Effect of pressure and CO2 dilution on soot formation in laminar inverse coflow flame at conditions close to autothermal reforming

Combustion and Flame, Год журнала: 2023, Номер 254, С. 112853 - 112853

Опубликована: Июнь 1, 2023

Язык: Английский

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Formation of Polycyclic Aromatic Hydrocarbons (PAHs) in Thermal Systems: A Comprehensive Mechanistic Review

Energy & Fuels, Год журнала: 2024, Номер 38(22), С. 21735 - 21792

Опубликована: Ноя. 1, 2024

Polycyclic aromatic hydrocarbons (PAHs) are formed invariably through oxidative and pyrolytic degradation of organic materials fuels. Understanding the highly complex reaction mechanisms that dictate their synthesis in thermal systems has been given a great deal focus. Such interest stems from two broad perspectives, namely, enhancing efficiency combustion system, energy recovery fuels protecting environment. Health environmental effects widely vary among PAHs where certain compounds exhibit carcinogenic tendencies. This critical review mainly aims to provide general mechanistic view commonly discussed formation pathways PAHs. The attained knowledge often incorporates experimental measurements kinetic modelings, as well mapped out by quantum chemical calculations. A sampling species is typically conducted via molecular beam (MB)–mass spectroscopy (MS) technique connected reactor (flow reactor, jet-stirred or shock tube). Generally, PAH precursors encompass four categories (radicals molecules): acetylenic compounds, alkyl radicals, phenyl resonance-stabilized cyclic radicals. Overall, relevance mechanism depends on consistency between proposed model pathways, profiles products at investigated conditions (i.e., temperatures, pressures, distance burners). effect seeding common precursors, with other explored surveying pertinent studies. Growth higher PAHs, including toxic pyrene, most likely involves hydrogen abstraction acetylene addition (HACA)-like starting anthracene bimolecular reactions involve benzyl radicals indene molecules. synergistic collaboration different suggested account for observed fast growth rate As experimentally shown, sequential mass 15 u, 24 26 74 indicate routes MAC, HACA, HAVA*, PAC routes, respectively. Whether physical process initial step conversion into soot (the inception step) still debated literature. Recent evidence underscores commence creating dimers clustering under real flame 400–1200 K). Formation synthetic natural polymers ensues condensation fragments structural arrangements polymeric entities, prior fragmentation. surveyed presented this will be useful readers who aim comprehend chemistry underlying systems.

Язык: Английский

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Understanding soot formation: A comprehensive analysis using reactive models in Inverse Non-Premixed Flames

Combustion and Flame, Год журнала: 2024, Номер 267, С. 113569 - 113569

Опубликована: Июль 2, 2024

Язык: Английский

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Application of the Y-Rule and Theoretical Study to Understand the Topological and Electronic Structures of Polycyclic Aromatic Hydrocarbons from Atomic Force Microscopy Images of Soot, Coal Asphaltenes, and Petroleum Asphaltenes

Energy & Fuels, Год журнала: 2022, Номер 36(16), С. 8725 - 8748

Опубликована: Июль 21, 2022

The molecular structures of polycyclic aromatic hydrocarbons (PAHs) from different sources (coal-derived asphaltenes (CA), petroleum-derived (PA) and soot (S)), that were obtained noncontact atomic force microscopy (nc-AFM) studies published in the literature, are systematically analyzed to understand electronic topological PAHs sources. characterization is accomplished by obtaining distributions number fused rings (nFAR), type abundance pentagonal rings, degree pericondensation. Electronic carried out π-electron distribution resonant sextets localized double bonds Clar using Y-rule, calculating HOMO–LUMO gap (optical transition) means ZINDO/S approximation. In addition, carbon ratio (the atoms isolated (IDB) sextet CR = IDB/sextet carbon) for all conclude stability reactivity. It found petroleum contain between four (4FAR) 10FAR, with a prevalence 6FAR–7FAR. coal present range 4FAR–11FAR, abundant 7FAR–8FAR. 6FAR–11FAR major 8FAR 9FAR. general, S, CA, PA one single PAH per molecule; however, fraction CA groups possess conjugated aryl-linked core, order > PA. Pentagonal re PAHs; nevertheless, these more predominant PAHs, most acenaphthylene-type ring. For FAR families PA, Y-carbons (triple bridgehead carbons) 7 8 soot, six as abundant. These numbers measure high pericondensation, which higher than asphaltenes. tend be extended, reflected low values Y-carbons. ratios show an intermediate asphaltenes, weight 300–700 g/mol 400–550 nm.

Язык: Английский

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The importance of accurately modelling soot and radiation coupling in laminar and laboratory-scale turbulent diffusion flames

Combustion and Flame, Год журнала: 2022, Номер 258, С. 112573 - 112573

Опубликована: Дек. 30, 2022

Язык: Английский

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