Fluidization characteristics of loaded vibrating fluidized bed and dewatering and deashing effect of moist fine-grained coal

ABSTRACT

The influence of a thermal vibrating fluidized bed on the dewatering and deashing effect of moist fine-grained coal was investigated by digital image processing and signal analysis methods. Comparative analysis results of the pressure signals of a loaded vibrating fluidized bed indicated that high or low gas velocity and strong or weak vibration conditions easily caused the formation of numerous irregular bubbles and contributed to violent fluctuations in the bed. An interaction between gas velocity and vibration energy was found, with vibration energy being the dominant factor influencing the bubble behavior at low gas velocities. Moreover, at high gas velocities, the advantages arising from vibrations were weakened. Under the condition of f = 20 Hz, A = 2 mm, v = 18 cm⋅s⁻¹, the contact efficiency between the gas – solid two phases was higher, and the pressure fluctuation of the bed became more stable. Under this condition, the ash content of clean coal and the moisture removal rate were 11.76% and 83.54%, respectively. Finally, comparison and analysis of the influence of different parameters on the calorific value of clean coal revealed that the influence of each parameter on heat generation of the selected product was found to be in the following order: f > A > V > T.

KEYWORDS:

• Loaded vibrating fluidized bed
• moist fine-grained coal
• dewatering-deashing
• synergistic mechanism

Nomenclature

A	=	Amplitude, (mm)
f	=	Vibration frequency, (Hz)
v	=	Gas velocity, (cm/s)
T	=	Temperature, (℃)
t	=	Time, (s)
Φ	=	Fluidized bed diameter, (mm)
E	=	Separation accuracy
δ	=	Separating density
Q	=	Calorific value

Acknowledgements

This work is financially supported by the China National Funds for Distinguished Young Scientists (52125403), the China Postdoctoral Science Foundation (2021M703505), the National Natural Science Foundation of China (52374285, 52261135540, 52204294), the Key Technology Project of China National Coal Group Corp (20231CY003) and the Inner Mongolia Central Government Guides Local Science and Technology Development Project (2022ZY0051).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the China National Funds for Distinguished Young Scientists [52125403]; China Postdoctoral Science Foundation [2021M703505]; National Natural Science Foundation of China [52261135540, 52204294]; Natural Science Foundation of Jiangsu Province [BK20220160, BK20221131]; Science and Technology Project of Xuzhou City [KC21091].