An experimental and kinetic modeling study on 4-methylheptane pyrolysis at atmospheric pressure

IF 5.8 2区工程技术 Q2 ENERGY & FUELS

Combustion and Flame Pub Date : 2024-10-12 DOI:10.1016/j.combustflame.2024.113790

Haikun Lang , Fangping Bin , Shuyao Chen , Xiaoli Zhang , Jiuzheng Yin , Jinzeng Pan , Zhandong Wang , Lixia Wei

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引用次数: 0

Abstract

Fischer–Tropsch synthesis is an important route for the productions of cleaner fuels from non-petroleum materials. Monomethylated alkanes are present in large quantities in Fischer–Tropsch synthetic fuels. However, side-chain position may make a difference in the combustion of the fuels. In this work, the 4-methylheptane (MH4) pyrolysis was investigated experimentally by using a jet-stirred reactor at 800–1125 K and at 760 Torr. Major pyrolysis products, including small molecules and aromatic products, were identified and measured by using the synchrotron ultra-violet photoionization method. Several species were detected and measured, including CH₄, C₂H₂, C₂H₄, C₂H₆, C₃H₄, C₃H₆, C₃H₈, C₄H₆, IC₄H₈, C₅H₆, C₅H₈1-3, C₅H₁₀-2, benzene, naphthalene, indene and C₆H₅C₂H, etc. A detailed kinetic model of MH4 pyrolysis was developed and validated against the experimental results in this work. Rate of production analysis of MH4 indicates that the most significant consumption pathways are H-abstractions. The unimolecular decomposition reactions by the breakages of CC bonds are also important pathways in MH4 consumption. The pyrolysis product distributions of 4-methylheptane, 3-methylheptane and 2-methylheptane were compared to demonstrate the effect of the methyl side chain position on the pyrolysis of those fuels. It is noted that the mole fraction distributions of the smaller species, including CH₄, C₂H₂ and C₂H₆, are not sensitive to the position of the methyl side-chain, while those of C3-C5 products, including PC₃H₄, C₃H₆, C₄H₆, IC₄H₈, C₅H₈1-3 and C₅H₁₀-2, are strongly affected.

Novelty and significance statement

The products of 4-methylheptane pyrolysis were identified and measured by using the synchrotron ultra-violet photoionization method. A detailed kinetic model of 4-methylheptane pyrolysis at atmospheric was constructed for the first time. The consumption pathways of 4-methylheptane pyrolysis were clarified. The effect of methyl side chain position on fuel pyrolysis was analysed. 4-Methylheptane is one of the important branched alkanes in Fischer–Tropsch synthetic diesel fuel. The present work extends the understanding of pyrolysis of long branched alkanes. The results of the study provide guidance in exploring ideal compositions for diesel alternative fuels.

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常压下 4-甲基庚烷热解的实验和动力学模型研究

费托合成是利用非石油材料生产清洁燃料的重要途径。单甲基烷烃大量存在于费托合成燃料中。然而，侧链位置可能会影响燃料的燃烧。在这项工作中，使用喷射搅拌反应器在 800-1125 K 和 760 Torr 下对 4-甲基庚烷（MH4）热解进行了实验研究。利用同步辐射紫外线光离子化方法对主要热解产物（包括小分子和芳香族产物）进行了鉴定和测量。检测和测量的产物包括 CH4、C2H2、C2H4、C2H6、C3H4、C3H6、C3H8、C4H6、IC4H8、C5H6、C5H81-3、C5H10-2、苯、萘、茚和 C6H5C2H 等。本研究建立了详细的 MH4 热解动力学模型，并根据实验结果进行了验证。MH4 的生成速率分析表明，最主要的消耗途径是 H-萃取。由 CC 键断裂引起的单分子分解反应也是 MH4 消耗的重要途径。比较了 4-甲基庚烷、3-甲基庚烷和 2-甲基庚烷的热解产物分布，以说明甲基侧链位置对这些燃料热解的影响。结果表明，CH4、C2H2 和 C2H6 等小分子物质的摩尔分数分布对甲基侧链的位置不敏感，而 PC3H4、C3H6、C4H6、IC4H8、C5H81-3 和 C5H10-2 等 C3-C5 产物的摩尔分数分布则受到很大影响。首次构建了4-甲基庚烷在大气中热解的详细动力学模型。阐明了 4-甲基庚烷热解的消耗途径。分析了甲基侧链位置对燃料热解的影响。4 甲基庚烷是费托合成柴油中重要的支链烷烃之一。本研究拓展了人们对长支链烷烃热解的认识。研究结果为探索柴油替代燃料的理想成分提供了指导。

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来源期刊

Combustion and Flame 工程技术-工程：化工

CiteScore

9.50

自引率

20.50%

发文量

631

审稿时长

3.8 months

期刊介绍： The mission of the journal is to publish high quality work from experimental, theoretical, and computational investigations on the fundamentals of combustion phenomena and closely allied matters. While submissions in all pertinent areas are welcomed, past and recent focus of the journal has been on: Development and validation of reaction kinetics, reduction of reaction mechanisms and modeling of combustion systems, including: Conventional, alternative and surrogate fuels; Pollutants; Particulate and aerosol formation and abatement; Heterogeneous processes. Experimental, theoretical, and computational studies of laminar and turbulent combustion phenomena, including: Premixed and non-premixed flames; Ignition and extinction phenomena; Flame propagation; Flame structure; Instabilities and swirl; Flame spread; Multi-phase reactants. Advances in diagnostic and computational methods in combustion, including: Measurement and simulation of scalar and vector properties; Novel techniques; State-of-the art applications. Fundamental investigations of combustion technologies and systems, including: Internal combustion engines; Gas turbines; Small- and large-scale stationary combustion and power generation; Catalytic combustion; Combustion synthesis; Combustion under extreme conditions; New concepts.