Investigation into the influence of the macro- and microstructure of textile filter media to the periodic detachment of mineral dust layers of inert particles with the aim of quantitative forecasting of long-term operating performance of cyclical regenerated surface filters

• Applicant: Professor Dr.-Ing. Eberhard Schmidt
• Subject Area: Mechanical Process Engineering
• Term: from 2014 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 251833911

Particle removal from gases with surface filters, periodic building and detachment of particle layers decisively determine the performance of the filter. Except on the particular type of loading, the quality and duration of regeneration depends mainly on the adhesion between the particle layer and the filter medium surface (adhesion), and the strength of the particle layer structure itself (cohesion). The adhesive and cohesive forces are decisively determined by the structure of the filter cake on the filter medium. The formation of the filter cake and thus the regeneration behaviour are influenced by the surface characteristics of the filter media. A sound theoretical description of these interactions has not yet succeeded.It is known that, after the filter cake removal, the filter surface is still coated with a thin layer of particles. As filter media in comparison with the magnitude of the deposited particles generally have a microscopically rough surface structure, a locally inhomogeneous layer structure is expected in the sectional planes of the near-surface, porous transition region between the filter cake and the filter medium. The resulting inhomogeneous distribution of adhesive forces affects the separation behaviour of the particle layer crucial. Detailed investigations are not yet known.Main aim of the research project is to experimentally and theoretically (supported by simulations) investigate the building of characteristic particle layer structures in the lower cake region as a function of different, quantitatively characterized, inhomogeneous, microscopically uneven filter media surfaces including their near-surface porous transition zones; this results in certain inhomogeneous adhesive forces distributions, in terms of size and in terms of their spatial distribution, which in turn affect the separation behaviour of the particle layer characteristics accordingly.For the first time it will be explored the quantitative relationship between the change of the release behaviour of the filter cake across multiple operating stages, and the quantitative parameters of the filter medium surface; starting from the correspondingly to characterize surface texture of any filter medium, a prediction of the change in the behaviour of the medium in the regeneration operation is possible on a quantitative basis. The newly created basic knowledge will work its way into industrial practice in terms of the sustainability concept, both through improved energy efficiency (cost) and a higher material efficiency (life-time).

• DFG Programme: Research Grants