Effect of methane doping on nascent soot formation in ethylene-based laminar premixed flames

Shao, Can; Guan, Bin; Lin, Baiyang; Gu, Hao; Gu, Chen; Li, Zhongzhao; Lin, He; Huang, Zhen

doi:10.1016/j.fuel.2016.08.081

Cited by 27 publications

(6 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, as the pressure increases, βcr,acet increases first, then decreases for P > 2.5 atm, revealing a non-monotonic behavior, which is qualitatively different from the experimental βcr behavior. These trends of βcr, βcr,benz and βcr,acet suggest that the soot formation may be better described by the concentration of benzene instead of C2H2 [46][47][48]. Fig.…”

Section: Kinetic Analysismentioning

confidence: 98%

Effect of dimethyl ether (DME) addition on sooting limits in counterflow diffusion flames of ethylene at elevated pressures

Amin

Liu

et al. 2018

Combustion and Flame

View full text Add to dashboard Cite

The effects of dimethyl ether (DME) addition to ethylene fuel on sooting tendencies with varying pressure were investigated in counterflow diffusion flames by using a laser scattering technique. Sooting limit maps were determined in the fuel (XF) and oxygen (XO) mole fraction plane, separating sooting and non-sooting regions. The results showed that when DME is mixed to ethylene, the sooting region was appreciably shrank, especially in the cases of soot formation/oxidation (SFO) flames as compared with the cases of soot formation (SF) flames. This indicated an inhibiting role of DME on sooting. An interesting observation was that the critical XO required for sooting initially decreased and then increased with the DME mixing ratio to ethylene β for the cases of SF flames, exhibiting a non-monotonic behavior. This implied a promoting role of DME on sooting when small amount of DME is mixed to ethylene. As the pressure increased, the sooting region generally expanded. Specifically, the range of β in promoting soot formation extended with pressure. This implies that a strategy in reducing soot by adding DME to ethylene at high pressures required a large amount of DME addition. To interpret the observed phenomena, kinetic simulations including reaction pathway and sensitivity analyses were conducted with the opposed-flow flames model using the KAUST-Aramco PAH Mech. The results showed that the thermal effect of DME addition on sooting tendency monotonically decreases with . The chemical effect was found to be the main contributor to the DME addition effect on sooting tendency, resulting in the non-monotonic sooting limt behavior. The pathway analysis showed the role of methyl radicals generated from DME promoted incipient benzene ring formtion when small amount of DME was added, which can be attributed to the soot promoting role of DME addition for small β.

show abstract

Section: Kinetic Analysismentioning

confidence: 98%

Effect of dimethyl ether (DME) addition on sooting limits in counterflow diffusion flames of ethylene at elevated pressures

Amin

Liu

et al. 2018

Combustion and Flame

View full text Add to dashboard Cite

show abstract

“…Evidence shows that PAH molecules attached to ultrafine particle surfaces can bond to critical targets in DNA molecules, and the PAH-DNA adducts increase the risk of cancer in humans, especially lung and skin cancers [1,2]. In addition, studies on PAH formation are motivated by soot pollution in megacities, as PAHs are regarded as the precursors to soot formation in flames [3][4][5][6][7][8][9][10][11]. On the other hand, PAHs are widely used as modelling molecules of 2D graphene-type materials [12,13], which present excellent optical, mechanical and electrical characteristic.…”

