Apparent viscosity of high-density fluidized bed and synergistic effect of density and apparent viscosity on particle separation

ABSTRACT

For gas-solid fluidization separation, mineral particles are separated under the joint action of bed density and apparent viscosity. In present study, the apparent viscosity of high-density binary mixture media was investigated by the falling ball method. Moreover, the significant effects of bed density and apparent viscosity on simulated mineral pellets and their interactions were investigated. The apparent viscosity model of high-density gas-solid fluidized beds was modified, and it was found that the Pearson correlation coefficient is 0.86. The results show that the apparent viscosity of high-density gas-solid fluidized bed decreases with increasing fluidization gas velocity. When the fluidization number is higher than 1.3, the apparent viscosity is basically stable in the range of 3.96–5.21 Pa·s. Under low apparent viscosity, when the pellet diameter is 20 mm and the density difference ∆ρ is greater than 0.27 g/cm³, gravity is the dominant factor affecting the settling behavior of the pellet. Under high apparent viscosity, the effect of viscous resistance on the settling behavior of pellets is dominant when the ∆ρ is less than 0.27 g/cm³. Based on the performed analyses, the low-viscosity medium can be selected for the separation of large mineral particles. Furthermore, for high-viscosity medium, the influence of bubbles on particle sedimentation can be effectively alleviated and it can be selected for the separation of small particles.

GRAPHICAL ABSTRACT

KEYWORDS:

• Gas-solid fluidized bed
• high-density separation
• fluidization properties
• apparent viscosity
• particle sedimentation

Highlights

• The apparent viscosity characteristics of gas-solid fluidized bed with high-density medium system was explored.

• The apparent viscosity calculation model of high-density gas-solid fluidized beds was modified.

• The effects of bed density and apparent viscosity on simulated mineral pellets were investigated.

Acknowledgements

This research was partially supported by the National Key R&D Program of China (2022YFC2905900), the National Nature Science Foundation of China (U2003126,52004282), the Fundamental Research Funds for Central Universities (2021YCPY0108, 2021GJZPY01), Inner Mongolia Science and Technology Project (2021EEDSCXSFQZD007).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the The Key Special Project of Inner Mongolia ”Science and Technology” Action - Key Technology and Application of Low Quality Power Coal Low Carbon Clean and Efficient Dry Sorting and Quality Improvement [2021EEDSCXSFQZD007]; National Nature Science Foundation of China [U2003126,52004282]; Fundamental Research Funds for Central Universities [2021YCPY0108, 2021GJZPY01]; Financial support by the National Key R&D Program of China [2022YFC2905900].

Notes on contributors

Yuqi Bai

Yuqi Bai, master, China University of Mining and Technology, mainly engaged in the research of fluidized dry separation.

Pengfei Zhao

Pengfei Zhao, Ph. D, China University of Mining and Technology, mainly engaged in the research of fluidized dry separation.

Mengyao Guo

Mengyao Guo, master, China University of Mining and Technology, mainly engaged in the research of Clean Coal Technology.

Guanghui Yan

Guanghui Yan, Ph. D, China University of Mining and Technology, mainly engaged in the research of comprehensive resource utilization.

Chenyang Zhou

Chenyang Zhou, Associate Prof, China University of Mining and Technology, mainly engaged in the research of fluidized dry separation.

Zongsheng Sun

Zongsheng Sun, Ph. D, China University of Mining and Technology, mainly engaged in the research of Coal Dewatering.

Tianyang Gao

Tianyang Gao, master, China University of Mining and Technology, mainly engaged in the research of fluidized dry separation.

Bo Zhang

Bo Zhang, Prof, is an outstanding young scholar of ”High-end Talent Program” of China University of Mining and Technology. He is mainly engaged in the research of dry separation and dewatering of low-quality coal, efficient utilization of solid waste resources and supercritical fluid upgrading. He has published more than 50 SCI papers in journals such as Fuel, Miner Eng and Journal of Coal.