Interactions between the structure of the filtering layer and the filtration kinetics during the clogging phase in the dust separation with fibrous filter media up to the beginning of the cake-forming filtration

用于表面过滤的新的清洁过滤介质总是从初始阶段开始，在该初始阶段中，可以通过给定介质中的深度过滤原理来描述灰尘分离。术语过滤动力学是指整个过滤层的分离效率的时间行为，其包括给定介质和介质中的沉积颗粒。如果在给定的过滤介质上进行灰尘分离足够长的时间，则在完成堵塞阶段之后形成灰尘饼，这通常是一个渐进的过程。完全形成的粉尘饼除了其中堆积密度实际上不再改变的饼的核心区域之外，还在其表面上具有高度多孔的堆积区域，该堆积区域在气流方向上具有特征性的、稳定的堆积密度高度分布。滤饼表面上的该填充区域用作滤饼的用于进入的灰尘颗粒的实际的、主动的分离区域，因为几乎没有任何颗粒渗透到下方的滤饼的核心区域中。因此，在表面过滤中（表面过滤是根据原始过滤介质命名的），在微观层面上，在尘饼的高度多孔填充区域中总是存在特殊的、高效的深度过滤。这种特殊的深度过滤实现了过滤动力学的动态平衡，其中活性分离区的结构在过滤层的意义上不再改变。为此，在给定的清洁过滤介质上的灰尘分离的整个过程的过滤动力学，实际上是过滤动力学的变化，可以通过描述在变化的多孔结构中新沉积的颗粒的沉积分布的系统变化的机制来表征。因此，在本研究中，整个过滤过程将从一个全新的角度进行观察：在给定的过滤系统中，活性分离区会发生连续、系统的变化，通过在给定的过滤条件下进行连续的颗粒分离，从最初的清洁过滤介质转变为一个新的、动态保持的稳定多孔结构-这就是尘饼的活性分离区。重组的动态过程背后的驱动力是过滤。在研究项目中，将从理论和实验上研究如何通过考虑在给定过滤条件下从给定清洁纤维过滤介质生长出来的整个多孔结构中新沉积颗粒的沉积轮廓的系统变化来描述过滤动力学。

A new, clean filter medium for surface filtration always starts with the initial phase in which the dust separation can be described by the principle of depth filtration in the given medium. The term filtration kinetics refers to the time behaviour of the separation efficiency of the entire filtering layer, which includes both the given medium and the deposited particles in the medium. If the dust separation on a given filter medium is carried out for a sufficiently long time, a dust cake is formed after a completed clogging phase, which is often a gradual process. A fully formed dust cake has, in addition to the core area of the cake, in which the packing density practically no longer changes, a highly porous packing area on its surface, which has a characteristic, stable height profile of the packing density in the direction of the gas flow. This packing area on the surface of the cake acts as the actual, active separation zone of the cake for the coming dust particles, since hardly any particles penetrate into the core area of the cake below. Therefore, with surface filtration which is named in relation to the original filter medium, there is always a special, highly effective depth filtration in the highly porous packing area of the dust cake on the microscopic level. This special depth filtration achieves a dynamic equilibrium of the filtration kinetics in which the structure of the active separation zone in the sense of a filtering layer no longer changes. For this reason, the filtration kinetics, actually the change in the filtration kinetics, of the overall process of dust separation on a given clean filter medium can be characterised through a description of the mechanism of the systematic change in the deposition profile of newly deposited particles in the changing porous structure. In this study, the overall filtration process is therefore viewed from a completely new perspective: There is a continuous, systematic change in the active separation zone of a given filtering system which is transformed from the initial clean filter medium via continuous particle separation under the given filtration conditions to a new, dynamically preserved stable porous structure - this is the active separation zone of the dust cake. The driving force behind the dynamic process of restructuring is the filtration. It will be theoretically and experimentally investigated in the research project, how the filtration kinetics can be described by considering the systematic change in the deposition profile of newly deposited particles in the entire porous structure that grows out of a given clean fibrous filter medium under given filtration conditions.