Series cyclones

Cyclones in series may be justified under some circumstances ... 

Bone black is sometimes ground veiy fine for paint, ink, or chemical uses. A tube mih often is used, the mill discharging to a fan which blows the material to a series of cyclone collectors in tandem. 

Most FCC unit regenerators employ 6-16 sets of primary and secondary cyclones in series, depending on unit size. These cyclones are designed to recover catalyst particles that are larger than 20 p. The recovered catalyst particles are returned to the regenerator via the diplegs. The flue gas exits the cyclones through a plenum chamber. 

ESPs), and some of the previously discussed novel devices. Series combinations of control devices may be necessary to achieve the required level of particulate matter emission. A commonly used system is a multiple cyclone followed by a fine-particle control system, such as a baghouse, scrubber, or ESP. 

The separation that a cyclone/hydroclone can achieve can be approximated from the following relation. The 0 50 (base) for a given diameter cyclone is multiplied times a series of correetion faetors designated by C, Cj, and C ... 

Perhaps the most important concern in cyclone selection is that they have the required collection efficiency. In a large cat cracker, two stages of cyclones in series must have a combined efficiency of 99.99% to keep catalyst losses to an acceptable... 

A series of theoretical analyses of the fluid and particle collection efficiency of cyclones were performed in the 1970s by Bloor and Ingham " and they have been found to be in good agreement with the experimental data. 

This unit is good to pre-thicken feed to centrifugal filters and similar applications. One cyclone may satisfy a requirement, or the units can be arranged in parallel for large capacities or in series for removal of extreme fines. See Figure 4-53 for a counter-current wash system. Solids as small as 10 microns can be separated. 

Cyclone filters are effective at removing larger particles and can operate over a wide range of temperatures, limited primarily by the material of construction. Cyclone filters are often designed as multiple units in series (multi-clones). They can remove >90% of particulates above about 5 microns in diameter at minimal pressure drops of 0.01 atm. Partial removal of material in the 1.5 micron range is also possible, but cyclonic filters become ineffective with sub-micron particles. 

The test unit used on Hutton consisted of two single-liner 60-mm [2.4-in.] hydrocydones that could be operated cither in series or parallel. The 35-mm [1.4-in.] cyclones exhibit potentially higher separation forces, but a 60-mm [2.4-in.] unit has approximately 2.5 times the capacity of a 35-mm [1.4-in.] cyclone for the same pressure driving force... 

---