Premixed ignition behavior of C{sub 9} fatty acid esters: A motored engine study

Journal Article · Mon Jun 15 00:00:00 EDT 2009 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2009.01.024· OSTI ID:21177445

Zhang, Yu; Yang, Yi; Boehman, Andre L ^[1]

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1. EMS Energy Institute, The Pennsylvania State University, University Park, PA 16802 (United States)

An experimental study on the premixed ignition behavior of C{sub 9} fatty acid esters has been conducted in a motored CFR engine. For each test fuel, the engine compression ratio was gradually increased from the lowest point (4.43) to the point where significant high temperature heat release (HTHR) was observed. The engine exhaust was sampled and analyzed through GC-FID/TCD and GC-MS. Combustion analysis showed that the four C{sub 9} fatty acid esters tested in this study exhibited evidently different ignition behavior. The magnitude of low temperature heat release (LTHR) follows the order, ethyl nonanoate > methyl nonanoate >> methyl 2-nonenoate > methyl 3-nonenoate. The lower oxidation reactivity for the unsaturated fatty acid esters in the low temperature regime can be explained by the reduced amount of six- or seven-membered transition state rings formed during the oxidation of the unsaturated esters due to the presence of a double bond in the aliphatic chain of the esters. The inhibition effect of the double bond on the low temperature oxidation reactivity of fatty acid esters becomes more pronounced as the double bond moves toward the central position of the aliphatic chain. GC-MS analysis of exhaust condensate collected under the engine conditions where only LTHR occurred showed that the alkyl chain of the saturated fatty acid esters participated in typical paraffin-like low temperature oxidation sequences. In contrast, for unsaturated fatty acid esters, the autoignition can undergo olefin ignition pathways. For all test compounds, the ester functional group remains largely intact during the early stage of oxidation. (author)

• OSTI ID: 21177445
• Journal Information: Combustion and Flame, Vol. 156, Issue 6; Other Information: Elsevier Ltd. All rights reserved; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBOXYLIC ACID ESTERS
COMBUSTION
DIESEL FUELS
PRESSURE RANGE KILO PA
AUTOIGNITION
HEAT
ENGINES
TEMPERATURE RANGE 0400-1000 K
BIOFUELS
QUANTITATIVE CHEMICAL ANALYSIS
COMBUSTION PROPERTIES
COMPRESSION RATIO
ACTIVATION ENERGY
INHIBITION
Low-temperature heat release
High- temperature heat release
Low-temperature oxidation
Motored engine