Experimental and Numerical Study of a Swirling Counter-current Dust Collector for High-efficiency Cleaning of Industrial Gas Emissions

Purpose. To determine the hydrodynamic characteristics and the collection efficiency of a swirling counter-current dust collector (UBO-200, body diameter 0.2 m) in which two tangentially supplied gas streams, the primary and the secondary one, meet each other inside a single body as swirling counter-current flows. Methods. The gas-phase flow was described by the Euler equations for the circumferentially averaged (axisymmetric) flow in the stream-function formulation and solved by an iterative finite-difference procedure, while the particle motion was modelled by Newton’s second law in cylindrical coordinates. Experiments were carried out on two industrial dusts, asphalt-concrete plant dust and cement clinker dust (particle density 2900 kg/m 3 ). Results. The pressure drop grew almost quadratically with the flow rate, from about 0.3 kPa at 1500 m 3 /h to about 2.1 kPa at 4000 m 3 /h. The collection efficiency increased with the flow-split ratio K = Q2/Q and reached its maximum at K ≈ 0.8: about 90% for asphalt-concrete plant dust and 84% for clinker dust. At K = 0.8 particles larger than about 4 µm were collected with an efficiency above 90%, and those of 8–9 µm with an efficiency close to 99.9%. An increase of the inlet dust loading reduced the hydraulic resistance coefficient by about one quarter. Conclusions. The results identify rational operating and design parameters of the collector for dry cleaning of gases in cement and asphalt-concrete production.

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