The purpose of this work is to build a model to predict in a more realistic way the collection efficiency of a gas cyclone recirculating system (Chibante et al., 2007; Salcedo et al., 2007). These systems consist in an optimised reverse-flow cyclone articles via a straight-through cyclone concentrator, with very high collection efficiencies for very fine particles.
As a first approach, in this paper a reverse-flow gas-cyclone without recirculation was studied. The model starts by solving the particle trajectory in a turbulent flow field inside the cyclone, and by employing a fixed set of parameters, it determines if a collision or an agglomeration occurs. In case of agglomeration, the initial particles will have a dynamic behaviour inside the cyclone as a newly formed agglomerate, thus having a different collection efficiency from that of the original particles. In fact, the observed efficiency will increase above theoretical predictions and this can be observed in various experimental results, usually referred as “hook-like” grade-efficiency curves.
The hypothesis of particle agglomeration within the cyclone turbulent flow seems a sound justification for the higher than predicted collection efficiencies observed for smaller particles in a gas-cyclone, being expectable with recirculation that this effect will become even more significant.