Cyclones of different sizes and underflow leakage for aerosol particles separation enhancement

Aerosol particle (especially PM2.5 and PM10) is one of the most serious environmental pollution worldwide and is urging the development of separation technology. Cyclonic centrifugation devoted to the separation of suspension systems whose component have a significant density difference, however, it has been difficult to separate the fine particles whose size are of several microns or sub-micron. Therefore, a series of cyclones of different sizes (cylinder diameter D of 25 mm, 75 mm, 100 mm, 150 mm and 200 mm) and different vortex finder depth (0.5D, 0.6D, 0.7D, 0.8D, 0.9D) were designed to separate aerosol fine particles. The result showed that the cyclone whose diameter was 75 mm and vortex finder depth was 0.7D was most efficient and energy saving. The efficiency of HLG75 cyclone reached 95% at a flow rate of 35.5 m3/h and kept above 80% within the range of 24–68 m3/h. When the cyclones were tested under underflow leakage condition, HLG75 cyclone also acquired a most significant improvement, from 95% to 98%, at a split factor of 11.2%. Based on the research above, an improvement to the gas-liquid cyclonic separation unit was put forward, that is, inducing the gas at the under-flow exit to maintain the stable gas-leaking condition of each cyclone in avoidance to the inhaling of separated liquid. The results can provide guidance for the design of cyclones and may serve better in the powder and chemical industry process concerning aerosol particles removal. [Display omitted] •Five cyclones of different sizes were developed to the aerosol separation.•The best vortex finder depth of cyclone for aerosol separation was obtained.•The structural and operation properties of the cyclone were optimized.•The separation performances of the cyclones were enhanced by underflow leakage.