Performance characteristics of a low pressure cyclone for axial-flow fan exhausts

Abstract

The implementation of the Federal Clean Air Act Amendments will force cotton gins to reduce particulate matter emissions. The first-stage lint cleaner is the emitting point of a gin with the highest emission rate of fine dust. Axial-flow fans pneumatically convey lint fiber to the first-stage lint cleaner. typically, covered condenser drums with fine mesh screens are the abatement devices used on a)axial-flow fan exhausts. A new ID2D Low Pressure Cyclone (LPC) was developed that could be used on axial-flow fan exhausts to significantly reduce particulate emissions. Average emission concentrations, cut-point diameters, PMIO emission concentrations, and fractional efficiencies from this cyclone operating at different cyclone inlet velocities and incorporating the use of a "bleed" or suction system at the cyclone's dust outlet were reported. A comparison of the ID2D LPC to ID3D and 2D2D cyclones was reported. A ID3D cyclone with traditional inlet vws compared to a ID3D cyclone with a 2D2D type inlet. Results indicated that the ID2D LPC had a pressure drop of only 3 73 Pascals (I. 5 in. w.g.) or less. The pressure drops across ID3D and 2D2D cyclones were 1132 and 1119 Pascals (4.6 and 4.5 in. w.g.), respectively, or less. The pressure drop across the ID3D cyclone with the 2D2D inlet was 1468 Pascals (5.9 in. w.g.) or less. The average emission concentrations from the ID2D LPC operating at an inlet velocity of 732 m/min (2400 fpm) for high lint trash/fine dust loadings were significantly lower than concentrations at an inlet velocity of 853 m/min (2800 fpm). The average emission concentrations from the ID2D LPC at all loading rates of high lint trash/fine dust were significantly lower than the other three cyclones. The average emission concentrations from testing the ID2D LPC at loading rates of fine dust were not significantly different than the other three cyclones. The average emission concentrations from the ID3D cyclone with a 2D2D inlet at high lint trash/fine dust loadings were significantly lower than concentrations from the ID3D cyclone with a traditional inlet. The addition of a 10% bleed at the cyclones' outlets significantly reduced the average emission concentrations compared to a 0% bleed.