Producing the Nano-Scale Aggregates by Using Plasma

分析重油不完全燃烧产生的炭黑等纳米颗粒的生长，对于控制纳米级聚集体的形状是至关重要的。然而，高温气溶胶中颗粒的生长过程包括燃料的热解、成核、表面生长、颗粒聚集、氧化等现象。在本研究中，我们进行了1摩尔%苯(在99摩尔%氮气中)在氧化铝试管中热解生成碳烟的实验，实验温度保持在1573K，停留时间从0.05秒到0.5秒不等。进行分类是为了获得对碳烟形成过程的全面表征。我们还研究了碳烟聚集体的周边分维(D&lt；peri&gt；)。反应动力学模型包括苯的热解、成核、颗粒生长和凝聚四种反应。此外，还建立了一种团簇-团簇聚集模型--聚集平均自由程(AMP)模型来模拟炉膛内的聚集。该模型利用颗粒和团聚体的平均自由程来模拟烟尘颗粒与团聚体之间的聚集过程。我们还考察了燃料和管内温度对碳烟形成过程的影响。此外，我们还提出了控制纳米级骨料形状的新方法。在未来，我们将在更高的温度(2000K-)条件下进行新型纳米骨料的制备。

Analysis of the nano-scale particle growth like carbon black, which is produced by incomplete combustion of heavy oils, is essential to controlling a nano-scale aggregate shape. However, the particle growth process in high temperature aerosol includes several phenomena, which are the fuel pyrolysis, nucleation, surface growth, particle aggregation, oxidation and so on. In this study, we carried out the experiment to form the soot by the pyrolysis of 1 mol% benzene (in 99 mol% nitrogen) in an alumina tube, which was kept at 1573K, with variations of residence time (from 0.05 to 0.5 sec). The classification was carried out in order to obtain an overall characterization of the soot formation process. We also investigated the peripheral fractal dimension (D_<peri>) of the soot aggregates. The reaction kinetics model includes four kinds of reactions (pyrolysis of benzene, nucleation, particle growth and coagulation). In addition, a cluster-cluster aggregation model called Aggregate Mean free Path (AMP) model was developed to simulate the aggregation in the furnace. The present model simulated the aggregation between soot particles and aggregates by using the mean free paths of particles and aggregates. We also investigated that the fuel and the temperature in a tube influence on the soot formation process. In addition to, we suggested the new method of controlling a nano-scale aggregate shape. In the future, we will carry out to produce the new nano-scale aggregate in higher temperature condition (2000K-).