School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 10081, China; Key Laboratory of Shaanxi Province for Development and Application of New Transportation Energy, Xi'an, 710064, China.
School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 10081, China.
Chemosphere. 2022 Jul;299:134445. doi: 10.1016/j.chemosphere.2022.134445. Epub 2022 Mar 29.
With diesel particulate filter and gasoline particulate filter periodical regeneration, more and more ash accumulates on the substrate of filter. Ash gathering on the substrate of filter leads to more contact area of particulate matter and ash. Specific ingredients in ash present catalytic effects on particulate matter oxidation. However, the catalytic effect of diesel particulate matter derived ash on its oxidation, mimicking the ash accumulating on filter substrate, is still uncovered using experiments. In this paper, diesel particulate matter derived ash was put at the bottom of particulate matter samples to imitating the soot loading on filter substrate which was covered by much ash. The results indicated that the burnout temperature of diesel particulate matter was in the range of 500-600 °C; while it was 600-700 °C for Printex (U). The burnout temperature drop by ash was lower than 10 °C for diesel particulate matter. The maximum mass loss rate corresponded to approximately 450 °C for diesel particulate matter, and it was changed minorly by ash and ramp rates. However, the temperature corresponding to the maximum mass loss rate was seriously retarded by high ramp rates for Printex (U), and ash presented limited effect on it. The maximum activation energy drop by ash was approximately 60 kJ/mol at the initial stage of oxidation for diesel particulate matter. The activation energy was approximately 132.19, 114.78, 157.26, and 144.67 kJ/mol for diesel PM, diesel PM-ash, Printex (U), and Printex (U)-ash, respectively. Organic compounds dropped gradually in the oxidation process of diesel particulate matter. Nanostructure evolutions of diesel particulate matter and Printex (U) were similar, experiencing smaller sizes and void cores at the end of oxidation process.
随着柴油机微粒过滤器和汽油机微粒过滤器的定期再生，越来越多的灰分积聚在过滤器的载体上。过滤器载体上的积灰导致颗粒物和灰分的接触面积增加。灰分中的特定成分对颗粒物氧化具有催化作用。然而，实验尚未揭示柴油机颗粒物衍生灰分对其氧化的催化作用，模仿过滤器载体上的积灰。在本文中，将柴油机颗粒物衍生的灰分置于颗粒物样品的底部，以模拟被大量灰分覆盖的过滤器载体上的烟尘负荷。结果表明，柴油机颗粒物的燃尽温度在 500-600°C 范围内；而 Printex (U) 的燃尽温度在 600-700°C。灰分对柴油机颗粒物的燃尽温度降低低于 10°C。柴油机颗粒物的最大质量损失速率对应约 450°C，灰分和升温速率对其影响较小。然而，对于 Printex (U)，高升温速率会严重延迟对应最大质量损失速率的温度，灰分对其影响有限。在柴油机颗粒物氧化的初始阶段，灰分导致的最大活化能降低约 60 kJ/mol。对于柴油机 PM、柴油机 PM-灰分、Printex (U) 和 Printex (U)-灰分，活化能分别约为 132.19、114.78、157.26 和 144.67 kJ/mol。在柴油机颗粒物氧化过程中，有机化合物逐渐减少。柴油机颗粒物和 Printex (U) 的纳米结构演化相似，在氧化过程结束时经历较小的尺寸和空心核心。
