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Title: Experimental and modeling studies of a biofuel surrogate compound: laminar burning velocities and jet-stirred reactor measurements of anisole

Lignocellulosic biomass is a promising alternative fuel source which can promote energy security, reduce greenhouse gas emissions, and minimize fuel consumption when paired with advanced combustion strategies. Pyrolysis is used to convert lignocellulosic biomass into a complex mixture of phenolic-rich species that can be used in a transportation fuel. Anisole (or methoxybenzene) can be used as a surrogate to represent these phenolic-rich species. Anisole also has attractive properties as a fuel component for use in advanced spark-ignition engines because of its high blending research octane number of 120. Presented in the current work are new measurements of laminar burning velocities, jet-stirred reactor (JSR) speciation of anisole/O 2/N 2 mixtures, and the development and validation of a detailed chemical kinetic mechanism for anisole. Homogeneous, steady state, fixed gas temperature, perfectly stirred reactor CHEMKIN simulations were used to validate the mechanism against the current JSR measurements and published JSR experiments from CNRS-Nancy. Pyrolysis and oxidation simulations were based on the experimental reactant compositions and thermodynamic state conditions including P = 1 bar and T = 675–1275 K. The oxidation compositions studied in this work span fuel-lean (φ = 0.5), stoichiometric, and fuel rich (φ = 2.0) equivalence ratios. Laminar burning velocities weremore » measured on a heat flux stabilized burner at an unburnt T = 358 K, P = 1 bar and simulated using the CHEMKIN premixed laminar flame speed module. Ignition delay times of anisole were then simulated at conditions relevant to advanced combustion strategies. Current laminar burning velocity measurements and predicted ignition delay times were compared to gasoline components (e.g., n-heptane, iso-octane, and toluene) and gasoline surrogates to highlight differences and similarities in behavior. Reaction path analysis and sensitivity analysis were used to explain the pathways relevant to the current studies. Under pyrolysis and oxidative conditions, unimolecular decomposition of anisole to phenoxy radicals and methyl radicals was found to be important due to the relatively low bond strength between the oxygen and methyl group, ~65 kcal/mol. Finally, reactions of these abundant phenoxy radicals with O 2 were found to be critical to accurately reproduce anisole's reactivity.« less
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [3] ;  [1] ; ORCiD logo [4] ;  [1] ;  [2] ; ORCiD logo [3] ;  [4] ;  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Material Science Division
  2. CNRS Inst. for Engineering and Systems Sciences (INSIS), Orléans (France)
  3. Lund Univ. (Sweden). Combustion Physics
  4. CNRS Inst. for Engineering and Systems Sciences (INSIS), Orléans (France); Univ. of Orléans (France)
Publication Date:
Report Number(s):
LLNL-JRNL-724920
Journal ID: ISSN 0010-2180
Grant/Contract Number:
AC52-07NA27344; 2015-04042; 291049 – 2G-CSafe; ANR-11-LABX-0006-01
Type:
Accepted Manuscript
Journal Name:
Combustion and Flame
Additional Journal Information:
Journal Volume: 189; Journal ID: ISSN 0010-2180
Publisher:
Elsevier
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lund Univ. (Sweden); CNRS Inst. for Engineering and Systems Sciences (INSIS), Orléans (France)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Bioenergy Technologies Office (EE-3B); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V); Centre for Combustion Science and Technology (CECOST) (Sweden); Swedish Research Council (VR); European Research Council (ERC); National Agency for Research (ANR) (France)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 10 SYNTHETIC FUELS; methoxybenzene; biomass; oxidation; burning velocity; kinetic mechanism
OSTI Identifier:
1438668