Kinetic Modeling Study of Polycyclic Aromatic Hydrocarbons and Soot Formation in Acetylene Pyrolysis

Abstract

The aim of this kinetic work is a critical and detailed analysis of the acetylene pyrolysis in a wide range of conditions, especially from 900 to 2500 K, in order to further validate and refine the kinetic mechanism of C2−C4 acetylenic species. In particular, the successive reactions of the intermediate products, such as C4 species and polyynes, were especially\ud investigated to better understand the primary C2H2 kinetics. The subsystem of acetylene pyrolysis reactions clearly constitutes an important portion in the overall kinetic scheme and also a crucial topic in the further extension of the model toward the formation of polycyclic aromatic hydrocarbons (PAHs) and soot particles. The analysis of acetylene experiments, often with the formation of large amount of soot, requires the coupling of the gas phase kinetic scheme with a soot kinetic model. The gas-phase kinetics involves the formation of the first polycyclic aromatic hydrocarbons up to the first components of the soot kinetic mechanism (C20H16 and C20H10). The soot kinetic model is based on a discrete sectional method with an extensive use of lumping rules. Analogy and similarity rules with gas phase kinetics are used to extend the soot mechanism up to the formation of species with more than 107 carbon atoms. The lumped approach, extensively applied in the kinetic modeling of large hydrocarbon species, becomes a necessity in treating chemical reacting systems of these dimensions. The analysis of the experimental data of acetylene pyrolysis obtained in a wide range of conditions permits us not only to highlight the competition between the molecular and the free radical pathways but also to analyze the successive condensation reactions for the formation of PAHs and the growing of soot particles

Influence of H 2 O, CO 2 and O 2 addition on biomass gasification in entrained flow reactor conditions: Experiments and modelling

“…It takes into account all the tars used here in the global pyrolysis reaction. It was validated in relevant experimental conditions and it predicts PAH formation up to C 20 which is convenient for the soot formation modelling [21]. Main studies dealing with this chemical mechanism were conducted on benzene in pyrolysis, partial oxidation and combustion conditions [22], on cyclopentadiene pyrolysis with a focus on the PAH formation [23], on heavy n-alkanes (nC 7 H 16 , nC 10 H 22 , nC 12 H 22 , nC 16 H 34 ) in pyrolysis, partial oxidation and combustion conditions [16].…”

First‐principles based group additivity values for thermochemical properties of substituted aromatic compounds

“…[1][2][3][4] In recent years, such reaction networks have been used in various areas such as steam cracking of hydrocarbons, 4 combustion processes, 5,6 and the formation of polycyclic aromatic hydrocarbons. [7][8][9] Current interests in the thermochemical conversion of biomass to liquid fuels or commodity chemicals leads to the need for kinetic models that describe the pyrolysis of its components cellulose, hemicellulose, and lignin. The decomposition of lignin yields mainly substituted monocyclic aromatic compounds with substituent groups such as hydroxy (AOH), methoxy (AOCH 3 ), formyl (ACHO), vinyl (AC@CH 2 ), and alkyl (AR).…”

Modeling of Fine-Particle Formation in Turbulent Flames

“…The determination of a comprehensive pathway for soot inception, especially under practically relevant conditions, has been the focus of a large number of studies (e.g., Bhatt & Lindstedt 2009, Richter & Howard 2000, Saggese et al 2014, Wang & Frenklach 1997. Similar comprehensive models for metal-oxide-particle inception are relatively less common.…”