Separation Performance Of Hydrocyclone Research Articles

Influence of inlet flow rate, pH, and beads mill operating condition on separation performance of sub-micron particles by electrical hydrocyclone

Experimental studies have been carried out about the separation performance of a special electrical hydrocyclone. In this study, effect of inlet flow rate, applied electrostatic potential, pH, and beads mill operating condition on separation performance of a special electrical hydrocyclone were investigated. A 0.5 wt% suspension of sub-micron silica dispersed by the beads mill was used as the test powder. A 20 mm electrical hydrocyclone in diameter with 20% of underflow was examined. A negative center electrode was vertically inserted inside the conical section and the potential difference up to 100 V was applied between the conical wall and the center electrode in the hydrocyclone. By use of beads mill, it was found that the negative values of zeta potential increases with the increase of the particles diameter. It was found that the separation performance of the electrical hydrocyclone increases significantly with the decrease of inlet flow rate and increase of the electrostatic potential, while the separation performance shows a less significant increase as the pH of suspension increases. Under several times of milling by use of the same beads, the values of zeta potential were not constant. The negative zeta potential of suspension attains the highest value under six times of milling by use of the same beads. A new model, based on the diffusive mass transfer equation in the conical section of the electrical hydrocyclone has been developed, and compared to the experimental results. It is found that the calculated results by the new model shows a qualitative agreement with the experimental results.

Experimental study on the separation performance of air-injected de-oil hydrocyclones

The developing status and separating principle of de-oil hydrocyclones are first simply introduced. The ways to enhance the hydrocyclone's separation efficiency are described based on theoretical analysis. One of the ways is to inject air into the hydrocyclones so as to combine them with oil to form oil–gas compound bodies, and then increase the de-oil efficiency. By means of injecting air into the hydrocyclone, a new type of hydrocyclone, i.e. air-injected de-oil hydrocyclone (AIDOH), was developed. The basic separation principle of the AIDOH, prototype structure, the experimental technical process and facilities are introduced. Laboratory experiments were carried out. The effects of different geometric parameters, including the vortex finder diameter, and the length, the micro-pore diameter, and different operating conditions, such as flowrate, split ratio, gas–liquid ratio, and especially the air-injecting position, were studied. It was also found that the best injecting part is at the fine cone segment. Further experimental studies were continued to confirm the detailed part in the fine cone segment, which included one-third segment and two-thirds segment. Results show that the best air-injecting part is the first one-third of the fine cone segment. Research indicates that the AIDOH has satisfied the separation effect.

1655 円筒型液体サイクロンの流動・分離性能(G05-9 流体機械(2),G05 流体工学)

1655 円筒型液体サイクロンの流動・分離性能(G05-9 流体機械(2),G05 流体工学)

Enhancement of hydrocyclone separation performance by eliminating the air core

A new hydrocyclone was designed with a solid core fixed along the central axis in this study. By introducing the solid core, the air core inside the hydrocyclone could be eliminated effectively. Comprehensive effects of eliminating the air core by the solid core on the hydrocyclone performance indices were experimentally investigated. To examine the influence mechanism of air core on the separation performance, a Laser Doppler Anemometer (LDA) was used to investigate the turbulent flow field inside hydrocyclones with and without air cores. The results showed that the radial and axial velocity components in the area near the entrance of the vortex finder, and the radial and axial turbulence components were all reduced by eliminating the air core, i.e. the flow field characteristics inside the hydrocyclone with solid core became more suitable for the separation process. By replacing the air core with solid core, the hydrocyclone separation performance was improved effectively. Comparing the hydrocyclones with air core and solid core, it was proved to be featured with higher total separation efficiency, larger reduced separation efficiency, smaller corrected cut size and higher separation sharpness, although the hydrocyclone cone shape changed from common type, to parabola type, and to hyperbola type. By increasing the inner space of the hydrocyclone cone, the improvement of separation performance became more remarkable.