Chemical Kinetics Study on Ignition Characteristics of Biodiesel Surrogates Osaka Institute of Technology

Format:

Conference/Event

Author/Creator:

Kuwahara, Kuwahara, author.

Contributor:

Ando, Hiromitsu

Nakahara, Koryu

Sakai, Yasuyuki

Senda, Jiro

Wada, Yoshimitsu

Conference Name:

SAE International Powertrains, Fuels and Lubricants Meeting (2011-08-30 : Kyoto, Japan)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2011

Summary:

Methyl butanoate (MB) and methyl decanoate (MD) are surrogatesfor biodiesel fuels. According to computational results with theirdetailed reaction mechanisms, MB and MD indicate shorter ignitiondelays than long alkanes such as n-heptane and n-dodecane do at aninitial temperature over 1000 K. The high ignitability of thesemethyl esters was computationally analyzed by means of contributionmatrices proposed by some of the authors.Due to the high acidity of an α-H atom in a carbonyl compound,hydroperoxy radicals are generated out of the equilibrium betweenforward and backward reactions of O₂ addition to methyl esterradicals by the internal transfer of an α-H atom in the initialstage of an ignition process. Some of the hydroperoxy methyl esterradicals can generate OH to activate initial reactions.MB has an efficient CH₃O formation path via CH₃ generated by theβ-scission of an MB radical which has a radical site on the α-Catom to the carbonyl group. MB has also other CH₃O formation pathsvia some of fragmental oxygenated radicals. Therefore, the CH₃Oconcentration is remarkably high in a thermal ignition preparationphase. The rich CH₃O decomposes into CH₂O and H, and then Hcombines with O₂ into HO₂. This exothermic reaction, H + O₂ + M =HO₂ + M, plays a key role in promoting initial heat release.MD has efficient paths for initial heat release starting fromthe O₂ addition to some of fragmental methyl ester radicals andending in the OH formation via the internal transfer of an α-Hatom. These paths considerably contribute not only to promotinginitial heat release but also to generating OH in the initial stageof an ignition process.In conclusion, these mechanisms for the high ignitability arecaused by a common local structure of methyl ester molecules, acarbonyl group in the molecule

Notes:

Vendor supplied data

Publisher Number:

2011-01-1926

Access Restriction:

Restricted for use by site license