Fuel dependence of benzene pathways

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• 作者：Hongzhi R. Zhang ; Eric G. Eddings ; Adel F. Sarofim ; Charles K. Westbrook
• 关键词：Benzene formation pathways ; Benzene formation potential ; Structural dependence of benzene chemistry ; Premixed flames
• 刊名：Proceedings of the Combustion Institute
• 出版年：2009
• 出版时间：2009
• 年：2009
• 卷：32
• 期：1
• 页码：377-385
• 全文大小：280 K

文摘

The relative importance of formation pathways for benzene, an important precursor to soot formation, was determined from the simulation of 22 premixed flames for a wide range of equivalence ratios (1.0–3.06), fuels (C₁–C₁₂), and pressures (20–760 torr). The maximum benzene concentrations in 15 out of these flames were well reproduced within 30 % of the experimental data. Fuel structural properties were found to be critical for benzene production. Cyclohexanes and C₃ and C₄ fuels were found to be among the most productive in benzene formation; and long-chain normal paraffins produce the least amount of benzene. Other properties, such as equivalence ratio and combustion temperatures, were also found to be important in determining the amount of benzene produced in flames. Reaction pathways for benzene formation were examined critically in four premixed flames of structurally different fuels of acetylene, n-decane, butadiene, and cyclohexane. Reactions involving precursors, such as C₃ and C₄ species, were examined. Combination reactions of C₃ species were identified to be the major benzene formation routes with the exception of the cyclohexane flame, in which benzene is formed exclusively from cascading fuel dehydrogenation via cyclohexene and cyclohexadiene intermediates. Acetylene addition makes a minor contribution to benzene formation, except in the butadiene flame where C₄H₅ radicals are produced directly from the fuel, and in the n-decane flame where C₄H₅ radicals are produced from large alkyl radical decomposition and H atom abstraction from the resulting large olefins.