Separation performance of hydrocyclones with medium rearrangement internals

The inlet section of hydrocyclone has a significant effect on separation efficiency. However, in most existing studies the inlet of conventional hydrocyclones (CH) only serves as a channel for the mixed liquid to enter the hydrocyclone body. Based on CH's tangential inlet with a rectangular section, a novel hydrocyclone with medium rearrangement internals (HMRI) was designed and the rearrangement internals (RIs) were installed inside the inlets. The RIs include one separating block and 3 division plates following the block. Thus, the rearrangement of immiscible media can be achieved after passing through this inlet, i.e., media with different densities flow into different layers. Most of the rearranged low-density phase flows directly into the central area of HMRI. Meanwhile, most of high-density phase flows to the wall zone, which is beneficial for the subsequent centrifugal separation process in HMRI's body. Taking the oil-water mixture as the example, three kinds of separating blocks, semi-cylindrical block (SCB), triangular prism block (TPB), and trapezoidal body block (TBB) were designed and compared to no-block cases (conventional inlet) through simulations. Results showed that RIs with SCB displayed excellent rearrangement effect as well as a low pressure drop. Additionally, the comparison between CH and HMRI was conducted via oil-phase distribution, velocity distribution, and separation efficiency. Our results show that the separation efficiency of the novel HMRI was 6.4-8.0% higher than the traditional CH, under various operating conditions. The application potential of HMRI in biological processes for wastewater treatment was also analysed and discussed.

Automated summary

The study examined the impact of the inlet section of hydrocyclones on separation efficiency and designed a novel hydrocyclone suitable for medium rearrangement. Simulations were used to compare the effects of different separating blocks on separation efficiency, with results indicating that SCB displayed excellent rearrangement effect and low pressure drop. Additionally, experimental data comparing CH and HMRI showed that HMRI achieved 6.4-8.0% higher separation efficiency than CH.