Abstract
There have been significant advances in understanding ignition behavior of oxygenated biofuels (mainly alcohols) and their blends with conventional fuel components. However, the oxidation behavior of lignocellulosic derived furanic compounds blended with hydrocarbons has received little attention. The present work is an experimental and numerical investigation of 2-methylfuran (2-MF) combustion and its blend with n-heptane. These results are compared with pure n-heptane results to better understand 2-MF reactivity. Ignition delay times of pure 2-MF and the 2-MF/n-heptane (50/50 2-MF/n-heptane molar %) blend in air were measured in three different facilities; a rapid compression machine and two different shock tubes. Experiments were performed in the temperature range of 861–913 K at a pressure of 20 bar for stoichiometric pure 2-MF. The ignition delay times of 2-MF/n-heptane blends were measured in the temperature range of 672–1207 K, at pressures of 10 and 20 bar, and at equivalence ratios of 0.5, 1.0, and 1.5. A comprehensive chemical kinetic model containing low- to high-temperature chemistry of 2-MF and n-heptane was formulated based on a combination of available 2-MF and n-heptane mechanisms and available theoretical studies on 2-MF form literature. The developed detailed kinetic model was validated against the ignition delay data measured in this work as well as against high-temperature shock tube ignition delay, flame speed, and flame species data from literature to ensure the competence of the model. The proposed mechanism predicts the measured and literature data to a reasonable extent. To elucidate fuel specific oxidation pathways, reaction path analyses were performed at various conditions. Furthermore, sensitivity analyses on the ignition delay times were conducted and the dominant reaction pathways in the oxidation of pure and binary mixtures at high, intermediate, and low temperatures were identified. It is found that the competition between n-heptane and 2-MF for ȮH radicals inhibits the consumption of n-heptane and promotes the consumption of 2-MF. This work provides the first insight into the global low-temperature oxidation behavior of a second generation furanic blended with a hydrocarbon.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 54-70 |
| Number of pages | 17 |
| Journal | Combustion and Flame |
| Volume | 196 |
| DOIs | |
| State | Published - Oct 2018 |
Bibliographical note
Funding Information:This work was performed as part of the Cluster of Excellence Tailor-Made fuels from Biomass, which is funded by the Excellence Initiative by the German federal and state governments to promote science and research at German universities. The work performed by the Clean Combustion Research Center was supported by competitive research funding from King Abdullah University of Science and Technology (KAUST). The authors would like to thank Dr. Christian Hemken (PCFC, RWTH Aachen University) for performing the flow reactor simulations s.
Publisher Copyright:
© 2018 The Combustion Institute
Keywords
- 2-Methylfuran
- Ignition delay
- Kinetic model
- Rapid compression machine
- Shock tube
- n-Heptane
ASJC Scopus subject areas
- Chemistry(all)
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology
- Physics and Astronomy(all)