Chemical insights into the larger sooting tendency of 2-methyl-2-butene compared to n-pentane

Journal Article · Thu Jul 11 00:00:00 EDT 2019 · Combustion and Flame

DOI:https://doi.org/10.1016/j.combustflame.2019.06.029· OSTI ID:1559481

León, Larisa ^[1]; Ruwe, Lena ^[2]; Moshammer, Kai ^[3]; Seidel, Lars ^[4]; Shrestha, Krishna P. ^[1]; Wang, Xiaoxiao ^[1]; Mauss, Fabian ^[1]; Kohse-Höinghaus, Katharina ^[2]; Hansen, Nils ^[5]

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1. Brandenburg Univ. of Technology, Cottbus (Germany)
2. Bielefeld Univ., Bielefeld (Germany)
3. Physikalisch Technische Bundesanstalt (PTB), Braunschweig (Germany)
4. LOGE Deutschland GmbH, Cottbus (Germany)
5. Sandia National Lab. (SNL-CA), Livermore, CA (United States)

A comprehensive, chemically detailed mechanism for the combustion of 2-methyl-2-butene and n-pentane is presented to provide insights into the different sooting tendencies of these two structurally different C5 hydrocarbons. A hierarchically assembled mechanism has been developed to specifically target speciation data from low-pressure premixed flames of 2-methyl-2-butene and newly measured mole fraction data for a fuel-rich (Φ = 1.8) n-pentane flame, in which species profiles up to phenol were quantified. The partially isomer-resolved chemical composition of this flame was determined using flame-sampling molecular-beam mass spectrometry with single-photon ionization by tunable, synchrotron-generated vacuum-ultraviolet radiation. The presented model, which includes a newly determined, consistent set of the thermochemistry data for the C5 species, presents overall satisfactory capabilities to predict the mole fraction profiles of common combustion intermediates. The analysis of the model predictions revealed the fuel-structure dependencies (i.e. saturated vs. unsaturated and linear vs. branched) of the formation of small aromatic species that are considered as soot precursors. Here, the propensity of the 2-methyl-2-butene flame to form larger concentrations of aromatic species was traced back to the readily available formation routes of several small precursor molecules and the efficient formation of “first aromatic rings” beyond benzene.

• Research Organization: Sandia National Lab. (SNL-CA), Livermore, CA (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1559481
• Alternate ID(s): OSTI ID: 1562981
• Report Number(s): SAND-2019-5117J; 675317
• Journal Information: Combustion and Flame, Vol. 208, Issue C; ISSN 0010-2180
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
2-Methyl-2-butene
n-Pentane
Laminar premixed flames
Molecular-beam mass spectrometry
Kinetic modeling
PAH formation