Uniflow cyclones compared with standard cyclones

U. Muschelknautz*, MK Engineering, Germany

A compact and competitive alternative to standard reverse flow cyclones for separa-ting solid particles from gases are uniflow cyclones. They have gas and particles passing through them in only one direction. The swirling flow inside the cyclone is usually generated either by swirl vane inserts or by a tangential inlet at the entrance of the device. Pure gas and collected particles are leaving the device at the same end. The compact design of uniflow cyclones is appropriate in space-limited applica-tions and generally allows simple and cheap implementation into piping systems.

Even though the principle of uniflow cyclones has been known for a long time, not much literature has been published on how to design them and to calculate their performance data. Furthermore, there is a need for comparing the performance of uniflow cyclones with that of standard cyclones in a systematic way. So far the investigation of uniflow cyclones has been restricted to special applications such as uniflow cyclones with high solids loading for the application as a short-contact time reactor. A major challenge to make uniflow cyclones accessible to general industrial practice and to compare uniflow cyclones with standard cyclones is an accurate, reliable and fast design and calculation method. For calculating the performance data of conventional reverse flow cyclones, approved analytical models with high precision exist which are often preferred over methods based on numerical simulation with long computing times. Similarly, industrial design practice for uniflow cyclones would benefit from an adequate analytical model. Former analytical approaches for calculating uniflow cyclones mostly assume a sedimentation process induced by the centrifugal force, neglecting the strong drag force on the particles directed towards the gas outlet. As a result, they incorrectly predict fundamental interrelationships like the dependency of the separation efficiency on the vortex finder diameter or on the cyclone length.

With this background, a new analytical approach for calculating the separation efficiency and the pressure of uniflow cyclones for practical design work has been developed. This approach is based on ...

Session: G8 - Modelling and Simulation I
Day: 12 October 2016
Time: 10:45 - 12:00 h