Bubble growth obtained from pressure fluctuation in vibration separation fluidized bed using wavelet analysis

[Display omitted] •The bubble induced pressure signals in a vibration fluidized bed was investigated.•Bubbles can be effectively suppressed under the appropriate operating conditions.•The effect of different operating parameters on the fine coal separation was studied. The dynamics of pressure induced bubble in vibration separation fluidized bed was identified and investigated by calculating the correlation of the approximate signals at different levels. Effects of gas velocity, vibration frequency, vibration amplitude and static bed height on the correlation coefficients of pressure signals at levels A7 and A8 were studied. It was shown that the correlation coefficients of A7 and A8 scale signals first increase and thereafter decrease with the increase in gas velocity, vibration frequency, amplitude, and static bed height parameters. Meanwhile, the formation and aggregation of bubbles can be effectively suppressed by vibration within the height range of 90–140 mm under the condition of A = 2 mm, f = 20 Hz, and v = 14 cm/s. In addition, the E values of the separation accuracy of 1–3 mm raw coal reaches the minimum, which indicate that fine coal has achieved the criteria of ash reduction and quality improvement after sorting.