Nonintrusive characterization of fluidized bed hydrodynamics using vibration signature analysis

Abstract

There are many techniques to characterize the hydrodynamics of fluidized beds, but new techniques are still needed for more reliable measurement. Bed vibrations were measured by an accelerometer in a gas-solid fluidized bed to characterize the hydrodynamics of the fluidized bed in a nonintrusive manner. Measurements were carried out at different superficial gas velocities and particle sizes. Pressure fluctuations were measured simultaneously. Vibration signals were processed using statistical analysis. For the sake of the evaluation, the vibration technique was used to calculate minimum fluidization velocity. It was shown that minimum fluidization velocity can be determined from the variation of standard deviation, skewness, and kurtosis of vibration signals against superficial gas velocity of the bed. Kurtosis was proved to be a new method of analyzing vibration signals. Results indicate that analyzing the vibration signals can be an effective nonintrusive technique to characterize the hydrodynamics of fluidized beds. V

Characterization of flow-induced vibrations in gas–solid fluidized beds: Elements of the theory

“…One of the main drawbacks of this approach results from the high computational cost of sampling at those high frequencies, as the great number of data in each sample complicates the measurement process, limiting the number of time series analysis techniques that can be used to handle the data. A more commercial low-cost measurement approach has been developed that uses sampling frequencies that are considerably reduced in the measurement ranges between 20 kHz to 50 kHz (Abbasi et al, 2010;Abbasi et al, 2009;Cody et al, 1996;Cody et al, 2008). With this low frequency approach, two very different interpretations of the measured accelerometer signals are used to understand the flow-dynamic information of the FB system.…”

“…Accelerometers can also be used to assess the behavior of specific fluidized bed operations, such as the liquid injection process in gas-solid fluidized beds . Fluidized bed dynamics have also been studied with vibration measurements using accelerometers (Abbasi et al, 2010;Cody et al, 1996).…”

Effect of internal tubes on the flow structures in gas-solid fluidized beds

“…It was found to be in a good agreement with the literature [15], which proposes the U mb to be 0.286 m/s. The maximum in the energy demarks the onset of turbulent flow regime [13,16]. While for the plain bed the maximum occurs at the velocity near to 1.9 m/s, it is shifted to 1.2 m/s by insertion of one tube.…”

Early detection of agglomeration in a polyethylene fluidized bed at high temperature and pressure by vibration signature analysis

“…The most common methods to characterize time dependent signals from fluidized beds are time domain analysis (Puncochar et al, 1985;Abbasi et al, 2010), frequency domain analysis (Abbasi et al, 2009) and state space analysis (Shiea et al, 2013).…”

“…Analyzing the vibration signatures has been used for detecting minimum fluidization velocity and transition from bubbling to slugging in gas-solid fluidized beds (Abbasi et al, 2009), determining regime transition (Azizpour et al, 2011;Shiea et al, 2013) and characterizing the hydrodynamics of fluidized beds (Abbasi et al, 2010;Sheikhi et al, 2012).…”