Bildung anorganischen Feinstaubs in turbulenter Kohlenstaubverbrennung

煤燃烧过程中形成的细颗粒物，特别是高钠高硅煤燃烧过程中形成的细颗粒物，是影响呼吸空气质量的世界性社会和健康问题；但目前还没有足够的技术解决方案。现有的颗粒设备（静电除尘器）需要过多的努力来保留0.1-2.5µm的相关尺寸范围内的颗粒。因此，要进一步减少细颗粒物的排放，必须考虑到煤炭燃烧过程中细颗粒物形成的全过程。然而，细颗粒物的形成原理还远未被理解。现有的模型只适用于早期燃烧阶段（热解），目前是针对层流发展起来的。因此，到目前为止，还没有考虑到整个湍流燃尽过程的细颗粒物形成模型。因此，湍流流场会影响一些量，例如细颗粒管道的温度或浓度，而这些量又会影响细颗粒物质的形成。确定发射粒子的特性需要粒子历史的知识（温度和局部物种浓度），因此cfd模拟是必不可少的。在拟议的项目中，将使用CFD和实验验证测量的互补方法来推进湍流煤燃烧过程中细颗粒物形成的模型开发。考虑到流场（层流到湍流）和颗粒载荷（从低颗粒载荷开始），所研究的构型的复杂性将会增加。除模型开发外，本项目旨在揭示煤燃烧过程中细颗粒物形成的基本变量。

The formation of fine particulate matter during coal combustion, especially of coal with high contents of sodium and silicon, is a worldwide social- and health relevant problem affecting the breathing air quality; no sufficient technical solution is available yet though. Existing particulate equipment (electrostatic precipitators) require an excessive effort to retain particles in the relevant size range of 0.1-2.5 µm. Thus, a further reduction of fine particulate emissions can only be achieved considering the entire process of fine particulate matter formation during coal combustion. However, the principle of fine particulate matter formation is far from being understood yet. Existing models are only valid for early combustion stages (pyrolysis) and were developed for laminar flow by now. Thus, up to now, no model for the formation of fine particulate matter exists that takes the complete turbulent burnout process into account. Hence, the turbulent flow field influences quantities, such as temperature or concentration of fine particle educts, that in turn affect the formation of fine particulate matter. Determination of characteristics of emitted particles requires the knowledge of particle history (temperature and local species concentrations), hence CFD-simulations are indispensable. In the proposed project, the model development for formation of fine particulate matter during turbulent coal combustion will be advanced using a complementary approach of CFD and experimental validation measurements. The investigated configurations will be increased in complexity with respect to flow field (laminar to turbulent) and particle load (starting with low particle load). In addition to model development, this project aims to reveal the essential variables determining the formation of fine particulate matter during coal combustion.