FSM: Liquid Desander – Cyclonic Technology Part 2 (B-FSM044)
The previous article defined the cyclonic unit process and introduced the cyclone family.
What makes cyclonic technology so valuable for the offshore oil & gas industry is that it has the highest throughput-to-size ratio of any partitioning device. For a given flow rate a cyclone will have the smallest size and weight of any separation piece of equipment.
There are several key design and operating factors that define a piece of equipment as a cyclone unit process;
- No moving parts – no motors, no seals, no bearings, etc. – very simple machine
- Tangential or involute inlet – starts the swirling flow pattern
- Cylinder-cone geometry – increases swirl down the length of the unit
- Free-forced vortex split flow pattern – defines how the two exit-streams form and where the separated phase goes
- Classifying device – separates based on weight, not size
Based on these parameters a centrifuge is not a cyclone (has moving parts), neither is the GLCC or swirl tube (both lack a cone section). All these are separating pieces of equipment, but they are not technically a cyclone.
Where are cyclonic devices used in the petroleum industry?
- 2/3 phase gravity separator inlet devices
- Fluid-catalytic cyclones in refining
- Produced water deoiler
- Produced water desander
- Multiphase desander
There is no “standard” cyclone. Each is designed for a specific duty. Many of these devices have become commodities, by commercial necessity, however each phase separation type above requires a specialty cyclone.
The photo below shows the author (many years ago) working hard testing an inclined hydrocyclone for slurry dewatering at the Bingham Canyon Mine tailings pond outside of Salt Lake City, UT. The good days where when the plant was down and I could hit the slopes at Alta.
The next article will discuss the history of Hydrocyclones through the development of Desanders.
- Green, D.W. 2007. Perry’s Chemical Engineers’ Handbook, 8th Edition, McGraw-Hill, New York.