Caracterização de hidrociclones com cilindros e cones permeáveis

Abstract

Published studies on hydrocyclones up to 2022 mostly report their use in the processing of dilute suspensions. However, high concentrations of solids, is more commonly encountered in industrial practices, and the use of hydrocyclones in these cases can result in inefficient separations. Possible changes in the structure of hydrocyclones have been studied to improve the performance of these separators, such as the association of filtration and hydrocycloning operation. The filtering hydrocyclone has a cylindrical wall, conical wall, or both, made of porous material, and has an additional outflow (filtered) for the fluid. Given this context, this experimental study intended to evaluate the performance of optimal geometries of hydrocyclones with filtering cylinders and cones (HCiCoF-OT1 and HCiCoF-OT3, HCoF-OT1 and HCoF-OT3), proposed by Salvador (2017), operating with suspensions with different solids concentrations. For this, an experimental design was developed for each hydrocyclone to evaluate the effects of filtration and three levels of the variables of interest: feed solids concentration (CVA), underflow diameter (DU), and pressure drop (–ΔP). In all cases, it was observed that the energy consumption was reduced for the filtering hydrocyclones; and the increase in the feed solids concentration led to a reduction in the total efficiency. For the hydrocyclones of HCiCoF-OT1 and HCoF-OT1 geometries, the total efficiency was minimized with the increase of CVA and reduction of the variables underflow diameter and pressure drop. The maximum tottal efficiency achieved was 85 % for HCiCoF-OT1 and 86 % for HCoF-OT1 operating with DU of 5 mm, pressure drop of 1.77 bar, and 1.0 %v. of solids in the feed. These hydrocyclones also provided high total efficiencies in suspensions containing 10.0 %v. solids, reaching 79 % (HCiCoF-OT1) and 77 % (HCoF-OT1). The hydrocyclones of HCiCoF-OT3 and HCoF-OT3 geometries showed low split ratios for all concentrations studied. HCiCoF-OT3 presented RL of 0.6 % for the most diluted suspension (CVA = 1.0 %v.), and 4.0 % for the most concentrated (CVA = 10.0 %v.). To these hydrocyclones the split ratio was lower for dilute suspensions, smaller underflow diameters, and conventional equipment; for concentrated suspensions, the filtering equipment presented a better alternative for providing a lower energy consumption and statistically equal RL.