Dual-fuel combustion fueled with diesel and renewable methanol provides a path toward low-carbon transportation in the heavy-duty engine sector. Exhaust gas recirculation (EGR) benefits NO_x reduction in diesel/methanol dual-fuel combustion engines and its introduction may alter soot features. In this work, we therefore examined the impact of EGR on diesel/methanol dual-fuel combustion soot oxidation reactivity and morphological and nanostructural characteristics. The results showed that under a specific experimental setting, the use of EGR increased the primary particle size compared to noEGR conditions. The increment varied from 3.682 nm to 6.609 nm, depending on various methanol substitutions. The soot nanostructure tended toward a more ordered organization by introducing EGR, which is indicated by longer fringe length but smaller fringe tortuosity and separation distance. EGR reduced the fractions of volatile organics and increased the soot ignition temperature. The average activation energies of particle samples with EGR operation increased by 10.2–56.8 kJ mol⁻¹ compared to noEGR operation, indicating a lower soot oxidation reactivity. The reduced oxidation reactivity when applying EGR is highly linked to the more ordered soot nanostructure.

中文翻译：

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研究有和没有 EGR 的柴油/甲醇双燃料燃烧产生的烟灰颗粒的纳米结构和反应性

以柴油和可再生甲醇为燃料的双燃料燃烧为重型发动机领域的低碳运输提供了一条道路。废气再循环（EGR）有利于减少柴油/甲醇双燃料发动机中的氮氧化物（NOx），并且它的引入可能会改变烟灰特征_。因此，在这项工作中，我们研究了 EGR 对柴油/甲醇双燃料燃烧烟尘氧化反应性以及形态和纳米结构特征的影响。结果表明，在特定的实验设置下，与无 EGR 条件相比，使用 EGR 增加了初级颗粒尺寸。增量从 3.682 nm 到 6.609 nm 不等，具体取决于各种甲醇替代品。通过引入EGR，烟灰纳米结构趋向于更加有序的组织，这表现为更长的条纹长度但更小的条纹弯曲度和间隔距离。EGR 减少了挥发性有机物的含量并提高了烟灰着火温度。与无EGR操作相比，有EGR操作的颗粒样品的平均活化能增加了10.2–56.8 kJ mol ^-1，表明烟灰氧化反应性较低。应用 EGR 时氧化反应性的降低与更有序的烟灰纳米结构密切相关。