Effect of Addition of Methyl Hexanoate and Ethyl Pentanoate on the Structure of Premixed n-Heptane/Toluene/O₂/Ar Flame

Abstract

The effect of adding isomeric esters ethyl pentanoate (EPe) and methyl hexanoate (MHe) to a model diesel fuel on the chemical structure of its flame has been investigated. A 7/3 (vol) n-heptane/toluene mixture was used as a model diesel fuel. The concentration of EPe or MHe additives to the n-heptane/toluene mixture was 50 vol %. The studied flames were stabilized over a flat burner at a pressure of 1 atm. The structures of three rich (φ = 1.6) flames of n-heptane/toluene/O2/Ar, MHe/n-heptane/toluene/O2/Ar, and EPe/n-heptane/toluene/O2/Ar mixtures were studied. The flame structure data were obtained using the method of molecular beam mass spectrometry (MBMS) with soft electron-impact ionization, gas chromatography–mass spectrometry (GCMS), and microthermocouples. In the flames studied, concentration profiles of more than 30 species were identified and measured, and, in particular, peak concentrations of heavy polycyclic aromatic compounds, the main soot precursors, were measured at a pressure of 1 atm for the first time by MBMS and GCMS techniques. The structures of the n-heptane/toluene and MHe/n-heptane/toluene flames were modeled using published chemical-kinetic mechanisms. For the EPe/n-heptane/toluene mixture, such a mechanism was first developed in this work. Comparison of the experimental and calculated species concentration profiles shows that they are mostly in satisfactory agreement. The key reactions involved in the formation of soot precursors were determined by analyzing the chemical-kinetic mechanisms of oxidation of the investigated fuel blends. The results of the study demonstrate that the applied mechanisms need to be considerably modified to provide an adequate description of the formation and consumption of heavy polycyclic aromatic hydrocarbons.

A study of the chemical structure of laminar premixed HC(O)OH/O2/Ar flames at 1 atm

“…An evaporator is a pyrex vessel filled with metal beads. The temperature of evaporator in the experiment was kept at 80 o C. The detailed description of burner, evaporator and fuel supply system is given in [25].…”

Mini Review of Current Combustion Research Progress of Biodiesel and Model Compounds for Gas Turbine Application

“…Considering that biodiesel components rarely have branched carbon chain structures, a review of the fuel isomeric effect here focuses on methyl esters and ethyl esters with the same carbon numbers. Several pairs of isomeric esters have been investigated in the literature, including methyl acetate and ethyl formate, − methyl butanoate and ethyl propionate, − methyl pentanoate and ethyl butanoate, , and methyl hexanoate and ethyl pentanoate . Among these pairs of esters, methyl butanoate and ethyl propionate are a frequently investigated pair.…”

High-Temperature Pyrolysis and Combustion of C5–C19 Fatty Acid Methyl Esters (FAMEs): A Lumped Kinetic Modeling Study

“…The lumped submechanisms for these hydrocarbon fuels are adopted from recent modeling work by this group for 50 hydrocarbon surrogate fuel components . For comparison, detailed kinetic models from the literature − are also adopted to compare against the present lumped model and the experimental data in the literature.…”

“…Comparison of measured (symbols) and predicted (lines) mole fraction profiles of (a) O 2 and H 2 O, (b) CO and CO 2 , (c) C 7 H 8 and NC 7 H 16 , (d) CH 4 and C 2 H 4 , (e) C 3 H 3 and C 6 H 6 , and (f) C 2 H 2 and MHX in the burner-stabilized flame of MHX/NC 7 H 16 /C 7 H 8 /O 2 /Ar at 1 atm and ϕ = 1.6. Solid and dashed lines represent predicted results from the present model and literature models, respectively.…”

“…Comparison between experimental data and predicted results by this lumped model, and from the detailed model in the literature, 65 appears in Figure S50 in the Supporting Information; it shows that both models reasonably predict the flame structures measured in the experiment. Osipova et al 66 measured the flame speciation data in the burner-stabilized premixed flame of MHX/ NC 7 H 16 /C 7 H 8 at 1 atm and ϕ = 1.6; they also developed a detailed model to describe the combustion chemistry of the fuel mixture. Their measured and predicted results are compared with the results predicted by the present lumped model.…”