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Could cyclone performance improve with reduced inlet velocity?

Funk, P. A., Elsayed, K., Yeater, K. M., Holt, G. A., Whitelock, D. P.
Powder technology 2015 v.280 pp. 211-218
electricity, energy use and consumption, filters, models, particle size distribution, particulate emissions, pollution control, powders
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 (PM(2.5)) collection of 1D3D cyclones (H = 4Dc, h = 1Dc) at inlet velocities from 8 to 18 m s(−1) (Stk = 0.7–1.5) using heterogeneous particulate as a test material at inlet concentrations from 3 to 75 g m(− 3). Cyclone exhaust was passed through filters. Laser diffraction particle size distribution analysis was used to estimate PM(2.5) 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 PM(2.5) emissions was less definitive and, surprisingly, predicted a 31% decrease in PM(2.5) 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.