ACS holds a patent of a recirculation system to increase the efficiency of cyclones. A mechanical ReCyclone® (ReCyclone® MH) is made up of a high efficiency Hurricane and a particle separator, placed downstream, called the “mechanical recirculator” (please see figure).
In 2016, ACS introduced more compact recirculators that can be placed on top of cyclones, exempting the need of additional footprint.
The main purpose of the recirculators is to reintroduce the uncaptured particles into the cyclones after they have been driven to the outer walls of the recirculators by centrifugal forces. While this gas is enriched in particles, the axial gas stream exhaust to the stack is clean of particles. Recirculation is achieved through an additional fan.
Since the recirculation system only serves the purpose of dust separation (and not collection), the particles are exclusively collected in the cyclones and the need of rapping mechanisms is avoided. Systems are arranged in groups of cyclones and recirculators.
Efficiency increases due to recirculation and agglomeration of very small particles with larger ones coming directly from the process. A ReCyclone® MH decreases emissions of Hurricane cyclones alone by 30 to 60%. Finally recirculation control has the benefit of handling variable process flow rates very well.