Pressure drop, hydroclones

In determining the proper size and number of cyclones required for a given application, two main objectives must be considered. The first is the classification or separation that is required, and the second is the volume of feed slurry to be handled. In the case of hydroclones, before determining whether these objectives can be achieved, it is necessary to establish a base condition as follows Feed liquid - water at 20 C. Feed solids - spherical particles of 2.65 specific gravity Feed concentration - less than 1 % solids by volume Pressure drop - 69 kPa (10 psi) Cyclone geometry - "standard cyclone" as described above. 

Six-tenths factor, 47 Yearly cost indices, 47 Critical flow, safety-relief, 438 Back pressure, 440 Sonic flow, 438 Critical flow, see Sonic Cyclone separators, 259-269 Design, 260-265 Efficiency chart, 263 Hydroclones, 265-267 Pressure drop, 263, 264 Scrubber, 269 Webre design, 265 Deflagration venting nomographs,... 

For liquid knockout the bottom head often is made dished as on Figure 18.10, which also shows standard dimensions. Liquid-solid separators are called hydroclones. Inlet velocities should be in the range 100-150 ft/sec, the higher the better, but may be limited by the occurrence of reentrainment and unacceptable pressure drop. The pressure drop is estimated in terms of velocity heads, a value of four being commonly taken. Accordingly,... 

The pressure drop Ap in a hydroclone varies with the feed rate raised to a power between 2.0 and 3.3. For dilute feeds the cut diameter varies with the 1.5 power of the cyclone diameter, so for a given pressure drop a small diameter gives better separation than a large one. Hydroclones are therefore small they range in diameter from 10 mm (0.4 in.) to about 1.2 m (48 in.). To handle large flows, many small hydroclones are connected in parallel, with as many as four hundred and eighty 10-mm units manifolded in a single assembly. 

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