On the coalescence performance enhancement for filter media with parallel strips of alternating wettability and their combinations

A new preparation method for a filter material with an inclined modification pattern is described herein. The effects of the inclination angle of the strips, the composition and the number of layers on the performance of the filter materials were analysed systematically. On this basis, the optimal structure and parameters of the filter materials were determined. The performance of this filter material was verified by preparing an industrial filter cartridge. The results demonstrated that the filter materials achieved the highest comprehensive filtration performance when the inclination angle of the modification strips was 75°. The steady-state quality factor improved by up to 137.1 % compared to the original filter materials with uniform wettability. The double-layer filter had the best filtration performance when the front and back layers were both modified filter materials and the strips were overlapped. In terms of the impact of layers, the seven-layer composite filter material achieved the optimal comprehensive filtration performance for oil mists of different sizes (1.18 and 2.60 kPa −1 for sub-micro and micro droplets respectively). After the modified filter material and the original filter material were processed into a filter cartridge, the modified filter cartridge showed significant advantages of ‘pressure drop and efficiency improvement’ under different superficial gas velocities compared to the unmodified filter cartridge.