The molecular structures of hydrocarbon fuels are known to have a substantial impact on their combustion properties. However, the relationship between the fuel structure and thermal decomposition intermediate products, which determine the global combustion behaviors, is not as well known. In this study, four octane isomers, n-octane, 2,5-dimethylhexane, 2,2,4-trimethylpentane (iso-octane), and 2,2,3,3-tetramethylbutane, are selected as the model compounds to illustrate the distinct product generation in the oxidative pyrolysis of large hydrocarbons with substantially different molecular structures. Both experimental and kinetic analysis show that all the octane isomers lead to the formation of a similar group of stable products, with the major ones being ethene, methane, propene, and isobutene. The distributions of these products vary from fuel to fuel; n-octane produces primarily ethene, while isobutene formation increases with increasing branching in the fuel molecular structure. The most branched isomer, 2,2,3,3-tetramethylbutane, produces predominately isobutene. Lumped, two-step reaction schemes are proposed for each octane isomer. Together with a detailed foundational fuel chemistry model, it is shown that the reaction models accurately predict the formation and subsequent consumption of the intermediate products for all octane isomers studied.

已知碳氢燃料的分子结构对其燃烧特性有实质性影响。然而，众所周知，燃料结构与热分解中间产物之间的关系决定了整体燃烧行为。在这项研究中，选择四种辛烷异构体正辛烷，2,5-二甲基己烷，2,2,4-三甲基戊烷（异辛烷）和2,2,3,3-四甲基丁烷作为模型化合物进行说明。在分子结构大不相同的大型烃类的氧化热解过程中产生了独特的产物。实验和动力学分析均显示，所有辛烷异构体均会导致形成相似的稳定产物组，主要产物为乙烯，甲烷，丙烯和异丁烯。这些产品的分布因燃料而异。正辛烷主要产生乙烯，而异丁烯的形成随着燃料分子结构中支链的增加而增加。最支化的异构体2,2,3,3-四甲基丁烷主要产生异丁烯。针对每种辛烷异构体，提出了集总的两步反应方案。连同详细的基础燃料化学模型一起，表明该反应模型可准确预测所研究的所有辛烷异构体中间产物的形成和随后的消耗。对于每种辛烷异构体，提出了两步反应方案。连同详细的基础燃料化学模型一起，表明该反应模型可准确预测所研究的所有辛烷异构体中间产物的形成和随后的消耗。对于每种辛烷异构体，提出了两步反应方案。连同详细的基础燃料化学模型一起，表明该反应模型可准确预测所研究的所有辛烷异构体中间产物的形成和随后的消耗。