(285a) Cyclone Dipleg Design and Operation Considerations

The correct cyclone design is often critical to the successful operation of many chemical processes. Cyclone system design most commonly refers to the design of the cyclone and its associated dipleg. In many (if not most) cases, poor cyclone system operation is due to poor operation of the cyclone dipleg – especially the secondary cyclone dipleg.

Cyclone dipleg operation is often the primary culprit in causing excessive carryover of solids from fluidized catalytic cracking (FCC) and other catalytic processes. Poor cyclone dipleg operation can also cause solids losses from other processes (gasification and circulating fluidized bed combustion).

How the correct design of various diplegs can mitigate excessive loss of solids will be discussed. This discussion will address the role and design of trickle valves, flapper valves, loop seals and dipleg configuration on dipleg design and operation.