Cyclones discharge hoppers

The strong vortex inside a cyclone reaches into the space underneath the sohds outlet and it is important that no powder surface is allowed to build up to within at least one cyclone diameter below the underflow orifice. A conical vortex breaker positioned just under the dust discharge orifice may be used to prevent the vortex from intruding into the discharge hopper below. Some cyclone manufacturers use a stepped cone to counter the effects of re-entrainment and abrasion, and Svarovsky (1981) demonstrated the value of this design feature. 

Fresh catalyst is normally delivered in hopper-bottom railroad cars. The catalyst may be withdrawn by gravity flow from the bottom of the car through a hose to a Fuller-Kinyon screw pump and transferred to the hopper by means of an air stream loss of catalyst is prevented by a cyclone on the air discharge from the hopper. Alternatively, the catalyst may be unloaded from the top of the ear by a vacuum lift. In this case, the suction line passes through a separator with bag filters, located above the storage hoppers. The catalyst collects in a chute and flows down through a rotating barrel-valve feeder into a screw conveyor which transfers the catalyst to the hopper (105). 

Fig. 2.8. Zirconium Chloride Plant. 1, feed hopper 2, star valve feeder 3, ball valve 4, silica brick 5, steel shell 6, insulating brick 7, clean out 8, water-cooled copper electrode connector 9, graphite electrode and nipple 16, chlorine inlet pipe 11, nickel cross-over pipe 12, primary condenser 13, condenser jacket 14, ba 3e 15, discharge valve 16, air heater 17, blower 18, cyclone-type aftercondenser 19, water scrubbing tower 20, caustic scrubbing tower 21, exit gas outlet to stack 22, caustic circulating pump 23, waste water inlet 24, caustic bleed line (Stephens, W. W. and Gilbert, H. L.

A true multicyclone is not only a parallel arrangement of cyclones, but also one wherein the individual cyclones are housed within a common casing that constitutes the inlet chamber. Furthermore, the dust (or liquid) discharge and the gas outlet pipes also report to their own common outlet plenum and hopper, respectively. Multicyclone systems of the type shown in Figs. 16.2.2 and 16.2.3 are usually comprised of numerous small diameter cyclones (typically under 250 mm in diameter) and this normally leads to excellent separation performance relative to fewer, larger units handling the same total volumetric flow. 

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