Video: µ-CT scan of oil structures (brown) on fibres (yellow: glass microfibre; green: PE-fibre) of a wettable filter media (length: 350 µm; width: 350 µm; thickness 160 µm).
Institut für Mechanische Verfahrenstechnik und Mechanik
Karlsruher Institut für Technologie (KIT)
Geb. 30.70
Straße am Forum 8
D-76131 Karlsruhe
Fundamental investigation on the influence of local oil distribution on the separation behaviour of coalescence filters in gas purification
Gas-carried, submicron oil droplets (so-called oil mist) usually occur as an undesirable by product, for instance in the crankcase ventilation of combustion engines or in oil-lubricated screw compressors. Solutions are therefore being worked on to reduce these oil emissions for a variety of reasons, such as health protection, long-term maintenance of components, etc. A common and efficient method of separating these droplets from the gas stream is to use coalescence filters made of fibreglass.
For unloaded air filters, the separation of liquid particles follows the same principles as the separation of solid particles. With the coalescence of oil inside the filter, dust and droplet filtration begin to differ fundamentally. In this process, chains of droplets are formed, while during the separation of solid particles dendritic or compact porous structures emerge. Depending on the wettability of the fibres, the oil is present in form of so-called barrel shape or clam shell droplets (see figure). At the interfaces of the filter the formation of an oil film is possible.
Figure: SEM image of solidified droplets on fibres of a wettable filter media
The main emphasis of this work is to examine fundamentally how collected oil droplets in oil mist filters change the filtration efficiency. Through µ-CT imaging (see video) and image analysis, parameters such as wetting angle, spacing, arrangement and diameter of the coalesced droplets on the fibres are to be determined. In addition to the mean oil volume fraction or the global mean saturation, the local oil distribution on different size scales (saturated and weakly saturated areas or local nearly closed oil films) should be considered. Thus, the change of the separation efficiency by separated oil should be investigated considering the different saturations and oil accumulation structures in flow direction.
Video: µ-CT scan of oil structures (brown) on fibres (yellow: glass microfibre; green: PE-fibre) of a wettable filter media (length: 350 µm; width: 350 µm; thickness 160 µm).
Title | Type | Date |
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Charakterisierung von lokalen Ölstrukturen auf abscheiderelevanten Fasern eines oleophoben Filtermediums | Bachelor or Master Thesis | as of now |
Title | Authors | Source |
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Influence of 3D printed downstream support structures on pressure drop and entrainment of oleophilic and oleophobic oil mist filters | C. Straube, G. Yang, D. Voll, J. Meyer, P. Théato, A. Dittler |
Separation and Purification Technology, 2022, 290, 120802, https://doi.org/10.1016/j.seppur.2022.120802 |
Identification of deposited oil structures on thin porous oil mist filter media applying μ-CT imaging technique | C. Straube, J. Meyer, A. Dittler |
Separations 2021, 8, 193, https://doi.org/10.3390/separations8100193 (open access) |
On aerosol formation by condensation of oil vapor in the crankcase of combustion engines | N. Nowak, T. Sinn, K. Scheiber, C. Straube, J. Pfeil, J. Meyer, T. Koch, G. Kasper, A. Dittler |
Aerosol Science and Technology, https://doi.org/10.1080/02786826.2021.1976720 |
Title | Conference | Authors |
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Identifikation von lokalen Ölstrukturen auf abscheiderelevanten Fasern von Koaleszenzfiltern - Ein Vergleich zwischen µ-CT und ESEM | Jahrestreffen der ProcessNet-Fachgruppen Abfallbehandlung und Wertstoffrückgewinnung, Energieverfahrenstechnik, Gasreinigung, Hochtemperaturtechnik, Rohstoffe |
C. Straube, J. Meyer, A. Dittler |
Characterization of deposited oil structures on thin, porous oil mist filter media applying µ-CT imaging | FILTECH 2022, The Filtration Event |
C. Straube, J. Meyer, A. Dittler |
Konzept zur Untersuchung des Einflusses der lokalen Ölverteilung auf abscheiderelevanten Fasern auf das Abscheideverhalten von Koaleszenzfiltern | Jahrestreffen der ProcessNet-Fachgruppen Computational Fluid Dynamics und Gasreinigung 2020 |
C. Straube, J. Meyer, A. Dittler |