Detecting regime transitions in gas-solid fluidized beds from low frequency accelerometry signals Articles uri icon

publication date

  • February 2011

start page

  • 104

end page

  • 112

issue

  • 1-3

volume

  • 207

international standard serial number (ISSN)

  • 0032-5910

electronic international standard serial number (EISSN)

  • 1873-328X

abstract

  • Low frequency accelerometry signals have been applied for detecting regime transitions in a gas-solid fluidized bed. Three solids have been fluidized to promote bubbling, churn and slugging regime. The Kolmogorov entropy and the power spectral density have been used to determine the regime transitions as well as to analyze the dynamical features characterizing the different regimes. Pressure and external acceleration measurements have been taken simultaneously. The accelerometry signal was sampled at 10 kHz; then, the envelope was extracted and resampled at 400 Hz. Pressure signal was sampled at 10 kHz and resampled at 400 Hz. Two problems were found during the work: the colored noise present in the envelope and the lack of low frequency information for one of the tested solids. FIR, wavelet and EMD filter strategies have been applied to remove the noise present in the envelope. It is concluded that the envelope of the accelerometry signal might be used to detect regime transition in the same way as the pressure fluctuation signals. Both Kolmogorov and spectral analysis exhibit common features to those obtained from pressure signal analysis, supporting the hypothesis of using low frequency accelerometry instead of conventional pressure measurements for monitoring fluidized beds.

keywords

  • fluidization ; regime transition ; nonlinear dynamics ; process control ; accelerometer ; acoustics