This program sizes a cyclone or a number of cyclones in parallel for a given duty. The design is based on an inertial model and two dimensionless groups (Euler number and Stokes number), which are constant for a geometrically similar family of cyclones, have to be known. The program first converts the task given, via three different input options, into the operating cut size required. The three options are for classification, gas cleaning or product recovery duties. It then offers the user two different corrections for the effects of dust loading on efficiency and pressure drop. Finally, it calculates, from the given operating conditions and the required cut size, the design options available (number of cyclones in parallel, their diameter and the operating pressure drop necessary) and lets the user choose the suitable set.
The program does not take into account the effects of dust re-entrainment and this empirical information, in the form of the maximum pressure above which the computed design options are to be ignored, has to be known by the user. Both the particle size distribution of the feed solids (by mass) and the reduced grade efficiency of the gas cyclone are assumed to follow the log-normal law which requires only two parameters to describe each curve: the median size (the size corresponding to 50% on the cumulative plot of the feed particle size distribution or the cut point on the grade efficiency curve) and the geometric standard deviation (the ratio of the particle sizes at 84% and 50% or at 50% and 16% on the same curve). These two parameters have to be known for the particle size distribution and are required as data by the program, whilst only the geometric standard deviation of the grade efficiency (a typical value is sufficient) is required. Some default input values have been programmed in as a worked example.
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Last modified on 10-12-03 20:18