped model is more reactive in the JSR at 600 K, while it shows larger ignition delay times at 650K in the shock tube conditions. Mainly the low temperature reactivity of unsaturated methyl esters require further kinetic analysis and experimental information.

2-Oxidation of n-decane mixtures with methyl palmitate and methyl oleate [20, 21]

2.a. Oxidation of n-decane mixtures with methyl palmitate [20]

Figure S4. Atmospheric and stoichiometric air oxidation of n-decane mixtures with 26% methyl palmitate at 1.5 s [20]. Comparisons of experimental (symbols) and predicted yields of CO, CO2, CH4, C2H6, C2H4 and C3H6 (lines with small symbols).

2.b Oxidation of n-decane mixtures with methyl oleate [21]

Figure S5. Atmospheric and stoichiometric air oxidation of n-decane mixtures with 26%

methyl oleate [21]. Comparisons of experimental (symbols) and predicted yields of CO, CO2, CH4, C2H6, C2H4 and C3H6 (lines with small symbols).

Figure S6Comparison of experimental and predicted ethylene and propylene yields from the oxidation of n-decane mixtures with methyl palmitate [20] and methyl oleate [21] in a JSR.

The similarity of the model predictions showsthat the 74% of n-decane in both fuel mixtures greatly influences the yields of oxidation and decomposition products. The difference in the experimental reactivity and C3H6yields at 800-900 Kseems to be at least partially due to experimental uncertainties.

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