(328h) Pressure Fluctuations in Gas-Solid Fluidized Beds: Measurement and Analysis

Pressure measurements are widely applied in commercial gas-solid fluidized beds for process supervision and control. Although tomography techniques were developed for medical research, such as magnetic resonance imaging (MRI), electrical capacitance volume tomography (ECVT) and X-Ray computed tomography (XRT), chemical engineering have successfully applied them to examine the hydrodynamics of gas-solid suspensions. However, they are rather costly, arduous to operate, and, more importantly, impractical at the industrial scale. In contrast, measuring pressure routine, robust, flexible, and inexpensive. Nevertheless, interpreting pressure fluctuation signals is non-trivial. Mapping measured signals to the corresponding hydrodynamic events requires a prior knowledge, and together with a proper selection of the methods of analysis to decompose the measured signals and extract essential characteristics.

In this contribution, we review the measurements of pressure fluctuations in gas-solid fluidized beds, concerning the cause of the fluctuations [1], mathematical methods and recent applications, including the studies in the domain of time, frequency and state, as shown in Fig. 1 [2, 3]. We also demonstrate the typical source of errors and the special cares to consider, intending to provide a systematic yet straightforward guide for carrying out pressure measurements in gas-solid fluidized beds.

[1] J. van der Schaaf, J. Schouten, C. van den Bleek, Origin, propagation and attenuation of pressure waves in gas—solid fluidized beds, Powder Technol. 95 (1998) 220-233.

[2] J.R. van Ommen, S. Sasic, J. van der Schaaf, S. Gheorghiu, F. Johnsson, M.-O. Coppens, Time-series analysis of pressure fluctuations in gas–solid fluidized beds – A review, Int. J. Multiphase Flow 37 (2011) 403-428.

[3] F. Johnsson, R.C. Zijerveld, J.C. Schouten, C.M. van den Bleek, B. Leckner, Characterization of fluidization regimes by time-series analysis of pressure fluctuations, Int. J. Multiphase Flow 26 (2000) 663-715.