Could cyclone performance improve with reduced inlet velocity?

Emission abatement cyclone performance is improved by increasing collection effectiveness or decreasing energy consumption. The object of this study was to quantify the pressure drop and fine particulate (PM2.5) collection of 1D3D cyclones (H=4Dc, h=1Dc) at inlet velocities from 8 to 18ms−1 (Stk=0.7–1.5) using heterogeneous particulate as a test material at inlet concentrations from 3 to 75gm−3. Cyclone exhaust was passed through filters. Laser diffraction particle size distribution analysis was used to estimate PM2.5 emissions. Response surface models showed a strong correlation between cyclone pressure loss (Euler number) and inlet velocity and predicted a 46% reduction in pressure loss for a 25% reduction in inlet velocity (Stokes number). The model for PM2.5 emissions was less definitive and, surprisingly, predicted a 31% decrease in PM2.5 emissions when operating 25% below the design inlet velocity. Operating below the design inlet velocity (at a lower Stokes number) to reduce pressure losses (Euler number) would reduce both the financial and the environmental cost of procuring electricity. The unexpected co-benefit suggested by these trials was that emission abatement may improve at the same time, though other empirical trials have shown emissions to be independent of inlet velocity and Stokes number. [Display omitted] •The significance of these results comes from the nexus of emissions and energy.•Producing electricity to power abatement devices results in air pollution.•Reducing inlet velocity reduced pressure drop and hence energy required.•Empirical PM2.5 emissions also appeared to decrease at lower inlet velocities.