Fundamental investigations of the filtration behaviour of surface filters under low operating pressures (p << 100 mbar)

对热敏性产品（如电池组件或药物配方）的干燥需要较低的工艺压力（p << 100 mbar），以避免产品过热。真空干燥器通常用于工业中的此目的。干燥过程中产生的蒸汽会夹带产品中的细小颗粒。为了防止污染下游设备并回收产品，颗粒在所谓的蒸汽过滤器中分离，通常是表面过滤器。蒸汽过滤器的设计通常基于灰尘过滤器标准压力范围内的过滤面积的经验值。然而，这会导致过滤面积的尺寸不正确，从而导致过滤性能不稳定、成本更高和能耗增加。只有对低压下表面过滤器的过滤行为有基本的了解，才能正确地确定过滤器的尺寸。然而，在文献中缺乏关于这一主题的基本工作。为了填补这一空白，在文献中，各种调查的表面过滤器在低压下的过滤行为进行。首先，将开发一个试验工厂并投入运行。将在该试验机构研究未加载和加载过滤介质的压差。使用针毡、涂覆有膜的针毡、烧结金属网和编织金属过滤器。将测量的压差与文献中现有计算公式计算的压差进行比较。此外，还对分离性能（分离效率、滤饼结构等）进行了实验研究。和再生（清洁效率、最佳清洁压力等）降低系统压力。在低压下收集的所有结果与环境条件下的结果进行了比较。

The drying of heat-sensitive products like battery components or pharmaceutical formulations requires low process pressures (p << 100 mbar) to avoid overheating of the products. Vacuum dryers are usually used for this purpose in industry. The steam generated during drying can entrain fine particles from the product bulk. In order to prevent contamination of downstream equipment and to recover the product, the particles are separated in so-called vapour filters, usually surface filters. The design of vapour filters is usually based on empirical values regarding the filter areas from the standard pressure range for dust filters. However, this leads to incorrectly dimensioned filter areas and consequently to unstable filtration behaviour, higher costs and increasing energy consumption. The filters can only be correctly dimensioned with a fundamental understanding of the filtration behaviour of surface filters at low pressures. However, there is a lack of fundamental work on this topic in the literature. In order to fill this gap in the literature, various investigations on the filtration behaviour of surface filters at low pressures are conducted. First, a pilot plant will be developed and put into operation. The differential pressure of unloaded and loaded filter media will be investigated at this test facility. Needle felts, needle felts coated with membranes, sintered metal mesh and woven metal filters are used. The measured differential pressures are compared with calculated differential pressures from existing calculation equations from the literature. In addition, experiments are realised on the separation behaviour (separation efficiency, filter cake structure, ...) and regeneration (cleaning efficiency, optimal cleaning pressure, ...) at reduced system pressures. All the results collected at low pressures are compared with those at ambient conditions.