Motion characteristics and density separation of fine coal in an inflatable-inclined liquid

Lv, B., Dong, B., Deng, X., & Fang, C. (2021). Motion characteristics and density separation of fine coal in an inflatable-inclined liquid–solid fluidized bed. Particuology, 58, 299-307. https://doi.org/10.1016/j.partic.2021.04.006

Motion characteristics and density separation of fine coal in an inflatable-inclined liquid–solid fluidized bed

Bo Lv ^{a b c}, Bobing Dong^{a b}, Xiaowei Deng ^{a b *}, Chaojun Fang ^{a b c}

a College of Chemistry and Chemical Engineering, Henan Polytechnic University, Jiaozuo 454000, China
b Henan Key Laboratory for Green and Efficient Mining & Comprehensive Utilization of Mineral Resources, Henan Polytechnic University, Jiaozuo 454000, China
c Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization, Henan Polytechnic University, Jiaozuo 454000, China

10.1016/j.partic.2021.04.006

Volume 58, October 2021, Pages 299-307

Received 1 March 2021, Revised 31 March 2021, Accepted 6 April 2021, Available online 4 May 2021, Version of Record 17 May 2021.

E-mail: shenland@hpu.ed.cn

Highlights

• A method to improve a fluidized bed for fine coal separation was proposed.

• The inflatable-inclined liquid–solid fluidized bed (IILSFB) was developed.

• Fluidization characteristics and separation performance were analyzed.

• Under optimal working conditions, the IILSFB has good separation performance.

Abstract

To improve the adaptability of fluidized beds for fine coal separation, a new type of liquid–solid fluidized bed was constructed, i.e., the inflatable-inclined liquid–solid fluidized bed (IILSFB). A combination of simulation analysis and separation experiments was used to analyze the fluidization characteristics and separation performance of the IILSFB. The results showed that there was upflow and downflow in the fluidized bed. The upflow was mainly composed of water flow, followed by light and heavy particles; on the other hand, the downflow was caused by the backflow of heavy particles that settled at the inclined section. In addition, the light particles that settled at the inclined section could return to the rising water flow under the action of secondary airflow. As the water velocity, separation time, and secondary gas velocity increased, the comprehensive separation efficiency of fine coal in the fluidized bed improved, while the value decreased as the feed quantity increased. This also indicated the order of importance for these four factors, i.e., water velocity, separation time, feed quantity, and secondary gas velocity, on fluidisation. Furthermore, the comprehensive separation efficiency of 0.1–1 mm fine coal varied significantly with various factors, while that of ∼0.1 mm and 1–3 mm fine coal was always at a low value. In the latter case, the classification process of the size fraction was significantly better than the separation process in the fluidized bed. Under optimal working conditions, an IILSFB was used to separate the fine coal (0.1–1 mm). The yield of clean coal was 37.95% with an ash content of 12.11%, and the possible error was 0.085 g/cm³, indicating that the IILSFB had good separation performance for 0.1–1 mm fine coal.

Graphical abstract

Keywords

Inflatable-inclined liquid–solid fluidized bed; Fine coal separation; Fluidization; Separation efficiency; Secondary gas velocity; Size fraction

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