Can low frequency accelerometry replace pressure measurements for monitoring gas-solid fluidized beds?

Abstract This paper is addressed to introduce a methodology based on low frequency accelerometry that can be used for gas-solid fluidized bed monitoring, and for dynamic diagnosis purposes. The proposed methodology consists on extracting the low frequency information encoded within an accelerometry signal, by means of the Hilbert transform method. The time and the frequency domain analysis show how this low frequency information is directly related to the conventional pressure fluctuation measurements, providing useful information on bulk and bubble dynamics. The cross-correlation and the coherence function analysis between the pressure and the envelope process of the measured accelerometer signals “E”, exhibit values approaching unity for frequencies ranging between 2 and 4 Hz. This reveals that pressure signals and accelerometry envelope are related processes. The results from the Coherent Output Power, COP, and the Incoherent Output Power, IOP, analysis confirms that both pressure and envelope time series exhibit the same global and local features open the possibility of using low frequency accelerometers instead of conventional pressure transducers for monitoring and for dynamic diagnosis purposes.

[1]  N. C. Nigam.  Introduction to Random Vibrations , 1983 .

[2]  Daw,et al.  Chaotic characteristics of a complex gas-solids flow. , 1990, Physical review. A, Atomic, molecular, and optical physics.

[3]  Charles E. A. Finney,et al.  Measuring Slugging Bed Dynamics with Acoustic Sensors , 1998 .

[4]  Cor M. van den Bleek,et al.  Rapid detection of defluidization using the standard deviation of pressure fluctuations , 2004 .

[5]  Joachim Werther,et al.  Measurement techniques in fluidized beds , 1999 .

[6]  Filip Johnsson,et al.  Characterization of fluidization regimes by time-series analysis of pressure fluctuations , 2000 .

[7]  M. Louge,et al.  Measurements of the effective dielectric permittivity of suspensions , 1990 .

[8]  A. P. Baskakov,et al.  A study of pressure fluctuations in a bubbling fluidized bed , 1986 .

[9]  John R. Grace,et al.  Microstructural aspects of the behaviour of circulating fluidized beds , 1993 .

[10]  Geert Versteeg,et al.  Measuring Bubble, Drop and Particle Sizes in Multiphase Systems with Ultrasound , 2004 .

[11]  Cor M. van den Bleek,et al.  Response characteristics of probe-transducer systems for pressure measurements in gas-solid fluidized beds: how to prevent pitfalls in dynamic pressure measurements , 1999 .

[12]  S. Simons,et al.  Experimental methods in fluidization research , 1994 .

[13]  Norden E. Huang,et al.  On Instantaneous Frequency , 2009, Adv. Data Sci. Adapt. Anal..

[14]  Cor M. van den Bleek,et al.  Early warning of agglomeration in fluidized beds by attractor comparison , 2000 .

[15]  Yang Yu,et al.  The application of energy operator demodulation approach based on EMD in machinery fault diagnosis , 2007 .

[16]  E. Levy,et al.  Characteristics of acoustic standing waves in fluidized beds , 2002 .

[17]  J. Varley,et al.  Measurement of gas hold-up in bubble columns from low frequency acoustic emissions , 2002 .

[18]  A. Marzocchella,et al.  Laser diagnostics of hydrodynamics and gas-mixing induced by bubble bursting at the surface of gas-fluidized beds , 2007 .

[19]  Xuesong Lu,et al.  Wavelet analysis of pressure fluctuation signals in a bubbling fluidized bed , 1999 .

[20]  Filip Johnsson,et al.  Non-intrusive determination of bubble and slug length scales in fluidized beds by decomposition of the power spectral density of pressure time series , 2002 .

[21]  Hadj Benkreira,et al.  Calculation of optic fibres calibration curves for the measurement of solids volume fractions in multiphase flows , 1996 .

[22]  Andrew N. Norris,et al.  Particle granular temperature in gas fluidized beds , 1996 .

[23]  W. Żukowski.  An acoustic method of studying sequential explosions during gas combustion in bubbling fluidized beds , 2001 .

[24]  Hsiaotao Bi,et al.  A critical review of the complex pressure fluctuation phenomenon in gas–solids fluidized beds , 2007 .

[25]  Julie Varley,et al.  The uses of passive measurement of acoustic emissions from chemical engineering processes , 2001 .

[26]  Vittorio Ferrari,et al.  Applied structural and mechanical vibrations - theory, methods and measuring instrumentation , 1999 .

[27]  Filip Johnsson,et al.  Fluidization regimes and transitions from fixed bed to dilute transport flow , 1998 .

[28]  Javier Villa Briongos,et al.  Phase space structure and multi-resolution analysis of gas–solid fluidized bed hydrodynamics: Part II: Dynamic analysis , 2007 .

[29]  Navid Mostoufi,et al.  Non-intrusive monitoring of bubbles in a gas-solid fluidized bed using vibration signature analysis , 2009 .

[30]  Hiroyuki Tsujimoto,et al.  Monitoring particle fluidization in a fluidized bed granulator with an acoustic emission sensor , 2000 .

[31]  L. Fan,et al.  Characteristics of slugging regime and transition to turbulent regime for fluidized beds of large coarse particles , 1985 .

[32]  H. Kage,et al.  Frequency analysis of pressure fluctuation in fluidized bed plenum. , 1991 .

[33]  M. P. Norton,et al.  Fundamentals of Noise and Vibration Analysis for Engineers , 1990 .

[34]  Geoffrey F. Hewitt,et al.  To churn or not to churn , 1993 .

[35]  Maurice A. Bergougnou,et al.  A novel calibration procedure for a fiber optic solids concentration probe , 1998 .

[36]  J. V. Briongos,et al.  Free top fluidized bed surface fluctuations as a source of hydrodynamic data , 2003 .

[37]  C. Harris,et al.  Harris' Shock and Vibration Handbook , 1976 .

[38]  Filip Johnsson,et al.  Characterization of fluid dynamics of fluidized beds by analysis of pressure fluctuations , 2007 .

[39]  Ethan Brue,et al.  Resolving dynamical features of fluidized beds from pressure fluctuations , 2001 .

[40]  Jinghai Li,et al.  Multiscale nature of complex fluid-particle systems , 2001 .

[41]  Javier Villa Briongos,et al.  Fluidised bed dynamics diagnosis from measurements of low-frequency out-bed passive acoustic emissions , 2006 .

[42]  Yongrong Yang,et al.  Multiscale resolution of fluidized‐bed pressure fluctuations , 2003 .

[43]  H. Bi,et al.  Propagation of pressure waves and forced oscillations in gas-solid fluidized beds and their influence on diagnostics of local hydrodynamics , 1995 .

[44]  Javier Villa Briongos,et al.  Phase space structure and multi-resolution analysis of gas–solid fluidized bed hydrodynamics: Part I — The EMD approach , 2006 .

[45]  B. Chao,et al.  Modeling of solids global fluctuations in bubbling fluidized beds by standing surface waves , 1994 .