Section: Introductionmentioning

confidence: 99%

The site effect on PAHs formation in HACA-based mass growth process

Liu

Bennett

et al. 2019

Combustion and Flame

Self Cite

View full text Add to dashboard Cite

Hydrogen-abstraction/acetylene-addition (HACA) pathway has long been postulated as the dominant pathway for the formation of polycyclic aromatic hydrocarbons (PAHs) and the surface growth of soot. In this study, the site effect on PAH formation following HACA pathway is systematically investigated using density functional theory, transition state theory and premixed flame kinetic modeling. The entire reaction network includes 186 elementary reactions, starting from benzene to pyrene. Analysis of the potential energy surface and kinetic parameters show that H abstraction and C2H2 addition reactions are greatly sensitive to the site position (ortho-, meta-and para-position) relative to the existing C2H chain and surface site type (zig-zag, free-edge and armchair). Specifically, H abstraction and C2H2 addition reactions on the ortho-position and armchair surface site are kinetically unsupported due to the relatively high energy barrier and orientation hindrance effect compared with other site options. Therefore, the formation of a new benzene ring by the addition of the second C2H2 molecule on the ortho-position (e.g., 1-ethynylnaphthalene+C2H2→phenanthrene) or the first C2H2 molecule on the armchair surface site (e.g., phenanthrene+C2H2→pyrene) is unlikely, as demonstrated by PAH simulations in a premixed C2H4/O2/N2 sooting flame. The yield distribution of various reaction products has been investigated using a 0-D reactor, where the combustion conditions are taken from experimental data. The results show that the dominant products are di-substituted PAHs in benzene-naphthalene reaction system and PAHs with 5-membered ring structures in larger PAHs reaction systems. The existence of abundant PAHs with 5-membered rings contributes to clarifying the PAHs signal detected using laser induced fluorescence technology. Additionally, the observed sequence of mass peaks at intervals of mass number 26 in C2H2/C2H4 pyrolysis is reasonably explained by the HACA pathway with considering site effect.

show abstract

“…The solid soot sample was collected from a laminar premixed ethylene‐air burner stabilized stagnation (BSS) flame . The BSS flame configuration in the King Abdullah University of Science and Technology (KAUST) consists of a McKenna burner with a diameter of 8 mm and a stagnation board, which is parallel to the burner surface.…”

Section: Methodsmentioning

confidence: 99%

Analyzing the solid soot particulates formed in a fuel‐rich flame by solvent‐free matrix‐assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry

Zhang

Shao

Sarathy

2020

Rapid Comm Mass Spectrometry

Self Cite

View full text Add to dashboard Cite

Rationale:The compositional and structural information of soot particles is essential for a better understanding of the chemistry and mechanism during the combustion. The aim of the present study was to develop a method to analyze such soot particulate samples with high complexity and poor solubility. Methods:The solvent-free sample preparation matrix-assisted laser desorption/ ionization (MALDI) technique was combined with the ultrahigh-resolution Fourier transform ion cyclotron resonance (FTICR) mass spectrometry (MS) for the characterization of solid soot particulates. Moreover, a modified iso-abundance plot (Carbon Number vs. Hydrogen Number vs. Abundance) was introduced to visualize the distributions of various chemical species, and to examine the agreement between the hydrogen-abstraction-carbon-addition (HACA) mechanism and the polycyclic aromatic hydrocarbon growth in the investigated flame system. Results:This solvent-free MALDI method enabled the effective ionization of the solid soot particulates without any dissolving procedure. With the accurate m/z ratios from FTICR-MS, a unique chemical formula was assigned to each of the recorded mass signals. The combustion products were proven to be mainly large polycyclic aromatic hydrocarbons (PAHs), together with a small amount (<5%) of oxidized hydrocarbons. Conclusions:The developed method provides a new approach for the molecular characterization of soot particulates like carbonaceous materials. The investigated soot particulates are mainly PAHs with no or very short aliphatic chains. The growth mechanism of PAHs during combustion can be examined against the classic HACA mechanism.

show abstract

Effect of methane doping on nascent soot formation in ethylene-based laminar premixed flames

Cited by 27 publications

References 35 publications

Effect of dimethyl ether (DME) addition on sooting limits in counterflow diffusion flames of ethylene at elevated pressures

Effect of dimethyl ether (DME) addition on sooting limits in counterflow diffusion flames of ethylene at elevated pressures

The site effect on PAHs formation in HACA-based mass growth process

Analyzing the solid soot particulates formed in a fuel‐rich flame by solvent‐free matrix‐assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry

Contact Info

Product

Resources

About